HomeMy WebLinkAboutAPA4130DOE/ID-1 0360
ENVIRONMENTAL MITIGATION AT HYDROELECTRIC PROJECTS
Volume 1. Current Practices for
lnstream Flow Needs, Dissolved Oxygen, and Fish Passage
s
U.S. DEPARTr,nENT OF ENERGY
IDAHO FIELD OFFICE
Cover Photo: Flow regulation weir constructed by the Tennessee Valley Authority
(TV A) below Norris Dam on the Oinch River, Tennessee. The weir is designed to
stabilize hydropower peaking releases, improve physical habitat conditions, and mitigate
adverse effects on the coldwater fishery in the Norris Dam tail water. Photograph provided
by staff of the TV A Engineering Laboratory in Norris, Tennessee.
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Available to the public from the
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This document contains new concepts and the authors' interpretation of new infonnation;
therefore, Martin Marietta Energy Systems, Inc. and EG&G Idaho, Inc. are required by
the United States Government to include the following disclaimer:
DISCLAIMER
This report was prepared as an account of work sponsored by an agency
of the United States Government. Neither the United States Government
nor any agency thereof, nor any of their employees, makes any warranty,
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ENVIRONMENTAL MITIGATION AT HYDROELECTRIC PROJECTS
Volume 1. Current Practices for
lnstream t=:low Needs, Dissolved Oxygen, and Fish Passage
M. J. Sale
G. F. Cada.
L.H.Chang
S. W. Christensen
S. F. Railsback
J. E. Francfort
B. N. Rinehart
G. L. Sommers
OAK RIDGE NATIONAL LABORATORY
Martin Marietta Energy Systems, Inc.
IDAHO NATIONAL ENGINEERING LABORATORY
EG&G Idaho, Inc.
Oak Ridge, Tennessee 37831 Idaho Falls, Idaho 83415
Contract No. DE·AC05-840R21400 Contract No. DE-AC07·761D01570
Published December 1991
Prepared for the
U.S. Department of Energy
Assistant Secretary for Conservation and Renewable Energy
Under DOE Idaho Field Office
REPRODUCED BY CE U S DEPARTMENT OF COMMER
• • NATIONAL TECHNICAL
INFORMATION SERVICE
SPRINGFIELD, VA 22161
ABSTRACT
CUITent environmental mitigation practices. at nonfederal hydropower
projects were analyzed. Information about instream flows, dissolved oxygen
(DO) mitigation, and upstream and downstream fish passage facilities was
obtained from project operators, regulatory and resource agencies, and
literature reviews. Information provided by the operators includes the specific
mitigation requirements imposed on each project, specific objectives or
purposes of mitigation, mitigation measures chosen to meet the requirement,
the kinds of post-project monitoring conducted, and the costs of mitigation.
Costs are examined for each of the four mitigation methods, segmented by
capital, study, operations and maintenance, and annual reporting costs. Major
findings of the srudy include: the dominant role of the Instream Flow
Incremental Methodology, in conjunction with professional judgment by
agency biologists, to set instream flow requirements; reliance on spill flows for
DO enhancement; and the widespread use of angled bar racks for downstream
fish protection. All of these measures can have high costs and, with few
exceptions, there are few data available from nonfederal hydropower projects
with which to judge their effectiveness.
Preceding page blank · iii
ARLIS
Alaska Resources
Library & Information Servtces
Anchorage. Alaska
EXECUTIVE SUMMARY
The purpose of environmental mitigation
requirements at hydroelectric projects is to avoid
or minimize the adverse effects of development
and operation. Hydropower mitigation usually
involves costs, such as reduced profits to
developers and reduced energy production.
Much of the existing hydropower capacity in the
United States will be subject to new mitigation
requirements in the near future because many
nonfederal projects are due for relicensing and
federal projects are being reevaluated and
upgraded. The relicensing process allows the
revision of mitigation requirements, and new
requirements could reduce existing energy
capacity. To address concerns about the effects
of environmental mitigation on these important
energy resources, the U.S. Department of Energy
(DOE) Hydropower Program has initiated a
study of environmental mitigation practices at
hydroelectric projects.
This· first report of the Environmental
Mitigation Study examines current mitigation
practices for water quality [specifically, dissolved
oxygen (DO)], instream flows, and upstream and
downstream fish passage. This review describes
infonnation on the types and frequency of
mitigation methods in use, their environmental
benefits and effectiveness, and their costs. The
project . is conducted jointly by Oak Ridge
National Laboratory (ORNL) and Idaho National
Engineering Laboratory (INEL).
lnfonnation on mitigation practices was
obtained directly from three sources: (a) existing
records from the Federal Energy Regulatory
Commission (FERC), (b) new infonnation
·provided by nonfederal hydropower developers,
and (c) new infonnation obtained from the state
and federal natural resource agencies involved in
hydropower regulation. The hydropower projects
targeted for study in this report were those
projects that could be identified as having
requirements for water quality, fisheries, or
instream flows from a FERC compliance
monitoring data base. The infonnation provided
by these projects includes the specific mitigation
Preceding page blank
v
requirements imposed on the project, the specific
objectives or purposes of mitigation, the
mitigation measures chosen to meet t.'le
requirement, the kind of post-project monitoring
conducted, and the costs of mitigation.
Information on specific mitigation practices
was obtained from 280 projects, more than 40%
of all the projects licensed during the 1980s that
were identified a priori as having the mitigation
requirements of interest. Of all projects
receiving FERC licenses or license exemptions
since 1980, instream flow requirements are the
most common mitigation requirement, followed
by requirements for downstream fish passage,
DO protection, and upstream fish passage
facilities. The proportion of projects with
environmental mitigation requirements has
increased significantly during the p~t decade.
lnstream Flows·
lnstream flows are water that is released to the
natural river channel below the project to
maintain various nonpower water benefits. 1bis
study considered only ins~ream flows designed
for protection of fish resources. Hydropower
operators provided infonnation on the methods
used to determine the instream flow requirements
at their projects. More than one method for
estimating instream flow needs was reported to
have been used at many projects. Of the
established and documented methods used to
determine requirements for instream flows, the
most frequently applied was the Instream Flow
Incremental Methodology (IFIM). This method
is complex and expensive to apply. Half of the
project operators reported that professional
judgment of resource agency staff was at least
one of the methods used to set instream flows.
Professional judgment was often cited in
conjunction with the IFIM.
It appears that monitoring sufficient to
evaluate the positive benefits of instream flow
requirements to fish resources is very
uncommon, a conclusion that has been
corroborated recently by an independent study by ·
the U.S. Fish and Wildlife Service. Infonnation
obtained for this DOE study indicates that flow
monitoring (continuous, daily, or less frequently)
is conducted . at about 50% of the operating
projects licensed with instream flow
requirements. Operators of 20% of constructed
projects licensed with instream flow requirements
reported collection of some fish data, either by
the project or by resource agencies.
Dissolved Oxygen
. Water released from hydropower reservoirs
can have low DO concentrations, especially
during the summer and at large projects with
deep reservoirs, low flushing rates, or warm
climates. In response to the need to maintain
adequate DO, which is necessary for respiration
of aquatic organisms, methods have been
developed to improve the quality of hydropower
releases. These methods have been reviewed
extensively in other studies, and they include
tailrace aeration techniques (weirs, surface
aerators, and diffusers), powerbouse aeration
techniques (turbine venting and draft tube
aeration), and operational techniques
(adjustments to spill flows and turbine operating
schedule).
Fifty-six projects provided information
concerning DO for this study. About half were
small (generating capacity <10 MW) projects.
Most responses were from the northeastern
United States. Of the DO mitigation
technologies, increasing nonpower discharges
(spill flows) is the most commonly used. More
than 60% of all responding projects use spill
flows, 9% use control of intake level to select
oxygenated water for release, and nearly 30%
use some form of artificial aeration of water
passing through the turbine. Several projects use
more than one mitigation method.
Of the projects that reported on DO
mitigation, -75% indicated that water quality
(most commonly water temperature and DO
concentration) is monitored, but biological
monitoring is rarely conducted. Consequently,
vi
the actual biological benefits of DO mitigation
are usually unknown.
Upstream Fish Passage
Blockage of upstream fish movements by
dams may have serious effects on fish species
whose life histories include spawning migrations
or other seasonal changes in habitat
requirements. Anadromous fish (e.g., salmon,
American. shad, blueback herring, and striped
bass), eels, and some resident fish (e.g., trout,
white bass, and sauger) have spawning
migrations that may be constrained by
hydroelectric dams. Maintaining or enhancing
populations of such fish may require facilities for
upstream fish passage.
Operators of 34 projects provided infonnation
on upstream fish passage ·facilities either in
operation or under construction. ·Fish ladders are
by far the most commonly reported means of
passing fish upstream at nonfederal hydroelectric
dams. Fish elevators are a less common
mitigative measure, but their use may be
increasing. Trapping and hauling (by trucks) of
fish to upstream spawning locations is used at
some older dams, but two of the projects
reported that trap-and-haul operations are being
replaced by fish ladders or elevators.
Preconstruction and postconstruction studies
and detailed performance criteria for upstream
passage facilities are frequently lacking. Forty
percent of the projects had no performance
monitoring requirements. Those projects that
monitor the success of upstream passage
generally quantify fish passage rates (e.g.,
fishway counts) or, less commonly, fish
populations.
Downstream Fish Passage
A variety of screening devices are employed
to prevent fish that are moving downstream from
being drawn into turbine intakes. The simplest
downstream passage technique is the use of spill
flows similar to those used to increase DO
concentrations or provide instream flows. Fish
are naturally transported below the hydropower
project in these nonpower water releases.
TechniqQes that incorporate more sophisticated
technology are under development. but are not
widely used. For example, light-or sound-based
guidance measures are being studied as ways to
pass migrating fish downstream with a minimal
loss of flow for power generation.
Information was obtained for 85 hydroelectric
projects that have downstream fish passage
requirements. A number of measures, some used
in combination, are employed to reduce turbine
entrainment of downstream-migrating fish in
turbines. The most frequently reported
downstream fish passage device is the angled bar
rack, in which the trash rack is set at an angle to
the intake flow and the bars may be closely
spaced (-2 em). This device is commonly used
in the Northeast. Other frequently used fish
screens range from variations of conventional
trash racks (e.g., use of closely spaced bars) to
more novel designs employing cylindrical,
wedge-wire intake screens. Intake screens
usually have a maximum approach velocity
requirement and a sluiceway or some other type
of bypass as well.
As with upstream fish passage measures,
performance monitoring and detailed
performance criteria for downstream passage
facilities are relatively rare. There are no
performance monitoring requirements for 82% of
the projects. Post-operation studies of passage
rates or mortality rates have been conducted at a
few of the projects.
Mitigation Costs
Environmental mitigation costs are estimated
for each mitigation type based on information
provided by hydropower developers. These costs
are segmented by capital, study, operation and
maintenance (O&M), and annual reporting costs.
All costs are presented in 1991 dollars and in
terms of average cost per project, average cost
per KW of capacity for capital and study costs,
and average mill/kWh for O&M and annual
vii
reporting costs. Because of the large ranges for
the mitigation costs, costs are also presented by
capacity categories.
Costs of providing instream flows vary widely
among projects. At diversion projects (where
flows for power generation are diverted around
a stream reach), instream flow in the diverted
reach must be subtracted from that available for
generation. Storage projects that generate
without a diverted reach can release instream
flows through their turbines. Operators of such
projects frequently reported no cost associated
with instream flow releases. The instream flow
capital costs averaged $99,000 per pla.11t.
Envirollii)ental studies averaged $100,000 per
plant. Even the requirements on instream flows
below the powemouses can cause significant
costs because of forced sales of energy at base
rates compared to peak rates. The average
annual revenue loss for instream flow
requirements amounted to $390,000 per plant.
Total mitigation costs for DO requirements are
generally the lowest of the four types studied in
this report. The capital costs averaged $162,000
per plant for DO mitigation equipment. The
energy generation lost because of water quality
environmental requirements was -107,000 kWh
per project.
The costs of upstream fish passage mitigation
are relatively easy to determine. In addition to
the capital costs of constructing the fishway,
there are operation and maintenance costs (e.g.,
for clearing debris from the fish ladder or
elevator and for electrical power to operate a fish
elevator), lost power generation resulting from
flow releases needed to operate a fish ladder or
elevator (including attraction flows), and any
monitoring and reporting costs. The average
costs for fish ladders at the sites where they were
required was $7.6 million for capital costs and
they resulted in an average loss of 194,000 kWh
of annual energy production. Other costs of
upstream fish passages were $51,000 for
environmental studies, $26,000 for annual
reporting, and $80,000 per year for additional
O&M for environmental requirements.
In addition to the capital costs of constructing
a downstream fish passage facility, costs
typically include those for cleaning closely
spaced screens or maintaining traveling screens,
lost power generation resulting from flow
releases needed to operate sluiceways or other
bypasses, and monitoring and reporting. The
average costs for angled bar racks was found to
be $332,000 per plant for capital costs and
$3,000 per year for O&M. Studies for angled
bar racks averaged $50,000 where they were
performed and $1,300 per year for annual
reports.
Occasionally hydropower projects are required
to make some contribution to environmental
projects not associated directly with· the hydro
plant to compensate for some environmental
damage caused by the plant Off-site compen-
sation was reported at a few sites that averaged
$136,000 per slte.
viii
Conclusions
Requirements for environmental mitigation at
hydropower projects have an important and
growing effect on U.S. domestic energy
resources. This study has identified both
technical and economic problems associated with
the most common mitigation measures: the
dominant role of the IFIM. in conjunction with
professional judgment by agency biologists, to
set instream flow requirements; reliance on spill
flows for DO enhancement; use of unproven
technology· such as angled bar racks · for
downstream fish -protection. All of these
measures can have high costs and, with few
exceptions, there is little information available on
their effectiveness. Additional study needs are
identified for each type of mitigation, as well as
in the areas of cost estimation, valuation of
benefits, and monitoring programs.
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CONTENTS
ABSTRACI' ................................................. _ . . . . . . . . . . . . iii
EXECUTIVE SUMMARY ............................................... _-. . . v
ABBREVIATIONS AND ACRONYMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
1. IN1RODUCTION ...................................................... 1-1
Hydropower Regulation and Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Study Objectives .......... ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Scope and Organization of This Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2. INFORMATION SOURCES AND STUDY METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Infonnation Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Target Population of Hydro Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . 2-3
3. CURRENT MITIGATION PRACI'ICES ...................................... 3-1
Instream Flow Requirements for Fish Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Dissolved Oxygen Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Fish Passage Requirements ....... _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
4. MITIGATION COST ESTIMATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Introduction . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Mitigation Costs Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
lnstream Flow Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Dissolved Oxygen Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Upstream Fish Passage Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Downstream Fish Passage Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23
Data Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-29
5. MITIGATION BENEFITS AND EFFECI'IVENESS .............................. 5-1
Introduction ................................................ · . . . . . . . . 5-1
ix
Instrearn Flow Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-l
Dissolved Oxygen Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Fish Passage Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
6. SUMMARY AND CONCLUSIONS ......................................... 6-1
CuiTent Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Mitigation Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
7. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Appendix A-summary of Infonnation Received from Developers . . . . . . . . . . . . . . . . . . . . . . A-1
Appendix B-summary of Infonnation Received from Agencies . . . . . . . . . . . . . . . . . . . . . . . B-1
Appendix C-Mitigation Cost Summary Worksheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
X
ABBREVIATIONS AND ACRONYMS
ASCE American Society of Civil Engineers
DO dissolved oxygen
DOE U.S. Depanment of Energy
ECP A Electric Comumers Protection Act
EPA U.S. Environmental Protection Agency
EPRI Elecbic Power Research Institute
FERC Federal Energy Regulatory
Commission
FWS U.S. Fish and Wildlife Service
ha hectare; equal to 2.471 acres
HEP Habitat Evaluation Procedures
m..crs Hydropower Licensing Compliance
Tracking System (a FERC data base)
HPRA Hydroelectric Power Resources
Assessment (a FERC data base)
IFIM
IFN
Instream Flow Incremental
MeUtodology
instream flow needs
INEL Idaho National Engineering Laboratory
kW kilowatt
xi
kWh kilowatt· hour
Mill A money of account equal to l/10
cent
MW megawatt
NES National Energy Strategy
NMFS .National Marine Fisheries Service
O&M Operation and Maintenance
ORNL Oak Ridge National Laboratory
PURP A Public Utility Regulatory Policies IV.
R&D Research and Development
Target Population
TVA
For this report, nonfederal
hydroelectric projects ~ceiving
FERC licenses (or exemptions from
· licensing) during or after 1980, and
having mitigation requirements for
instteam flows, DO; or fish passage.
Termessee Valley Authority
USACE United States Army Corp . of
Engineers
WUA Weighted Usable Area (a measure of
fish habitat used by IFIM)
1. INTRODUCTION
This report is the first product in a series that
is planned as part of the Environmental
Mitigation Study being conducted by the U.S.
Department of Energy (DOE) through its
Hydropower Program. The mission of the
Hydropower Program is to promote environ-
mentally sound development of hydroelectric
resources. This study of mitigation practices is
intended to provide better understanding of
environmental problems and solutions that are
associated with the construction and operation of
hydropower projects.
Hydropower Regulation and
.Mitigation
The regulatory process that controls the
development of hydropower projects in the
United States has become increasingly complex
over the past decade. The most recent changes
·to hydropower regulations have come as a result
of the Electric Consumers Protection Act of 1986
(ECP A), which significantly strengthened the
role of fish and wildlife agencies and reinforced
the "equal consideration" standard for evaluating
nonpower values in hydro development. During
the public hearings on the National Energy
Strategy (NES), much testimony focused on the
regulatory burden on hydro developers that has
grown to the point where it is now a serious
hinderance to development. The NES hearings
also highlighted a strong divergence of opinions
on the value of hydropower resources. For
example, the following two extremes are typical
of public comments:
"Hydropower projects are among the most
versatile, efficient, dependable (many have
service lives exceeding 100 years),
environmentally benign, and safest modes of
energy production available."
"Hydro dams deplete oxygen in rivers,
curtail nutrient flows, interrupt or
completely eliminate fish migrations, reduce
1-1
the vital up-and downriver exchange of
genetic material, separate terrestrial wildlife
habitats from one another, alter stream side
ecology and instream conditions for ~quatic
species, and prevent natural depositions of
beaches and cobbles."
Some facts about hydropower are clear:
(a) hydropower is by far the largest developed
renewable energy resource in the United States
(e.g., hydro provides 10 to 13% of the electricity
in the country) and (b) its undeveloped resource
potential is great (preliminary estimates by DOE
indicate -52,000 MW ~mains undeveloped).
Renewable energy resources, including
hydropower, will be an important part of this
nation's energy future, especially as concern for
acidic and greenhouse emissions increases. If
hydropower's contribution to the U.S. energy
portfolio is to increase, or even be maintained at
its current level, hydroelectricity must be
generated without unacceptable environmental
effects.
Hydropower projects can have, and have had,
serious adverse effects on fish populations and
other natural resources. 1 The Federal En~rgy
Regulatory Commission (FERC) is required to
inClude m'itigation of identifiable environmental
impacts in the licenses it issues for nonfederal
hydro projects. The President's Council on
Environmental Quality (40 CFR Part 1508.20)
defines mitigation to include one or more of the
following:
• Avoiding an impact by not taking a proposed
action
• Minimizing an impact by changing the design
of a proposed action
• Rectifying an impact by repairing, rehabil-
itating, or restoring the affected environment
• Reducing or eliminating an impact over time
by preservation/maintenance operations
• Compensating for an impact by replacing or
by providing substitute resources.
Natural resource agencies generally
recommend mitigation options in the priority
listed above. Although there are mitigation
techniques available for use at hydro projects,
their costs can be very high, and their
effectiveness is often poorly understood. These
problems are the subject of this study.
Study Objectives
The overall goal of this study of
environmental mitigation practices is to clarify
some of the controversial environmental issues
that surround the hydropower industry. Answers
are being sought for important questions that are
not well understood, such as:
• How frequently is mitigation of different
types required at hydro projects?
• Are there any important trends (e.g., across
regions, by project type, or over time) in the
types and frequency of mitigation
requirements?
• How much are mitigation requirements
costing individual developers, the hydropower
industry as a whole, and the nation?
• What are the measurable benefits of particular
mitigation practices?
• What effects do the mitigation practices have
on the operation and maintenance (O&M) of
a hydropower facility?
• Are current mitigation practices effective in
meeting their stated objectives, or are there
any specific areas where increased research
and development (R&D) could improve the
current situation?
The answers to these questions can provide
new guidance to hydropower developers,
regulators, and natural resource managers
concerning more effective mitigation practices
1-2
and regulations. The study results will also help
to prioritize R&D efforts by DOE, as well as
other agencies and organizations.
The DOE Environmental Mitigation Study is
intended to produce a series of reports on
mitigation practices. The first phase of the
study, of which this report is part, is limited to
the examination of three specific issues that have
been identified as the most problematic to
hydropower development: instream flow
requirements, dissolved oxygen, and fish
protection. More detailed analyses of benefits
and costs of these issues are planned for future
volumes.
The reports following this first volume will
concentrate more on case studies of specific
mitigation issues. Some of the details not
included in this first volume, such as regional
analyses of regulations and cost patterns, are also
planned for the later volumes. Subsequent
studies are planned to address additional
mitigation issues and expand on the ·findings of
the first phase of the mitigation study.
Additional mitigation issues that may be
evaluated in later years of the study include: ·
• Protection of wetland/riparian ecosystems
• Recreation and aesthetics
• Terrestrial habitat evaluation procedures
(HEP)
• Reservoir management
• Multiple-use water allocation
• Cumulative impact assessment.
More specific environmental studies are
planned for later years to develop new
assessment techniques or to generate and
synthesize new infonnation on specific issues.
Studies will expand into development of
improved assessment methods and mitigation
procedures, where appropriate. These later
mitigation studies may include consolidation of
existing monitoring data with new monitoring
)
'{
l
s
~s
re
w
ld
:s.
of
)n
:er
of
llg
programs for further study and guidance to
industry. The issue of instream flow needs
(IFN), or minimum flow requirements, has
already been identified as an important area
needing more research. Other environmental
issues that may be addressed in the later years of
this program include water quality, fish passage,
and cumulative environmental impacts.
The fmal products of the Environmental
Mitigation Study are expected to be a series of
issue-specific Guidance Manuals for the selection
and design of appropriate mitigation practices,
targeted at a broad audience of developers,
regulators, and resource managers. These
manuals will be based on the best available data
on the success of mitigation practices, but this
infonnation base may take several years to
accumulate (see Section 6).
Scope ·and Organization of This
Report
This first report is limited to an examination
of the three environmental issues that are most
often important in hydro development:
• Instream flow requirements for fish
• Water quality [specifically, dissolved oxygen
(DO)]
• Fish passage upstream and downstream of
dams.
The contents of this report focus on mitigation
practices as they have been applied to
hydropower projects over the last decade,
between 1980 and 1990. The objectives are:
· (a) to identify, compile, and analyze infonnation ·
1 on the implementation and monitoring of specific
mitigation practices; and (b) to detennine the
degree to which the costs, benefits, and
effectiveness of these practices can be measured.
The report is primarily a systematic, statistically
based analysis that examines nonfederal
hydropower projects that have been licensed, or
exempted from licensing, by FERC. A second
analysis approach using selected case studies of
1-3
hydropower projects was originally considered
for presentation in this volume but is now
planned for later volumes in this report series.
The report is divided into 7 sections beginning
with this introduction. The infonnation sources
and analysis methods used in this first volume
are described in Section 2. Specific mitigation
practices for IFN, DO, and fish passage, and
their frequency of application, are described in
Section 3. In Section 4, estimates are presented
for average annual costs for each of these
mitigation requirements. In Section 5, benefits
of mitigation are discussed with attention to how
well they can be quantified within the group of
hydro projects studied. Section 6 contains the
conclusions and recommendations of this initial
report on environmental mitigation practices.
References cited are listed in Section 7.
This research has been conducted jointly by
staff from Oak Ridge National. Laboratory
(ORNL) and Idaho National Engineering
Laboratory (INEL). ORNL staff provided
project design and analyses of environmental
benefits and mitigation effectiveness. INEL staff
conducted the economic and engineering
analyses. A number of individuals and
organizations provided invaluable assistance
during the course-of this· study in the fonn of
advice and technical reviews, including staff
from FERC's Office of Hydropower Licensing,
the National Hydropower Association, the
Northwest Hydropower Association, the Edison
Electric Institute, the Electric Power Research
Institute (EPRI), the Southwest Power
Administration, the Tennessee Valley Authority
(TVA), the U.S. Environmental Protection
Agency (EPA), the U.S. Fish and Wildlife
Service (FWS), the Michigan Department of
Natural Resources, and private consultants.
Further infonnation concerning this study can
be obtained by contacting the following
individuals:
• Environmental Analyses: Michael J. Sale,
ORNL (615/574-7305)
• Cost Issues: Garold L. Sommers, INEL
(208/526-1965)
• DOE Project Management: Peggy A. M.
Brookshier, DOE Idaho Field Office
(208/526-1403)
• DOE Program Management: John V. Flynn,
DOE Headquarters (202/586-8171).
1-4
il
~
(
c
5
I
(
2. INFORMATION SOURCES AND STUDY METHODS
This ·section describes the sources of
information and analysis methods used to select
the hydropower projects described in this report.
Originally, two different approaches were
considered to examine mitigation practices: (a) a
systematic study of all nonfederal hydropower
projects that have been licensed during the past
decade and (b) case studies of representative
projects that have relatively more information for
quantifying either benefits or costs. This report
concentrates on the first approach, because it has
been relatively successful and is more objective
and comprehensive than selected case studies
would be. Case studies are now planned for
later volumes as described in the previous
section. The first part of this section describes
the existing and new information sources used in
the systematic identification of projects with
mitigation practices of interest. The second part
of this section describes the characteristics of the
hydro projects that were targeted in this study
and how our information sources represented this
population.
Throughout this report, the term target
population is used to refer to those nonfederal
hydropower projects that were licensed or
exempted between January 1, 1980, and July l,
1990, and that have mitigation requirements for
one or more of the issues of interest (IFN, DO
protection, and fish passage). Within the target
population there are several different subsets of
projects that are also of interest to the study,
such as projects that have surrendered their
licenses and successfully developed projects that
are now generating hydroelectricity.
Information Sources
This initial report of the Environmental
Mitigation Study relies on existing information
as much as possible, but several new sources of
information have also been developed. Available
FERC licensing records were used to identify a
priori those projects that were likely to have
2-1
been required to mitigate environmental impacts
related to IFN, DO, and either upstream or
downstream fish passage. To complement the
existing FERC data and confirm the existence of
these requirements, additional information was
obtained directly from hydropower developers
and from state and federal resource agencies.
The decision to rely on existing, computerized
data bases was made early in the project because
the size of the target population (more than 700
projects) made it infeasible to directly examine
all FERC licenses given available time and
funding constraints. The limitations of existing
data bases do, however, have important
influences on how the results of the study can be
interpreted.
Existing FERC Data. The hydropower
licensing records used in this study come from
two sources: (a) FERC's Hydroelectric Power
Resources Assessment (HPRA) data base and
(b) FERC's Hydropower Licensing Compliance
Tracking System (HLCI'S).
Hydroelectric Power Resources
Assessment Data. The HPRA data base
system is a comprehensive repository of
information on developed and undeveloped
hydropower resources in the United States. The
data management system has been developed for
FERC by a private contractor to the DOE Energy
Information Administration? HPRA data are the
basis for FERC's biennial assessment of the
nation's hydropower resources.3 In July 1990 a
partial copy of the HPRA data base was obtained
from FERC describing developed and
undeveloped conventional hydropower resources
(only pumped storage projects and other
non-conventional hydro projects were excluded).
For this study, HPRA was used to obtain
descriptive information on existing projects in
the study's target population, including such
characteristics as licensing and construction
status, project location, and developer type.
~ ~ ~ fi
fl
11:1 ~ ~J li ~~
Hydropower Licensing Compliance
Tracking System. The lll...CfS data base is
used by FERC's Division of Project Compliance
and Administration to track license requirements
and compliance actions. lll...CfS includes codes
for all study and reporting requirements that are
defined in each project's license, license articles,
or exemption order. Although these codes do
not completely describe all mitigation measures,
m...crs is the only computerized data base
available that contains general information on
mitigation requirements for recent FERC licenses
and exemptions.
A partial copy of the HLCI'S data was
obtained for this study in July 1990. The
lll...CfS data obtained included all records, or
observations, in the data base, but not all the
information on each record. For example, initial
license requirements (information from the
HLCI'S "A, B, and C Screens") were included,
but infonnation on specific compliance actions
(e.g., reports submitted by the developers or
compliance letters sent out from FERC) were not
included. Envirorunental mitigation requirements
specified in FERC license articles are coded into
lll...CfS in broad categories, so FERC project
numbers with general envirorunental mitigation
license conditions can be identified.
Hydropower projects in this study's target
population were identified from the HLCI'S data
by extracting FERC project numbers with
License Article Requirement Description Codes
associated with IFN, water quality, or fish
passage.
Three lll...CfS descriptor codes were used to
identify 583 projects with potential instream flow
requirements: No. 87, Minimum Flow -Interim;
No. 89, Minimum Flow Requirement; and No.
90, Minimum Flow Study. lll...CfS descriptor
code No. 139, Water Quality, was the only one
used to identify 206 projects with potential DO
requirements. Two different codes were used to
identify 336 projects with potential fish passage
requirements: No. 64, Fisheries Resources; and
No. 71, Fishway Facility Design.
Because there are not one-to-one corre-
spondences between the HLCI'S Description
2-2
Codes and the three specific mitigation
requirements of interest here, there are some
unavoidable errors in our a priori target
population definition. · For example, some
projects that have "Water Quality" requirements
may not have DO requirements. However, after
consultation with PERC staff at the beginning of
the project, it was decided that this application of
lll...CfS data was the best way to use existing
information and to identify hydro projects of
interest, short of a direct examination of each
license.
Information Obtained from Hydropower
Developers. Information available from FERC
data bases was not ·sufficient to evaluate
site-specific mitigation practices or their costs
and benefits. Therefore, a major effort was
made to acquire new information directly from
the developers of projects in the target
population. Developers were contacted in
October 1990 and asked to voluntarily ·provide
information on their mitigation practices.
Developers were asked to describe the specific
mitigation measures that were required by their
FERC licenses, the extent to which the
requirements have been implemented, the extent
to which data have been collected to determine
if mitigation was successful, and the success of
mitigation requirements in protecting aquatic
resources. This part of the study was designed
in consultation with a group of hydropower
industry representatives, which met at a
workshop in Atlanta in September 1990. The
information provided by developers is sum-
marized in Appendix A.
The information provided by hydro developers
was voluntary in nature and not part of a survey
explicitly designed to reach all subgroups of
hydro projects. Therefore, the sample of
information does not represent all subgroups
equally well. An examination of potential bias
in the developer information is presented in the
next part of this section.
Information Obtained from Natural
Resource Agencies. To obtain additional
information on mitigation policies, effectiveness,
and available data and to ensure a balanced view
on
ne
tet
ne
ltS
ter
of
of
ng
of
lCh
rer
~c
ate
•Sts
{as
)m
get
in
ide
:es.
ific
1eir
the
ent
ine
of
ltic
1ed
IVer
a
rhe
liD-
ers
vey
of
of
ups
>ias
the
1ral
1nal
ess,
iew
of current practices, state and federal agencies
· that have responsibilities for recommending
environmental mitigation at hydro projects were
alSo asked for information. In February 1991
two or more agencies in each of the 50 states, as
well as the regional offices of the FWS, EPA,
and the National Marine Fisheries Service
(NMFS), were contacted and asked to provide
information on instream flow, DO, and fish
passage issues; Agencies were provided with a
list of the hydro projects of interest in ~eir
respective state or region, asked to describe their
mitigation policies and practices, and asked to
identify any studies that could be used to
quantify benefits and costs.
A total of 66 agencies provided information on
mitigation policies and practices, covering 36
states, five of the six regions of FWS, two of the
four regions of NMFS, and three of the 10
regions of EPA. Among the states that
responded, 10 have written policies regarding
instream flows, nine have written policies for
fish passage, and 13 have written DO policies
(often state water quality standards). States that
have policies relating to these i~sues are. also
those that have had the greatest number of
hydropower projects (e.g., Pennsylvania, Idaho,
Michigan, Maine, and Washington). The
'specific results of the agency information request
are discussed in Sections 3, 4, and 5, and
summarized in Appendix B. ·
Target Population of Hydro
Projects
The first step in studying mitigation practices
was to define the population of hydropower
projects that have been required to mitigate for
IFN, DO, or fish passage.
-· Projects Developed In the 1980s. Benefits
· to small hydropower developers, such as those
derived from the Public Utility Regulatory
Policies Act (PURPA) (Pub. L. 95-617) and
other incentives for energy development, led to
an extraordinary increase in applications for
hydropower development during the early
1980s.4 Much of this proposed development was
2-3
speculative, and many of the applications for
new projects have either been abandoned during
the FERC licensing process or have expired prior
to development. More than half of the project
applications received since 1978 are now
inactive, and a disproportionate share -of these
abandoned projects (-75%) were proposed by
private nonutility developers. 4
According to FERC data, there currently are
-1700 nonfederal hydroelectric projects that hold
active FERC licenses or active license
exemptions. Approximately 650 of these active
projects are small projects with exemptions, and
many of both the licensed and the exempted
projects have not been developed to the point
that they are generating hydroelectricity. The
m..crs data set used for this project contains
information on -3300 projects with licensing
status ranging from preliminary permits to
surrendered licenses. Projects that have
surrendered their licenses during the past decade
are considered to be potentially of interest in
evaluating mitigation practices, since those
projects were subjected to environmental
assessment, design, and cost assessment.
However, preliminary permits are not of interest
because their mitigation requirements have not
been determined. Eliminating preliminary
permits and projects developed before 1980, the
total population of hydro projects considered to
be of interest to this study is 1638. This total
population number includes projects that are no
longer active because they have surrendered their
licenses. Of these licensed or exempted projects
of interest to this study, m.crs records indicate
that256 projects have officially surrendered their
licenses or license· exemptions (Figure 2-1).
Projects with Mitigation of Interest.
Initially, 707 projects were identified from
HLCfS as being in the study's target population
because of indications they had mitigation
requirements for IFN, DO, and/or fish passage.
An attempt was made to contact the developers
of all of these projects. However, information
could not be obtained from some of these
projects, because their addresses and phone
numbers listed in HLCfS were incorrect. The
number of projects that were not contacted
Surrenders
(256 or 16%)
Total population
.N = 1638
Tar:get population
N=707
Surrenders Gf -,:,': :-·,:a (9 or 3%)
•' . ~ .... · ..
Sample
n=280
Figure 2-1. Proportion of inactive, or
surrendered, projects in the total and target
populations and in the sample of projects
obtained from hydro developer information (the
shaded portion of the pies and th,e numbers in
parentheses represent surrendered projects) ..
is estimated to be in the range of 25-50 (3 to
6% ). A total of 280 of the targeted projects
eventually provided information for this study.
This response rate of more than 40% represents
a high degree of cooperation from the
hydropower community.
The active projects in the target population
that were considered a priori to have mitigation
of interest are 47% of all active projects that
have received licenses or exemptions since 1980.
However, experience from this study indicates
that there are some inaccuracies in our a priori
identification of the target population of projects.
For example, a significant number of projects
that were originally identified from HLCfS data
2-4
as not having instream flow requirements
subsequently provided information to the
contrary. Overall, 17, 13, 8, and 31 projects that
were initially identified as not having instream
flow, DO, upstream fish passage, and
downstream fish passage requirements,
respectively, reported that they do in fact have
these requirements. There are several
explanations for these apparent errors: e.g.,
missing HLCfS codes (i.e., incomplete data), the
incorporation of mitigation requirements into
standard articles ("L-form" articles) that are not·
coded in HLCfS, and situations in which
mitigation was requested and implemented after
licensing by resource agencies. The implication
of these problems is that our estimates of the
frequency of mitigation requirements are likely
to be an underestimate of the actual frequency of
mitigation practices. Our best estimate is that
the number of projects with mitigation
requirements has been under-reported by our
study by at least 6% for instream flows, 4% for
DO, 3% for upstream fish passage, and 10% for
downstream fish passage. No further steps have
. been taken to account for these relatively minor
errors in the statistical analys~s.
The sample of the target po?ulation
underrepresents the frequency of license
surrenders relative to active projects (Figure 2-1).
For example, only 3% of the projects providing
developer information were surrendered projects,
whereas 8% and 16% of the target and total
populations, respectively, are surrendered
licenses or license exemptions. However, if only
active projects are considered, the sample data
does accurately represent the licensing status
distribution (i.e., full licenses versus license
exemptions) and regional distribution of projects
in the target population.
The sample also appears to be biased in terms
of developer type, because private utility
develo~rs are overrepresented and private,
nonutility developers are underrepresented
(Figure 2-2). Therefore, our sample of developer
information must be used cautiously in
extrapolating to the target population of
hydropower projects. It seems reasonable to use
the sample data to describe active projects
ts
1e
at
m
ld
:s,
fe
al
~ ..
1e
to
ot
::h
er
Jn
tle
:ly
of
tat
em
ur
or
or
ve
tor
on
tSe
1).
ng
:ts,
tal
ed
lly
ilta
tus
tSe
cts
ms
.ity
lte,
ted
per
in
of
1se
:ts
400
£} 300
W.,?a Target population, excluding sample (n = 427}
~ Sample obtained for this study (n = 280}
(,)
Q) ·e
a.
0 200 ....
Q)
..0
E
::3
z 100
0
Private,
non-utility
Municipality Private utility Industry Cooperative
Project developer type
Figure 2-2. Proportion of various types of hydro project developers, in the target populations and in the
sample of projects obtained from hydro developer infonnation.
but not to describe inactive projects. The results
of these extrapolations may be biased slightly
toward the experiences of utility developers.
Statistical Extrapolations. Inferences about
the frequency of occurrence of specific practices
within the target population of projects require
that assumptions be. made of the sample
characteristics, including (a) the assumption that
the original population definition included all
projects with the mitigation of interest and (b)
the assumption that the sample was unbiased and
random: Because of the voluntary nature of the
information request to hydropower developers,
there· were violations in at least the first of these
assumptions. Nevertheless, the statistics
presented in Section 3 do assume that the a
priori population definition was complete and
that the sample was random.
2-5
Estimates ·of the percentage of projects with
particular mitigation requirements are calculated
as the ratio of affirmative responses to total
responses for the specific question asked.
Percentages within the target population are
assumed to be the same as those within the
sample. Extrapolations from the target to the
total population of projects can be made by
multiplying the target population percentages by
the ratio of the number of targeted projects to
total projects. The implication of violations of
the statistical assumptions described in this
section are believed to result in an overall
tendency to underestimate mitigation frequencies,
rather than overestimate them, and are not large
enough to affect the overall conclusions of this
report. Further analysis of these data is planned
for future volumes of the Environmental
Mitigation Study.
3. CURRENT MITIGATION PRACTICES
This section describes the types and
frequencies of application of mitigation practices
that have been required at FERC-licensed
hydropower projects over the past decade.
Background infonnation is presented for each
mitigation issue to define tenninology and
concepts and to review other relevant studies.
Unless indicated otherwise, the des~ription of
current practices in this section is based solely
on the new infonnation provided by hydropower
developers and agencies for this study (see
previous section for details).
Instream flows are the most common
mitigation requirement at nonfederal hydropower
projects. From data provded by hydropower
developers, it is estimated that 56% of the target
·population of projects licensed between 1980 and
·. 1990 had instream flow requirements. DO
mitigation are estimated to hav~ been required at
20% of the projects, upstream fish passage at
11% of the projects, and downstream fish
passage at 28% of the projects. Although there
is no significant regional bias in the sample of
projects providing infonnation for this study, the
.···frequency of occurrence of the different
mitigation requirements does differ by region
(Figure 3-1). Generally, instream flow
requirements are more common in the west and
northeast. whereas DO requirements are
morecommon in the east. Downstream fish
; passage requirements are more common than
• upstream passage requirements, and all fish
; passage requirements are more common in the
i western regions than in the east. There is a
·distinct temporal pattern in the frequency of
mitigation requirements (Figure 3-2). Over the
10 years, instream flow requirements have
· increased in frequency among the target
··population of projects from 54 to 65%. DO
· requirements have increased from 19 to 28% in
··the same period. Upstream fish passage
requirements have not shown a significant
increase, but downstream fish passage
requirements have increased from 22 to 35% in
.. ?he, target population.
3-1
lnstream Flow Requirements for
Fish Resources
An instream flow requirement is a fonn of
environmental mitigation that limits the amount
of natural stream flows that can be used for
hydropower generation. Instream flow require-
ments usually focus on lower flow limits (e.g.,
minimum flow requirements that ensure aquatic
habitat will not be degraded), but they may also
include limits on the maximum flow or on the
rate of change of flows to downstream areas.
This study focused on instream flows that are
required primarily for fisheries resources
(including fish populations and sport and
commercial fish harvests). Instream flows
intended to improve temperatures or water
quality, with subsequent benefits to fish, were
not the primary focus of the instream flow
mitigation discussed here.
Environmental mitigation at federally-owned
and operated hydroelectric projects js not
regulated by FERC or by states. Providing
instream flows for protection of fisheries has not
historically been an authorized purpose of federal
projects, but this trend is changing. At many
federal projects instream flow releases are now
provided by the agency operating the dam,
usually in coordination with state and federal fish
and wildlife agencies. However, an examinati.on
of instream flow requirements at federal dams
was not within the scope of this report.
Background on lnstream Flow Issues.
The environmental benefits and costs of instream
flow releases depend on the type of hydropower .
project, the resource to be protected, and the
instream flow rate itself. The flow rate is a
function of the methods used to detennine IFN,
so the selection of a method of detennining the
instream flow rate is an important mitigation
decision. The following infonnation is provided
as background for understanding the effects of
instream flow practices.
~ ~ ....
80
~ 60
E
C1) ... ·:;
C"
~ 40
0
i:'; r::
~ 20
C"
Q) ... u.
0
Dissolved oxygen
....
C>
lnstream flow
FERC Regions and Regional Offices
-Atlanta
c::J Chicago
mmJ NewYork
c::::J Portland
lllllllllll San Francisco
Upstream passage Downstream passage
Mitigation practice
Figure 3-1. Regional distribution of different types of mitigation requirements in the target population
of hydropower projects.
~ 80
~ .... 70 r::
C1)
E 60 C1)
.!::::
5-50
~
0 40
>-0 30 r::
C1)
5-20
C1) u: 10
0
...
·······
...............
1980-1983 1984-1987
Period of regulation
1988-1990
Figure 3-2. Temporal trends of mitigation requirements in the target population of hydropower projects
(symbols are plotted at mean and whiskers represent ±1 S.E. of estimate).
3-2
Types of lnstream Flow Releases.
Instream flow requirements are implemented in
many different ways, depending largely on the
design and mode of operation of hydro projects.
Diversion projects, storage reservoirs, and low
head dams involve different instream flow
requirements and costs.
Diversion projects transfer water out of
natural stream channels into conduits and
penstocks leading to a powerhouse. When
diversion projects are operated in run-of-river
mode (i.e., by releasing flows equal to inflow
rates), natural flows are reduced only in the
bypass reach between the upstream diversion
dam and the powerhouse, where flow from the
project reenters the stream channel. Many small
diversion projects do not have storage capacity at
the diversion dam and are required to operate in
run-of-river mode. Other diversion projects have
a large enough dam and reservoir to store water
.·and release it over seasonal or daily cycles,
which alters the flow downstream of the
powertu?use as well as in the bypass reach (see
the following discussion of storage projects).
· Instream flow requirements in the bypass reach
are enforced below the diversion dam in the
bypass reach and are therefore unavailable for
power generation. Except when stream flows
exceed the sum of the maximum power plant
flow capacity plus the instream flow
requirement, instream flow requ,irements for
diversion projects reduce power generation.
.. Instream flow requirements at diversion projects
, are usually minimum flows to provide a lower
· . threshold of habitat condition, but they may also
· ··include flushing flow requirements that are short-
tenn, high flows designed to provide sediment
transport capability.
"
.. · Storage projects are defined for this report as
JII'Qjects without bypass reaches, where
,generation occurs as water is released from the
:dam, and where flows can be stored in a
reservoir and released later. Storage projects do
not alter the overall volume of water passing any
point in the stream (except for evaporation from
. ~ecreservoir that is usually minor), but do alter
.. th~ timing of releases over seasonal and daily
)illle scales. Storage projects typically store
3-3
water during high runoff seasons and augment
power-producing flows by releasing it during low
runoff seasons. Daily releases from storage
projects can be .made in three modes:
(a) baseflow mode, in which flows are relatively
constant throughout the day; (b) peaking mode,
in which power production (and flow releases)
follow the power demand rates throughout the
day, with higher releases during the hours when
power demand is greatest; and (c) pulsing mode,
in which flow varies with power demand but the
degree of variation is limited by a limited water
storage capacity. Instream flows are required to
protect fisheries during periods when the project
would otherwise release little or no flow.
Instream flow releases can be made through the
existing turbines or, if flow requirements are
small compared with turbine capacities, through
sluice gates or special small turbines designed
specifically for the instream flow release. At
some storage projects these flow releases can be
used to generate power and do not result in a
loss of net power production. However, instream
flow requirements can result in lost power
production when they are enforced during times
when power demand, and therefore the economic
value of the power, is lower than during the peak
demand periods.
Low head projects without storage capacity
have been and are being developed at many
sites, such as existing navigation dams on larger
river systems. These projects are also sometimes
referred to as run-of-river projects, but they are
distinct from diversion projects. At these
low-head projects, there is no bypass reach and
no storage of water to alter instream flows.
However, water flows may become more
concentrated into a portion of the river channel
in the turbine tailrace as the result of
development of this type of project. A fonn of
instream flow requirement common at low-head
projects is the requirement to maintain a portion
of the original spill flows over the dam or
through gates, instead of through turbines, to
maintain downstream water quality (by providing
aeration) or to provide turbulent, high velocity
fish habitat downstream of the dam. Such spill
flows may be considered instream flow
requirements because they are partially designed
to provide fish habitat. (Spill flows for DO
· mitigation are discussed in the following section
on DO Mitigation Methods and in Table 3-2.)
Spill flow requirements reduce the flow available
for power production (except when streamflow is
greater than the sum of the power plant flow
capacity plus the spill flow requirement).
Determination of Flow Requirements. A
number of different assessment methods are used
by resource agencies and FERC in determining
what instream flow releases should be made to
protect fisheries. These methods have been
compiled and compared several times over the
last decade.5•6•7 Methods vary in complexity
from recommendations based on fixed standards
to analyses using complex hydraulic and habitat
simulation models.
Instream flow requirements at some sites are
based on the judgment of fisheries biologists
without the use of formal methods. Such
decisions may take into account experience with
other similar projects and streams, observations
of fisheries under past low-flow conditions,
historic flow distributions, and other information
that is not incorporated in a formal method.
The Aquatic Baseflow method is a typical
simple "desktop" instream flow method (i.e .• not
requiring field studies) that is commonly used in
the Northeast7 This method is based on the
assumption that a specific flow rate per unit of
watershed· area will provide an adequate
minimum flow. lnstream flow requirements are
determined simply by multiplying the watershed
area of the stream at the project site by a
parameter that is constant for a state or region.
The method is not specific to individual fish
species or lifestages.
The IFIM appears to be the most widely used
formal instream flow method, although there are
many others. The IFIM is used in 38 states and
is required for instream flow studies in
California, Oregon, and Washington.7 The IFIM
typically involves the use of a ·hydraulic
simulation model and physical habitat models to
predict the availability of physical habitat (as
defined by area, depth, velocity, substrate type,
3-4
and sometimes cover and temperature) as it
varies with flow.u Extensive site-specif..c field
studies are required. Judgment of the biologist
applying the IFIM is required in conducting the
modeling and in interpreting the results.
Determination of an instream flow requirement
from the relationship between physical habitat
availability and flow may be either a matter of
agency policy or judgment or the product of
negotiation among agencies and project
proponents.
Frequency and Type of lnstream Flow
Requirements. This section presents data on
mitigation practices for IFN at PERC-licensed
projects. Information was obtained from a
sample of 185 target population projects that
have instream flow requirements (i.e., 185
individual power plants, some of which are
grouped under the same FERC license number;
170 different PERC license numbers are
included). These projects are among the ...;.580
identified as potentially having instream flow
requirements in their FERC license; the regional
distribution of both the instream flow target
population and the sample of these projects
described here are shown in Figure 3-3.
The projects that provided infonnation have a
wide distribution of required instream flow rates,
ranging from 0.25 to 4,000 cfs. The distribution
of flow requirements is shown in Figure 3-4; the
values used in the· figure are time-weighted
averages for projects at which instream flow
requirements vary seasonally or daily. Other
information· describes the objectives of the
instream flow requirements, the methods used to
determine instream flows, and the kind of
monitoring conducted. The responses of
operators of hydropower projects with instream
flow requirements to specific questions about
these issues are summarized in Appendix A.
The statistical analysis of this information
indicates that instream flow mitigation is
required at 56% of projects licensed since 1980
(see previous section).
Of the 185 projects with instream flows, 29%
had flow requirements that vary seasonally or
daily. Restrictions on the rate of change in
) it
ield
gist
the
Jlts.
tent
)itat
r of
t of
1ject
low
l on
tsed
n a
that
185
are
.ber,
are
;sso
flow
onal
lfget
rects
ve a
ates,
ltion
; the
hted
flow
lther
the
:d to
l of
of
-earn
bout
~ A.
ltion
l is
l980
29%
y or
e in
Figure 3·3. Distribution of sample of target population projects with minimum flow requirements.
Light-shaded points are members of sample, block-shaded points are all other projects in target population.
'~ows (ramping rates) were reported at 11% of
· · projects. The projects with instream flow
~equirements were categorized as (a) diversion
o;? ::::.!,.. 80
IUQ)
::I ::I g~ 60
....• ,,;,,Q),c:
~.g 40 ..... ,., ..... , .. , ........................ , ..
c: Q)C/)
~ ~ 20 ·····-········· ....................... , ..
Q)...,... : : • :
Ct.'..._ o o----=-...._ ...... ....__.._.._ ............. _ .........
0.1 1 10 100 1000
lnstream flow requirement (cfs)
~~;figure 3-4. Distribution of instream flow
'-· ~ .... ,.t#quirements. The y axis is the percent of
;pn)jects that reported instream flow requirements
that have an annual average instream flow less
·.than or equal to the value on the x axis (e.g.,
· 50,% of projects had instream flow requirements
·of40 cfs or less).
3-5
projects, including diversions with storage
(b) storage projects with the powemouse at the
dam; and (c) others. which include run-of-river
projects at navigation dams with spill flow
requirements (Figure 3-5).
Diversions
(97 or
(68 or 37%)
Figure 3·5. Kinds of projects with instream
flow requirements, based on infonnation
provided by developers. Values in parentheses
represent numbers and percentages of projects in
each category.
Only projects with specific instream flow
requirements for protection of fisheries were
included in these results, although some projects
may have had instream flow requirements
designed for other purposes as well as for fish
(e.g., recreation). Most of the projects (55%)
reported that instream flows were intended to
protect all life stages of sport or commercial fish
(e.g., resident or spawning populations), whereas
only 4% reported that instream flows were
intended to protect only adult sport or
commercial fish (e.g., at a stocked put-and-take
fishery). lnstream flows to protect nongame
species were reported at 26% of the projects, and
threatened or endangered species were reported
as a concern at only 7%.
Objectives other than those directly aimed at
fish, such as temperature and water quality
requirements for aquatic biota, were commonly
cited as being involved in instream flow
requirements (Figure 3-6). These other
objectives also include recreation, such as
boating, ·protecting riparian vegetation,
preventing harmful accumulation of sediments,
and other objectives that frequently included
aesthetics. It is apparent from these results that
temperature, water quality, and sediment types
are fish habitat parameters recognized as
important at a number of sites, and that these
issues may be regulated in conjunction with
instream flows for the benefit of fish resources.
30
;?
~ 25 ~
Q) 20 "2'
0. ·-15 0
Q)
~ 10 ...
t:
Q) 5 u ....
Q) a.. 0
It is also apparent that riparian vegetation· and
recreation are important benefits of instream
flows at a significant number of sites. Because
instream flow assessment methods for several of
these secondary objectives are less developed
than those available to assess fish habitat, they
are an important subject for future instrearn flow
research. Instream flow requirements are
obviously complex, with requirements for fish
often inseparable from other resources.
Many different methods have been used to
determine IFN (Figure 3-7). Project operators
apparently believe that the professional judgment
of agency staff ("Judgment" in Figure 3-7) is a
common part of instreani flow decisions. This
result is not surprising, considering that other
methods (especially the IFIM) require judgment
in their implementation. Also, project operators
who were unaware of or have forgotten what
methods were used by agencies . to s~t flow
requirements (the participating projects were
licensed as many as 10 years ago) are likely to
have chosen professional judgment as the method
used. Of the 89 projects reporting judgment as
a method, 45% reported other more formal
methods as also being used (e.g., 50% of
operators reporting use of the IFIM also reported
judgment as a method). However, 26% of all
the projects with instream flow requirements
reported that agency judgment was the only
method used to determine the requirements.
Water quality Recreation Temperature Riparian Sediments Other
lnstream flow objective
Figure 3-6. Additional objectives of instream flow for fisheries, based on information provided by
developers.
3-6
md
am
use
l of
:>ed
11ey
low
are
tish
.to
tors
tent
is a
:b.is
ther
tent
tors
rhat
low
rere
~to
hod
tas
mal
of
rted
fall
ents
Jnly
1 by
50---------------------------------------------------------,
~
.e.... 40
~
...........................................................................................................
0
Cl) ·e-30 .................................................................................................................
c.
0
~ 20 g
..........................................................................................
c:
.. ·~ 10 ~-
Study methods
.. Figure 3-7. Methods used to detennine instream flow requirements, based on infonnation provided by
developers.
The reliance on a relatively high degree of
prof~ssional judgment in detennining instream
,,',.now requirements may be unavoidable, but it is
· troublesome. When practiced by a professional
with a high degree of training and experience,
.... JwJgment is invaluable and often cost-effective.
···~However, when it is a substitute for well-defined
standard practices, such as exist widely in other
,. ''"engineering disciplines, an excessive reliance on
·;(>rof(:ssional judgment can contribute directly to
--··'the;:tincertainty and controversy in the regulatory
process faced by hydropower developers.
Unfortunately, it can also be argued that the
blind. application of simplified, or canned,
methods by inexperienced personnel is worse
than reliance on professional judgment.
However, the worst situation is probably the
application of professional judgment by
inexperienced personnel, and this is too often the
case today. A very real example of this problem
is the selection of target fish species and
appropriate habitat suitability functions for IFIM
Stupies, Furthennore, once habitat response
· funsf!ons (an index of habitat conditions at
v~Jious flow rates) are produced by an IFIM
s~dy, professional judgment is unavoidable in
~~l~~ting a limiting habitat value, and
· .··consequently the minimum flow. Despite more
3-7
than 15 years of IFIM studies, every application
is site-specific and relatively subjective.
An additional problem with excessive reliance
of professional judgment in setting instream
needs is that it may result in inflexible
recommendations that do not inClude the
supporting evidence, rationale, or incremental
tradeoffs that are needed by PERC in its
licensing decisions. Ultimately, it is not possible
to detennine for the available data or the
analyses in this report whether specific instream
flow requirements are defensible or not; to do
that would require much more detailed
examination of the environmental assessments
for each of the projects included in the sample.
However, this level of analysis is planned on a
case-study basis for future volumes of the overall
Environmental Mitigation Study.
These results concerning instream flow
requirements indicate that more research is
needed to improve. assessment methods by
making them more predictive and objective.
This conclusion is supported by other recent
evaluations by the American Fisheries Society7
and by the FWS.10 It is apparent that project
developers understand the IFIM well enough to
acknowledge the role of professional judgment in
its application. It can also be concluded that
many projec~ have instream flow requirements·
set without the benefit of an established,
documented assessment method. The value to
developers and · to aquatic resources of
conducting more sophisticated instream flow
studies at such projects appears to be an
important research subject.
Agency Positions on lnstream Flow
Mitigation. Information provided by natural
resource agencies on instream flow practices is
summarized in Table 3-1 and Appendix B. Less
than half of the states responding reported that
they did not have had any written policy on
instream flow requirements, and of the states that
do have written pOlicies, most are general
statements of intent rather than specific
requirements that clearly define assessment
methods or requirements. The IFIM was by far
the most frequently identified assessment
methodology by state agencies. This finding is
consistent with asirnilar survey of state policies
conducted in 1988 by the American Fisheries
Society.' Every state providing information
stated that they develop instream flow
recommendations or requirements based on non-
fishery as well as fishery values. ·
The FWS is the most active federal agency in
determining instream flow requirements. All 6
of the FWS regional offices responded to this
study's request for information. The general
FWS policy with regard to instream flow
requirements is contained in two position
statements: the Mitigation Policy of 1981 11 and
their unpublished Hydropower Policy 12 that was
originally issued in 1988 and has never been
fmalized. Neither of these policies are specific
on any aspects of instream flow mitigation. The
FWS Northeast region (FWS Region 5) does
have a very specific instream flow policy, called
the New England Flow Policy, which relies on
the median August historical flow as an instream
flow standard (referred to as the Aquatic
Baseflow method above). While all FWS
regions cited the IFIM as the most common, and
usually preferred method used to determine IFN,
all regions listed more than one assessment
Table 3·1. Summary of state resource agency responses to agency information request regarding instream
flow mitigation (see Appendix B for additional information).
Yes No No response
Does the state have a written policy regarding instream flow 13 21 14
requirements?
Does the state accept compensation for fish losses through off-site 16 13 17
mitigation?
Does the state have instream flow requirements for FERC-licensed 23 4 19
projects?
Does the state utilize more than one assessment methodology to 15 7 22
develop instream flow recommendations or requirements?
Is operational monitoring for effects of instream flows on habitat or 10 13 21
fish populations conducted?
Are instream flow recommendations or requirements based on 22 0 22
non-fishery values?
3-8
'~
·-
on
)W
In-
in
l 6
his
ra1
[)W
ion
illd
II' as
~n
ific
be
:>es
led
on
am
ltic
NS
md
:=N,
.ent
:am
-;e
-
method as being used. The Northeast Region
placed less emphasis on the IFIM and more on
its simpler Aquatic Baseflow standard. "No net
loss" in habitat potential was cited often as the
. objective of instream flow requirements by the
. FWS regions. A large number of different
ecological considerations were also cited as
being important factors in detennining IFN,
including endangered species, migration and
spawning ·needs of anadromous fish, and
·.integrity of wannwater fish communities. A
large number of non-fishery issues were also
;;·:Cited as important (e.g., recreation, riparian
,;, ~~getation, invertebrate communities, wetlands,
, ~and aesthetics).
A recent evaluation of IFIM applications by
'"t.hefWS10 documcnted 616 applications since the
IFIM was developed in approximately 1976.
More than 80% of these applications were in the
:·:•. we~tem sta,tes, and most applications were by
· ndn~f.<WS personnel. Two major problems were
.· . associated with JAM applications: (1) it is
;;yJechn;!=allY too simplistic, and (2) it is too
c cQmplex to apply. This apparent. contradiction
'•· i\}~strates the uncertain nature of detennining
LJ'· jps~e;mt flow requirements and the fact that
::.,.1: mP~ research is needed in this area.
:fhe·NMFS and EPA were also contacted for
· Jnf'o!J.llationon instream flow requirements. EPA
:.~r1:;~gene,r.aJ.ly differs to FWS for· instream flow
: .:.ii recgQ:unendations. The most active NMFS
;r;~r;JegipnJn .tenns of setting instream flow policies
to · i,s;~in· tbe · J>acific Northwest, where anadromous
, .• ::'~.a,lroon'and trout populations are declining due to
~,,,,:hy~.rppower and other impacts. The only written
.·;;c ·· . .NMf'S policy on mitigation practices is
;u COJ1tam~~ in an unpublished report entitle
. "~'·''fcqJi~i.es· .. and Roles in Reviewing Small
'.~:~ Hydi'Qelectric Developments in the Pacific
.: ,·NQrthwest", which is available from the NMFS
.;,J::~g~ol)3].:office in Portland.
,t:'f~~~l~·s_olved Oxygen Requirements
.. .i-~-·r~: >~ :::l~;''.\~<":··· ::~d.li!.,i?~ground on Dissolved Oxygen Issues.
;>~.i·;J#}~~cts of hydropower operations on DO below
3-9
dams have not been as common a mitigation
issue as either instream flow or fish passage in
the last ten years (Figure 3-2). DO impacts
have, however, become more frequently
regulated and will continue to increase in
importance to hydropower developers as large
reservoirs come up for relicensing. FERC
therefore considers DO mitigation as the third
most important environmental mitigation issue to
face the hydropower industry today.13 A brief
description of ·processes affecting DO in
hydropower releases and a review of available
DO mitigation techniques are presented in the
first parts of this section. Current practices, as
detennined by a systematic examination of a
sample of the target population of hydropower
projects, are presented in the second part. State
and federal resource agencies' positions
regarding DO impacts and mitigation are
presented in the last part.
Environmental Issues. Man-made
impoundments, and the hydroelectric projects
that may be developed at them, can have adverse
effects on downstream DO concentrations
through two primary modes of impact: (1) the
release of water with reduced DO, and
(2) reduction in the large air-water oxygen
transfer that occurs at dam spill ways. Awareness
of this potential problem has caused mitigation
of DO problems to become a relatively common
requirement in hydropower development licenses.
Hydropower operation can also significantly
affect tailwater temperature regimes and other
physical and chemical tailwater characteristics.
Comprehensive discussions of these other effects,
not considered in this report, are available.14•15
Effects of Hydropower Development on
Dissolved Oxygen and Tal/water
Ecosystems. The effects of a hydroelectric
installation on the DO of a river can be quite
variable, depending on the mode of operation of
the project (e.g., daily pattern of generation,
minimum flow policies), and the physical
characteristics of the project and tailwater (e.g.,
natural river flow rates, nutrient inputs to the
reservoir, depth at which flow is released from
reservoir, climate, topography).15
The effects of larger impoundments on
tailwater DO have been well documented,
perhaps because changes in downstream quality
are more pronounced at deep reservoirs with
long retention times. 16 Deep storage reservoirs
tend to thermally stratify during the summer, and
thermal stratification promotes chemical changes
in reservoir outflow.14 Isolated hypolimnetic
zones tend to become oxygen-depleted or anoxic
during the summer as a result of benthic oxygen
demand, flow patterns, and the oxygen demand
associated with decay of algae that have settled
to the hypolimnion. DO in releases will depend
on reservoir retention time, outlet depth, and
.metalimnetic and hypolimnetic DO; factors
influencing reservoir DO include organic loading
from inflows and sediment oxygen demand.17
Several recent studies have also documented
negative effects on DO concentrations resulting
from hydropower projects that eliminate
well-aerated spill flows at smaller projects.18
DO is necessary for the metabolism of aquatic
animals, so low DO releases from hydropower
projects can have detrimental effects ranging
from reduced feeding and growth rates to
mortality and the elimination of some or all
species. The effects of DO concentrations on
aquatic biota have been summarized and
quantified.19
According to FERC records, of the 1638
projects licensed or exempted from licensing
since 1980, about 200, or 13%, have a license
article for mitigation of water quality impacts,
most of which are for mitigation of dissolved
oxygen impacts. Water quaiity license articles
included in new licenses began to appear with
increasing frequency in the mid-1980s
(Figure 3-2). Although this study focuses on
nonfederal hydropower in the United States,
some insight about the extent of DO ·problems
can be gained by considering the experience of
federal agencies. For example. out of 52 dams
operated by TV A. releases from about 20 fall
below state DO standards (a problem being
addressed by the TV A through its Lake
Improvement and Reservoir Releases
programs).Z0
3-10
Mitigation Methods. There have been
several aeration and DO mitigation research
programs conducted in the past two decades, and
a considerable volume ofliteratu·re on the subject
is available. The major sources of information
are research and literature reviews published by
the hydropower industry and industry consortia,
such as EPRI,21 by the federal agencies that
manage much of the hydropower in the United '
States such as United States Army Corp of
Engineers (U!?ACE),22.23 and the American
Society of Civil Engineers' (ASCE) biennial
waterpower engineering conference. The most
recent, comprehensive guide to DO mitigation
technologies includes descriptions of each
method, working examples, engineering costs,
design principles, and industry examples?1
Much of the information in Table 3-2 was
extracted from this guide.
At least a dozen wholly distinct DO mitigation
methods exist and have been applied at
hydroelectric installations in the United States
and other countries. Some of these techniques
are similar in principle or mechanism, such as
the use of oxygen diffusers in the tailrace and in
the reservoir hypolimnion; but because they
differ in point of application and immediate
objectives, they are considered in this report to
be distinct Figure 3-8 illustrates a generic
hydroelectric reservoir, dam, and tailwater, and
indicates the locations where 12 of these
well-known mitigation technologies are
commonly applied. Table 3-2 presents
descriptions, advantages, and disadvantages of
these technologies. All systems have been tested
to varying degrees, although some methods have
been tested only in pilot studies or have been
applied primarily in wastewater treatment or
other nonhydroelectric generating situations.
Some methods, such as spill flows and turbine
aeration, appear to have become popular among
hydro license holders (following paragraphs).
Frequency and Type of Requirements.
The analysis of DO mitigation requirements
presented in this section is based on a systematic
study of the target population of hydropower
projects licensed during the 1980s and identified
een
lrch
and
dect
tion
I by
rtia,
that
dted
1 of
ican
lnial
nost
1tion
~ach
lSts,
es?1
was
ltion
at
tates
:tues
has
ld in
they
Jiate
rtto
teric
and
hese
are
;ents
s of
:sted
have
been
.t or
ions.
bine
10ng
i).
··~
Table 3-2. Dissolved oxygen (DO) mitigation technologies.
Technology
(1) Tailrace weirs: structure built
zig zag' across a tailwater, typically
resulting in headJoss of 2-5 ft and
plunge poOl of 4-10 ft, where air is
entrained as water is exposed an mass
trarisfer occurs when the nappe
impinges on the tailwater and bubbles
·,are submerged for some residence
.. time.2J.24
.(2) Submerged tailrace diffuser:
an air-supplied diffuser array
anchored in the tailrace, supplied by
compressed air from the stream
.,,bank.2 1
(3) Surt~ce tailrace aerators: these
.siJJ'Ply air ~y negative head produced
.by)h~ rotOr -oxygen is transferred
·t,y slllface renewal and interchange .7A
_, , Asplrazing surface aerators are
' "' moiillted at an angle to the surface
and direct a strong milling current of
, ijirt"and water downward. 21
,, (~).J~~rv~ir epilimnion pumps for
. ') int8kti' aeration or local
1 .,;.•:i~~~titifi~atitJn: a. floating platform
''·'fljted to the dam or shore with a
Jn,~t~(~iul~cted to a submerged
impeller; capable of moving large
volumes of warm, oxygen-rich
--epilirimetic water at low velocities
i>ci•o;mtg;.~he~.withdrawal zone.21
. ;i{~)'':.i&6r'oxygen injection in
','.''f~l'eiJaf(intake aeration): fine
;.,..,~uWii:~iffuser systems located
''"'witJlirl'ihe withdrawal zone of the
:'~iJlti&'~,,~tipplied with pure ollygen,
·, 'Which ,takes advantage of high
pressures in the forebay to increase
oxygen transfer and of local currents ' Jo aerate' only water that passes
· Jhrough the turbine.21
General
advantages
Can produce large (5+) mg/L
increases in 00,21 be relatively
maintenance free, and require no
direct energy expenditure. ·Can be
used especially beneficially when
there is "free head" available,24 and
to achieve both minimum flow and
aeration objectives.25
Diffusers have been widely accepted
as aeration devices and may have
some stream applicability. High
diffuser efficiencies (17-35%) have
been reported. 21 .24
Considered highly applicable to
stream reaeration except where they
may pose recreational or aesthetic
hazards,24 and may especially be
suitable for smaller flow volumes, or
for large flows with small oxygen
deficits. Performance of such
aerators is fairly predictable.21
Field applications of localized mixing
in reservoirs, near hydroturbines,
demonstrates that it can be simple
and cost-effective.26 The working
principles are well-documented and
tests have been favorable.21
Well-suited for high-head, high
hydraulic capacity (>3,000 cfs) with
large DO deficits (>4 mg/L) where
energy revenue is important. Oxygen
transfer efficiency can approach
100% with sufficient depth. Only
water which passes through turbines
need be aerated.21
General
disadvantages
Capital cost can be high and efficiency
low (depending on height of weir).
Power and head loss can be induced,
and performance may be difficult to
predict. 21 Safety problems in the
plunge poOl must be considered in
design. Weirs are non-navigable and
can require excessive crest height for
high flow applications.25
Low transfer efficiencies can occur
because of shallow tailwater depths.
Diffuser systems can have high initial
costs and possible maintenance
problems,24 and can require large
tail water areas. 21
Initial equipment cost can be high .7A
Sites with shallow tailwater depths ( <10
ft), flows lower than 2000 cfs, or
oxygen deficits greater than 3 mg/L
may require considerable surface areas
for efficient operation}1
This technology can be difficult and
costly to install. Reservoir sediments
can be disturbed and coldwater releases
that may support downstream fisheries
can be eliminated.:11 This technology
can be constrained when reservoir
depths are less than 150 ft or during
low surface DO episodes (e.g. caused
by high respiration and low
photosynthesis).17
Improper location of the system can
lead to problems associated with
incomplete adsorption of oxygen (e.g.
corrosion in the turbine systems and
unollidized hydrogen sulfide).21 •11
These systems must be sized for the
project's maximum hydraulic capacity
at highest DO deficit.21 Ollygen, not
air, must be used in deep reservoirs due
toN-supersaturation possibility.27
nts. f*~"''':*"l,·•'""'•:'i;•'~-, ........... ,, .. -................ , .. ·----------------------------------------aents
11atic
lwer
ified
3-11
Table 3-2. (continued).
Technology
(6) Turbine draft tube venting:
injection ports in draft tube
immediately downstream of turbine
are used to introduce air into the
flow, taking advantage of high
turbulence?•
(7) Turbine venting through
vacuum breaker system: air
passage through the turbine head
cover with exit ports on the turbine
hub. Hub baffles over the ports can
be used to increase suction.2 1
(8) Selective withdrawal: the
withdrawal of water from selected
reservoir depths where 00 (and
temperature) may be desirable.
Structures used to accomplish
selective withdrawal include wet
wells and submerged weirs.21
(9) Reservoir destratification: this
method involves the input of mixing
energy (mechanical pumping-or
compressed air systems) at the
deepest point in the reservoir to
break down the thermal and chemical
stratification that contributes to
hypolimnetic 00 depletion.21
(10) HypoHmnion aeration: the
hypolimnion of a reservoir is aerated
or oxygenated through systems of
diffusers submerged and anchored in
the reservoir .21
General
advantages
This method uses existing (or
modified) structures and is therefore
advantageous.2 1.l4·28 Draft tube
venting is sometimes already used to
effectively control cavitation and
swinging in high-bead installations.
Similar to draft t~be aeration.
Can be well suited for small
( <15 MW) projects; applications at
large projects (>500 MW) also exist.
Makes use of stratification in
reservoirs with high epilimnetic 00,
and can be low-cost.21 •29.3°
Destratification can be inexpensive
and performance can be closely
predicted especially in small
reservoirs. It can be effective
especially when used to prevent initial
stratification, and can also prevent
related water quality problems21 .3 1 or
control undesired effects of cold
hydropower releases on tailwaters.21
This technology is considered suitable
for large storage I peaking
impoundments (volume >3,000 ac-ft)
with cold tailwater fisheries. Pure
oxygen use is efficient and avoids
nitrogen supersaturation problems.
Use of the hypolmnion as storage for
aerated water may reduce the required
capacity of the system. Reservoir
water quality can benefit (e.g. through
oxidation of hydrogen sulfide and
dissolved iron).21 •17
3-12
General
disadvantages
Oxygen uptake potential is limited.
Generator output will be reduced by
1-5%, and installation of apparatus can
be difficult and expensive.21
Performance is difficult to predict
accurately .17
Disadvantages are similar to those for
draft tube venting. Also, this type of
venting has been associated with
increased cavitation damage on older
turbine runners and increased wear on
turbine bearings.2 1
Most prior uses of selective withdrawal
have been at non-hydro sites. Release
temperatures may rise and interfere
with tailwater fisheries objectives.
Retrofit for selective withdrawal is
difficult and costly, and this method is
inappropriate for sites with large
reservoir level fluctuations or for some
navigation projects.2 1
Application can be difficult at large,
high-flow projects,17 can affect
reservoir fisheries by changing habitat
characteristics, can disturb Sediments,
and may be incapable of achieving 00
standard. 21 Energy requirements for
this technology can be prohibitive.21
Hypolimnion aeration is not considered
suitable for large run-of-river projects
where the system would have to be
sized for maximum hydraulic capacity
of plant. It is crucial to closely
estimate hypolimnetic oxygen demand
and rates of oxidation. The highest
cost item is pure oxygen.ll.l7
f
-
can
or
Jf
~r
on
,wal
lSe
I is
tat
:s,
DO
=red
:ts
ity
llld
-
:!.'
:~
if
··~ ;;;
~ ~
i '
Table 3-2. (continued).
· Technology
(11) SpiU · nows and other iurbine
bypass now aeration techniques:
spill flows involve the non-power
release of water over spillways, via
. bypass valves, through gated
conduits, or other hydraulic
slructures.21
/(12) U-tube aeration and other
·· sidesti'eam injection methods:
' U-tubes divert a portion of water
flow downward in a deep entering
channel and upward into an exit
channel; air is inlroduced at the top
· of the downward channel.21 .2A
General
advantages
The performance of spill flows can
be accurately predicted. 21 Spill flows
, can be suitable at small projects
( <15 MW) where costs of artificial
aeration are high and the extent of
DO problems is limited or uncertain.
Existing structures can often be
readily modified for aerating
capability. 18.3'-3J
Sideslrearn injection techniques are
considered to hold much promise,
particularly for run-of-river
applications, for saturating a flow
with oxygen at reasonable costs.2 1•17
(13) Reservoir water quality No documentation available.
management: the reduction of point
and nonpoint sources in watershed
and. inflows of organic material and
nutrients that lead toward
eutrophication and anoxia in
reservoirs.
(14) Operational considerations for
hydropower turbines: measures to
conttol tailwater DO, such as
· slr~gic choice of which and how
m&ny :turbines to operate. 17
Measures such as these lack capital
or maintenance expenses and can
contribute at a substantially reduced
cost the balance of tailwater aeration
needed to achieve a fixed numerical
standard.17
General
disadvantages
Lost power revenue can make this
technology economically undesirable.
Spill flows can increase wear on
bypass structures, and the costs of
adding bypass structures can be.21
No applications of these technologies
are available at a scale comparable to
hydro tailwaters; these methods are
considered experimental or
developing.21 •11
Additional treatment of point sources,
beyond levels achievable by modern
secondary lreatment and effluent
standards, is costly, and such
additional treatment may not lead to
measurable improvements in :00 in
hydropower releases. 34
Operational considerations alone may
not be sufficient to meet a specified
numerical 00 standard. 17
a<priori to have water quality requirements.
Results and conclusions are applicable
industry-wide to the extent that the sample
reflects the characteristics of the target
population.
requirement) also reported on their DO
mitigation.
In total, our sample contains infonnation on
56 projects that operate DO mitigation
(Figure 3-9). Mitigation infonnation was
obtained from 43 projects in the target
population. In addition, thirteen projects from
·~e target population that, according to FERC
-··•n, .. ;f~cords• do not have a water quality requirement
·~~·-z.·(l)u.t. had a fish passage or minimum flow
,:~,~·~~.'!.;~,\?; "j{>f•'
3-13
Of the 56 projects providing infonnation, most
have a capacity below 50 MW. Thirteen projects
are less than 1 MW, 17 are between 1 and 10
MW, 21 are between 10 and 50 MW, 2 are
between 50 to 100 MW, and 3 are greater than
100 MW. The distribution of these projects into
project generating capacity classes and into
geographic regions matches broad patterns in the
target population. In tenns of project size. our
sample well reflects the target population bias
away from extremely small (<1 MW) projects
•
(11) --......
{4)
I I I I I I I I I I I I I I I I I I I I I I I I I I I I"' I I I I I I I I I I I I I I I I I I I I I I I I .. I I I I I I I I I I I I I
(1) Tailrace weirs
(2) Submerged tailrace diffuser systems
(3) Surface tailrace aerators
(4) Reservoir epilimnion surface pumps
(5) Air or oxygen injection in forebay
(6) Turbine venting (draft tube)
(7) Turbine venting (vacuum breaker system)
(8) Selective withdrawal
Ge>) (8)
(5)
(1 0)
(6), (7) _...,. \\ \\\ \
(9) Reservoir destratification
(1 O) Hypolimnion aeration
(11) Spill flows
(12) U-tube aeration
(1 ), (2),
(12)
Figure 3-8. Dissolved oxygen mitigation technologies and their points of application, shown on a,
schematic hydropower reservoir, dam, and tailrace.
Figure 3-9. Distribution of sample of target population projects with dissolved oxygen requirements.
Light-shaded points are members of sample, black-shaded points are all other projects in target population.
3-14
[2),
)
r
2)
1 on a
ments.
lation.
60 r---------------------------------------------~--------,
50
40 ::::::::::::::::::::::::::::::::::::::::::::: ........... :::::::::1 (with water qu~~:;~~~ui~~~~~~ :
30
20····-~·-·······
10 ~.... .. .... ·-.
·~ 0 -:::::::::§a:::::::::::::::::::·:::::::::::::::::::::::::::
·~ 60 ~--------------------------------------------------------------~
Q) 50 ~---··············-·········-·············----··················--..--~----------, ·e-40 ......... _ ....... _ .. __ .. _ ~ B: . _ .. _ ... _ .... _ .. _ .. _ ..... _ .. ) Target population (n = 206) i . ~g ::::::::::::::::::::::::: ::::::::: ~~~~ :::::::: ~-~~-i~~-~-~t-~~ ~~~~i~-~~:-~i~~~~-~~)-.. N 10 ···--··-· ......... ~ ............................................ .
~ ~ 0
~ 60~----------------------------------------------------~ . ~" 50
..• 40
30
20
_1q
"; .• "•.0 L-~~~l:::L...-----....a:::QQ~~L...---......ti~~~-----------------l
<1 MW 1 to <10 MW 10 to <50 MW 50 to <100 MW 100 MW and larger
Capacity categories
Figure 3-10. Distribution of total population, target population (with water quality requirements), and
sample (with water quality requirements) projects, in megawatt capacity classes. Based on data from
'-~-· F:~aeral Energy Regulatory Commission data sets (described in Section 2) and on information provided
·.);by· developers.
"· ····.: ····· :"'; .:'··.·::·
and toward small to medium hydro (1 to 50
MW)~ However, our sample overrepresents the
IO.to 50 MW group, while underrepresenting the
l to 10 MW projects (Figure 3-10). In terms of
project . regions, our sample in a· broad sense
r·..;tepr:oduces the pattern of bias in the New York
L.~<!.AtJanta regions. However, our sample has i a~ar higher proportion of observations from the
f New York region than the proportion for this
·J · -region in the target population, and a lower
1.)1'9portiqn of observations in the Atlanta and San
f F~ancisco regions (Figure 3-11). The most
~ .. -sigillficant point to be kept in mind in the
fAollowing··discussions is that projects from the
~ .. New ·.LYork region are substantially
Y'>O"~overrepresented.
: ._ -:.-·-
·;>Frequency of Mitigation Method. Spill
flows Jll'ld turbine aeration are the most common
. pti~gationmethods among the sample of projects
•rj• 'f!1!JP,.,~~) mitigation (Figure 3-12). Of the 53
t · 0 PI9JectS providing information on mitigation
3-15
methods. 66% indicated that spill flows had been
selected as the sole mitigation measure or as one
of several measures. Six percent indicated spray
devjces had been selected, 9% indicated intake
level controls, 6% indicated reservoir water
quality improvements, 28% indicated turbine
aeration, 9% indicated tailrace aeration, and 11%
indicated some other method. "Other" methods
include the use of tailrace aeration weirs, intake
aeration, reservoir destratification. and
operational constraints. No developers indicated
that reservoir aeration had been selected as a
mitigation technology. A combination or a set
of alternative mitigation technologies had been
selected at 25% of the projects.
Figure 3-13 displays the distribution of
mitigation types in project capacity classes
(<1 MW, 1 to <10 MW, 10 to <50 MW, 50 to
<100 MW. and >100 MW). For all projects
under 50 MW, spill flows are much more
frequently selected than other methods. Turbine
~r--~--~--~ .. -~--~--~--~---~--~---~--~--~---~--~--~---~--~ .. ~--~ .. -iiiij~ .. -~.-~ .. ;-======;=;=~~~ 50 .... --..... --...... .. .. .. .. . .. .. . .. .. . .. . .. . .. . .. . .. . . . S~mple . (n = 56) ~8 :::::::::::::::::::::: ::::::::::::::::::::::::,II::::::::-~~~~~-~~:~~.:~~-~~-~-~~~~~~~-~-~~~~·-·
~ ~g :::::~--~--~--gs:---~·--···--.. ·····----· .. ·--·------~ ............................................ ..
~ o ummt.~~~~~
u 70 r-------------------------------------------------------------~ -~ 60 .. -.. -.... --.. -.---.... -.. -........ -.. -.. -.............. -....... r--::--------'--~----,
~ 50 .. -..... -... -. -............... -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Target population (n = 206~
~ 40 .................................................. _ ........ _ . . . . (with water quality requirement
~ ~g -----~w.~ ............................................. .
c: 10 ..... ......... .. .. .
~ 0
~ 70r-~---------------------------------~====================~ ~g ~ ~ ~:: ~:::::::::::::::::::: ~::::::::::::::::::::::::::::::::::: J Total population (N = 1638) j
30 ·············································· ·····························-~~
20 ·············································· .......... . ......... ~
10 ..... .............................. ......... . ....... ..
0 ' Atlanta Chicago New York Portland San Francisco
Federal Energy Regulatory Commission region
Figure 3-11. Distribution of total population, target population (with water quality requirements), and
sample (with water quality requirements) projects, in Federal Energy Regulatory Commission (FERC)
regions. Based on data from FERC data sets (described in Section 2) and on infonnation provided by
developers.
70
"0 ~60
U)
t> 50 Q)
·[4o
0 30 &
.£9 20 c:
~ 10
Q)
CL 0
................................................................................................................
...... 0 ................. 0 ............... 0 ..................................................................... .
.....................................................................................................
Turbine aeration Intake level control Spray devices Reservoir aeration
Spill flows Other methods Tailrace aeration Reservoir water quality
Mitigation methods
Figure 3-12. Frequency of dissolved oxygen mitigation methods, based on infonnation provided by
developers.
3-16
J
J
J
, and
~RC)
:d by
1tion
d by
16
14
ell 12 -u
.Q) . ·o 10 ... a. -8 0 ...
Q) 6 .0
E
::I 4 z
2
I Spill
flows
~Turbine ~Other ~Intake
~aeration ~methods ~level
I:Q!Tailr~ce f71Spr~y I0J Res~rvoirDRese?'oir
~aeration k:Ljdev1ces ~quality aerat1on
0 <1 MW 1 to <10 MW 10 to <50 MW 50 to <1 00 MW 1 00 MW and larger
. ,_~,;
Capacity categories
:,'.'Figure 3-13. Frequency of dissolved oxygen mitigation methods, by project capacity category, based
... ··':on information provided by developers.
;~ ,_,"~, ·-~ . '. ~ ; -'
:'i'"jfra~onis selected frequently among developers
: .. ·5~tprojects between 1-50 MW. Other aeration
·· ·' ''techniques, such as intake level control (selective
· · ''witildrawal), reservoir aeration, or improvements
.. ' .. to .. reservoir water quality. were infrequently
-~;~.·-· :s~le~ted by developers of all sizes of projects.
:~·"---.. =---~ -. •':
· .... ·
. ·f.~~f}:,~·A;·~-:-. ~-: ·-·-_ • •
. { , ,]'he overwhelmmg preference toward sptll
M_ ··flows:. as a mitigation measure deserves
,.~, Af$~~~~ion, since the costs of spill flows in
,,,. 't6regorie power generation can by far exceed
total costs of virtually all other mitigation
options. Developers providing information for
this report indicate that spillage for aerating
,;.,..~\~J)yil_~rs can cause losses of more than 30% of
f tpta). arinual power production (see Section 4).21
f .. ;.?\J.t)Jough other mitigation technologies may have
; greater capital costs, they typically do not r in.volve substantial losses of power production
J. potential. ' .. l:. : . l . · .. This pattern may be attributed to several
j-' faCto~> : First, projects from the FERC New
I Yor.k;"region in this sample almost invariably use
~--~pilLflows as one mitigation method; projects
frUmi\the New York region account for 81% of
projects in this sample using spill flows. Thus
~prevalent use of spill flows may be explained
:£<1i~V4~.~~ by a regional bias in the sample and by
:. .. ,.'·' · .. ····
3-17
the very high frequency of spill flow use in the
overrepresented region.
Second, FERC commonly requires continuous
spill flows to mitigate DO problems at low-head
projects.35 As Figure 3-10 illustrates,most of the
projects considered in this study were small
(over half with capacity <10 MW). FERC
policy may explain much of the preference
toward spill flows.
Spill flows, moreover, may be attractive to
small hydro developers because other
technologies require prohibitive capital
investment Such capital investments appear
especially inappropriate when the frequency and
severity of sub-standard DO periods are
uncertain or low18.36; and developers may only
rarely have to implement mitigative spill flows.
In addition, the oxygen transfer efficiency of
· spill flows is highly predictable and reliable,
compared with that of other mitigation methods
like reservoir destratification.
It is also possible that developers and their
contractors are unaware of the variety and
effectiveness of alternative mitigation strategies,
or are hesitant to invest in technologies that are
not as well tested (see Table 3-2). Selective
withdrawal, for example, has been identified as
an economically feasible option for small
developers where facilities exist and where lake
stratification occurs,18 but only 9% of developers
indicated that intake level modifications were
used to mitigate· DO problems. Reservoir
destratification has also been highly regarded as
an economical and efficient mitigation method,
but was rarely identified by developers.
Another reason that spill flows are used so
frequently may be that spill flows and other
bypass flows can be used to provide instream
flows for fisheries and other purposes. This
expectation. can -be explored by examining
infonnation provided by hydro developers for
this study. Of the 53 projects providing
infonnation on DO mitigation methods used, 23
have a concurrent instream flow requirement. Of
this group with a concurrent instream flow
requirement, 78% use spill flows. 'This is in
contrast with the 66% of all projects with DO
mitigation that use spill flows (Figure 3-12).
Clearly, the frequency with which spill flows are
selected as the DO mitigation method is higher
for projects with a concurrent instream flow
requirement. This result suggests that the
observed general preference for spill flows as a
DO mitigation method may be explained in part
by the usefulness of spill flows for IFN.
However, of the 30 projects that perfonn DO·
mitigation and do not have a concurrent instream .
flow requirement, a clear majority (57%) still use
spill flows (the next most popular method is
turbine aeration, employed at 27% of the projects
in this group). This result suggests that spill
flows' usefulness for IFN does not entirely
explain the popularity of spill flows as a DO
mitigation method among hydro developers.
Mode of Operation. Of the 53 developers
reporting on mitigation teclmology, 45 provided
infonnation on when the mitigation is used
(Figure 3-14). Of these 45, 40% report that
mitigation is used at all times, 38% report that
mitigation is implemented only when necessary
(e.g., when DO monitors indicate that DO levels
in releases or upstream of the intakes has fallen
below a critical level), and 9% indicate that
mitigation is used only during a specified season.
Mitigation methods are reported to be used
seasonally, only when necessary, at 13% of these
projects. Significant differences in power losses
and operating costs can be involved when, for
example, a spill flow is maintained only during
episodes of sub-standard tailwater DO, or if it is
maintained continuously throughout the summer.
It appears that a large fraction of projects with
DO mitigation are required, or choose, to
mitigate only when a DO problem occurs; but an
~
50-r-------------------
-;; 40
()
Q)
·e-30
0.
15 • {1!,20 -.............. , .............. . nl . ' ••••.•.••.• ~ 10 t-""·""·11-.............. ~ -~ . ·~:.,, a.
0
···············•·····.························································ . ~ ......... .
• <
Always When necessary Seasonally
Mitigation schedule
Seasonally, when
necessary
Figure 3-14. Times when dissolved oxygen mitigation must be implemented, based on infonnation
provided by developers.
3-18
DO
earn
luse
d is
jects
spill
irely
DO
•pers
'ided
used
that
that
;sary
~vels
allen
that
iSon.
used
these
lsses
1, for
uing
'it is
1mer.
with
:, to
ut an
ation
>i
:-~;
.~
3
.d ri ~
';!! I I
Capacity categories
~<1 MW ~1 to <10 MW f§ho to <50 MW ··
[81so to <1 00 MW l2h oo MW and larger · ·
Always or seasonally When necessary
Mitigation schedule
:,_\.~; >J'.:,'
~::J:f:lgure 3-15. Times when dissolved oxygen mitigation must be implemented, by project capacity
category, based on information provided by developers.
.,, almost equally large group are required, or
-g , 'ch00.se. to mitigate even at times when it may
t notbe needed. It appears that smaller capacity
:: -?t~llydtopower projects have more stringent DO
\Vi,:{lllitigation requirements (Figure 3-15); of all .
') ,;pryj~9ts required to mitigate at ali times or over
'P'":.;a'se~on, the majority are <10 MW. Of the
pAP.jebts . required to mitigate only when
"1~1H!O~-~~ssary, the majonty. are > 10 MW.
;tit{;··.: -~.:r~,!~j~{; ..
:.~eollcles and Objectives. Fifty-four
:-±Htb~y~iopers provided infonnation on the objective
·:~:t}!i~~~~!~t~t :f .
of the mitigation (Figure 3-16). Multiple
mitigation objectives were reported at 41% of
these projects. Developers at 76% of the
projects indicated that maintenance of state water
quality standards were a mitigation objective, 9%
indicated state antidegredation objectives (i.e.,
compliance with requirements, usually applied to
selected waterbodies, that no degradation of
water quality be allowed), 9% indicated state
site-specific standards, and 39% indicated fish
and wildlife agency management objectives.
Eleven percent indicated that FERC determined
Federal Energy State site-specific Unknown objective
standards Regulatory Commission standards
Fish and wildlife State anti-Other objective
agency objective degradation standards
Objective of mitigation
. _.· .....
~~Mifl~ .. ~~~·3, .. 16. Objectives of dissolved oxygen mitigation requirement, based on information provided by
·· .··. :~~vetopers.
'-·:;.;-
· .. ,.-... ·.
3-19
the DO objectives, 4% indicated other objectives,
and 4% indicated that water quality objectives
were not clarified during the licensing process.
It is apparent that compliance with state water
quality standards is the most common purpose of
DO mitigation. It is also interesting to note that
antidegradation requirements have rarely been
applied to hydropower projects, but many
projects report having DO mitigation at least
partially as a result of fisheries agency concerns.
Forty-eight of the '56 respondents provided
infonnation on specific DO requirements.
Eighty percent indicated a specific chemical DO
· requirement; these range from 4 mg/L to 7 mg/L
(Figure 3-17). In some cases, the chemical DO
requirement or objective was stated as a percent
saturation or as an unspecified state DO standard.
The variety in DO criteria reflects, among other
things, differences among state DO standards.
Method Used to Determine Mitigation
Requirement. Fifty-four developers provided
infonnation on the method of study used to
detennine license requirements (Figure 3-18).
Forty-six percent of those projects providing
infonnation indicate that pre-startup or early
water quality monitoring was the only basis for
the DO requirement. A modeling study was the
only basis for detennining the n~ed for DO
mitigation at 15% of the projects. As many as
13% of the projects indicated that both
monitoring and modeling work were used to
detennine the license requirement. At 13%,
professional judgment was the basis for
detennining the need for DO mitigation. Nine
percent indicated no studies were used. It ·is
noteworthy that monitoring is most frequently
used to detennine DO mitigation requirements,
because it has been suggested that monitoring is
expensive. DO modeling, while also costly .
because monitoring is needed to calibrate, verify,
and provide input for the model, can be an
appropriate, less expensive, and potentially more
useful method for detennining the nature and .
extent of a DO problem and the need for DO
mitigation.18
The cost of inappropriate mitigation can far
exceed the costs of conducting effective studies.
Moreover, pre-and post-operational reseiVoir
and tailwater quality monitoring and modeling
can be very useful in identifying optimum
strategies. For example, one developer reported
that a 150 cubic feet per second (cfs) spill flow
was assigned, based on professional judgment, to '
a 1 MW project in New York.. This spill flow
represents a large portion of flow available for
power generation. However, a subsequent water
quality monitoring study demonstrated that
although turbine releases cause some DO
reduction, DO stays well above the minimiun
standard even in the absence of spill flows.
40 ~--------------------------------------------------------~ ~
Cl)
t) 30
-~ .... a.
o20
Q)
N 5i 10
~
···························::: ... ·:,· .. ·.:·······················-················
Q) c.. or ml Wiil ~ lffi@ aJ [m 1
4 5 5.5 6 6.5 7
Minimum dissolved oxygen concentration (mg/L)
Figure 3·17. Dissolved oxygen standards for reservoir releases, based on infonnation provided by
developers. .
3-20
:d to
13%,
for
Nine
It ·is
ently
1ents,
.ng is
:ostly
erify,
~ean
more
:and
r DO
50
"0'. 0' 40 -(/) -:,c•g
·a 30 .... c.. -0
CD .•.
Cl
.£!!
20
c::
8 10 ...
·CD a..
Monitoring only Modeling only Monitorin~ and P~ofessional
modeling JUdgment No studies Other methods
Method for determining mitigation requirement
Figure 3·18. Method of study used to develop dissolved oxygen mitigation requirements, based on
111 far illfollilation provided by developers.
Jdies.
~rvoir
leling
imum
K>rted
. flow
mt, to
flow
lefor
water
that
DO
imum
ed by
Agency Positions on Dissolved Oxygen
MI~Jga!Jtlon. The positions of state and federal
re.sou~e agencies on DO. mitigation at
hydropower developments was solicited with the
Agency\_Information Requests, described in
. ~.ef;tl_l?n .. 2 of this report. State agency responses
Q~, D() mitigation policies are summarized in
i;~tile:·'3-3. and are presented in greater detail in
~ppendix B. Responses from federal agencies
·.are ~so discussed below, with data presented in
Appe(id~x B.
' ' ;. ~~!.t:;_,·:~.~.·t~.f'· :~-·. .
;itPfi-36 states for which policy information was
~c;j,y~, .about 40% (14 states) have a written
OOUF¥·CI:able 3 .. 3) applicable to DO mitigation at
~~~i"Pow~r developments. Nearly 60% of states
~~~P~iJ1g. to the question indicated that state
WJl~r., qu~ity standards were the objective of
.· ntiijg~~iQn; about 30% cited antidegradation
· o!?!~tive~, and only 16% cited other fish and
•wn~fe objectives of mitigation (Table 3-3).
Ho~~yer,. when state standards were indicated,
t~~~.;e$P,<)qse was often worded similarly to "the
•~•··. Q!lj~tiye of mitigation is to maintain state water
· 9Y~J~Y>•~plndards which protect fish and other
'ffil!~ic, life."
states that provided information on
>•B!Sl!~Pdl(s) used to determine a need for DO
;;:'f,•'~•:qg~ltiQn, 43% cited water quality monitoring
3-21
as one of the methods, 29% cited modeling as
one method, and 14% cited professional
judgment as one method. As from the
information obtained from developers, it appears
that water quality monitoring to determine the
need for mitigation is the most common method;
however, the information from the agencies
suggests that modeling is more frequently
employed than the information from the
developers indicates (Figure 3-18).
Federal resource agency (EPA, FWS, NMFS)
positions on hydropower mitigation were also
examined in this study. Information obtained
suggests that while federal agencies can and do
play a vigorous role in setting DO mitigation
objectives, they do not do so consistently.
The FWS is directly involved in studies to
determine the need for DO mitigation at hydro
projects, performing onsite direct measurements ·
and monitoring in addition to reviewing
historical water quality data and existing
information in at least one region. Although this
level of involvement is probably exceeded in
other regions,37 responses from other FWS
regions indicate that this is not always true
(Table B-4). In general, the responses from
many offices of federal resource agencies
indicate that the agency is not directly involved
Table 3-3. Numbers and percentages of state resource agency responses to agency information request
regarding dissolved oxygen (DO) mitigation (see Appendix B for additional information).
Written DO mitigation policy
DO requirements for FERC-licensed projects
Professional judgment used as a method to determine the need for
DO mitigation at a project
Water quality modeling used as a method to determine the need for
DO mitigation at a project
Water quality monitoring used as a method to determine the need
for DO mitigation at a project
States citing state water quality standards as the objective of DO
mitigation
Antidegradation standards are the objective of DO mitigation
Other fish and wildlife objectives are the objective of DO mitigation
Spill flows suggested as a mitigation method or one of several
methods
Turbine aeration suggested as a mitigation method or one of several
methods
Improvements to reservoir water quality suggested as a mitigation
method or as one of several methods
Intake level control suggested as a mitigation method or as one of
several methods
Studies of DO mitigation effectiveness with respect to water quality
Studies of DO mitigation effectiveness with respect to biological
endpoints
Studies of DO mitigation effectiveness, with endpoint unspecified
Total number of states with studies of DO mitigation effectiveness•
•some states reported both biological and water quality effectiveness studies.
3-22
Percent
responding Number of
"yes" responses
39 36
57 30
14 28
29 28
43 28
58 31
32 31
16 31
41 27
22 27
15 27
26 27
17 30
13 30
17 30
40 30
at hydropower sites, but primarily reviews
infonnation provided by other resource agencies
and by the developer (Table B-4).
None of the federal agencies cited policies
specific to dissolved oxygen problems at
hydropower projects; no written poliCies at all
regarding mitigation at hydropower projects were
cited by responses from EPA respondents. In
contrast, FWS involvement in hydropower
mitigation issues is governed by two policies: a
Mitigation Policy published in 1981, and a more
recent Hydropower Policy drafted in 1988 and as
yet in review.12 The goals of the FWS'
Mitigation Policy are to clarify the agency's
objectives and approaches to protecting and
conserving important fish and wildlife resources
while facilitating balanced development of the
nation's natural resources.11
The underlying goal of the FWS Hydropower
Policy is to "ensure that hydropower projects are
planned and implemented with full and equal
consideration for the protection, mitigation, and
enhancement of fish and wildlife resources. The
intended effect of this policy is to protect and
conserve the most important and valuable fish
and wildlife resources while meeting the
Nation's energy demands."
Protection of fish and wildlife resources, rather
than the protection of water quality criteria, are
the driving objectives of the agency. The
distinction between fish and wildlife objectives
and state water quality objectives is important.
Pursuit of fish and wildlife objectives can be
much more complex, requiring greater agency
involvement, data, and analysis, than pursuit of
a simple numerical dissolved oxygen standard
(e.g., 5 mg/L).
However, state water quality objectives only
were identified as the mitigation objective by the
EPA and by several of the FWS offices.
Descriptions of respondents' objectives behind
involvement in hydro DO mitigation issues read
similarly to, in a number of cases, "maintain
state ambient water quality standards''. In some
cases, the issue of water quality problems at
3-23
hydropower plants is deferred to state water
authorities. Variability in the stated policy and
objectives of agency involvement in mitigation
probably leads to variability in the degree to
which agency offices are involved in the
detennination of mitigation requirements.
Fish Passage Requirements
Hydropower projects can affect fish by
blocking their movements in both upstream and
downstream directions. These movements are
most important to anadromous and catadromous
fish, which spend part of their life cycles in
rivers and part in oceans or other large
waterbodies such as the Great Lakes. Other fish
species can migrate long distances within a river.
For fish trying to move upstream, a dam can
pose an impassable barrier unJess mitigation is
provided. Fish moving downstream are likely to
be entrained in the turbine intake and may be
killed by the turbine if downstream passage
mitigation is not provided.
Mitigation practices that are intended to
facilitate upstream and downstream movement of
fish are described in this section, including
background information on fish passage
mitigation, current fish passage practices (as
determined from the information requested from
project developers), and agency positions on fish
passage mitigation.
Background on Upstream Fish Passage.
The blockage of upstream fish movements by
hydroelectric dams may have serious impacts to
species whose life history includes spawning
migrations. Anadromous fish (e.g., salmon,
American shad, blueback herring, striped bass),
catadromous fish (e.g., eels), and some resident
fish (e.g., trout, white bass, saugcr) could all
have spawning migrations constrained by such
barriers as hydroelectric dams. Maintenance or
enhancement of these species may require the
construction of facilities to allow for upstream
fish passage.1 Descriptions of the basic types of
upstream fish passage measures are provided in
earlier reviews.3842 Upstream passage measures
can be placed into three general categories:
trapping and hauling, fishways, and fish lifts.
Trapping and hauling is a labor-intensive
mitigation measure that can be used when fish
need to be transported long distances upstream or
around a large number of obstacles. Upstream-
moving fish may be collected at a single location
(e.g., the farthest downstream dam) and
transported by tank truck to upstream stocking
locations. The techniques and factors important
to the survival of transported fish are relatively
well understood 38 based on experit:nce with
hatchery fish. where collection of fish in the
raceways is relatively easy. It is less efficient as
a method for moving wild fish past a dam
because collection is more difficult and target
fish may be present in the vicinity of the dam in
large numbers for only short periods of time.
Fishways (or fish ladders) are widely used to
transport fish above single obstacles such as
dams and may also be used to collect fish for
hauling to upstream stocking locations. The
tennflShway describes any flow passage that fish
negotiate by swimming or leaping; it can be a
high-velocity chute, a cascade or vertical
waterfall, or an artificial structure such as a
culvert, a series of low walls across a channel
(weir-and-pool fishway), or merely a chute up
which the fish swim.41 Hydroelectric plants have
commonly employed such general types as pool-
and-weir, vertical slot, Dcnil, and Alaska steep
pass fishways. The key difference between
fishways and the other two categories of
upstream fish passage measures is that fishways
rely more on the swimming ability of fish to
negotiate an obstruction.
The wide variety of fishway designs have been
reviewed periodically8A0.4t. As with the hauling
of fish, substantial experience in design and
operation of fishways, dating back to early in the
last century, has led to the development of
standard design criteria.l8•39 There are four
general elements that are important to the design
of efficient fishways: (a) speed and success of
fish passage must be optimized to minimize
delay, stress, damage, and fallback of fish;
(b) water use should be minimized in order to
maximize water for such other uses as power
production; (c) the range of stream flows under
which the fishway is operable should be
maximized; and (d) construction, operation, and
maintenance costs should be minirnized.41
Optimizing the first element may be relatively
difficult if the goal is to pass a variety of fish
species that have different behaviors, sizes, and
swimming abilities. For this reason, the most
successful (and cost-effective) fishways are often
those that can be designed to transport a specific
run of anadromous fish that have a uniform size
and predictable behavior. Some species (e.g.,
striped bass, smelt, sturgeon, and blueback
herring) are reluctant to pass through fishways.40
There are, however, numerous examples of
nontarget fish species using fish ladders to
surmount obstacles.43 -46
Fish lifts (elevators) and fish locks rely less on
active movement of the fish than do fishways.
In these devices, fish are attracted to a water-
filled chamber or hopper in the tailrace and then
are transported passively to the top of the dam.
The primary disadvantages of fish lifts or locks
are that they have an intermittent mode. of
operation that can delay upstream-moving fish at
the base of the dam and are more susceptible to
mechanical problems than fishways. Because of
the potential for failure of mechanical parts,
automated operation is difficult and, unlike
fishways, personnel must be present during
operation.40 A major biological advantage of
fish locks and lifts is that they can pass
practically all species of fish, including small or
weakly swimming fishes. For this reason, locks
and lifts may be favored for restoration of such
weak swimmers as American shad and blueback
herring.47 Although fish locks have been installed
in Europe39 and South America,41 they are
uncommon in North America.38 Az Compared to
fishways, the capital costs of fish lifts/locks are
in the same order of magnitude, O&M costs are
higher, water requirements are lower, and the
ranges of species that can be transported are
broader.1
The effectiveness of fish lifts for transporting
American shad has been studied at the Holyoke
Dam on the Connecticut River.47 An average
passage efficiency of 50% was observed among
radio-tagged fish, which was consistent with
independent shad passage estimates ranging from
40% to 60% of the total run from 1976 to 1983.
Adverse conditions can drastically reduce
passage efficiency, however; extended high flows
in 1978 reduced passage at the Holyoke fish lifts
to 18% of the shad run.47
Background on Downstream Fish
Passage. A variety of downstream fish
passage screening devices have been employed
to prevent fish from becoming entrained in the
turbine intake flows. The simplest, spill flows,
can transport fish over the hydropower dam
rather than through the turbines. At the other
end of the scale, sophisticated physical screening
and light-or sound-based guidance measures are
being studied to bypass downstream migrating
fish with a minimal loss of water that could
otherwise be used for power generation.
Extensive reviews of downstream fish passage
mitigation measures are available.38•49 .s0• There is
presently no single fish protection system or
device which is biologically effective, practical
to install and operate, and widely acceptable to
regulatory agencies.
Increased spillage may be used to flush fish
over a dam or through a bypass; this measure
may be especially cost-effective when the
downstream migration period of a target species
is short, when migration occurs during high river
flows when water would be spilled anyway, or
when spill flows are needed for other reasons,
(e.g., to increase DO concentrations or maintain
minimum instream flows in a diverted reach).
Although the costs of construction and labor are
low for this mitigative measure, additional costs
. are incurred because spilled water is not
available for power production.' As with any
fish passage device, care should be taken to
ensure that mortality associated with spillway
passage does not exceed turbine passage
mortality.
Sluiceways. or bypasses are used to transport
fish to below the dam, either alone or, more
commonly, in conjunction with some other
mitigative measure such as screens. If fish tend
3-25
to be concentrated in the upper portion of the
water column, they may use orifices or overflow
areas leading to ice and trash sluiceways to
bypass the turbine intakes. 50 Designing an
effective bypass for low-head dams can be
relatively easy, given proper consideration of
scale. However, at high dams or where the
amount of debris or ice in the water is high, fish
may suffer injury or mortality in the bypass
channel or pipeline. Criteria for designing
effective bypass systems have been described.51
A simple and common means of reducing
turbine passage of fish is to modify the trash
racks that power plants use to prevent large
debris from entering the intake. One common
modification is the angled bar rack, where the
trash rack is set at an acute angle to the flow
direction (rather than perpendicular to flow), and
individual bars may also be set at an angle to the
flow. Water entering the turbine must abruptly
change direction as it passes through the angled
bar rack. The belief is that fish can sense and
avoid this change in direction of the bulk flow
and will be guided downstream along the angled
rack to a bypass. Frequently, the bars within an
angled bar rack are spaced more closely than in
a conventional trash rack; spacing between the
bars may be reduced fro111: typical values of 8 to
20 em (3 to 8 in.) to no more than 2.5 to 5 em
(1 to 2 in.). Oosely spaced bars will prevent
large fish from becoming entrained in the intake
flow even if the behavioral guidance aspect of
the device fails. Although this measure is
commonly employed in the Northeast, many of
the installations are relatively recent. There
appears to be only one study of the effectiveness
of angled bar racks, at the Wadhams
hydroelectric project.~2 Only small numbers of
Atlanta salmon smolts were tested, but diversion
efficiency was good. The effectiveness of angled
bar racks at other installations is as yet unknown.
Traveling screens are also used to prevent fish
from passing through the turbines. Vertical
traveling screens are commonly used at steam
electric power plant intakes and rotary drum
screens are often used at irrigation diversions;
these designs have been modified for
hydropower intakes. The most frequently
studied traveling screens for hydropower
applications are the gatewell screens installed at
several dams in the Columbia River basin.
These screellS are installed in the upper portion
of the turbine intake gatewell. Because some
downstream migrating salmonids are surface
oriented, they encounter the screen and are
forced upward into gatewells, where they pass
into a flume and are routed either to a collection
point (for truck or barge transportation
downstream) or are discharged into the tailrace
to continue their downstream migration. Five of
the USACE dams on the Columbia and Snake
rivers now include submersible traveling screens
and fingerling bypass systems; plans are in
progress to provide similar systems at other dams
in the basin.53 Recent research indicates that
there is considerable site-to-site, year-to-year,
and· species-to species variability in the
efficiency of gatewell screens53 ; the high guiding
efficiencies of gatewell screens in early
applications have been followed by disappointing
results at other dams. For example, juvenile
chinook salmon bypassed with gatewell screens
at the Bonneville Dam second powerhouse had
significantly lower survival rates than those
which passed through the turbines54; it is
speculated that predation by squawfish in the
tailrace may be a cause of this observation.
A variety of other fish screens have been
suggested for hydropower applications, but some
are recent developments and few have received
the extensive biological testing at hydropower
plants that is needed to determine their general
effectiveness. Inclined plane screens, vertical
punched plate screens, Coanda screens,
submersible traveling screens (described above),
and cylindrical wedgewire screens have been
recommended.55 One version of an inclined
plane screen (known as the passive pressure or
Eicher screen) has been installed in a penstock at
the Elwha Dam in Washington. In this design,
downstream-migrating fish can be diverted out of
the penstock and into a bypass. Studies of the
diversion and survival of coho and chinook
salmon smolts and steelhead yearling smolts
have been encouraging.s6-ss A cylindrical screen
fabricated of w~gewire has recently been
installed at the Arbuckle Mountain Hydroelectric
3-26
Plant in Califomia.59 Although there are no
bypasses associated with this . installation, the
narrow openings of 2.4 mm (0.094 in.) between
the wires would prevent entrainment of even
small resident fish such as juvenile trout. Static
angled wedge-wire screens were installed at the
Leaburg Dam in Oregon. Biological testing of
the screens began in 1984 and is continuing.
Initial studies indicate that salrnonids >60 mm
(2.4 in.) in length are protected by the screen,
but large numbers of smaller fry (which are too
large to pass through the screen slots) are
impinged on the screen and killed. 60
Barrier nets have been tested at both steam
electric and hydroelectric power p1ants 50 but have
not gained wide acceptance. Deployfnent and
maintenance can be very labor intensive. A
mesh size sufficiently small to exclude a variety
of fish species and sizes will also collect water-
borne debris, thereby requiring cleaning and
protection from wave action. The usefulness of
barrier nets for preventing fish entrainment is
being studied at two hydroelectric projects in the
Midwest, the Pine Hydroelectric Plant in
Wisconsin61 and the Ludington Pumped Storage
Plant in Michigan.62
Other mitigative measures depend on fish
behavior rather than physical screens to exclude
fish from turbine intakes. Behavioral barriers
that have been studied include electric screens,
bubble and chain curtains, chemical repellents,
underwater lights, and sounds. Although the
results of studies of these measures have been
equivocal, 1 some refinements of behavioral
barriers continue to be examined at hydropower
plants. For example, studies of the utility of
strobe and mercury vapor lights to draw
downstream-migrating American shad away from
turbine intakes are being conducted at the York
Haven plant on the Susquehanna River.63 •64
Strobe lights will be used to repel downstream-
migratory salmon at the Mattaceunk Project in
Maine; installation of the lights is scheduled to
be completed by November 1992, and
performance monitoring would begin soon after.
In contrast to the nonspecific, high-energy
underwater sounds previously found to be
ineffective, investigators have begun
studied traveling screens for hydropower
· applications are the gatewell screens installed at
several dams in the Columbia River basin.
These screellS are installed in the upper portion
of the turbine intake gatewell. Because some
downstream migrating salmonids are surface
oriented, they encounter the screen and are
forced upward into gatewells, where they pass
into a flume and are routed either to a collection
point (for truck or barge transportation
downstream) or are discharged into the tailrace
to continue their downstream migration. Five of
the USACE dams on the Columbia and Snake
rivers now include submersible traveling screens
and fingerling bypass systems; plans are in
progress to provide similar systems at other dams
in the basin. 53 Recent research indicates that
there is considerable site-to-site, year-to-year,
and· species-to species variability in the
efficiency of gatewell screens53 ; the high guiding
efficiencies of gatewell screens in early
applications have been followed by disappointing
results at other dams. For example, juvenile
chinook salmon bypassed with gatewell screens
at the Bonneville Dam second powerhouse had
significantly lower survival rates than those
which passed through the turbines54 ; it is
speculated that predation by squawfish in the
tailrace may be a cause of this observation.
A variety of other fish screens have been
suggested for hydropower applications, but some
are recent developments and few have received
the extensive biological testing at hydropower
plants that is needed to determine their general
effectiveness. Inclined plane screens, vertical
punched plate screens. Coanda screens,
submersible traveling screens (described above),
and cylindrical wedgewire screens have been
recommended.55 One version of an inclined
plane screen (known as the passive pressure or
Eicher screen) has been installed in a penstock at
the Elwha Dam in Washington. In this design,
downstream-migrating fish can be diverted out of
the penstock and into a bypass. Studies of the
diversion and survival of coho and chinook
salmon smolts and steelhead yearling smolts
have been encouraging.s6-ss A cylindrical screen
fabricated of w~gewire has recently been
installed at the Arbuckle Mountain Hydroelectric
3-26
Plant in Califomia.59 Although there are no
bypasses associated with this installation, the
narrow openings of 2.4 mm (0.094 in.) between
the wires would prevent entrainment of even
small resident fish such as juvenile trout. Static
angled wedge-wire screens were installed at the
Leaburg Dam in Oregon. Biological testing of
the screens began in 1984 and is continuing.
Initial studies indicate that salmonids >60 mm
(2.4 in.) in length are protected by the screen,
but large numbers of smaller fry (which are too
large to pass through the screen slots) are
impinged on the screen and killed.60
Barrier nets have been tested at both steam
electric and hydroelectric power plants50 but have
not gained wide acceptance. Deployfnent and
maintenance can be very labor intensive. A
mesh size sufficiently small to exclude a variety
of fish species and sizes will also collect water-
borne debris, thereby requiring cleaning and
protection from wave action. The usefulness of
barrier nets for preventing fish entrainment is
being studied at two hydroelectric projects in the
Midwest, the Pine Hydroelectric Plant in
Wisconsin61 and the Ludington Pumped Storage
Plant in Michigan.62
Other mitigative measures depend on fish
behavior rather than physical screens to exclude
fish from turbine intakes. Behavioral barriers
that have been studied include electric screens,
bubble and chain curtains, chemical repellents,
underwater lights, and sounds. Although the
results of studies of these measures have been
equivoca1,1 some refinements of behavioral
barriers continue to be examined at hydropower
plants. For example, studies of the utility of
strobe and mercury vapor lights to draw
downstream-migrating American shad away from
turbine intakes are being conducted at the York
Haven plant on the Susquehanna River. 63 •64
Strobe lights will be used to repel downstream-
migratory salmon at the Mattaceunk Project in
Maine; installation of the lights is scheduled to
be completed by November 1992, and
performance monitoring would begin soon after.
In contrast to the nonspecific, high-energy
underwater sounds previously found to be
ineffective, investigators have begun
experimenting with particular frequencies of
underwater sound to repel fish from turbine
intakes.65'67 Initial results indicate that
customizing the sounds by broadcasting
frequencies actually produced by the target
species can repel a statistically significant
number of fish.
The choice of mitigative measures is
dependent on the species and behavior of fish in
need of protection. If the intent of the mitigation
is simply to prevent resident fish from becoming
entrained in the turbine intake flow, then a
physical exclusion device (e.g., angled bar rack.
cylindrical wedge-wire screen, banier net)
without bypass facilities may suffice. If there is
a need to transport downstream-migrating fish
below the dam, then the mitigative measure must
also incorporate some means of safely
conducting the fish (e.g., through bypasses, trash
sluices, collection and hauling). In such cases,
not only the intake exclusion device but also the
subsequent downstream transport measure must
be evaluated for effectiveness.
Frequency and Type of Requirements.
This section describes current mitigation
practices for fish passage at nonfederal projects.
Costs of these mitigation practices are also
summarized. The methods used for these
analyses are described in Section 2.
Ail.alysis of FERC's m..crs data base
indicated that there are 79 projects where fish
passage facilities have been specifically
mentioned in the license. These projects are
~apped in Figure 3-19. In addition, however,
information on fish passage mitigation was
requested from 295 other projects where HLCI'S
indicated that some kind of fishery resource
requirements were in the license.
Upstream Fish Passage. Information for
34 projects with upstream fish passage facilities
was obtained from hydropower developers.
More than 90% of these facilities were either in
operation or completed. Figure 3-20 shows the
general types of upstream fish passage measures
that are employed and their relative frequencies.
Figure 3-19. Distribution of sample of target population projects with fish passage requirements.
Light-shaded points are members of sample, black-shaded points are all other projects in target
population.
3-27
80~-------------------------------------------------------,
..........................................................................................
Fish ladder Trapping and hauling Fish elevator Other
Type of mitigation measure
Figure 3-20. Relative frequency of upstream fish passage measures at nonfederal hydroelecbic projects,
based on information provided by developers.
Fish ladders, more than 70% of the upstream
passage de:vices reported, were by far the most
common. Fish ladders are employed throughout
the United States. Some of the ladders are quite
old, dating back to the tum of the century. Fish
elevators are a less common (12%) but relatively
recent mitigative measure. Trapping and hauling
of fish (by trucks) to upstream spawning
locations are used at some older dams (15% of
the projects with upstream passage facilities) but
in two of the projects fish ladders or elevators
are replacing this labor-intensive mitigative
measure. The "Other" category in Figure 3-20
includes an assortment of upstream passage
measures that are used at very few sites, such as
berms (to encourage upstream migrating fish to
avoid a powerhouse discharge) and the use of
navigation locks.
Projects with upstream fish passage
requirements were categorized as (1) diversion
projects, in which the powerhouse is on a
different stream than the diversion dam;
(2) run-of-the-river projects, in which the dam is
:SJO feet high and with minimal storage capacity;
or (3) storage projects, in which the dam is
> 10 feet high. Based on information provided
by the developers, diversion, run-of-the-river,
and storage projects accounted for 17, 75, and 8
3-28
percent respectively of the nonfederal,
PERC-licensed hydropower facilities with
upstream fish passage requirements. Among the
29 upstream fish passage facilities that are in
operation, 41% reported that the facilities are in
operation at all times (Figure 3-21). Another
35% of the projects reported that the mitigative
measure is operated only during specified
seasons, whereas 14% are required to operate
only during certain hours (e.g., nighttime) during
specified seasons.
Specified seasons
{35%)
No response
{10%)
Seasons and hours
{14%)
Figure 3-21. Frequency of operation of
upstream fish passage measures at nonfederal
hydroelectric projects, based on information
provided by developers. Values in parentheses
represent percentages of projects in each
category.
Anadromous fish are protected at 68% of
projects with upstream passage mitigation
(Figure 3-22); 35% of the projects are required
to protect only anadromous fish. On the other
harid, some hydroelectric projects are required to
maintain upstream movements of resident
(nonanadromous) fish as well. Thirty-eight
percent of the projects reported resident fish
passage requirements, and 12% reported only
resident fish passage requirements. Not all of
these facilities presently transport the fish they
were designed to protect. Some upstream
passage facilities were installed on the
expectation that future fish restoration efforts
will result in the need for passage.
In the view of the developers that provided
infonnation to the study, professional judgment
by the agencies was the most common basis for
the incorporation of an upstream fish passage
requirement; 50% reported that professional
judgment contributed to the requirement, and
35% reported that this was the sole basis for the
requirement. Licensee-conducted and agency-
conducted studies contributed to the development
of the fish passage requirement in 21% and 18%
of the projects, respectively. Twenty-four
percent of the project operators were not aware
of any studies conducted to determine a need for
upstream fish passage at their sites. Regard~g
80
;? 70
0 -.!!! 60
(,)
'~50 ....
Q.
0 40
G) N 3o
c: B 20 ....
G)
a.. 10
0
the role of professional judgment in setting fish
passage requirements, it should be noted that in
many cases the agency position may reflect
knowledge or studies unknown to the developer.
For example, the need to p·ass anadromous fish
upstream of an existing dam may have been
identified long before submission of a FERC
license application. Existing information about
the fish community and the effectiveness of fish
passage measures at other, similar sites may save
the developer both time and financial resources
needed to carry out new studies.
Performance objectives are an important part
of assessing the benefits of a fish passage
facility. Performance objectives can be defined
as the measurable benefits provided by a
mitigation facility. Benefits may be expressed,
for example, as the ability of a measure to
extend the upstream range of an anadromous fish
species or the ability to pass without mortality a
particular number or percentage of fish moving
either upstream ordownstream. Information was
obtained from 30 projects on whether
performance objectives were specified for the
upstream fish passage measure by the fisheries
agencies (Figure 3-23). The majority (57%)
indicated that "no obvious barriers to upstream
movement" was one of the criteria used to judge
effectiveness; 50% reported that this was the sole
Anadromous Resident migratory
Types of fish protected
Other
Figure 3-22. Types of fish that are transported by upstream fish passage measures at nonfederal
hydroelectric projects, based on information provided by developers.
3-29
i:
I
~ 60 ~ u 50
Q) ·e-40 a.
0 30
Q)
Cl
.!!! 20 c:
Q)
~ 10
Q) c...
No barriers· None Other Percentage passage
Performance objectives
Figure 3-23. Performance objectives for upstream fish passage measures at nonfederal hydroelectric
projects, based on information provided by developers.
criterion. One facility (3%) was required to pass
a specified percentage, and one facility a
specified number, of migratory adults. Thirteen
percent had some other performance criterion,
which generally was consistent with goals of a
larger fishery restoration program. Operators of
ten of the projects (33%) were unaware of any
performance objective for the upstream fish
passage measure at their sites.
Downstream Fish Passage. Information
was obtained from 85 hydroelectric projects that
have downstream fish passage requirements. The
fish passage measure is in operation at 68% of
these projects. A wide range of measures is
employed · to reduce turbine entrainment of
downstream-migrating fish, some of which are
used in combination with others (Figure 3-24).
The single most frequently required downstream
fish passage device is the angled bar rack. This
mitigative measure, in which the trash rack is set
at an angle to the intake flow and the bars may
be closely spaced (ca. 2 em), is commonly
required in the Northeast. Angled bar racks are
used by 38% of the projects with downstream
passage facilities. Other types of fixed fish
screens (34% of the projects) range from
variations of conventional trash racks (e.g .. use
of closely spaced bars) to more novel designs
employing cylindrical, wedge-wire intake
screens. Traveling screens are used at three of
the projects ( 4% ); these screens are commonly
3-30
installed in the gatewells of large hydroelectric
projects.
Intake screens of all kinds may have a
maximum approach velocity requirement and a
sluiceway or some other type of bypass
(Figure 3-24). The maximum approach velocity
is designed to enable fish to avoid being drawn
into · the turbine intake area; the requirement
should reflect the swimming abilities of the fish
that are protected. Bypasses or sluiceways may
be required because projects on streams with
migratory fish must provide a means not only to
prevent turbine entrainment (e.g., by screens) but
also to transport the fish below the dam. In
some cases a properly designed trash sluiceway
may serve to transport screened fish safely
downstream. Twenty-four percent of the projects
have a velocity limit on the intake flows and
22% have a sluiceway or some other form of
bypass. Only three of the projects (4%) have a
maximum approach velocity requirement as the
sole measure to reduce turbine entrainment.
Eight of the projects (9%) have a sluiceway or
bypass as the only mitigative measure to enhance
downstream fish passage.
The other types of downstream fish passage
measures reported are barrier nets, blockage of
the top portion of the trash rack to guide surface-
oriented fish to a sluiceway, modi.fication of the
sequence of operation of multiple-unit projects,
I
L
40~--------------------------------------------------, ~ ~
...... ·········································· ~::~::::
f~@ ::::x::.
Traveling screens
Spill flows Barrier net
Other
Types of mitigative measures
Figure 3·24. Relative frequency of downstream fish passage measures at nonfederal hydroelectric
projects, based on infonnation provided by developers.
and the experimental use of strobe lights or
underwater sound to drive fish away from the
turbine intake area.
Projects with downstream fish passage
requirements were categorized as (I) diversion
projects, in which the powerhouse is on a
different stream than the diversion dam; (2) run-
of-the-river projects, in which the dam is s;to
feet high and with minimal storage capacity; or
(3) storage projects, in which the dam is> 10 feet
high. Based on infomation provided by the
developers, diversion, run-of-the-river, and
storage projects accounted for 8, 87, and 5
percent respectively of the nonfederal, PERC-
licensed hydropower facilities with downstream
fish passage requirements. As with upstream
fish passage facilities, a large percentage (57%)
of. the downstream fish passage measures are in
operation at all times (Figure 3-25). Twenty-one
percent of the projects operate the mitigative
measure only during specified seasons. whereas
4% are operated only during certain hours of
specified seasons. Seventeen percent of projects
did not report when the downstream fish passage
measures are used, perhaps because many are
still under construction and specific requirements
have not been detennined.
Downstream fish passage facilities were most
frequently designed to protect adult resident fish
3-31
(55% of projects with such facilities;
Figure 3-26}. Juvenile resident fish (41 %) and
juvenile anadromous fish (25%) were also
important targets for these mitigative measures.
Downstream fish passage facilities are intended·
to protect fish eggs and larvae at only 8% of the
projects.
In the view of the developers providing
infonnation to this study, professional judgment
by the agencies was the most common basis for
the incorporation of a downstream fish passage
requirement; 51% of the 85 projects reported that
professional judgment contributed to the
requirement, and 38% reported that this was the
Specified seasons
(21%)
response
(17%)
Seasons and hours
(4%)
Figure 3·25. Frequency of operation of
downstream fish passage measures at nonfederal
hydroelectric projects, based on infonnation
provided by developers.
Adult resident Juvenile anadromous Eggs and larvae
Juvenile resident Adult anadromous
Types of fish protected
Figure 3-26. Types of fish that are protected by downstream fish passage measures at nonfederal
hydroelectric projects. based on infonnation provided by developers.
sole basis for the requirement. As with upstream
fish passage requirements, the agency position on
the need for downstream fish passage facilities
may have been based on knowledge or studies
unknown to the developer. Further, professional
judgment in selecting a type or design of a
needed downstream fish passage system may
have been necessitated by lack of data on the
effectiveness of most · protection systems.
Licensee-conducted and agency-conducted
studies contributed to the development of the fish
passage requirement in 22% and 9% of the
projects. respectively. Twenty-six percent of the
projects reported being unaware of any studies
related to downstream fish passage at their sites.
lnfonnation was provided on performance
objectives for the downstream fish passage
measure that were specified by the fisheries
agencies (Figure 3~27). Most (70%) of the 71
projects providing this information reponed that
no performance objectives· had been specified.
Four facilities (6%) were required to exclude a
specified percentage of fish from entrainment,
and three facilities (4%) were required to limit
mortality of downstream migratory fish to a
~BO r---------------------------------------------------------------~ ~ Jeo r·······fmmm .................................................................................. ..
a.
0 40 r .......
Q)
~ c:
~ 20 r .......
Q) a..
0
. ...................................................................................... .
""'"""'"'"'"t"'':'~:o::=~••••••••,.••••••"''"''"'"'"""""""'''''''"''''''''''''
001
None Other Percentage exclusion Percentage mortality
Performance objectives
Figure 3·27. Perfonnance objectives for downstream fish passage measures at nonfederal hydroelectric
projects, based on information provided by developers.
3-32
:,;oo_
specified level. Twenty percent had some other
perfonnance objective, usually a qualitative goal
such as "effective operation."
Agency Positions on Flsl:' Passage
Mitigation. As described in Section 2,
infonnation on the role of state and federal
resource agencies in fish passage mitigation was
solicited by means of the Agency lnfonnation
Request State agency responses to the Agency
Infonnation Request regarding fish passage
issues are summarized in Table 3-4 and
described in greater detail in Appendix B.
Relatively few responding states have required
mitigation of fish passage impacts associated
with nonfederal hydroelectric projects, and these
have been most often associated with runs of
anadromous fish. Nine of the state agencies
providing infonnation to .. this study ·have a
written policy regarding mitigation of fish
passage impacts of hydropower (Table 3-4).
Tiiese policies range in stringency from advisory
recommendations to requirements by state law
that every dam or-other obstruction across a
stream be provided with fish passage measures
(Appendix B). Twelve of the agencies
responding indicated that they would accept
compensation for losses of fish through off-~ite
mitigation, but often only as a last resort. Five
agencies reported setting quantifiable
perfonnance objectives for fish passage
mitigation measures (e.g., a defined number or
percent passage), and an equal number are aware
of or participate in operational perfonnance
monitoring (Table 3-4). None of the federal
resource and regulatory agencies contacted for
this study has a specific written policy regarding
Table 3-4. Summary of .state resource agency responses to agency infonnation request regarding
upstream and downstream fish passage mitigation (see Appendix B for additional infonnation).
Number of Upstream Downstream
responses fish passage fish passage
Number of states with a written policy re fish passage 34 9 9
mitigation
Number of states that accept compensation for fish 28. 12 12
losses through off-site mitigation
Number of states that have required fish passage 22 8 11
facilities at PERC-licensed projects
Number of states which require fish passage facilities 22 7 7
for anadromous fish only
Number of states which require fish passage facilities 19 3 7
for resident fish only
Number of states which require fish passage facilities 22 1 4
for both anadromous fish and resident fish
Number of states in which perfonnance monitoring of 19 6 5
fish passage measures is conducted
Number of states with quantifiable perfonnance 19 5 5
objectives for the mitigative measure
3-33
'I
I I
! 1
mitigation of fish passage impacts at
hydroelectric projects (Appendix B). The FWS
has two policies related to the hydropower
licensing/exemption process. The first, published
in-1981, covers impacts of all types of
development projects, including hydropower.
lbis policy does not specifically address
instream flows, DO, or fish passage
requirements, but rather identifies a procedure
which the FWS uses to determine all types of
3-34
mitigation. The FWS also has a Hydropower
Policy. issued in 1988. Although the Hydro-
power Policy is in effect, public comments on
the need, scope. and content have been
requested,68 and the policy is currently under
review. Neither the National Marine Fisheries
Service nor the EPA regions that responded to
this information request have written hydropower
mitigation policies.
4. MITIGATION COST ESTIMATES
The cost estimates presented in this section are
based on a subset of the hydropower projects
described in Section 3. The infonnation
available for mitigation costs was less extensive
than that for the more general mitigation
requirements, because only 141 of the 280
projects that provided information included
sufficient cost data. This volume's scope was to
only provide infonnation as it was reported.
Future volumes of the Environmental Mitigation
Study report series are planned to include more
detailed cost infonnation and refmed analyses.
The cost data are presented in figures, tables
and narrative. The figures provide a general
view of the cost data. The tables provide the
average cost for each capacity category, type of
cost and mitigation method. The number of
projects reporting the respective data is also
listed in each table. The narratives provide
details explaining some of the practices and the
associated costs. Providing the cost data by
figures, tables and narratives allows the reader to
view the cost infonnation at various levels of
detail~
Capital and study costs are presented in the
same tables as they are both generally one-time
expenditures. The capital and stUdy costs are
also presented as dollar costs per kilowatt of
capacity, again because of their single
expenditure nature. The O&M and annual
reporting costs are also presented together
because they are both annually occurring costs.
The O&M and annual reporting costs are also
presented as annual mills per kilowatt-hour of
·energy to reflect their recurring nature. Each
type of cost is presented by mitigation method
with a brief overview. The data handling
assumptions that were used to anive at these cost
estimates are described in the data assumptions
section at the end of this section. All of the
costs presented in this report. regardless of when
they occurred, have been converted to 1991
dollars. The index used to convert the costs to
1991 dollars is also discussed at the end of this
4-1
section. A cost conclusions and recommenda-
tions section is included in the final section of
this report (Section 6).
Estimates of generation loss are presented for
each mitigation method. However, the
generation loss data was difficult to interpret It
is difficult to detennine from available data
whether an entire water source represents
potential energy or if only a partial quantity of a
water resource is available for generation. Some
regulatory agencies, for example, may not view
that part of a river trui.t is reserved for minimum
flows as a resource that is available for
generation. The developer may hold a dissimilar
view. For reasons such as this, the generation
losses will be subject to future analysis in latter
volumes and are simply presented in this volume
as they were provided by project developers ..
Introduction
The analyses conducted for this volume
indicated that, within each mitigation method,
costs were quite variable. Upstream fish passage
mitigation methods, for example, include fish
ladders and trapping and hauling. Fish ladders
are very capital intensive whereas the trapping
and hauling procedures generally have high
O&M costs. Future analysis will break down the
individual upstream fish passage methods, as
well as the other three mitigation methods, into
specific practices for closer examination. Future
analysis are also planned to attempt to identify
associations such as DO and instream flow costs
as a function of stream flows. It must be noted
that these cost data do not represent an unbiased
sample of all PERC-licensed projects.
Literature Search. An initial literature search
was conducted to identify previous cost studies
of the issues of DO, instream flow, and fish
passage that included subelements of costs
(actual costs only, no estimated or modeled
costs) and engineering. The following resources
1.
q t
. were used in this literature search: HCI
Publications, Bureau of Reclamation, EPRI,
USACE, and the INEL library. The results are
from the 5,162 references that were obtained for
the period 1985 to August 1991. There were
1,881 abstracts of papers/reports chosen for
review. From this group, 133 papers/reports
were chosen for further review, with only one
reporf9 showing any potential information that
could be useful in future cost analysis. It
appears that there has been a lot of work done in
the issue areas, but very little actual cost or
engineering iliformation is included in the
published reports. The lack of information
· indicates that a substantial level of effort will be
required to obtain and develop factual cost and
engineering analysis to support the environmental
miti_gation study.
Sample Characteristics. The cost estimates
presented in this section are based on a sample
of 141 hydropower projects that provided
mitigation cost information. The 141 projects is
a subset of the 280 projects that provided
information for this study. Sample sizes for each
mitigation issue are shown in tables throughout
this section. Figure 4-1 provides a breakdown
by capacity categories of the number of projects
providing mitigation cost data. Several projects
(Figure 4-2) provided cost data for more than
one mitigation requirement, in a variety of
combinations. The cost data is dominated by
projects with major licenses and run-of-river
operation (Table 4-1). Average project
chcu:acteristics are shown in Table 4-2. Of the
141 projects used for cost analysis, none of the
projects provided data for all of the attributes
and costs requested. This was because either the
projects did not have all of the mitigation
requirements or did not have access to the
various data requested.
Analysis Approach. Unless otherwise noted,
all of the costs in the tables are averages for the
projects in each capacity category and mitigation
method. The capacity categories are (a) projects
<1 MW; (b) projects 1 MW to <10 MW;
(c) projects 10 MW to <50 MW; (d) projects
50 MW to <100 MW; and, (e) projects 100 MW
and larger. Additionally, some of the tables
4-2
1 to <10 MW
(70)
10 to <50 MW
(25) / ~
50 to <100 MW .
(3)
100 MW and larger
(8)
Figure 4-1. Number of projects providing cost
information, by project capacity category.
Numbers in parentheses are the actual numbers
of projects in that category.
contain a column titled "Summary." This is a
weighted average of all of the aforementioned
capacity categories. Under each cost, within
several of the tables, is the number of projects
that provided data for the respective costs. The
lower the number of projects reporting costs, per
category, th~ increased likelihood tltat the
average project cost may be skewed by one or
Table 4-1. The type of licenses and operation
modes of the 141 projects used for cost analysis.
Type of Licenses
Major Minor Exempt
81 36 20
Operation mode
Run of river Store & release Other
97 30 9
Mitigation methods:
Dissolved oxygen and
instream flow
lnstream flow and
upstream fish passage
lnstream flow and
downstream fish passage
Upstream and downstream
fish passage
Dissolved oxygen, instream
flow. and upstream and
downstream fish passage
0 10 20 30 40
Number of projects
Figure 4-2. Number of projects providing cost infonnation for various combinations of mitigation
requirements. Other combinations are possible. A total of 141 projects provided cost infonnation.
more projects. For instance, the average capital
cost for the 15 projects reporting DO capital
costs is $162,000. However, one of these 15
projects reports a DO capital cost of $2,049,000.
Temporarily eliminating this project from the
data set results in an average DO capital cost of
$27,000, which is -$135,000 lower than the
original average. For reasons such as this the
costs are broken down into· capacity categories to
best reflect the costs that similarly sized projects
would encounter.
The intent of providing cost breakdowns by
capacity sizes is so that a developer of a new
project or of an operating project facing
relicensing, can study the past mitigation costs
encountered by similarly sized projects. It would
be imprudent to compare the costs of a 300 KW
project with the average costs of the entire
database ·with its average capacity size of
29,000 kW. Instead, by using the capacity size
categories, a developer can study the costs
associated with projects in the <1 MW capacity
category if the project was of the aforementioned
300 KW size.
4-3
Table 4-2. Average capacity, annual energy
and design head of the 141 projects used for cost
analysis.
Total capacity 4,117 MW
Average capacity 29 MW
Average design head 166 ft
Total annual energy 18,719,000 MWh
Average annual energy 137,000 MWh
Average turbine flow 3,900 ft!/s
When the cost tables are viewed it should be
noted that N/A in a table indicates that there
were not any projects providing costs for a type
of mitigation within a capacity class. Associated
with the N/ A will be a zero in the "Number of
projects" row, indicating that there are not any
projects providing cost infonnation for this
i:
+ ~ ! ,,,
i'
,, '
' I
: ~ , I
mitigation method and capacity category. When
a zero is provided in the cost row, it indicates
that the costs for a mitigation issue are zero. It
may be argued that if the cost was zero. than
there is not any cost. True, but the costs
associated with mitigation issues are being
measured, and this cost may sometimes be zero.
Perhaps an example would clarify this. The
instream flow capital costs reported by two
projects in the 100 MW and Larger capacity
category is $0. Both of these projects satisfy
their instream flow requirements by releases
through the turbines with no additional capital
cost to implement instream flow requirements.
So a zero value in a cost row does not indicate
an unknown value; rather, a zero value indicates
that no additional cost was incurred to meet a
mitigation requirement. The significance of this
is that the average costs are lowered when
including zero ·costs.
The various mitigation methods each contain
a wide range of costs that appear to be
dependant on a project's size. Simply viewing
the average cost for each type of mitigation
requirement provides too broad of an
examination. Analysis suggests that the
breakdown of costs by capacity categories may
provide the best illustration of costs. The reader
can best anticipate the mitigation costs associated
with individual issues for select project sizes by
reviewing the costs based on capacity categories.
For instance, the downstream fish passage capital
costs are vastly different when viewed as
averages for all projects ($958,596 or
$17.39/K.W), averages for projects in the
capacity category 10 to <50 megawatts
($650,025 or $35.45/K.W), and average for
projects <1 MW capacity ($25,911 or
$80.02/K.W).
Generally, the following data show that the
smaller the project, the smaller the average per
project capital cost expenditure to satisfy
downstream fish passage mitigation require-
ments. The dollar per kilowatt of capacity
method also indicates that there is a variation of
costs based on capacity size. The low average
cost of Llte downstream fish passage capital costs
for All projects (141) ($17.39/KW of capacity) is
4-4
a reflection of the low capital cost ($14.05/K.W
of capacity) exhibited by two large projects.
These two projects represent 1,836 MW of
capacity. or 90% of the total capacity of all
projects that provided downstream fish passage
capital costs. It is recommended that the reader
be aware that analyzing the cost data can provide
a variety of results. It is best to view the data by
capacity categories.
The quality of the data presented is based on
the ability of the project owners to accurately
provide the cost information. The data presented
has been filtered for errors and inaccuracies.
Although the authors acknowledge that some of
the data may not be expHcit and exact costs, the
results presented here should be useful to
accurately reflect the costs of mitigation issues
hydropower developers have encountered.
Each project presents a unique .set of
circumstances, and it should be acknowledged
that a developer's specific site may differ from
the characteristics of the projects presented here
(Table 4-3). All of the costs presented here
should be used as a guideline, not a guarentee, of
the types and magnitudes of expenses that may
be encountered in conjunction with the various
mitigation methods.
Mitigation Costs Overview
This section provides an overview of the
average costs reported. None of the 141 projects
in the cost database provided information for
every question. Only 15 projects, for example,
contain DO capital costs. Although it Dight be
assuined that this reflects that only 15 of the 141
projects have DO requirements and associated
capital costs, the reality is that only 15 projects
reported DO capital costs. Twenty-two projects
indicated that they actually had some type of DO
requirements. It is presently· uriknown whether
the 7 projects not indicating any DO capital costs
did not have any DO capital cost, did not know
the DO capital cost, were simply unable to
obtain a breakdown of the DO capital cost for
their project, or did not want to furnish their DO
capital costs.
Table 4-3. Breakdown by capacity category of the physical characteristics of the 141 projects in the
database. Because not all of the 141 projects in the database provided infonnation for every question, the
number of projects reporting data in the table will often be less than 141. The various unit values are
stated in the left hand columns.
<lMW
Total number of projects 35.
Average capacity (KW) 375
Number of projects 35
Average annual energy (MWh) 1,670
Number of projects 34
Average design head (feet) 94
Number of projects 30
Average turbine flow (cfs) 165
Number of projects 29
Capital Costs and Study Costs. The capital
and study costs are provided as average costs per
project (Figure 4-3a) and as average costs per
kilowatt of capacity (Figure 4-3b). Upstream
fish passage mitigation is the most capital
intensive mitigation method. This is due to the
high cost of structures such as fish ladders and
fish elevators. Instream flow and DO mitigation
methods have the ·lowest capital costs. Instream
flows and DO projects report that their capital
costs are often low as they meet mitigation
requirements by flow releases through turbines or
spillways with no mitigation required capital
structures. Downstream fish passage mitigation
has the highest average study cost. This may
reflect the difficulty of detennining the safest
methods to protect fish from the turbines.
The upstream fish passage average capital
costs are influenced by three large projects,
averaging 783 MW capacity each. Removal of
these projects and their $74 million of upstream
fish passage capital costs lowers the average
upstream fish passage capital cost to $421,000.
This ag~n suggests that costs should be
Capacity categories
I to <10 tOto <50 50 to <100 100MW,
MW MW MW and larger
70 25 3 8
3,787 19,804 75,607 389,619
70 25 3 8
18,763 89,813 293,000 1,785,108
4-5
67 25 3 8
177 209 402 153
58 22 3 7
707 3,673 497 41,840
58 23 1 8
examined on the basis of relative plant capacity
size. One project constituted more than half of
the total DO study dollars. Removal of this
512 MW capacity, $307,000 study provides an
average DO study cost of $25,000.
A review of the instream flow study costs
indicates that a single project has a significant
influence on the amplitude of the average cost of
a study. Removal of this $1,083,000 study
results in an average instream flow study cost of
-$67,000.
The downstream fish passage study costs are
greatly influenced by two projects, having
combined study costs of almost $12 million.
The removal of these two projects results in the
remaining 19 projects reporting an average
downstream fish passage study cost of $90,000.
Operation and Maintenance, and Annual
Reporting Costs. The O&M and annual
reporting costs are provided as average annual
costs per project (Figure 4-4a). and as average
mills per kilowatt-hour of energy (Figure 4-4b)
i '
I .\
i
lnstream flows Dissolved oxygen Upstream fish passage
Mitigation methods
----------------------_(~)_-.
Downstream fish
passage
Figure 4-3. Capital and study costs as (a) average cost per project and (b) average cost per kilowatt of
capacity. Costs are provided for each of the four types of mitigation.
....
.... :::::1
Q) 0 ~-7 0.4
(/)-
8 ~ 0.3
&g 0.2
CU.::.!
Q) Q) 0.1
~~ 0 ·e -
• Annual reporting costs
~ Operations and maintenance costs
• Annual reporting costs
~ and maintenance costs
lnstream flows Dissolved oxygen
--...... -. -. -. ~ .. -----... -. -
Upstream fish
passage
Mitigation methods
Downstream fish
passage
Figure 4-4. Annual reporting costs and operation and maintenance (O&M) costs as (a) average cost per
project and (b) average mills per kilowatt-hour of energy per project for each of the four types of
mitigation.
4-6
for each project. Upstream and downstream fish
passage mitigation requirements have the highest
annual reporting and O&M costs.
Upstream fish passage O&M costs contain a
single project representing 90% of the total
reported upstream fish passage O&M costs.
Removal of this single $717,000 project results
in an average upstream fish passage O&M cost
of $9,300. ntis figure is considerably closer to
the other O&M averages. Upstream fish passage
annual reporting costs are considerably larger
than the reporting costs of all of the other
mitigation methods. In fact, the upstream fish
passage costs for annual reporting are almost 13
times more expensive than the downstream fish
passage costs.
Removal of the two projects with the highest
costs produced an average upstream fish passage
annual reporting cost of $7,280. ntis is still the
highest average arulUal reporting cost but
significantly closer to the demonstrated averages
for the other mitigation issues. The two projects
with the highest costs have an average annual
reporting cost of -$108,000. Both of these
projects are in the Pacific Northwest and involve
anadromous fish.
Lost Generation. The concept of lost
generation due to mitigation is controversial. In
some cases, spills required for mitigation may be
a resource that is not available for hydropower
use. There has not been any attempt here to
support either viewpoint of this potential
controversy. The loss generation data is merely
presented as it has been obtained from the
hydropower developers.
Two of the downstream fish passage projects
have combined generation losses of
129,171,000 kWh per year. Removal of these
two projects results in an average downstream
fish passage generation loss of 295,000 kWh per
year. These two projects both use spill flows for
downstream fish passage. They have average
flows of 122,500 cfs. Assuming an average
generation loss of 64,585,500 kWh per year and
an average value of $0.05 per kWh, this
generation loss equates to a $3.2 million yearly
loss for each of these two projects as a result of
downstream fish passage mitigation practices.
Average generation loss varies by mitigation
requirement (Table 4-4). The generation losses
also vary by project capacity (Table 4-5).
lnstream Flow Costs
ntis section contains a breakdown of the costs
associated with instream flow requirements. It
must be recognized that the capital and study
costs may not be for the same projects.
Respondents, for example, may have provided
capital costs for instream flow mitigation only or
study costs for instream flow mitigation only or
Table 4-4. Average generation losses by mitigation issue.
Average
Total kWh Number of Average project project loss
yearly loss projects kWh loss @ $0.05/kWh
Instream flow 119,480,910 48 2.489,186 $124,500
Dissolved oxygen 1,177,520 11 107,047 $5,350
Upstream fish passage 4,488,480 4 1,122,120 556,100
Downstream fish passage 135,066,000 22 6,139,364 $307,000
Total 260,212,910 85 3,061,328 $153,100
4-7
il
. i
r ' ..
I I
! !
>tl ~ I I
i:ii
:I'
,, : ,,
Table 4-5. Breakdown by capacity category and mitigation issue of the average annual generation lost
per project for the 141 projects. Because not all of the 141 projects in the database provided information
for every question. the number of projects reporting data in the table will often be less than 141.
<lMW
Instream flow (kWh/year) 160,938
Number of projects 10
Dissolved oxygen (kWh/year) 46,260
Number of projects 2
Upstream fish passage (kWh/year) 88,480
Number of projects 1
Downstream fish passage (kWh/year) 87,500
Number of projects 8
both capital and study costs for instream flow
mitigation. Four projects have provided capital
costs for instream flow mitigation in the
1 to <10 MW capacity category, but only two
projects provided study costs for instream flow
mitigation in the same capacity category.
Similarly, the O&M costs, and the annual
reporting costs may be for different projects, but
they are also summed. Capital and study costs
for instream flow mitigation are summarized by
project capacity categories in Table 4-6. O&M
and annual reporting costs are summarized in
Table 4-7.
Capital Costs for lnstream Flow
Requirements. A graphical summary
(Figure 4-Sa) is provided in this section, as well
as descriptive narrative detailing the ranges,
averages and project characteristics for instream
flow capital costs.
<1. MW. These projects reported required
release rates from <1 cfs to 230 cfs. Eight of
the projects reported that the release
requirements are required in a diverted reach.
Two projects have release requirements through
the turbines.· One project reports release
Capacity categories
1 to <10 10 to <50 50 to <100 IOOMW
MW MW MW and larger
1,719,600 11 ,4 71,000 4,464,260 0
30 5 2 1
12.500 345,000 N/A 0
4 3 0 2
300,000 100,000 N/A 4,000,000
1 1 0 1
464,444 338,333 N/A 64,585,500
4-8
9 3 0 2
requirements both ·through the turbine and a
diverted reach. Three of the projects either
provided unclear or insufficient data on release
requirement locations. Three projects reported
that they did not experience any additional
capital expenses because of instream flow rele~e
requirements. The largest capital cost, $340,000,
was for a multilevel outlet tower. One project
reported spending $124,000 for a minimum flow
turbine. One project spent $100,000 on a bypass
structure and monitoring equipment, the
proportion of which is unknown. Several
projects monitor flows on an hourly basis with
monitoring equipment whereas other projects
perfonn weekly visual checks. Of the 11
projects reporting if the instream flows are for
objectives other than fisheries, 4 reported they
are for vegetation, 1 reported they are for
recreation and 1 reported instream flows are only
for the benefit of fisheries. Four projects
reported releases are for a combination of
factors, including vegetation, recreation, flushing
sediments, and water quality and temperature.
The eleventh project indicated that the instream
releases are for the flushing of sediments. Three
projects reported that they do not have a capital
cost associated with instream flows. One of
Table 4-6. Average capital and study costs for instream flow mitigation, provided by capacity categories.
Because not all of the 141 projects in the database provided complete information, the number of projects
reporting data in the table will often be less than 141.
1 to <10
<1MW MW
Capital costs:
Average per project $48,008 $38,731
Average per KW capacity $119.53 $9.78
Number of Erojects 14 33
Study costs:
Average per project $14,279 $46,636
Average per KW capacity $24.69 $11.67
Number of Erojects 4 22
Totals:
Average per project $62,287 $85,368
Average per KW capacity $144.22 $21.44
these three capital cost-absent projects releases
minimum flows through the turbine, one releases
minimum flows through a diverted reach, and the
third project's minimum flow requirement of 5
cfs from ·June to March is met by leakage past
the flood gate and its minimum flow of 50 cfs
during April and May is met by overtopping. If
the most expansive capital cost project,
$340,000, is removed from the data set, the
average instream flow capital cost drops from
$48,000 to $26,000 for the <1 MW category.
The average release requirement for projects
reporting release requirements in this category is
14 cfs. Cost Range: $0 to $339,396.
1 to <10 MW. Five projects in this group of
33 projects indicated that they did not have any
capital costs resulting from instream flow release
requirements. Of the projects reporting capital
costs greater than zero, the range was $324 to
$226,264. Known capital costs include $174,000
for fish habitat improvement structures and a
flow measurement gate at one project, and
Capacity category
10 to <50 50 to <100 100MW
MW MW and larger Summary
$183,689 $1,255,378 $0 $99,083
$10.24 $17.14 $0 $5.24
7 2 2 58
$231,452 $1,083,530 N/A $99,756
S10.89 $12.04 N/A $11.66
I 4 1 0 31
$415,141 $2,338,908 N/A $198,839
$21.14 $29.18 N/A $16.90
$25,000 for equipment to constantly record the
water releases at another project. Of the 33
projects in this category, 23 projects released
through the project and 1 project had release
requirements both via the project and a diverted
reach. Twenty-nine projects indicated if the
instream flow releases were for objectives other
than fisheries. Of these 29, 17 indicated fish
protection is the only objective, 3 indicated water
quality is a significant objective, 5 indicated
recreation is a significant objective, and 2
indicated that visual objectives are significant.
Two projects listed a combination of objectives.
Significant objectives means what objectives are .
present other than fisheries and instream flow
releases. meant to enhance or support these
significant, secondary objectives. Several
projects indicated that even when fish protection
is the overriding primary objective for instream
flow releases, other objectives such as water
quality and temperature, recreation, and
vegetation are usually secondary considerations
to some degree that they influence the operation
4-9
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Table 4-7. Average operation and maintenance, and annual reporting costs for instream flow mitigation,
provided by capacity categories. Because not all of the 141 projects in the database provided complete
infonnation, the number of projects reporting data in the table will often be less than 141.
Capacity category
1 to <lO
<1 MW MW
Operation & maintenance:
Average per project $1,833 $5,436
Number of projects 13 27
Average mills per KW capacity 1.28 0.28
Number of (!rojects 12 26
Annual reporting:
Average per project S1,305 $2,121
Number of projects 11 26
Average mills per KW capacity 1.13 0.11
Number of (!IOjects 10 25
Totals:
Average per project $3,138 $7,557
Average mills per KW capacity 2.41 0.38
of the hydroelectric site. The average reported
release requirement for this category of projects
is 111 cfs. Cost Range: $0 to $226,264.
10 to <50 MW. Of the seven projects in this
group, one project reported that it did not have
an associated capital cost. The reported capital
costs range from $0 to $915,000. The median
value is $40,000, considerably lower than the
average of $184,000. Removal of the single
· largest capital cost for instream flow lowers the
average project capital cost to $62;000. Five
projects release instream flows via a diverted
reach, one releases 2,200 cfs through the
turbines, and the seventh project releases
instream flows by both methods. Six of the 7
projects indicate they have release requirements
in addition to fisheries considerations. The
seventh project does not answer this question.
Of the instream release requirements in addition
4-10
10to <50 50 to <100 lOOMW
MW MW and larger Summary
$8,956 $5,122 $0 $4,768
7 1 2 50
0.11 0.04 0 0.07
7 1 2 48
S11,600 $0 $0 $3,381
8 1 2 48
0.14 0.00 0.00 0.46
8 1 2 46
$20,556 $5,122 $0 $8,149
0.25 0.04 0 0.11
to fisheries considerations, water quality or water
temperature are the other objectives, listed four
times, and recreation is the other objective,
mentioned twice. One project . reported that an
objective of instream flow releases is that
wildlife and raptores feed on fish, and this is
supported by the releases. The average reported
release rate is 444 cfs for projects in this
category. Cost Range: $0 to $91S,4SO.
50 to <100 MW. Only two projects reported
having instream flow capital costs in this
capacity range. The two costs are $745.000 and
$1,766,000. The $1,766,000 cost is for a
minimum flow unit. The lower cost project
reported instream flow releases only for fisheries,
whereas the more expensive project listed all
aquatic resources as its instream flow release
objective. Both required releases are via a
diverted reach, with an average release
2000
1500
1000
High •$' (a) Capital costs J ........................................................................................................
Average ..
f-.................................................................................................... .
Low -..... 500 f-................................................. . ................................................. .
0 I _I
1200
1 ooo ~-: ................................................................................ J (b) Study costs I
; 800 ,.. ..................................................................................................... .
:g 600 1-.................................................................................................... .
0
Q) ·e-
a. ...
Q)
f-···'"··""···· ............... .
200 1-· .......................... ..
No data
0 L-------~~~==~--~L-------~----~~~~
35
:~ :::::::::::::::::::::::::::::: :::::::::::::::::::::: j (c) Open~tions and maintenance costs I
; 20 ................................ .
~
0
15 1-............................ . . ... · .............................................. .
10 1-. . . .. • . • • • . • .. • • .. • . .. .. • .. • • ..................... -· .......................................................... .
5 1-................... ; ... --41---.......... . ............ ----······ .. ···· .. ··········
0
50
40 ~ · · · · • · · · · · · · · · · · · · · · · · · · · • · · · · · · · · · · • · · · · · · · · · · · · · · · · · · · · · ·······I (d) Annual reporting costs j
30 r-................................................ .
20 _ ............. · ................................... .
1 o -· .... · .. · ~-· · · · · .... · .... ·· .. I .. ··· ....... '!"!' •• "!"!.-~-.+-.'!'!' .. "!"! .. !"!" .... •• .... •• .... ••••••••••••••••• ........ • .. •••
0
<1 MW 1 to <10 MW 10 to <50 MW 50 to <1 00 MW 100 MW and larger
Capacity categories
Figure 4-5. Range and average costs per project for instream flow mitigation, by project capacity
category. Types of cost shown are (a) capital, (b) study, (c) operation and maintenance (O&M), and
(d) annual reporting. Only one project in the 50 to <100 MW capacity category reported study costs; in
the same capacity category, only one project reported O&M costs. Two projects in the 100 MW and
larger capacity category reported . zero O&M costs, two other projects in the same capacity category
reported zero annual reporting costs, and the single project in the 50 to <100 MW capacity category
reported an annual reporting cost of zero.
4-11
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requirement of 90 cfs. Cost Range: $744,657 to
. $1,766,100.
100 MW and Larger. Neither of the two
projects in this category has any capital costs
because of instream flow releases. They both
release through their powerhouse. One project
has a minimum yearly flow requirement of 3,900
cfs. The average annual flow at this project,
however, is 29,000 cfs. The second project has
a minimum flow requirement of 450 cfs. The
first project's minimum flow objective is for
water quantity, not quality. The second and
smaller project's objectives include water
temperature and quality, recreation, vegetation,
and the flushing of sediment. Cost: $0.
Study Costs for lnstream F'ow
Requirements. A graphical summary
(Figure 4-5b) is provided in this section, as well
as descriptive narrative detailing the ranges.
averages and project characteristics for instream
flow study costs.
<1 MW. The project with the highest study
costs perfonned the following types of studies:
IFIM, HEP, wetted perimeter, and specified flow
duration standard. A second project did not
disclose the reasons for its costs. A third
project, at $1,079, perfonned IFIM, water
temperature, or quality studies. The fourth
project, at $8,634, studied the wetted perimeter.
Cost Range: $1,079 to $43,519.
1 to <10 MW. The seven projects with the
highest costs in this category all perfonned IFIM
studies. The flip side of this is that of the eight
projects with the lowest study costs that included
the kind of studies performed, six projects did
not perform IFIM studies. Although perhaps not
conclusive statistical confinnation of relative
IFIM cost, this association was interesting to
note. Three projects, all performing IFIM
studies, had costs of more than $100,000.
Removal of these three projects' costs results in
an average study cost of $18,870. The project
with the highest study costs in this category, at
$446,794, reported the following breakdown of
costs for performing an IFIM study: biologists,
45%; attorneys, 30%; engineers, 23%; and
4-12
miscellaneous, 2%. Nine projects reported costs
below $10,000. Combinations of single studies
and multiple studies were performed, including
the following: IFIM, HEP, aquatic baseflow
standard, wetted perimeter, water temperature
and quality, and a 1 day field effort series of
controlled releases with federal and state
biologists. Another study, at $10,792. verified
the nonexistence of crayfish on a river reach.
Cost Range: $1,288 to $446,794.
10 to <50 MW. All four projects perfonned
IFIM studies. The highest reponed study costs,
at $767,209, included IFIM and wetted perimeter
studies as well as initial fisheries studies to gain
license approval. Cost Range: $21,584 to
$767,209.
50 to <100 MW. This project's study costs
were for the following studies: wetted perimeter,
Tennant or Montana method, and 4 years of
operational fisheries monitoring study. Cost:
$1,083,530.
100 MW and Larger. There are not any
projects reporting instream flow study costs in
this capacity category. Cost: no data.
Of the 12 projects with the most expensive
study costs in all of the instream flow capacity
categories, 11 projects report performing IFIM
studies exclusively or in conjunction with
another type of study. Of the 161east expensive
projects in all capacity categories, 6 did not
provide study types, 3 perfonned IFIM studies
and 7 did not perfonn IFIM studies.
Operation and tJialntenance Costs for
lnstream Flow Requirements. A graphical
summary (Figure 4-5c) is provided in this
section, as well as descriptive narrative detailing
the ranges, averages and project characteristics
for instream flow O&M costs.
<1 MW. Eight projects in this group of 12
appear to have instream flow requirements in a
diverted reach. The average cost for this group
is $780. Two projects release via the turbines
and 1 of these projects' cost for O&M is $0, and
the other project's cost is $10,792. This second
project uses a multilevel outlet tower for
instream flow releases. Another project has
release requirements downstream of the plant as
well as. in a diverted reach. This project's
reported O&M cost is $574. Cost Range $0 to
$10,792.
1 to <10 MW. Four projects indicate that
their O&M annual costs are $0. It appears that
3 of these 4 projects pass minimum flows via the
powemouse and the fourth via a diverted reach.
The project with the most expensive O&M costs,
at $32,376, has a constant minimum flow, eight
to ten hours a day minimum flows from June
through September, run-of-river releases for
boating on weekends and holidays from
Memorial Day through Labor Day, and run-of-
river releases on weekends after Labor Day.
Seventeen projects have O&M costs below the
average, and 9 projects have O&M costs above
the average. Cost Range: $0 to $32,376.
10 to <50 MW. Three projects have costs
below the group average and four are above the
group average. The only project that releases
exclusively through the powerhouse has an O&M
cost of $0. One project has release requirements
through the powemouse and a diverted reach at
an O&M cost of $17,807. The five projects with
a diverted reach release requirement have an
average O&M cost of $6,977. Cost Range: $0
to $17,807.
50 to <100 MW. The $5,122 O&M cost for
this project is for a minimum flow unit. Cost:
$5,122.
100 MW and Larger. One project has a
minimum flow of 450 cfs and it has an actual
average flow of 9,600 cfs via the turbines. The
second project also releases via the turbines, and
its minimum flows are 3,500 cfs for 3.5 months,
5,000 cfs for 3.5 months, 7,500 cfs for 1 month,
and 10,000 cfs for 1 month. This project's
average annual flow is 29,000 cfs. Neither of
these two projects indicated any O&M costs.
Cost: $0.
Annual Reporting Costs for lnstream Flow
Requirements. A graphical summary
4-13
(Figure 4-5d) is provided in this section, as well
· as descriptive narrative detailing the ranges,
averages and project characteristics for instream
flow annual reporting costs.
<1 MW. Six of the 11 projects in this
category reported they did not have any annual
reporting costs. Two of the six reported not
having any monitoring requirements. One of the
six did not provide sufficient infonnation to
detennine this project's situation. Of the
remaining three projects with $0 costs, all
perfonned visual checks on a weekly basis. One
of these three reported using a reference mark on
a ledge. The project with the highest costs, at
$5,122, reported monitoring a V notch weir in a
diverted reach and the use of an automatic
electronic gauge every 15 minutes. Cost Range:
$0 to $5,122.
1 to <1 d MW. Three projects reported $0
costs. Two of the three did not monitor, and the
third project reported daily monitoring by the
operators but the annual reporting costs were
negligible. The project with the highest costs, at
$10,792, measures fish and habitat quality on a
daily basis. This project also logs flow
measurements, and annual reports are sent to
FERC and fisheries agencies. The project with
the second highest cost, at $7,171, uses a United
States Geological Service instream flow
monitoring station, and the information is
telemetered to a main dispatch station for
real-time, continuous monitoring. Other
measures employed by various projects include
the continuous measurement by a stage recorder,
the measurement of flows four times a year, a
river gauging station downstream of a diversion,
and the recording hourly in the powedl.ouse via
a pressure transmitter of the data, and monthly
summaries of minimum flows. Cost Range: $0
to $10,792.
10 to <50 MW. The project with the most
expensive annual reporting cost, at $42,089,
monitors flow continuously and perfonns an
enumeration of salmon. The second most
expensive cost, at $30,733, is for a project that
perfonns continuous monitoring at the intake and
uses a bypass notch configuration flow meter. A
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single project reports $0 costs. This project
monitors only during ponding, after flashboard
repairs. One project, at $5,396, perfonns salmon
incubation and preemergent sampling. Cost
Range: $0 to $42,089.
50 to <100 MW. It appears some type of
monitoring is perfonned by this project but the
owner estimates an annual reporting cost of $0.
Cost: $0.
100 MW and Larger. One project indicates
some monitoring is done several times during the
fall and winter. The other project perfonns some
monitoring in the tailrace on a varied scheduled.
Cost: $0.
Lost Generation for lnstream Flow
Requirements. It is difficult to ascertain the
practices associated with the generation losses
resulting from instream flow releases. A few
projects reported no losses because releases are
via the turbines. Another project with zero
losses indicated instream flow release
requirements are met by nonnalleakage past the
floodgates. To present more accurate
infonnation for the individual projects would
require more assumptions than we were willing
to make in this initi~ report. Table 4-5 provides
lost generation averages for projects with
instream flow mitigation.
<1 MW. Two projects reported zero losses.
Six of the ten projects reported losses from
16,000 to 70,000 kWh, at an average loss of
48,000 kWh. The entire category's average is
skewed by the largest project Loss Range: 0 to
1,125,000 kWh.
·1 to <10 MW. Five projects report 0 kWh
losses. Twelve projects reported generation
losses in excess of one million kWh. Loss
Range: 0 to 13,960,000 kWh.
10 to <50 MW. Loss Range: 450,000 to
32,205,000 kWh.
50 to <100 MW. Loss Range: 2,728,520 to
6,200,000 kWh.
4-14
100 MW and Larger. Loss Range: 0 kWh.
Dissolved Oxygen Costs
This section contains a breakdown of all costs
associated with DO mitigation requirements. It
must be recognized that the capital and study
costs may not be for the same projects. For
example, respondents may have provided capital
costs for DO only or study costs for DO only or
. both capital and study costs for DO. Four
projects have provided capital costs for DO in
the 1 to <10 MW capacity category, but only
two projects provided study costs for DO in the
same capacity category. Similarly, the O~M
costs and the annual reporting costs may be for
different projects, but they are also summed.
Capital and study costs for DO mitigation are
summarized by project capacity categories in
Table 4-8. O&M and annual reporting costs are
summarized in Table 4-9.
Capital Costs for Dissolved Oxygen
Mitigation. A graphical summary (Figure 4-6a)
is provided in this section, as well as descriptive
narrative detailing the ranges, averages and
project characteristics for DO mitigation capital
costs.
<1 MW. Only one project reported a DO
requirement in the < 1 MW class. The reason for
the capital costs is unknown. The DO
requirement is ~5.0 mg/1 or equal to the DO
level in the upstream reach when it is <5.0 mg/1.
When mitigation is necessary, this project stops
the turbine and measures the DO level in the
bypass reach. Cost: $1,099.
1 to <10 MW. The four projects in this
category have an average DO · capital cost of
$29,925. One project noted that its DO capital
cost was for the purchase of a DO meter. Two
projects noted DO requirement levels of 5.0
mg/1, and a third project had a 6.0 ppm DO
requirement. Two projects use spill flows when
necessary to raise the DO levels. The third
project uses spray devices, aeration in the
turbine, and aeration of the weir in the discharge
channel The fourth project, while having a DO
Table 4-8. Average capital and study costs for dissolved oxygen mitigation, provided by capacity
categories. Because not all of the 141 projects in the database provided complete infonnation, the number
of projects reporting data in the table will often be less than 141.
1 to <10
<1 MW MW
Capital costs:
Average per project $1,099 $29,926
Average per KW capacity $7.33 $9.48
Number of (!rojects 1 4
Study costs:
Average per project $1,000 $33,940
Average per KW capacity $2.50 $13.42
Number of (!rojects 1 2
Totals:
Average per project $2,099 563,866
Average per KW capacity $9.83 522.89
requirement level of 5.0 mg/1, has never had DO
levels below this minimum since 1975, and there
was not any indication of the type of action that
would be used if DO minimums were to fall to
unsuitable levels. Cost Range: $0 to $107,921.
10 to <50 MW. The DO requirements
generally range from 4.0 mg/1 to 6.0 mg/1. The
6.0 mg/1 DO requirement on one project was
required only if the water temperature was higher
than HfC. One project is required to measure
DO levels only if river flow is below 300 cfs.
(The average river flow is 2,500 cfs).
Thisproject would employ spill flows as would
most projects in this capacity category. One
project uses aeration in the turbine and uses spill
flows when the aeration is insufficient to meet
minimum DO requirements of 5.5 mg/1 for 4
months a year and 5.0 mg/1 the other 8 months.
Cost Range: $0 to $62,170.
50 to <100 MW. The single project in this
class has a 5.0 mg/1 DO requirement that is met,
Capacity category
10 to <50 50 to <100 lOOMW
MW MW and larger Summary
$19.375 $11,191 $1,079,352 $161,754
$1.11 S0.14 $3.49 $2.91
7 1 2 15
$25,654 N/A 5307,328 $50,526
$1.06 N/A $0.60 $0.81
7 0 1 11
$45,029 N/A $1,386,680 $212,280
52.17 N/A $4.09 $3.72
when action is required, by shutting off the flow
through the plant. Cost: $11,191.
4-15
100 MW and Larger. These two large
projects both have DO requirements of 5.0 mg/1.
At one of these projects the 5.0 mg/1 requirement
is the average daily minimum requirement and
4.0 mg/1 is the absolute DO minimum. This
project uses turbine aeration to met DO
requirements. The second project employs the
following practices, when necessary and in the
stages listed, to meet DO requirements: First, the
turbine aeration systems present in the six of
seven units are acti~ated; second, the project
continues turbine aeration and shuts down the
nonaerated seventh unit; third, when steps one
and two fail, this project will shut down all
seven units and spill water via a regulating gate
at a rate of 4,000 cfs. This project noted that it
can also employ intake aeration, but it was
unclear when this practice is employed. Cost
Range: $109,854 to $2,048,851.
1., ':
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Table 4-9. Average operation and maintenance, and annual reporting costs for dissolved oxygen
mitigation, provided by capacity categories. Because not all of the 141 projects in the database provided
complete information, the number of projects reporting data in the table will often be less than 141.
1 to <10
<1MW MW
Operation & maintenance:
Average per project $706 $1,420
Average mills per KW capacity 0.77 0.12
Number of projects 1 3
Annual reporting:
Average per project $1,413 $1,941
Average mills per KW capacity 1.54 0.16
Number of projects 1 3
Totals:
Average per project S2,119 S3,361
Average mills per KW capacity 2.30 0.28
Study Costs for Dissolved Oxygen
Mitigation. A graphical summary (Figure 4-6b)
is provided in this section, as well as descriptive
narrative detailing the ranges, averages and
project characteristics for DO mitigation study
costs.
<1 MW. This project has had both pre-and
postlicense studies done. It is unknown what the
cost represents. Cost: $1000.
1 to <10 MW. Both of these projects had
identical study costs, and neither performed
prelicensing studies. Both projects performed
postlicensing DO and water temperature studies.
Cost: $33,940.
10 to <50 MW. The project with the highest
study cost, at $83,718, conducted prelicensing
studies in conjunction with a state resources
agency. The DO, water temperature, pH, and
specific conductance were all measured. Five of
the study costs in this category were
4-16
Capacity category
10 to <50 50 to <100 100MW
MW MW and larger Summary
$4,204 $4,610 $5,396 $3,415
0.05 0.01 <0.01 0.03
7 1 1 13
$3,556 $512 $19,668 $5,141
0.03 <0.01 0.02 0.02
7 1 2 14
$7,760 $5,122 $25,064. $8,556
0.08 0.01 0.03 0.05
postlicensing studies. Four of the five measured
DO and water temperature levels. Cost Range:
$3,238 to $83,718.
50 to <100 MW. There are not any projects
reporting DO study costs in this capacity
category. Cost: no data.
100 MW and Larger. Only one project of
this magnitude provided study costs. DO and
water temperature studies were funded. Cost:
. $307,328.
Operation and Maintenance Costs for
Dissolved Oxygen Mitigation. Little
information was available that explained what
the DO O&M costs encompassed. It is generally
not known if the O&M costs are for the facilities
to actually maintain DO levels or for another
purpose such as the O&M of monitoring
equipment. It is assumed here that the O&M
costs are for the facilities to maintain minimum
DO levels. However, in either case the costs
2500 ~----------------------------------------------------~
2000 ._j(a) Capital costs I .............................................. ~~~~-, ...... ~-.............. .
1500 1-.......................................................................................... . ........ .
1000
Average--.... 1-.......................................................................................... . ........ .
500 1-........................................................................... 1:-R"l'. ·x ............ .
0
350
300 (<b) Study costs l· · · · .. · · · · · · · .. · · .. · .. · .. · .... · .. · · · · · · · · · · · · · .. · · · · .. · · · · · · · · · · · · · · · · · · · · · ....
250 -Cl) 200 ... ~
0 150 "0 -100 0
Cl)
"0 50 c:
Cd
Cl) 0 :::1
. . .. . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . . . . . .. .. . .. . . . . . .. . .................................................... .
No data
0 .r:. 14 .::.
u 12 Q)
"0' 10 _j(c) Operations and maintenance costs l::: ::::::::::::::::::::::::::::::::::::::::::::::::::: ... c. 8 ...
Q) c. 6 j!3
4 Cl)
0
0 2
-................... • ............................. . .. ....................................................... .
···········································--+--············································· .............. ._ .............. I ................. .
0 I
40
30 I (d) Annual reporting costs I ...................................................... .
20 1-................................................................................... ---~~--
10 1-................................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ .
0
<1 MW 1 to <10 MW 1 0 to <50 MW 50 to <1 00 MW 100 MW and larger
Capacity categories
Figure 4-6. Range and average costs per project for dissolved oxygen (DO) mitigation, by project
capacity category. Types of cost shown are (a) capital, (b) study, (c) operation and maintenance, and
(d) annual reporting. Only one project in both the <1 MW and in the 50 to <100 MW capacity categories
reported capital costs; only one project in both the <1 MW and in the 100 MW and larger capacity
categories reported study costs. Both projects in the 1 to <10 MW capacity category reported the same
study costs. Only one project in each of the <1 MW, the 50 to <100 MW, and the 100 MW and larger
capacity categories provided O&M costs. Only one project in both the <1 MW and in the 50 to <100
MW capacity categories reported annual reporting costs.
4-17
presented are costs that are imposed on the
owner because of DO mitigation requirements.
A graphical summary (Figure 4-6c) is provided
in this section, as well as descriptive narrative
detailing the ranges, averages and project
characteristics for DO mitigation O&M costs.
<1 MW. Only one project fit this category.
This project did not have to take any action to
meet minimum DO requirements. The
mitigation method that would be employed, if
necessary, is not mentioned. Cost: $706.
1 to <10 MW. One project, with $0 costs,
has a minimum DO level, but no DO levels
below the minimum have been measured since
1975. It is unknown what type of methods
would be employed if necessary. The other two
projects both use spill flows, and the higher cost
project also uses aeration in the turbine and an
aeration weir in the discharge channel. Cost
Range: $0 to $3,237.
10 to <50 MW. All seven projects use spill
flows when action is required to maintain
minimum DO levels. One project, with a yearly
O&M cost of $4,856, employs turbine aeration
as well as spill flows. The $0 cost project has
not needed to employ spill flows as the DO
minimum level has not be attained. The removal ·
of the highest cost project, at $12,293, reduces
the average for the remaining six projects to
$2,856. This would result in a distribution of
three projects below and three projects above the
average. Cost Range: $0 to $12;293.
50 to <100 MW. This single project shuts
off flow through the plant when necessary to
maintain DO requirements. Cost: $4,610.
100 MW and Larger. The single project
providing O&M costs reported using turbine
aeration as its DO mitigation method. Cost:
$5,396.
Annual Reporting Costs for Dissolved
Oxygen Mitigation. A graphical ' summary
(Figure 4-6d) is provided in this section, as well
as descriptive narrative detailing the ranges,
4-18
averages and project characteristics for DO
mitigation annual reporting costs.
<1 MW. Cost: $1,413.
1 to <10 MW. Cost Range: $1,024 to
$3,073.
10 to <50 MW. One of the projects in this
group of seven reports an annual reporting cost
of $0. This project is required to monitor DO
levels when the minimum flow drops below 300
cfs. Spill flows would be used for mitigation if
necessary. However, the project has a minimum
instream flow requirement of 300 cfs, and
consequently, they do not currently monitor DO
levels. The project at the high end of the cost
range, at $12,293, measures DO levels at the
intake and tailrace. Continuous .meters that
record on a chart and translation by hand are the
methods used by the project operator at this
second project. . This process is done on a daily
basis. Cost Range: $0 to $12,293.
50 to <100 MW. This project reports that
DO levels are measured hourly, and the data is
stored in a computer system. It is unknown if
the data is measured manually or by computer.
The low reported cost for annual reporting and
monitoring conflicts with the indication ·that
measurements are taken hourly. It may be that
the computer time is not included in the costs, or
the $512 represents the time to compile a report
on monitoring but not the actual cost of
monitoring itself. The actual situation is
unknown, and the $512 figure should be used
cautiously. Cost: $512.
100 MWand Larger. The project with the
annual reporting cost of $33,940 measures DO
levels every 15 minutes during the May to
October period. This project provides data to its
state Department of Natural Resources and the
state Department of Energy. The other project in
this group, reporting costs of $5,396, measures
DO levels in the tailrace using continuous
monitors from May tluOugh October. Cost
Range: $5,396 to $33,940.
Lost Generation for Dissolved Oxygen
Mitigation. Table 4-5 provides lost generation
averages for projects with_DO mitigation.
<1 MW. The project with the 17,520 kWh
generation loss maintains a half-inch spill flow
over its dam for DO and aesthetic reasons. The
75,000 kWh loss is associated with a 3 cfs spill
flow. Loss Range: 17,520-75,000 kWh.
1 to <10 MW. Three projects report 0 kWh
generation losses. Two of these three projects do
not have to take mitigation .. action to meet DO
levels. . One of the projects indicates that DO
levels have not fallen to the minimum level since
1975. No information is provided for the
circumstances associated with the third, 0 kWh
generation loss or the project with the 50,000
kWh generation loss. Loss Range: 0 to
50,000 kWh.
10 to <50 MW. One project reports 0 kWh
losses because no mitigation ~ction was taken as
DO levels are acceptable. The 35,000 and 1
million kWh losses at two projects are for spill
flows. Loss Range: 0-1 million kWh.
50 to <100 MW. There are not any projects
reporting DO generation losses in this capacity
category. Loss: no data.
100 MW and Larger. Both projects use
turbine aeration when necessary for DO
mitigation. Loss: 0 kWh.
Upstream Fish Passage Costs·
1bis section contains a breakdown of all of
the costs associated with upstream fish passage
mitigation. It must be recognized that the capital
and study costs may not be for the same
projects. For example, respondents may have
provided capital costs for upstream fish passage
only_ or study costs for upstream fish passage
only or both capital and study costs for upstream
fish passage. Four projects have provided capital
costs for upstream fish passage in the 1 to < 10
MW capacity category, but only two projects
provided study costs for upstream fish passage in
4-19
the same capacity category. Similarly, the O&M
costs and the annual reporting costs may be for
different projects, but they are also summed.
Capital and study costs for upstream fish passage
are summarized by project capacity categories in
Table 4-10. O&M and annual reporting costs
are summarized in Table 4-11.
Capital Costs for Upstream Fish Passage.
A graphical summary (Figure 4-7a) is provided
in this section, as well as descriptive narrative
detailing the ranges, averages and project
characteristics for upstream fish passage capital
costs.
<1 MW. The one project in this class uses a
fish ladder for its upstream fish passage
requirements. Cost: $42,721.
1 to <10 MW. The three projects in this
class all employ fish ladders. The costs are
$22,000, $43,000, and $183,000. The project
with the $22,000 capi~ cost for upstream fish
passage has a design head o~ 244 feet and an
average annual flow of 42 cfs. The project with
the $43,000 cost did not provide design head or
flow information. The project with a cost of
$183,000 has a design head of 33 feet and an
average flow of 500 cfs. Although the flow size
for the $183,000 project is larger than the
$22,000 project, no correlation should be drawn
from such a limited sample of two projects.
However, it may be worthwhile to investigate
correlations between capital costs and flow r:ates
and/or design head during future analysis. Cost
Range: $21,584 to $183,090.
10 to <50 MW. Of these six projects. two
projects use fish ladders at an average capital
cost of $380,000; two projects use fish elevators
at an average cost of $1.5 million; one project is
currently trapping and hauling fish with a truck
at a capital cost of $154,000 while designing a
fish ladder to replace this method; and the sixth
project is using navigation locks which are
operated by the state and are opened
approximately seven times a day during
navigation season. The opening of the locks is
dependent on boat traffic, and the locks were
installed for transportation. The blue back
-,··
~ , I,
j:f,
I ~ . :
!::1' :1 ,•'
'!: ';I
I .!i
:ill
1\1 '! i
,, I
'I
!:I; ,,
Table 4-10. Average capital and study costs for upstream fish passage mitigation, provided by capacity
categories. Because not all of the 141 projects in the database provided complete infonnation, the number
of projects reporting data in the table will often be less than 141.
1 to <10
<lMW MW
Capital costs:
Average per project $42,721 $82,614
Average per KW capacity $106.80 $72.49
Number of [!rejects 1 3
Study costs:
Average per project $3,238 $36,280
Average per KW capactiy $8.10 $31.83
Number of Erojects 1 3
Totals:
Average per project $45,959 $118,894
Average per KW capacity $114.90 $104.32
herring at the project thaf uses navigation locks
for upstream fish passage are not naturally
present; they were introduced by lock operators.
An upstream capital cost of $22,oo0 is reported
for this project. It is highly doubtful that this is
the cost of the locks, and no infonnation was
provided to indicate what this cost represents.
Cost Range: $21,584 to $1,810,113.
50 to <100 MW. There are not any projects
reporting upstream capital costs in this capacity
category. Cost: no data.
100 MW and Larger. Two of these three
projects employ fish ladders. These projects
have average flows of more than 100,000 cfs.
One project has three fish ladders on-site, and
the second project has a single fish ladder. The
average upstream fish passage capital cost for
these two projects is $30 million. The third
project reporting capital costs in this category
employs fish elevators as part of its trapping and
hauling system. The fish are trucked around
Capacity category
10 to <50 50 to <100 100MW
MW MW and larger Summary
$653,997 N/A $24,745,007 $6,034,582
$35.09 N/A $31.62 $31.85
6 0 3 13
$97,786 N/A N/A $51,275
$5.99 N/A N/A $8.43
2 0 0 6
$751,783 N/A N/A $6,085,857
$41.08 N/A N/A $40.28
three other upstream dams. The capital cost of
$15 million for this third project includes the two
fish elevators used to raise the fish to sorting
tanks. Cost Range: $14,597,040 to
$37,093,227.
Study Costs for Upstream Fish Passage.
A graphical summary (Figure 4-7b) is provided
in this section, as well as descriptive narrative
detailing the ranges, averages and project
characteristics for upstream fish passage study
costs.
<1 MW. This project did not provide study
type infonnation. Cost: $3,238.
1 to <10 MW. Of these three projects one
did not provide study type data. At a second
project, with a study cost of $2,698, the licensee
and state fisheries agency perfonned fisheries
studies. The third project. at $100,745,
perfonned fisheries studies with the National
Marine Fisheries Service and the state fish and
4-20
Table 4-11. Average operation and maintenance and annual reporting costs for upstream fish passage
mitigation, provided by capacity categories. Because not all of the 141 projects in the database provided
complete infonnation, the number of projects reporting data in the table will often be less than 141.
Capacity category
1 to <10
<lMW MW
Operations & maintenance:
Average per_project $2,158 $9,308
Number of projects 1 3
Average-mills per kWh
capacity 2,158.00 2.26
Number of Erojects 1 2
Annual reporting:
Average per project $1,619 $3,853
Number of projects 3
Average mills per kWh
capacity 1,619.00 1.16
Number of (!!Ojects 1 2
Totals:
Average per project $3,777 $13,161
Average per KW capacity 3,777.00 3.42
wildlife department Cost Range: $2,698 to
$100,745.
10 to <50 MW. The highest cost project
perfonned a mitigation study and the other
project did not provide study infonnation. Cost
Range: $5,122 to $190,451.
50 to <100 MW. There are not any projects
reporting upstream fish passage study costs in
this capacity category. Cost: no data.
100 MW and Larger. There are not any
projects reporting upstream fish passage study
costs in this capacity category. Cost: no data.
Operation and Maintenance Costs for
Upstream Fish Passage. A graphical
4-21
10 to <50 50 to <100 lOOMW
MW MW and larger Summary
$9,918 N/A $717,080 $79,675
5 0 1 10
0.12 N/A 0.41 0.37
4 0 3 10
$7,964 N/A $78,536 $25,513
4 0 3 11
0.11 N/A 0.02 0.03
4 0 3 to·
$17,882 N/A $795,616 $105,188
0.23 N/A 0.43 0.39
summary· (Figure 4-7c) is provided in this
section, as well as descriptive narrative detailing
the ranges, averages and project characteristics
for upstream fish passage O&M costs.
<1 MW. This project uses a fish ladder.
Cost: $2,158.
1 to <10 MW. All three of these projects use
fish ladders. No specific evidence was present to
indicate the reasons behind the range span. Cost
Range: $944 to $21,584.
10 to <50 MW. Of these five projects, one
uses a fish ladder at a yearly O&M cost of
$1,024. Two projects use elevators at respective
costs of $21,584 and $5,396. The founh project
uses a trapping and hauling system at a yearly
40,000
30,000
20,000
I (a) capital costs [. ................................. ·;,~;=~~ ... ~. ·t-...... ..
············ ······ ······ ·········································· ······c.aw·~· ··········
10,000
0
200
150 . 1-l (b} Study costs l.. ...................... .
~ 0 100 1-........................... . ············--4.,_._ .......................................... .
"t:l -0
"'
50 1-.•..•..•..•..•.....••.•••••.
~
"' ::1
0
§.
0
t) 800
Q) .§'
0.. 600 ...
Q)
Nn rl~t~ No data
I (c) Operations and maintenance costs l .................................................. .
0.. 400 .............•.....•.....•.........................•...•..........••..............•.....•..........
~ 0 200 ....••.•....•.....................•...............•.•..•................................••...... ; ..
0 Nod a
200 ~ I (d) Annual reporting costs I 150 r .................................................... .
100 ~-...................................................................................... .
50 1-······ .. ··•• .......................................................................... .
0 . No data
<1 MW 1 to <10 MW 1 0 to <50 MW 50 to <1 00 MW 1 00 MW and larger
Capacity categories
Figure 4-7. Range and average costs per project for upstream fish passage mitigation. by project
capacity category. Types of cost shown are (a) capital. (b) study, (c) operation and maintenance, and
(d) annual reporting. Only one project in the <1 MW capacity category provided capital costs. Only one
project in the <1 MW capacity category provided study costs. Only one project in both the <1 MW and
in the 100 MW and larger capacity categories provided O&M costs. Only one project in the <1 MW
capacity category provided annual reporting costs.
4-22
O&M cost of $21.584. The fifth project reports
a yearly O&M cost of $0. The upstream fish
passage facility for this fifth project is a
navigation lock. The operation of which is
dependent on the amount of boat traffic for its
operation schedule. The opening of the lock to
allow upstream boat passage is the only way the
blueback herring have of passing upstream.
Cost Range: $0 to $21,584.
50 to <100 MW. There are not any projects
reporting upstream fish passage O&M costs in
this capacity category. Cost: no data.
100 MW and Larger. This project uses a
fish elevator to raise the fish 40 feet to a sorting
tank where biologists sort the fish to be hauled
by truck upstream around this project as well as
three additional upstream dams. This upstream
fish passage facility is operated 6 hours per day,
2.5 months per year. Cost: $717,080.
Annual Reporting Costs for Upstream
Fish Passage. A graphical summary
(Figure· 4-7d) is provided in this section, as well
as descriptive narrative detailing the ranges,
averages and project characteristics for upstream
fish passage annual reporting costs.
<1 MW. This project checks the fish ladder
once a month and logs fish passage rates. Cost:
$1,619.
1 to <10 MW. The project with the $0 cost
does not perform any monitoring. The project
with the highest cost, at $10,792, monitors the
fish passage rates. The third project did not
disclose the reasons for its costs. Cost Range:
$0 to $10,792.
10 to <50 MW. The project at the high end
of the range monitors the fish passage rates and
populations. The project at the low end of the
cost range reports on its trapping and hauling
program. Of the other two projects in this
category, one perfonns hydro-acoustic
monitoring of passage rates and the other project
stated it also monitors passage rates. Cost Range
$2,158 to $12,805.
4-23
50 to <100 MW. There are not any projects
reporting upstream fish passage O&M costs in
this capacity category. Cost: no data.
100 MW and Larger. The project at the low
end of the cost range monitors fish passage rates
and population size. The middle cost project, at
$61,456, monitors fish passage rates with a fish
counting program running from April through
November. This is done to evaluate the
upstream fish passage design. The $61,456 cost
also includes the counting of the anadromous and
resident fish populations, and an annual fish
facility operations report is filed. This project,
which is located in the Pacific Northwest, uses a
fish ladder. The project with the highest cost, at
$153,664, is located in the Northeast. It has an
annual fish passage counting program for April
through November. Fish populations are also
counted. Passage and population rates are
counted for the evaluation of operating
procedures. Cost Range: $20,488 to $153,664.
Lost Generation for Upstream Fish
Passage. Little information was obtained
concerning generation losses and upstream fish
passage mitigation association. Additionally,
with a single project or no project in each
category, reporting the range is superfluous.
Table 4-5 provides lost generation averages for
projects with upstream fish passage mitigation
requirements.
Downstream Fish Passage Costs
This section contains a breakdown of all costs
associated with downstream fish passage
mitigation. It must be recognized that the capital
and study costs may not be for the same
projects. Respondents, for example, may have
provided capital costs for downstream fish
passage only or study costs for downstream fish
passage only or both capital and study costs for
downstream fish passage. Four projects have
provided capital costs for doWnstream fish
passage in the 1 to <10 MW capacity category,
but only two projects provided study costs for
downstream fish passage in the same capacity
,··
category. Similarly, the O&M costs and the
annual reporting costs may be for different
projects, but they are also summed. Capital and
study costs ·for downstream fish passage
mitigation are summarized by project size
category in Table 4-12. O&M and annual
reporting costs are summarized in Table 4-13.
Capital Costs for Downstream Fish
Passage. A graphical summary (Figure 4-8a)
is provided in this section, as well as descriptive
narrative detailing the ranges, averages and
project characteristics for downstream fish
passage mitigation capital costs.
<1 MW. Twelve projects fit this category,
with an average capital cost of $26,000.
However, seven projects report capital costs less
than $8,000. Three projects report costs of less
than $1,000. These three projects use angle bar
racks to project fish from turbine entrainment.
Two of these three angle bar rack facilities are
for the protection of resident adult fish, and the
third project protects anadromous adults. The
median cost for all12 projects is $5,000. Four
of the 12 projects report costs over the $26,000
average. The average design head for the entire
group is 159 feet and the average flow is 70 cfs.
Of the 12 projects in the <1 MW capacity
category, 4 projects use only angle bar racks; 4
use angle bar racks in conjunction with another
measure such as sluiceways/bypasses (2
projects), velocity limits (1 project), or angle bar
racks and wedge wire 1/8-inch screens with
traveling cleaning brushes. Two projects use .
other screens such as stationary screens ( 1
project), wedge wire cylinder screens (1 project),
and velocity limits. Eight of the projects employ
downstream fish passage facilities for resident
fish, one for anadromous fish, and three projects
provide protection for both resident and
anadromous fish. Cost Range: $416 to
$122,060.
Table 4-12. Average capital and study costs for downstream fish passage mitigation, provided by
capacity categories. Because not all of the 141 projects in the database provided complete information,
the number of projects reporting data in the table will often be less than 141.
Capacity category
1 to <10 10 to <50 50 to.<lOO 100MW
<lMW MW MW MW and larger Summary
Capital costs:
Average per project $25,912 $277,125 $650,025 N/A $12,900,020 $958,596
Average per KW capacity $80.02 $77.24 $35.45 N/A $14.05 $17.39
Number of J:!rojects 12 15 8 0 2 37
Study costs:
Average per project $9,848 $80,047 $198,824 N/A $5,850,713 $638,887
Average per KW capacity $21.24 $22.87 $10.94 N/A $6.37 $6.88
Number of J:!rojects 4 11 4 0 2 21
Totals:
Average per project $35,760 $357,172 S848,849 N/A $18,750,733 $1,597,483
Average per KW capacity $101.25 $100.11 $46.39 N/A $20.43 $24.27
4-24
Table 4-13. Average operation and maintenance, and annual reporting costs for downstream fish passage
mitigation, provided by capacity categories. Because not all of the 141 projects in the database provided
complete infonnation, the number of projects reporting data in the table will often be less than 141.
Capacity category
I to <10
<lMW MW
Operation & maintenance:
Average per project $4,486 5-11,182
Number of projects 11 13
Average mills per KW capacity 2.92 0.69
Number of J.!rojects 11 11
Annual reporting:
Average per project 51,058 51,640
Number of projects 8 10
Average mills per KW capacity 1.10 0.11
Number of Erojects 8 9
Totals:
Average per project $5,544 $12,822
Average mills per KW capacity 4.02 0.81
1 to <10 MW. Of these 15 projects, -3
projects use sluiceways or bypasses exclusively
to satisfy downstream fish passage requirements,
2 projects use screens meeting the California
Department of Fish and Game screen standards,
and 4 projects use another type of fish screen.
One project has modified its sequence of
operating its three units (2 Kaplans and 1
Francis) to protect fish. Five projects use a
combination of methods such as angle bar racks
and other screens or a velocity limit on intake
screens. One project employs angle bar racks, a
velocity limit on intake screens, and sluiceways
or bypasses, all at a reported capital cost of
$3,238. This project's protection facilities are
designed for resident fish. The most expensive
facility, at $2,374,268, employs angle bar racks
and a velocity limit on intake screens to protect
both anadromous and resident juvenile fish.
Eight projects employ facilities to protect
4-25
10 to <50 50 to <100 lOOMW
MW MW and larger Summary
$31,443 N/A N/A 513,946
8 0 0 32
0.41 N/A N/A 0.52
87 0 0 30
$4,157 N/A N/A $1,985
5 0 0 23
0.06 N/A N/A 0.09
5 0 0 22
$35,600 N/A N/A $15.931
0.47 N/A N/A 0.62
resident fish, four to protect anadromous fish,
two to protect boUl types and one project's
protection intents are unknown.
The average for this category ($277 ,125) is
heavily influenced by a single project.
Removing the largest project's cost of
$2,374,268 produces an average of $127,329. At
the actual average of $277,125, the dispersal of
costs is skewed with 12 projects under the
average and three over. At the reconfigured
$127,329 average, eight projects are under the
average and six are. above the average. Initial
observation does not lead to a correlation
between costs and methods employed. The
$3,238 cost project employs angle bar racks,
velocity limits, and sluiceways or bypasses. The
$2,374,268 project employs angle bar racks and
velocity limits on intake screens. Future analysis
may provide greater insight into the relationship
16,000
14,000
12,000
10,000
8,000
J (a) Capital costs J '· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ~i-~~ · · ~-· · • · · · · · · · · • ·
·····I I··············· I · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·······"Average··~······· .l. · · · · · · ·; · ......................................... ······· ................................. ·-;#-· .......... .
Low
6,000
4,000
2,000
0 Nod ta
8,000
6,000 -~ 4,000
l<b) Studycosts I + .................................................................................................... -. .. .. .. . . ...
0
"C -~ 2,000
"C c:
ctl
1/'i 0 ::I
Nod ta
0
§. 120 -(.)
Q) 100 "i5' f-1 (c) Operations and maintenance costs J .................................................... .
.... a. 80 ....
Q)
~................................................. . ................................................. .
a.
.!!! 60 ~................................................. . ......................................... ~ ....... .
1/'i
0
(.) 40 ~............................. . . . . . . . . . . . . . . . . . . . . ................................................. .
20
0
~........ .•. . . . . . . . . . . . . . . . . . . . ................. .
No data No data
12
. 10 ~ (d) Annual reporting . . . .......................•..•.....•..............•........•.............
costs
8 ~............................. . ..................................................................... .
6
4
2 ::::::::::.:::::::::::.::::::: :::::::::.:: r::.: :::::::.::.:::::::::::::::::::::::::::.:
0 No data No data
<1 MW 1 to <1 0 MW 1 0 to <50 MW 50 to <1 00 MW 1 00 MW and larger
Capacity categories
Figure 4-8. Range and average costs per project for downstream fish passage mitigation, by project
capaCity category. Types of cost shown are (a) capital, (b) study, (c) operation and maintenance, and
(d) annual reporting.
4-26
among costs, methods used and benefits. Cost
Range: $0 to $2,374,268.
10 to <50 MW. The most expensive
mitigation cost in this category is almost three
times more expensive than the next expensive
downstream fish passage cost Removal of this
single $2.807,381 cost lowers the average to
$341,832. This project uses as its downstream
protection facility a static angled wedge wire
screen, sluiceways or bypasses, and a velocity
limit on intake screens to protect anadrornous
and resident fish. The lowest cost facility
employs barrier nets, at $92,996, for downstream
protection of resident Kokanee. One product
employs a punch plate and overflow screening
device, at $614,655, to protect resident fish. One
project uses sluiceways or bypasses, at $215,843,
to protect anadromous and resident fish. Five
projects, including the most expansive project,
apply a combination of methods, including angle
bar racks, velocity limits, sluiceways or bypasses,
and fish screens for downstream fish passage.
Cost Range: $92,996 to $2,807,381.
50 to <100 MW. There are not any projects
reporting downstream fish. passage capital costs
in this capacity category. Cost: no data.
100 MW and Larger. Only two projects,
employing similar downstream fish passage
methods, indicated they have capital costs as a
result of downstream fish passage requirements.
The cost range reflects the relative similarity in
characteristics. Both projects report that the
capital costs are for fish hatcheries that are the
imposed downstream fish passage mitigation
requirement. Additionally, both projects indicate
fish screens are being developed and prototypes
have been tested. Both employ spill flows, one
project for 12 hours per night, at 20% of the
daily average flow, during the period from April
20 to June 1. The second project spills 10 hours
per night. at 10% of daily average flow, from
April 20 to May 20. Both projects indicated
their imposed downstream fish passage
requirements are for juvenile anadromous fish.
Cost Range: $12,022,430 to$ 13,777,611.
4-27
Study Costs for Downstream Fish
Passage. A graphical summary (Figure 4-8b)
is provided in this section, as well as descriptive
narrative detailing the ranges, averages and
project characteristics for downstream fish
passage mitigation study costs.
<1 MW. Minimal specific infonnation
detailing the activities associated with
downstream fish passage study costs was
accumulated. Any pertinent infonnation
provided by the respondents will naturally be
conveyed. Cost Range: $3,238 to $21,584.
1 to <10 MW. One project's study costs, at
$16,970, was to study the mortality rates of
brown trout passing through the downstream
bypass facility. The highest cost study, at
$281.428, was a licensee-conducted study of the
turbine impact on fish passage. Another study,
at $102,443, used radio telemetry to measure the
percentage of srnolts bypassing the turbine. Cost
Range: $5,657 to $281,428.
10 to <50 MW. Of these four projects only
one, with a study cost of $259,515, indicated the
type of study perfonned. This project used
hydro acoustics, with a fixed beam in the
penstock, to scan the intake/bypass area. Cost
Range: $18,428 to $455,888.
50 to <100 MW. There are not any projects
reporting downstream fish passage study costs in
this capacity category. Cost: no data.
100 MW and Larger. The $4,408,831 study
cost includes hydro acoustic studies of spill
efficiency, powerhouse passage, and
orifice/bypass channel efficiency. The other
study cost was for hydro acoustic studies of spill
.efficiency and powerhouse passage. Cost
Range: $4,408,831 to $7,292,595.
Operation and Maintenance Costs for
Downstream Fish Passage. A graphical
summary (Figure 4-8c) is provided in this
section, as well as descriptive narrative detailing
the ranges, averages and project characteristics
for downstream fish passage mitigation O&M
costs.
<1 MW. · The majority of these projects
employ angle bar racks or angle bar racks and
sluiceways or bypasses. The two projects with
the highest O&M costs in this category employ
different methods of fish protection. The most
expensive project, at $20.489, uses stationary
screens and a wiper system. The second highest
O&M cost. at $8,195, is for a project that uses
angle bar racks, wedge wire screens, a traveling
brush to clean screens. and sluiceways or
bypasses. Cost Range: $216 to $20,489.
1 to <10 MW. Two projects report $0 costs.
One of these projects uses angle bar racks and
sluiceways or bypasses. The second project with
$0 O&M costs modifies · the sequence of the
operations of its thre~ turbines to provide
downstream fish passage. Most of the projects
in the 1 to < 10 MW category use sluiceways or
bypasses. Two projects, at O&M costs of
$10,792 each, use screens that meet California
Department of Fish and Game screen standards.
The most expensive cost, at $43,169, is for the
O&M of stationary screens, and sluiceways or
bypasses while attempting to limit fish mortality
to zero. Of the two projects with the next
highest reported O&M costs, both· at $21,584,
one employs traveling screens and a hydraulic
trash rack, whereas the other project uses another
type of fish screen. Cost Range: $0 to $43,169.
10 to <50 MW. The three lowest O&M
costs, all less than $10,000, are at projects that
use sluiceways or bypasses exclusively or in
conjunction with spill flows. The project at the
high end of the cost range, at $98,532, employs
a static angle wedge wire screen. The second
costliest project, at $51,221 uses angle bar racks,
velocity limits, and sluiceways or bypasses. The
third highest project uses a punch plate and an
overflow screening device. One project, at
$23,562, installs 3250 feet of barrier nets at the·
beginning of each irrigation season. which runs
-5 months ·a year. Cost Range: $2,561 to
$98,532.
4-28
50 to <100 MW. There are not any projects
reporting downstream fish passage O&M costs in
this capacity category. Cost: no data.
100 MW and Larger. There are not any
projects reporting downstream fish passage O&M
costs in this capacity category. Cost: no data.
Annual Reporting Costs for Downstream
Fish Passage. A graphical summary (Figure
4-8d) is provided in this section, as well as
descriptive narrative detailing the ranges,
averages and project characteristics for
downstream fish passage mitigation annual
reporting costs.
Unfortunately, suitable data was not obtained
that would exemplify the types of annual
reporting functions performed in association with
the reported costs. For this reason only the
ranges are provided below with minimal
explanation.
<1 MW. Four projects reported $0 costs.
Cost Range: $0 to $5,122.
1 to <10 MW. Four projects reported $0
costs. Cost Range: $0 to $10,792.
10 to <50 MW. Cost Range: $2,049 to
$5,657.
50 to <100 MW. There are not any projects
reporting downstream fish passage annual
reporting costs in this capacity category. Cost:
no data.
100 MW and Larger. There are not any
projects reporting downstream fish passage
annual reporting costs in this capacity category.
Cost: no data.
Lost Generation for Downstream Fish
Passage. Table 4-5 provides lost generation
averages for projects with downstream fish
passage mitigation requirements.
<1 MW. Five projects reported 0 kWh
generation losses. The average generation loss
of the three projects reporting generation losses
exceeding zero is 233,000 kWh. Loss Range: 0
to 500,000 kWh.
1 to <10 MW. Four projects reported 0 kWh
generation losses. Four projects reported
generation losses in the 150,000 to 320,000 kWh
range. The highest loss, at 3,240,000 k.Wh, is
ten times the loss of the next highest loss. The
four mid-range generation losses average
233,000 kWh. Loss Range: 0 to
3,240,000 kWh.
10 to <50 MW. One project reported a 0
kWh generation loss. Loss Range: 0 to 565,000
kWh.
50 to <100 MW. There are not any projects
reporting downstream fish passage generation
losses in this capacity category. Loss: no data.
100 MW and Larger. These two projects,
both in the Pacific Northwest, r:eported extremely
similar and very significant generation losses
resulting from downstream fish passage
mitigation practices. A generation loss of the
magnitude of 64.5 million kWh equates to a
yearly dollar loss, assuming $0.05/kWh. of
$3,225,000. Loss ·Range: 64,197,000 to
64,974,000 kWh.
Data Assumptions
The following are the assumptions and
considerations in screening, identifying, and
reporting lhe data:
Annual Reporting. It is sometimes difficult to
accurately differentiate what specific functions
are being perfonned in conjunction with the
annual reporting costs that were provided by the
project owners. It appears that the distinction
between annual reporting and study costs may be
ambiguous. Additionally, the respondents were
not specifically queried to provide an explanation
of annual reporting costs. Consequently, the cost
data will be presented as gathered, with minimal
explanation provided.
4-29
A conclusion some may draw concerning
annual reporting costs is that, generally, the
fiscal demands for annual reporting of mitigation
measures are not substantial especially when
compared with the other mitigation costs.. It
might be assumed that the developers do not
view the reporting costs as distinct, exorbitant
costs, and as a result, they are not tracked
precisely.
Capital Costs. Two owners included the
capital cost of a fish . hatchery as their
downstream fish passage capital cost because
construction and operation of a fish hatchery is
a downstream fish passage requirement. This
cost was employed as p~sented by the owners.
Several project owners provided data on
projects planned for the future. These projects
were discarded because the costs are estimates
that may be pure conjecture. The estimated
environmental mitigation costs may be based on
the results of studies that have yet to be
concluded, if even inaugurated .. Future costs are
subject to unknown constraints (i.e. licensing
requirements), and they are too unreliable to use.
Also, a project may never be built because of
some factor such as financing shortages. It
would have been a dubious practice to use these
potentially phantom projects.
Co~ts. Some costs may have been unobtainable
because many projects do not have accurate cost
figures broken down.
Cost Normalization. All costs were converted
to the base year of 1991. The March issues of
Business Conditions Digest for the years 1988
through 1991 were used to construct a price
index based (Table 4-14) on the consumer price
index.
Cost Years. If the year that a cost was
incurred was not provided by the developer, it
was assumed that the year the cost was incurred
was 1989 for the sake of establishing the .
present value of the respective cost. For the
costs that had associated years, the average years
that the various costs were incurred were pre-
Table 4-14. Present value adjus~ent index used to equate all study costs to 1991 dollars.
Year Consumer price index70 Multiplier index
1991 133.79 1.0000
1990 130.60 1.0244
1989 123.97 1.0792
1988 118.26 1.1313
1987 113.63 1.1774
1986 109.61 1.2206
1985 107.60 1.2434
1984 103.90 1.2877
1983 99.60 1.3433
1982 96.50 1.3864
1981 90.90 1.4718
1980 82.40 1.6237
1979 72.60 1.8428
1978 65.20 2.0520
1977 60.60 2.2078
1976 56.90 2.3513
1975 23.80 2.4868
1974 49.30 2.7138
1973 44.40 3.0133
1972 41.80 3.2007
1971 40.50 3.3035
1970 38.80 3.4482
1969 36.70 3.6455
1968 34.80 3.8445
1967 33.40 4.0057
1966 32.40 4.1293
1965 31.50 4.2473
1964 31.00 4.3158
1963 30.60 4.3722
1962 30.20 4.4301
4-30
1989. For the lack of better infonnation, 1989
was used to better reflect reality.
Future Costs 1992-2010. The future costs of
mitigation have been estimated for the time
period 1992-2010 and provided in the cost
conclusion section (Section 6). Some 436
projects have· been identified as due to expire
during this period and it is estimated another
1316 new projects will be licensed. As was
mentioned previously in this report (Figure 3-2),
the number of projects having mitigation
requirements escalated during the 1980's and
there is every likelihood that this trend will
continue in the future. For the purpose of
estimating future mitigation costs it has been
estimated that the frequency of mitigation
requirements during the 1990's will be: DO -
.31 %, instream flows -73%, upstream fish
passage -12%, and downstream fish passage -
48%. It was assumed that the frequency of
mitigation requirements for the 2001-2010 time
span will be: DO-49%, instream flows-95%,
upstream fish passage ~ 14%, and downstream
fish passage -82%.
lnstream Flows. It was apparent that some
owners provided the percent of required release
that flowed through the turbines, whereas others
provided the percent of total flow through the
turbines that was the required release. Thus, the
data obtained concerning required release rates as
a percent of the average annual flow through the
turbines was not used for any analysis.
A few projects have been included that
indicated that a part of or all of their instream
flow requirements are for aesthetic reasons. This
was not a clear issue, and for these few projects
it is difficult to ascertain what percentage of
instream flow requirements were for aesthetic
reasons only, versus a combination of fish
mitigation issues and aesthetic reasons.
However, it is felt that only 2 to 5 projects have
this possible conflict, and no attempt was made
to segregate these projects.
Mitigation Study Requirements. One owner
indicated a preimplementation study was
perfonned, and it was determined that it was not
4~31
necessary to take any mitigation action based on
the results of the study.
Plant Factors. Plant factors for the database
were computed in an effort to identify projects
that had obviously erroneous data. The fonnula
used was as follows: (Annual Energy (MWh) X
1000 ) I (Plant Capacity x 8760). Four plants
had a plant factor of zero because of missing
data. Ooser examination of these four projects
did not provide any evidence of erroneous data.
Two projects exhibited plant factors under I%.
The circumstances surrounding these two plants
explained the low plant factors (i.e., no water at
a project in California). Three projects had plant
factors over 85%. Again these appear to be
legitimate values, such as, municipal power
systems. The range of plant factors is 0.03% to
93.4%. The average plant factor is 53.9%. The
extreme plant factors do not appear to be the
result of data errors, rather, the results of low
water flows and municipal water systems,
respectively.
Pumped Storage. Projects identified as being
pumped storage were excluded from the
database. The operating mode of these projects
would skew the data, they are not conventional
hydroelectric projects, and they may be closed or
semiclosed systems without any associated
mitigation issues.
Study and Annual Reporting Clarity. It is
difficult to detennine if a study was a
preimplementation study to determine mitigation
needs as required by an agency or if the study
was performed after mitigation implementation
and the study .was a follow-up study to detennine
the success of the mitigation issue. Additionally,
the distinction between monitoring and annual
reporting is blurred. The only option available
was. to report the data as obtained.
Study Costs. The costs provided by the
owners appear to represent the costs of single
studies as well as the combined costs of several
studies. This report has attempted to present all
of the study costs associated with a mitigation
issue. Regardless of whether the study costs
presented by the project owners represent single
-,.
or numerous studies, the costs are presented as
the study costs associated with the respective
mitigation practices.
It was attempted to measure the study costs
required for project licensing and for the design
of mitigation requirements. These costs are
provided, but it appears other study costs are
included. For instance, studies that measured the
effectiveness of mitigation implementation and
studies that were requested by state agencies but
not FERC, were included in the study costs
provided by the developers. These are costs that
were imposed on the developer in conjunction
with mitigation requirements, and they have not
been excluded. It also would be extremely
difficult to distinguish between prelicense and
postlicense study costs as provided by the
developers. Several owners indicated that
various agencies continue to require various
studies unrelated to the license conditions.
The study costs are not always the cost of a
single specific study; rather, they are the study
costs associated with a specific mitigation issue.
The study may have taken place over several
years, or a licensee may have been required to
complete more than one study by more than one
agency.
If an owner did not indicate a study was done,
it cannot be assumed that no study occurred. It
may be that a study was done but the developer
is unaware of the cost. It was felt that when the
responsibility to conduct a study was not
assigned to the developer, the cost of a study
cannot be zero to the developer since the
developer is not responsible for the study cost
Study Years. If multiple years for a study are
provided, each year's cost is converted to 1991
dollars and entered into the database as a single
sum amount but no date is provided in the
database to avoid the appearance that it is a hard,
single date. Dates are noted on the work sheets.
Work Hours. Annual O&M Costs, and Annual
Reporting Costs were reported for several
4-32
projects in tenns of work hours expended per
year. This data was converted to dollars per year
so it would be in an usable media (dollars). A
per-hour figure of $25 was used to represent
salary, benefits, any overhead charges, and any
inefficiencies involved in such small function
tasks.
Zero Costs. Considerable discussion transpired
concerning the indication of no capital cost
(zero) in the database. A DO requirement, for
example, may be satisfied through the
application of spill flows and not involve any
additional capital structure, thus no capital costs.
If the developers indicated this was the situation,
a zero was entered into the database in the DO
capital cost field. Each cost field in the database
has an associated logic· field to indicate if the
cost field contains pertinent data. The setting of
the DO capital cost logic field to true indicates
that a zero value (or any other cost for that
matter) was an actual depiction of the capital
cost associated with DO.
It may be argued that zero costs should not be
included in a sum or average measurement.
However, it has been attempted to measure the
costs associated with the respective mitigation
methods, not to purely measure the costs of
specific acts such as the building of a capital
structure to meet a DO requirement. If a project
complies with DO requirements without
additional capital expenditures, then that
project's true capital cost is zero.
An exception to the general treatment for the
handling zeros is study costs. Several projects
reported that a study was done but the cost was
zero. The true cost of the study was, in reality,
unknown to the developer. Thus, only actual
study costs greater than zero were used. The ·
entire matter . of how to handle study costs is
compounded by the fact that pre-and
postimplementation study costs, monitoring
costs, and reporting costs were not acutely
defined.
5. MITIGATION BENEFITS AND EFFECTIVENESS
For the purposes of this study, mitigation
benefits are defmed as any positive responses,
measured in either monetary or nonmonetary
values, in the natural resources that are the
subject of mitigation requirements. The
evaluation of mitigation benefits does not require
that dollar values be placed on all environmental
attributes, and in many situations monetary
values are either inappropriate or impossible to
· calculate (e.g., endangered species, non-game
species, or biodiversity values).
Introduction
The benefits of mitigation include a continuum
of values (Figure 5-l), depending on the nature
of the impact that is being mitigated. For
example, as instream flows are implemented, the
benefits derived may include wetted surface area
of the river channel, suitable habitat for fish,
higher standing crops of harvestable sport fish,
and ultimately, an increase in the economic value
of a downstream fishery. Similarly, the benefits
of DO mitigation may include the concentration
of oxygen in a river, higher productivity of the
downstream aquatic ecosystem, greater survival
and reproduction of individual fish; and, again,
an economic increase in a fishery. ·Fish passage
requirements may also lead to benefits such as
increases in suiVival and reproduction of
individual fish, more robust fish populations, and
greater economic value of fisheries. The
appropriate measures of mitigation benefits
depend on local resource management objectives
and resource management targets (e.g., an
endangered species vs a put-and-take fishery).
Available data can also be a serious limitation to
the types of benefits that can be evaluated.
One important goal of this study is to
detennine the degree to which available
infonnation allows mitigation benefits to be
evaluated. This current volume answers this
question at a generic level, while more detailed
case studies are planned for later reports from
5-1
this study (see Section 1 for plans). Unfor-
tunately, the results of the study to this point
lead to the conclusion that for most hydropower
projects that have been licensed recently, there is
insufficient infonnation to conduct any
quantitative analysis of benefits.
lnstream Flow Benefits
Mitigation for IFN, defined as the flow of
water required below a dam to avoid adverse
impacts on downstream fish and other aquatic
biota, may be the most universal and costly issue
in relicensing hydroelectric plants. Most states
now recognize the need to protect instream flows
and their associated values, including fishing and
recreation. Under the new regulatory policies
established by ECPA, environmental constraints
such as IFN are more likely than ever to place
operational restrictions on hydropower projects.
_ The FERC expects that environmental analysis
and mitigation (e.g., minimum flows) will be the
keys to effective relicensing. Many of the hydro
projects subject to relicensing will be faced with
the question of IFN for the first time.
Previous Studies and Evaluation Methods.
Very few studies have been able to quantify the
benefits derived from instream flow
requirements. This problem is the basis for the
frequent challenges to established instream flow
methodology.6 •71 "73 One interesting study that did
estimate economic fishery benefits was done on
the John Day River in the Columbia River
Basin?4 These results indicated that increased
summer flows to enhance fishing had a marginal
value of -$2.40 per acre-ft. but they also
suggested that the value may be 10 times higher
if other methods. were used. Another study75
examined the trade-offs between agricultural
water use and IFN and estimated that instream
flow values ranged from $14 to $27 per acre-
foot. Both these studies used a marginal value
approach, and neither looked at instream flows in
the context of hydropower trade-offs. A
lnstream Flow Water Quality Fish Passage
Benefits Benefits Benefits
Flow Sp111/aeration Ladder/screen
~ D ..0
Wetted perimeter Dissolved oxygen Fish movement and
or surface area survival D B . Fish growth, survival, ..0
Habitat condition or reproduction Fish biomass or
D D standing crop
Fish biomass or Fish biomass or D
standing crop standing crop Dollar value
D D
Dollar value Dollar value
Figure 5-1. Series of benefits resulting from each of the three types of hydropower mitigation.
literature search for more studies of this type did
not uncover any other significant contributions.
Although they are few in number, there have
been some successful demonstrations of instream
flow benefits to fish. For . example, new
minimum flow requirements at Rob Roy Dam (a
non-hydro water supply project) on Douglas
Creek in Wyoming were studied to determine
fish response.76 Below the point of water
diversion on Douglas Creek, as minimum flows
were increased from 1 cfs to 5.5 cfs, wetted
stream width increased by a factor of 2,
Weighted Usable Area (WUA) for adult brown
trout increased by a factor of 5, and brown trout
numbers increased from four-to sixfold. These
fish benefits were attenuated several miles
downstream as unregulated tributaries entered the
stream. Another study of biological response to
instream flows on the Susquehanna River below
Conowingo Dam17 demonstrated up to a 100-fold
increase in macroinvertebrate abundance when
minimum flows were increased from essentially
zero to 5000 cfs. This study below Conowingo.
Dam did not quantify fish response. These and
other successful case studies are planned to be
presented in later volumes of this DOE
mitigation study.
5-2
Quantifying Mitigation Benefits. To
estimate the benefits of instream flow releases,
the units by which benefits will be measured
must be defined. Since maintaining fish
populations is usually the ultimate objective of
instream flow releases, population size (i.e.,
numbers, weight, or productivity) should be the
primary measure of instream benefits. However,
it is often more feasible to relate instream flows
to physical habitat than to population sizes, and
therefore physical habitat is the resource value
most commonly used to determine instream flow
requirements. When physical habitat is used as
the primary resource value, an assumption that
habitat value is proportional to population value
is also implicit Other resource values may
nevertheless sometimes be appropriate measures
of the benefits of instream flows.
Physical Habitat. Physical habitat is
coinmonly used as a measure of instream
benefits to fish. This is largely because physical
habitat is more easily related to flow rates than
are fish populations. Many methods using
physical habitat as an indicator of instream flow
benefits have been developed.!~ One of the
earliest of these methods78 defmed the area of
usable habitat as the stream area having usable
depths and current velocities. The diversity of
fish species in streams and rivers has been
related to the diversity of physical habitat, as
defined by depth. velocity, and substrate type.79•80
The physical habitat indexes that are currently
used include stream width and wetted perimeter
(indicating only the area or volume of stream
available for fish), and the WUA parameter used
by the IFIM. The WUA parameter combines the
stream surface area, depth, velocity. and substrate
type with habitat requirements specific to fish
species and life stages. The value of WUA is
intended to represent the aggregate quality and
amount of space in a stream that is usable by a
particular life stage of a fish. Physical habitat
indexes are commonly evaluated by using
hydraulic models and, in the case of the IFIM, a
fish habitat suitability model. These models
allow prediction of the amount of habitat over a
range of instream flows. Measured instream
flow rates can be used with a model-generated
relation between flow and habitat index to
develop a time series of physical habitat. If
models are not used, physical habitat indexes can
be measured for individual flow rates in· the
stream.
Uncertainties in the value of the habitat index
arise from inaccuracies in the models used to
estimate the relationship between flow rate and
the physical habitat index. Errors in the
hydraulic modeling as a result of (a) errors in the
parameters used in the specific application and
(b) systematic errors that result from the
approximations and assumptions built into the
model. These hydraulic modeling errors can be
checked by compariqg results with field data.
Uncertainty in evaluation of WUA also arises
from the suitability function used for each fish
species and life stage for each of the hydraulic
parameters .. Important issues in the development
of suitability functions include (a) interpretation
of field data to develop suitability functions that
can accurately represent a fish's selection among
available habitat types, (b) the validity of using
suitability functions in streams or regions other
than where the field data they were developed
from were collected, and (c) the effects of
5-3
interspecific competition on suitability
functions. 81 "83
As an indicator of instream flow benefits to
fish, it is desirable to use a habitat measure that
is related to fish populations as closely as
possible. There are uncertainties in how physical
habitat indexes such as WUA can best be related
to fish populations, either at the level of a
specific stream reach or a longitudinal mosaic of
different types of reaches, each of which may
respond differently to stream flows. For
example, investigators sometimes try to predict
populations. as a function of the WUA present at
the time populations were measured and
sometimes try to predict populations as a
function of the WUA occurring over some past
time period. As discussed below, some field
studies have shown that fish populations are best
related to some function of minimum habitat
availability.
Relations Among Physical Habitat,
Flow, and Fish Populations. When WUA is
used as an indicator of biological benefits of
instream flows, the issues of how WUA is
related to instream flow rates and to fish
populations become critical. Although the
relationship between WUA and flow varies
among study sites and fish species, WUA
typically rises to a peak as flows increase from
zero, and then .decreases at relatively high
flows. 84 Therefore, there is not a linear
relationship between physical habitat and flow,
and increases in flow cannot be assumed to
always provide an increase in physical habitat.
Under current theory. the amount of WUA in
a stream should have a strong effect on fish
populations during (and only during) times when
physical habitat limits 'population size.83 Such
times may include either periods of peak runoff
(typically· in spring), when juvenile life stages
that are unable to swim well are present and are
susceptible to being washed away; or periods of
low flows (typically in late summer and fall),
when there may be inadequate habitat space for
adults. During other times populations may be
controlled by factors other than physical habitat,
such as food availability, fishing mortality, and
predation. Therefore, relations between WUA
and fish populations are frequently complex and
difficult to identify.83
Fish Population Benefits. Stream fish
populations are most commonly evaluated by the
number of fish and sometimes weight (biomass)
of fish per unit of stream length or surface area.
Field measurements, along with common data
analysis techniques, provide these data. Field
measurements of fish numbers and weight taken
periodically at the same location can also be
used, with more elaborate analysis tectmiques, 85 •86·
to estimate the biomass production of a stream
fish population. Production estimates indicate
not only the numbers of fish but also their
growth and reproductive success. To examine
the success of instream flow requirements at
hydro projects, estimates of fish population sizes,
biomass, and production can be compared with
values measured . prior to construction of a
project or values in undisturbed and similar
stream reac;hes.
One source of uncertainty in the use of fish
population data is the uncertainty in the
population measurements. In small streams fish
populations can be measured relatively
accurately, although variation over time and
stream length in populations commonly
introduces considerable uncertainty into estimates
of long-term population size and production
rates. Data analysis techniques allow for
quantification of these uncertainties.86 In streams
too large to block off with fish barrier nets and
to wade in, fish populations may be measured
using other methods such as mark-and-recapture,
which usually produce results with even higher
uncertainties.
When fish populations are used as a measure
of instream. flow benefits, the question of what is
an adequate or desirable population arises.
Measured fish populations at a site affected by a
hydroelectric project are most likely to be
compared with populations at the site prior to
development of the project (if such information
is available) or to populations at nearby sites that
are similar and unaffected. Before it can be
54
determined whether an instream flow provides
acceptable fish populations, an acceptable
population level (including consideration of
variability and measurement uncertainties) must
be defined. Unfortunately, reliable estimates of
fish populations and carrying capacity are
generally not available, even for undisturbed
streams. Lack of adequate data is a serious
limitation to fisheries managers.
A number of other important uncertainties and
complications occur in the use of fish population
parameters as· a measure of instream flow
benefits. Complications generally arise because
flow rates may control population size only some
of the time, and the times when flow rates exert
greatest control on fish populations can change.
If fish populations are adequately high, it can be
concluded that instream flows are sufficient If
populations are low, factors other than low
flows, such as water quality or short-duration
high flows, may be the cause. For these reasons,
it is difficult to determine from population data
alone if an instream flow is too low. However,
additional studies, such as monitoring of feeding
habits, water quality, and temperature, can be
used to identify causes of low fish populations.
In general, fish population data, without other
studies, can show that (1) fish populations are
adequate, so it can be assumed that instream
flows are not too low (and possibly higher than
necessary), or (2) fish populations are lower than
desired, and inadequate instream flows are one of
several possible reasons. Additional studies can
be used to determine with greater confidence
whether instream flows are higher or lower than
necessary to maintain a target fish population.
Other Measures of lnstream Benefits to
Fish. In some cases, measures of instream flow
benefits other than fish populations or physical
habitat are appropriate.87 On streams that
provide important recreational fisheries, fishing
use rates (e.g .• fishing visits per day) and fishing
success rates (e.g., fish caught per fishing day)
can be monitored to determine if inStream flows
are successful. Fish harvests are important
benefit measures where instream flows affect
commercial fisheries, especially salmon. In
streams where preservation of certain fish species
or populations (which may be rare, threatened, or
endangered) is an important fisheries
management objective, the continued presence of
self-sustaining populations of the target species
is an appropriate indicator of instream flow
benefits. These and other measures of benefits
are appropriate in some cases but are ·not given
detailed consideration in this study.
Available Data on lnstream Flow Benefits.
Monitoring the benefits of instream flow releases
appears to be relatively uncommon. Figure 5-2
shows the percentage of operating projects with
instream flow requirements that conduct
monitoring of different resources. (Monitoring
practices of projects that are licensed but not yet
operating are generally unknown.) Nearly half
of the projects monitor flow rates, although
flows are measured only occasionally at some of
these. Only about 20% of the projects reported
any monitoring of fish populations that could
indicate whether the instream flow mitigation is
biologically successful. Monitoring of habitat
quality, sediments, and water quality is
conducted even less frequently.
It is possible that some projects providing
information for this study chose not to report
their monitoring practices out of concern with
license compliance issues. However, the resuJts
~50
~
i14o
<D
"0'
0.30
0
~20 ~
~ 10 ....
<D a.
0
Flow rate Water quality
Fish
do illustrate that many projects appear unable to
verify that the required flows are provided. The
benefits of instream flows to fish populations are
measured at relatively few _projects, which is at
least partially a result of the expenses and
uncertainties of fish population moriitoring.
State respondents did identify 13 specific PERC-
licensed projects at which instream flow
monitoring is being conducted to quantify the
response of fish populations or habitat to flow
alternation. The monitoring activities at these
projects will be examined in more detail in
future volumes of this study.
The FWS recently completed an independent
study to identify lAM applications where
instream flows were established10 and to evaluate
their success. This study estimated that 616
lAM studies have been conducted since the
lAM was developed (approximately 1976) and
that only 6 of these studies included any
followup infonnation on the response of fish
populations. This FWS study concluded that the
degree of protection provided by IFIM stud~es
was essentially unknown. The primary reasons
for this uncertainty were that (a) very little post-
project monitoring has been conducted, and
(b) negotiated flow requirements do not appear
to be implemented in many cases.
Fishing use Other
Habitat Sediments
Variable monitored
Figure 5-2. Monitoring at operating projects with instream flow requirements.
5-5
Dissolved Oxygen Benefits
The effectiveness of DO mitigation can be
measured at several points along the continuum
of benefits {Figure 5-l). Mitigation-induced
increases in DO concentrations can be measured,
and the effectiveness of . mitigation then
expressed as increases in average summer DO
concentrations or other physico---chemical terms.
DO conditions can in tum affect aquatic
organisms at all levels of biological organization,
from algae and zooplankton to mollusks, snails,
crayfish. and other macroinvertebrates to fish.
As specific indicators of stream ecosystem
condition, benthic macroinvertebrates have
significant advantages over fish. Their greater
species diversity makes changes in species
composition easier to detect and interpret. In
addition, because they are substantially less
mobile than fish are, responses can be better
linked to the location where samples are taken.
A vari~ty of specific endpoints may be
evaluated. Useful endpoints are those expected
to respond to improvements in DO. For
invertebrates, occurrence and relative abundance
of species (or higher taxon) are most relevant.
Interpretation is based in part on knowledge of
the relative sensitivity of different types of
invertebrates to low DO concentrations.
Fish are of particular importance for economic
and recreational reasons. Also, because they
tend to be at the top of the food web, they serve
as biological integrators of system function.
Besides species occurrence and abundance of
fish, endpoints expected to respond to changes in
DO concentrations include growth rates and
condition factors (e.g. plumpnes~).
In short, there. are a number of endpoints that
can be used to measure the effectiveness of DO
mitigation. The following sections (1) review
previous research on this subject, focussing on
biological research, and describe scientific
methods available to investigate biological
benefits, and (2) discuss the extent to which
benefits of mitigation have been measured at
U.S. hydropower sites, based on information on
5-6
monitoring activity provided by hydropower
developers and resource agencies.
Previous Studies and Evaluation Methods.
Researchers in the past several years have
attempted to relate improvements in DO
concentrations to enhancement of biological
resources in streams. Some reports for example
have described measures to provide DO
mitigation and have presented observations on
subsequent fishery improvements. Efforts have
also been made to more rigorously examine
biological responses to changing DO regimes by
subjecting fishery and benthological data sets to
statistical and other analytical examinations.
Finally, other studies have employed biological
models to translate changes in DO conditions
into changes in such biological endpoints as fish
growth over one or more seasons. The following
paragraphs summarize published research found
by a literature search covering the period
1985-1991, and collected from agencies and
developers providing information on their work
regarding DO mitigation as described in
Section 3.
A report on DO mitigation in the St. Croix
river basin between Maine and New Brunswick,
Canada, provides interesting qualitative
information on biological benefits ofmitigation.88
Pulp and paper mill effluents and river regulation
transfonned the lower 14 km of the St. Croix
river from an exceptionally prolific salmon
stream to a waterway virtually unable to support
fish populations. In the late 1970s, treatment of
mill effluents was much upgraded and summer
DO concentrations dramatically increased. In the
early 1980s, prompted by improvements in river
water quality, steps were taken to restore the
stream's anadromous fishery. These steps
included construction of fishways at dams on the
lower St. Croix and fish_ stocking programs.
Counts of returning salmon and alewives through
the 1980s suggest that restoration has succeeded.
The author emphasizes that the coexistence of
both a reviving fishery as well as much increased
pulp and paper production was almost
unimaginable in the 1950s, when it was felt that
development of environmental resources and
paper products industry were incompatible. The
author reported that the contribution of DO
improvements to the fishery restoration was
crucial although it would be difficult to separate
the contribution of DO improvement from other
factors such as removal of barriers to fish
passage.
Occasional fish kills in the tail waters of
USACE dams in eastern Oklahoma spurred
efforts by USACE staff to develop DO and water
temperature mitigation· measures for these
projects. A report on measures to mitigate
critical fishery conditions at two USACE
hydroelectric projects in eastern Oklahoma
descri~s preliminary benefits of mitigation
efforts.89 At Eufaula Lake, a 90 MW reservoir
with maximum depth of 28 m and surface area
of 43,000 ha, a continuous low-level sluice
release of .7 m3/sec considerably raised tailwater
DO during a test of this summer release scheme.
The volume of water used in this regime was
found to be insignificant compared to
evaporative losses for the same period.
Similarly, at Fort Gibson Lake, a 45 MW
reservoir with a maximum depth of 15 m and
surface area of 8,000 ha, continuous sluice
releases, with some releases from tainter gates,
were selected to mitigate critical fish habitat
conditions in four small stilling basin bays below
the spillway. During the summer-long tests, no
fish mortalities were reported. Based on these
results, the USACE plans to regularly implement
the release schemes to prevent future fish
mortality.
A case study was perfonned in Missouri to
measure the impacts of changing DO conditions
both in biological and economic tenns.90.91 The
economic value of a trout fishery in the tailwater
of Table Rock Dam, a 200 MW
USACE-operated project, was estimated using
several alternative economic valuation
approaches. 90 The economic cost of annual DO
declines in the tailwater was then estimated,
using a quantitative model of the relationship
between summertime DO depletion and declines
in fishing success in the tailwater.90 Summertime
DO depletion caused by hydropower operation
led to losses of between $270,000-$430,000, or
roughly 4% of the local economy. The authors
5-7
speculated that reduced metabolic rates caused
by low DO concentrations led to a decline in fish
feeding activity. Lowered feeding activity in
tum led to reduced angler success and
diminished fishery value.
Management actions to aerate and stabilize
flow regimes in the tailwater of Norris Dam, a
100 MW tributary storage project on the Clinch
River in Tennessee, were related to changes
observed in long-tenn data sets of benthic
invertebrates and trout collected from the
tailwater.92 The tail water changes were related to
increased abundances of several invertebrate taxa
known to be intolerant to low DO conditions.
Although important conclusions regarding the
improvements to benthic communities resulting
from tailwater improvements were made, the
study noted that a clearer picture was expected
from future additional survey data on aquatic
invertebrates. Among the samples of stocked
rainbow and brown trout from the tailwater. the
changes in tailwater conditions were associated
with less severe summertime declines in
condition, although it is not cl<~ar from the data
to what extent this biological response was due
to flow stabilization, as opposed to DO
improvements.
A model of the energy transfonnation
processes of fish that result in growth was used
to explore possible effects of varying annual DO
regimes on the growth of brown trout (Salmo
trutta).93 The model included algorithms to
account for the effects of both DO and water
temperature on food consumption and
respiration. DO and watertemperature data from
a TV A hydroelectric project from periods both
prior to and following the start of turbine
aeration at the dam were used as inputs to the
model. Small growth improvements were.
simulated as a result of increased DO
concentrations in the post aeration model run;
however, weight loss was simulated in both runs
in late summer as increasing water temperature
raised fish DO requirements beyond the available
concentrations. Although the model was not
calibrated or validated against field data, the
authors suggest that i~ results can potentially
produce valuable infonnation for better
mitigation and management of tailwater
resources. Several key research needs were
identified, including (a) further research on DO
impacts on energy transfonnation processes of
fish, (b) consideration of other habitat variables
such as streamflow velocity in the model, and
(c) procurement of high quality fishery,
benthological, and water quality data sets to use
in calibrating and validating the model.
Available Data on Dissolved Oxygen
Benefits. Nearly 75% of the developers in the
DO sample described in Section 3 reported that
water quality monitoring is perfonned at their
project.· Parameters monitored included DO in
all cases, frequently included water temperature,
and occasionally included others such as
biological oxygen demand. It is not surprising
that DO monitoring is so frequently perfonned,
as FERC generally requires such monitoring
when DO mitigation is required at a project. 13
. In sharp contrast. only 4% of the developers
with DO mitigation requirements in the sample
conduct biological monitoring in the tailwater.
In order to account for biological studies that
may have been perfonne~ by state and federal
natural resource agencies, infonnation on such
studies was requested from resource agencies
from each state and from the EPA, FWS, and
NMFS.
State resource agencies more frequently
conduct biological monitoring studies at
hydropower projects with DO requirements
(Table 3-3). Thirteen percent of state agencies
providing infonnation for this stUdy said that
biological monitoring had been perfonned;
among these, four reports on this biological work
were identified, two of which were obtained and
discussed in previous paragraphs.90•91 .2' On the
other hand, federal agency respondents did not
cite any studies on the effectiveness of mitigation
(Table B-4). Because a limited number of
federal agency offices were contacted, it is likely
that a systematic search through listings of the
agencies' technical studies, and inquiries to a
greater number of field offices would likely
produce additional reports.
5-8
This exploratory collection of infonnation
through a literature search, through contact with
hydro developers and resource agencies, reveals
several points. First, some field and modeling
research has been perfonned to increase the
understanding of biological responses to DO
mitigation. These studies demonstrate that
biological benefits that could accrue from DO
mitigation can be clear and substantial (as in the
case of the Table Rock dam tailwater fishery)
but may be difficult to describe with certainty,
depending on confounding factors operating in
the tailwater and lack of sufficient post
mitigation biological data (as in the case of the
Norris Dam tailwater studies).
The research discussed above has several
limitations. Of the field reports on ·biological
responses to changing DO conditions, most were
perfonned at relatively large (50-200 MW)
projects, rather than at smaller projects
(1-50 MW) that characterize the bulk of the
currently regulated hydropower community.
Most of the studies available lack adequate
fishery, benthological, and water quality data sets
from which strong quantitative empirical
conclusions about biological responses to DO
mitigation can be drawn. Finally, while water
quality data are more abundant, modeling
methods to translate DO changes into biological
responses are in the early stages of development.
Fish Passage Benefits
The specific purpose offish passage mitigation
is to reduce the barrier to fish movement that a
hydropower project presents. The results of
achieving this purpose can include expanding the
range · and enhancing the populations of
anadromous fish species, allowing migration of
other species, and reducing entrainment and
mortality in the turbines.
Benefits of fish passage facilities are
commonly measured. using such methods as
counts of anadromous fish in the passage facility
(either adults moving upstream to spawn or
juveniles moving downstream to the ocean);
population measurements of anadromous,
migratory, or other species that are affected by a
project, and counts of fish being entrained in a
turbine or being passed successfully through a
downstream passage facility. Many of the
uncertainties associated with quantifying the fish
population benefits of instream flows are also
relevant to fish passage mitigation.
Evaluation Methods.
Upstream Fish Passage. The benefits of
effective upstream fish passage measures, while
potentially great, are not always easily
quantified. In some river systems. fish passage
measures may restore the upstream distribution
of anadromous fish runs that were extirpated
many decades ago. These are intangible benefits
of a species restoration effort that, like benefits
of preserving endangered species, are not readily
translated into dollars. At most projects,
effective. upstream fish passage can increase the
numbers and standing crops of fish populations
above the dam. which may enhance the
commercial and recreational fisheries.
Many resource agencies consider an upstream
fish passage measure to be effective if it presents
no obvious barrier to movement, as determined
by aggregations of fish in the tailwaters. Such a
performance objective is difficult to quantify
(and comply with), because upstream-migrating
fish may stop at the base of a dam for periods of
hours or even days before finding and
successfully moving up a fish ladder. Strictly
speaking, such a delay represents a barrier to fish
movement, although natural areas of
congregation in the absence of physical barriers
are well known. More important, the
significance to subsequent reproductive success
of whatever energy the fish loses during this
delay is unknown.
Another criterion for success is whether the
upstream fish passage measure is able to
transport enough fish to saturate upstream
spawning and rearing habitat. It may be
unnecessary to design and construct a fish ladder
that can pass large numbers of spawners if
upstream spawning habitat or water quality is
poor. This is a reasonable upper limit to the
5-9
number of migrating fish that need to be
transported for a measure to be considered
effective, but such goals are also very difficult to
measure. Further, the numbers may change as
other improvements in the watershed create more
potential egg and juvenile habitat, resulting in a
mitigative measure no longer able to pass enough
fish to comply with the changing performance
goals.
Downstream Fish Passage. The benefits
of a downstream fish passage measure may be
expressed as the ability of the mitigation measure
to extend the upstream range of an anadromous
fish species by allowing the life cycle to be
completed safely. Also, benefits may be
expressed as the ability to pass a particular
number or percentage of downstream-moving
fish, or the increase in fish population numbers
or biomass as a result of operation of the device.
For example, the effectiveness of fish bypass
systems at the USACE Bonneville Dam is
judged not only by the survival of juvenile
salmon transported to the tailwaters, but also by
the numbers of adult salmon returning years
later. The benefits of downstream fish passage
measures are directly related to the additional
numbers of fish that are safely transported to the
tailwaters. Resident fish that are lost from the
reservoir may still support a tailwater fishery.
Attempts to restore anadromous fish runs by
developing upstream fish passage facilities could
be nullified by the lack of a method to
subsequently transport juvenile life stages safely
past the turbines.
Performance goals for screens and other
measures used to prevent turbine passage are
rarely expressed in a way that would allow
quantification of benefits. Objectives may be
expressed in terms of safely passing a given
percentage of downstream migrants, which can
then be compared with management goals or the
value of a downstream fishery. An implicit
assumption in detennining the benefit of a
downstream passage device is that the mortality
associated with the mitigative measure is
significantly less than the mortality associated
with turbine passage. This assumption has not
always been borne out at hydroelectric power
'' 'I
plants with large, efficient turbines (where
turbine passage mortality may be low), but is
likely to be reasonable at many small-scale
hydropower facilities.
Available Data on Fish Passage Benefits.
Upstream Fish Passage. In addition to
developing specific, verifiable objectives, it is
desirable to monitor the operational performance
of fish passage facilities. Without performance
monitoring, neither an objective evaluation of
site-specific mitigation effectiveness nor the
application· of knowledge gained at that site to
other sites is possible. According to the
licensees contacted for this study, performance
monitoring at nonfederal hydroelectric projects
has been relatively neglected. Many of the
projects with upstream fish passage monitoring
requirements are recently licensed or constructed,
and· results of monitoring studies are not yet
available. Among the 30 operating projects that
provided information, 17 (57%) have not
monitored the performance of the upstream fish
passage measure (Figure 5-3). Those projects
that have monitored the success of upstream
passage generally quantify passage rates or, less
commonly, fish populations. Forty percent of
operating facilities monitor fish passage rates;
these are generally fishway counts that are
conducted by either the licensee or a fishery
-o ~50 u
-~40
a.
'030
Q)
~20 -c::
Q)
~10 Q) a..
None Fish passage rates
resource agency. Although monitoring studies
determine the number of fish that passed through
the facility, they rarely provide information about
the numbers of fish that were unable to
successfully negotiate the facility, and therefore
are not useful for comparing effectiveness of
different devices or at different sites.
Where two or more proximal, mainstream
dams have upstream fish passage facilities,
fishway counts may provide useful information
about passage effectiveness. In this case,
fishway counts at the lower dam may be good
estimates of the number of fish available for
passage at the nearby, upstream dam. When
appropriately corrected for natural and fishing
mortality in the river between the dams and
straying into tributaries, the efficiency of the
upper dam fishway can be determined by
dividing the fishway counts at the upper dam by
the counts at the lower dam.
A smaller number of operating projects (23%)
monitor the specific fish populations !hat are
protected by the mitigation measure. Population
monitoring studies provide a longer-term view of
the success of a mitigative measure because they
can estimate whether the fish populations have
been maintained or enhanced during the
operation of the facility. Because other factors
may influence fish numbers or standing crops,
Fish populations Other
Performance monitoring,
Figure 5-3. Relative frequency of performance monitoring of upstream fish passage measures at
nonfederal hydroelectric projects, based on information provided by developers.
5-10
however, fish population monitoring by itself
may not yield widely transferable infonnation
about the effectiveness of a device.
Downstream Fish Passage. The degree of
performance monitoring for operating
downstream fish passage facilities at the
nonfederal projects examined in this study is
relatively low. At 79% of the 66 projects with
operating downstream fish passage measures, no
performance monitoring was reported
(Figure 5-4). The expected performance of the
"'most commonly installed downstream fish
passage mitigative measure, the angled bar rack
(Section 3), appears to be based on the results of
a single study.52 ·
Among the 14 projects that have conducted
operational monitoring, 11 monitor passage rates.
10 estimate mortality rates, and I monitors fish
populations.
_100~---------------------------------------------------------, c
None Fish passage rates Mortality rates Fish populations Other
Type of performance monitoring
Figure 5-4. Relative frequency of performance monitoring of downstream fish passage measures at
nonfederal ·hydroelectric projects, based on information provided by developers.
5-11
plants with large, efficient turbines (where
turbine passage mortality may be low), but is
likely to be reasonable at many small-scale
hydropower facilities.
Available Data on Fish Passage Benefits.
Upstream Fish Passage. In addition to
developing specific, verifiable objectives, it is
desirable to monitor the operational performance
of fish passage facilities. Without performance
monitoring, neither an objective evaluation of
site-specific mitigation effectiveness nor the
application· of knowledge gained at that site to
other sites is possible. According to the
licensees contacted for this study, performance
monitoring at nonfederal hydroelectric projects
has been relatively neglected. Many of the
projects with upstream fish passage monitoring
requirements are recently licensed or constructed,
and· results of monitoring studies are not yet
available. Among the 30 operating projects that
provided information, 17 (57%) have not
monitored the performance of the upstream fish
passage measure (Figure 5-3). Those projects
that have monitored the success of upstream
passage generally quantify passage rates or, less
commonly, fish populations. Forty percent of
operating facilities monitor fish passage rates;
these are generally fishway counts that are
conducted by either the licensee or a fishery
-o cso u
·~40
c.
'030
Q)
~20 -c:::
Q)
~10 Q) a..
None Fish passage rates
. resource agency. Although monitoring studies
determme the number of fish that passed through
the facility, they rarely provide information about
the numbers of fish that were unable to
successfully negotiate the facility, and therefore
are not useful for comparing effectiveness of
different devices or at different sites.
Where two or more proximal, mainstream
dams have upstream fish passage facilities,
fishway counts may provide useful information
about passage effectiveness. In this case,
fishway counts at the lower dam may be good
estimates of the number of fish available for
passage at the nearby, upstream dam. When
appropriately corrected for natural and fishing
mortality in the river between the dams and
straying into tributaries, . the efficiency of· the
upper dam fishway can be determined by
dividing the fishway counts at the upper dam by
the counts at the lower dam.
A smaller number of operating projects (23%)
monitor the specific fish populations !hat are
protected by the mitigation measure. Population
monitoring studies provide a longer-term view of
the success of a mitigative measure because they
can estimate whether the fish populations have
been maintained or enhanced during the
operation of the facility. Because other factors
may influence fish numbers or standing crops,
Fish populations Other
Performance monitoring,
Figure 5-3. Relative frequency of performance monitoring of upstream fish passage measures at
nonfederal hydroelectric projects, based on information provided by developers.
5-10
however, fish population monitoring by itself
may not yield widely transferable infonnation
about the effectiveness of a device.
Downstream Fish Passage. The degree of
performance monitoring for operating
downstream fish passage facilities at the
nonfederal projects examined in this study is
relatively low. At 79% of the 66 projects with
operating doWnstream fish passage measures, no
perfonnance monitoring was reported
(Figure 5-4). The expected perfonnance of the
--most commonly installed downstream fish
passage mitigative measure, the angled bar rack
(Section 3), appears to be based on the results of
a single study.52 ·
Among the 14 projects that have conducted
operational monitoring, 11 monitor passage rates,
10 estimate mortality rates, and 1 monitors fish
populations.
_100r------------------------------------------------------------, ~ . .. . .................................................................................................... . ,..,.
None Fish passage rates Mortality rates Fish populations Other
Type of performance monitoring
Figure 5-4. Relative frequency of perfonnance monitoring of downstream fish passage measures at
nonfederal ·hydroelectric projects, based on infonnation provided by developers.
5-11
6. SUMMARY AND CONCLUSIONS
The importance of environmental mitigation at
hydroelectric projects is growing for two reasons.
First. -22,000 MW of existing hydro capacity
will require relicensing by the year 2010. The
relicensing process will undoubtedly involve
changes (often increases) in mitigation
requirements that can result in reductions in
existing hydropower production. Second, plans
for expanding the nation's renewable energy
resources, including the NES, call for
development of significant new hydro resources.
The magnitude of undeveloped hydropower
resources is still being investigated, but
preliminary DOE estimates indicate it to be as
much as 52,000 MW. The amount of this new
renewable energy that can eventually be
developed will depend, in part, on mitigation
costs and their effect on project economics.
Through the use of a systematic examination
of projects developed over the past decade, costs
and benefits of three important environmental
issues (instream flows for fish, DO, and fish
passage) have been studied. This section
presents the conclusions to date from the
Environmental Mitigation Study, including an
extrapolation of total costs to past and future
projects and recommendations for additional
research.
Current Practices
Based on information obtained from
hydropower developers and resource agencies,
the following trends are apparent in mitigation
for IFN, DO, and fish passage.
lnstream Flow. Instream flow requirements
are the most common mitigation practice applied
to hydropower projects. Since the passage of
ECPA, this type of mitigation has been required
at more than 65% of the projects examined in
this study (non-federal projects licensed in the
past decade). Although instream flow
requirements are more frequent in the western
6-1
states, their frequency of application is intreasing
everywhere in the country.
Most instrcam flow requirements for fisheries
are intended for maintenance of reproducing
populations of sport or commercial fish. Few
projects (7%) have involved threatened or
endangered species. Therefore, if applicability to
a wide range of hydro projects is desired, then
further development of mitigation methods
should focus on sport and commercial species.
However, the importance of threatened or
endangered species may change in the future
(e.g., salmon stocks in the Columbia River Basin
have recently been listed as endangered).
Of the established methods for assessing
instream flow needs, the IFIM is most commonly
used, so research on improving instream flow
assessment methods should focus on this suite of
methods. However, many project operators
believe that their instream flow requirements
were set without the application of any
established method. This belief may arise
because agencies have been unsuccessful in
communicating the methods they use to
recommend instream flows. It appears, though,
that a substantial proportion of projects are
licensed without a site-specific assessment of
instream flow needs. Project applicants would
benefit from guidance on what studies they
should conduct, in the absence of studies by
agencies, to avoid conservatively high-flow
release requirements.
Factors affecting physical habitat that are not
usually incorporated in the WUA physical habitat
index of the IFIM, such as sediment transport,
temperature, and water quality, are recognized as
important instream flow benefits at many
projects. Likewise, instream flow needs for
recreation and riparian vegetation are recognized
at many sites. Methods for assessing instream
flow needs for sediments, recreation, and riparian
vegetation are less well developed than those for
fisheries and water quality. Further evaluation of
these other mitigation benefits, and appropriate
assessment methods, is planned for later stages
of this mitigation study.
Approximately half of the active projects with
instream flow requirements reported that they
monitor the instream flow rate. Therefore, many
projects do not conduct this basic level of
monitoring and would be unable to verify that
they provide the flow rates required by their
licenses. This problem was independently
identified by a FWS survey of instream flow
compliance in Colorado, Montana, and
Wyoming.94 '95
A minority of operating projects ( -20%) report
any biological monitoring of the benefits of their
instream flow releases. Ecological theory and a
review of current literature indicate that the
relations between fish population measurements
and instream flow releases are complex.
However, fish population data can be used
successfully in some cases to conclude that an
instream tiow requirement is sufficient to protect
fish resources. Adaptive instream flow
management techniques that base future flow
releases on biological monitoring results may
eventually play a more dominant role in
hydropower regulation. Guidance for developers
on the potential benefits of conducting biological
monitoring would be useful. However, such
real-time management of instream resources will
require a better understanding of the response of
fish to altered flows than currently exists.73 •96
Dissolved Oxygen. In the years since the
enactment ofECPA, DO mitigation requirements
have been increasing at hydropower projects. As
hydropower projects at large reservoirs come up
fQr relicensing, mitigation of DO problems will
become an even more important environmental
issue for the hydropower industry. Fortunately.
a substantial body of federal and industry
research has developed numerous DO mitigation
technologies applicable to a wide range of
project configurations. The unresolved problems
with DO mitigation are (a) detennining
appropriate DO targets to protect aquatic biota
and (b) quantifying the tradeoffs between
mitigation costs and benefits.
6-2
The analysis of FERC data reveals that most
projects currently with water quality
requirements have capacities from < 1 to 50 MW
and are most frequently in the northeast,
southeast and southwest, in that order. In
contrast, hydropower development in general has
been most active in the northeast, southwest, and
northwest, in that order.
The sample of nonfederal FERC-licensed
projects indicates that spill flows are used for
DO mitigation far more frequently than other
mitigation methods (e.g., selective withdrawal,
tailrace weirs, and reservoir destratification).
This preference can be explained in part by a
bias in the sample toward hydro projects in the
northeast, where spill flows are used with
exceeding frequency. This trend may also be
explained by the usefulness of spill flows for
meeting concurrent instream flow requirements,
by FERC policies encouraging spill flows, and
by financial constraints preventing small projects
from investing in expensive or high-risk
technologies.
In the sample of projects, there is a tendency
for smaller projects to operate mitigation at all
times, and larger projects to mitigate only when
necessary. This may be due to agency or FERC
requirements, or by developer choice.
The results show that DO mitigation is
required generally to meet the primary objectives
of state water quality, site-specific, or
antidegradation standards, or explicit fish and
wildlife objectives. State numerical DO criteria
range from 4 to 7 mg/L.
In addition, among the sample of developers
studied in this report, water quality monitoring is
used at over half of the projects, alone or in
combination with other measures such as
modeling studies or professional judgment, to set
DO requirements. The infonnation also shows
that investment in pre-and post-operational
water quality studies can be a cost-effective way
to help identify optimum DO mitigation
strategies.
Many states report having written policies that
are applicable to DO mitigation at hydropower
projects, and most of these pertain to state water
quality or antidegradation standards. The FWS
also has written policies clarifying the agency's
position on hydropower mitigation and its
commitment to protecting and conserving
important fish and wildlife resources while
facilitating balanced development of the nation's
natural resources. The results presented in
Section 3 suggest that although federal and state
agencies can and do play a clear and vigorous
role in setting DO mitigation objectives, they do
not do so consistently across agencies, states, or
regions.
The effectiveness of DO mitigation can be
measured at several points along a continuum of
responses ranging from simple increases in DO
concentrations in the tailwater to measurements
of response in biological variables such as
benthic macroinvertebrate biomass and species
occurrence, and fishery endpoints (e.g~ growth
rates and condition factors). The results of the
literature review presented in Section 5 indicate
that researchers in the past several years have
related mitigation-induced improvements in DO
conditions to enhancements in biological
resources. Both field and modeling approaches
have been applied, and the biological benefits
that could accrue from DO mitigation have been
described. It is clear from the literature that
methods, case study opportunities, and incentives
exist to produce valuable infonnation about how
to optimize management of tailwaters for
biological resources and to provide quantitative
data on biological benefits of DO changes that
can aid regulatory decisions associated with
balancing power and nonpower resources. It
does not appear, however, that past studies have
benefitted from adequate fishery, benthological,
and water quality data sets. General conclusions
about biological responses to DO mitigation that
can be developed from available data are limited.
Also, biological modeling meUtods are as yet in
early stages of development.
Another limitation to the usefulness of prior
research for the hydropower community is that
there have been few studies at smaller projects
6-3
( 1 to. 50 MW) that characterize Ute bulk of the
currently regulated hydropower community. At
the same time, studies at large projects will be of
increasing importance because many of the
projects that are coming up for relicensing are
large.
Within the population of hydropower projects
with DO mitigation, it appears that although DO
and other water quality parameters are commonly
monitored in project releases, biological
monitoring is rarely perfonned. State resource
agencies appear to perform studies on biological
relationships to mitigation more frequently than
developers, but there is still relatively little
research in this-area. Review of federal agency
technical report listings may reveal more federal
activity in this area.
Fish Passage. Upstream fish passage
requirements are applied to nonfederal, PERC-
licensed hydro projects relatively less frequently
than are downstream fish passage requirements,
and both are more common in the western states
than in the east. Downstream fish passage
requirements have grown in recent years to
become the second most common mitigation
issue at hydropower projects after instream flow
requirements.
Upstream Passage. The blockage of
upstream fish movements by hydroelectric dams
may have serious impacts to species whose life
history includes spawning migrations.
Anadromous fish. catadromous fish, and some
resident fish could all have upstream spawning
migrations constrained by barriers such as
hydroelectric dams. Upstream passage measures
can be placed into three general categories:
trapping and hauling, fishways, and fish lifts.
Trapping and hauling is a labor-intensive
mitigation measure that can be used when fish
need to be transported long distances upstream or
around a large number of obstacles. Trapping
and hauling (by trucks) of fish to upstream
spawning locations is used at some older dams
(15% ofnonfederal. FERC-licensed projects). but
in some projects this measure is being replaced
by fish ladders or elevators.
Fishways (or fish ladders) are widely used to
transport fish above single obstacles such as
dams and may also be used to collect fish for
hauling to· upstream stocking locations. Fish
ladders are by far the most common means of
passing fish upstream at nonfederal hydroelectric
dams, accounting for more than 70% of the
upstream passage devices reported. Fish ladders
are employed throughout the United States, and
some are quite old, dating back to the tum of the
century. Fish lifts (elevators) and fish locks rely
less on active movement of the fish than do
fishways, and consequently, they may be favored
where restoration of such species as American
shad and blueback herring is of paramount
importance. Fish lifts are less common than
fishways (fish lifts were reported for 12% of the
nonfederal projects that provided infonnation for
this study), but most are relatively recent
installations.
Upstream fish passage facilities are most
frequently used to enhance the migration of
anadrqmous fish, although some hydroelectric
projects are required to maintain upstream
movements of resident (nonanadromous) fish as
well. Performance monitoring has been
relatively neglected. Fifty seven percent of the
operating projects that provided information have
not monitored the performance of the upstream
fish passage measure. Those projects that have
monitored upstream passage generally quantified
passage rates (i.e., fishway counts) or, less
commonly, fish populations. Performance
objectives of upstream fish passage measures are
rarely specified precisely. Most developers
indicated that "no obvious barriers to upstream
movement" was one of the criteria used to judge
effectiveness; 50% of the respondents felt that
this was the sole criterion. Only small
percentages of the projects are required to pass
a specified percentage or a specified number of
migratory adults.
Downstream Passage. A variety of
devices have been employed to prevent fish from
becoming entrained in the turbine intake flows.
The spill flows that may be used to increase DO
concentrations or provide instream flows can also
transport fish over the hydropower dam rather
6-4
than through the tutbines. Higher technology
options also exist, including sophisticated
physical screens and light-or sound-based
guidance measures that are being studied to
bypass downstream moving fish with a minimal
loss of water that could otherwise be used for
power generation.
The angled bar rack is the single most
frequently required downstream fish passage
device, particularly in the Northeast. Angled bar
racks are used by 38% of the nonfederal, FERC-
licensed hydroelectric projects that provided
infmmation for this study. Other types of fixed
screens were installed at 34% of such projects.
Traveling screens similar to the vertical traveling
screens used at steam electric power plants have
been installed in the upper portion of the turbine
intake gatewells of some Columbia River dams,
but have been used at only 4% of the nonfederal
projects.
Intake screens of all kinds may have a
maximum approach velocity requirement and a
sluiceway or some other type of bypass.
Twenty-four percent of projects have a velocity
limit on the intake flows and 22% have a
sluiceway or some other form of bypass.
Downstream fish passage· facilities were most
frequently designed to protect adult resident fish
at the nonfederal hydro projects examined in this
study; juvenile resident fish and juvenile
anadromous fish were also important targets for
these mitigative measures. Downstream fish
passage facilities are rarely required to protect
fish eggs and larvae. The amount of
performance monitoring for operating
downstream passage facilities is relatively low.
This study indicated that there arc no
performance monitoring requirements for 79% of
the projects with operating downstream fish
passage measures. Those projects that have
conducted operational studies monitor passage
rates, mortality rates, or fish populations.
Seventy percent of the projects with downstream
fish passage facilities indicated that no
performance objectives had been specified for
their mitigation requirement.
Mitigation Costs
This study examined several different types of
environmental mitigation costs that are incurred
by hydropower developer. At this stage of the
DOE Environmental Mitigation Study it is not
possible to provide highly specific. unqualified
costs for mitigation practices and project types,
because costs have been found to be too
variable. Attempts to apply the average costs
presented in this report to specific projects may
be misleading. For example, capital costs for
upstream fish passage have an average cost of $6
million and a cost range of $21,000 to $37
million. None of these three figures would be a
fair representation of the costs a developer would
likely encounter because of the site-specific
nature of mitigation requirements. Therefore, it
is strongly recommended that the average
mitigation costs presented here not be applied to
individual projects. The most appropriate way to
view these cost estimates is by capacity size
categories (Section 4). Average costs are
presented primarily to give a broad picture of the
economics of environmental mitigation.
Opinions will vary as to whether the costs
presented here a·re underestimated or
overestimated, and these opposing views have
already been received, in equal amounts, during
the technical review of this report. The costs
reported here are -presented as objectively as
possible. The scope of this volume dictated that
cost data be described as they were obtained
with minimal analysis except for filtering out
obvious errors. Several assumptions, however,
were required to calculate the target population's
total cost of environmental mitigation as well as
the estimated future costs of environmental
mitigation. These assumptions include the
extrapolation of the frequencies of mitigation
requirements from the sample population to the
target population (see the next two subsections
and Section 2). The frequencies of future (1992
to 2010) mitigation requirements were estimated
based on temporal historical trends of mitigation
frequencies.
6-5
Costs to Developed Projects. The
following procedure was used to estimate the
mitigation costs of the target population: (a) the
average costs are those presented in Section 4 by
capacity category (i.e., based on 141 projects that
provided usable cost data); (b) the frequency of
mitigation requirements in the target population
(707 projects) was based on the frequency of
mitigation requirements in the sample (280
projects); (c) the average costs for each
mitigation requirement, capacity category, and
cost type were multiplied by the anticipated
frequencies of the target population projects with
mitigation requirements; and (d) for the annually
occurring costs (O&M and annual reporting), a
time period of five years, or half the study
period, was used. Table 6-1 provides a summary
of the various mitigation costs.
The total cost of the target population's
hydropower mitigation requirements during the
study period is estimated at -$500 million
(Table 6-1 ). This does not include the cost of
lost generation which, if an energy value of
$0.05/kWh is assumed, amounts to -$33 million
yearly (Table 6-2). Using an average five-year
time span (some projects incur losses for 1 year,
some for 10 years, depending on when
mitigation is implemented), the target
population's generation loss from 1980 to 1990
is -$165 million ($33 million/yr for 5 years). It
must be emphasized that $665 million ($500
million + $165 million) is not the total cost to
the nation for hydropower mitigation
requirements. These costs are only for the
projects identified as the target population
(Section 2). This set of 707 projects is only
about one-third the total number of all federal
and nonfederal hydropower projects currently
operating in the United States. This is not to
suggest that the remaining two-thirds of the
operating hydropower projects in this country
have similar mitigation requirements and costs;
rather. that the . remaining. two-thirds· of the
projects were not within this study's target
population, but they definitely do have
additional, non-zero mitigation costs.
Table 6-1. Average mitigation costs per project and total mitigation costs for the target population of
hydropower projects by mitigation issue (N = 707; all costs in thousands of 1991 dollars). The total costs
are a function of the frequency of mitigation requirements in the target population (see Appendix C for
more details).
Upstream Downstream
Instream Dissolved fish fish
flows oxygen passage passage Totals
Average cost
per project $216 $145 $3,409 $708 $615,000
Total costs
1980-1990 $85,810 $20,614 $252,234 $141,642 $500,229
Table 6·2. Average annual and total generation losses by mitigation issue for the target population of
hydropower projects· (N = 707; energy values assumed to be $0.05/k.Wh; dollar values in thousands of
1991 dollars). All losses in this table are for yearly generation losses. The total generation lost is a
function of the estimated frequency of the target population's generation losses (see Appendix C for
details).
Instrearn Dissolved
flows oxygen
Average armual
generation loss
(MWh per project)
2,489 107
Total generation
lost (MWh)
301,192 2,997
Total generation
lost ($1000) $15,060 $150
Costs to Future Projects. Attempts to
measure the future costs of hydropower
mitigation involve many asswnptions and
uncertainties. It is relatively easy to identify the
numbers and sizes of projects that will require
relicensing, but the relicensing outcomes and
requirements, including the frequency of
environmental mitigation requirements, are
6-6
Upstream Downstream
fish fish
passage passage Totals
1,122 6,139 2,464
11,221 343,804 659,214
$561 $17,190 $32,961
difficult to predict. The number of new projects
that will be developed is also uncertain and
highly dependent on future trends in energy
prices and regulatory requirements. While
temporal trends of mitigation requirements are
evident for the 1980's, it is not certain whether
these trends will increase, decrease, or stagnate
in the future. Nevertheless. recent experience
strongly suggests that the number of projects
with mitigation requirements will increase in the
future. The frequencies assumed for future
mitigation requirements are discussed in the cost
assumptions section (Section 4). The time span
used for future cost estimation is 1992 to 2010.
The magnitude of the future costs of mitigation
is influenced by the substantial number of large
hydropower projects due for relicensing during
the next 18 years.
The following procedure was used to estimate
the future costs of mitigation: (a) the past
mitigation costs used were those estimated from
the 141 projects with usable cost data (Section
4); (b) it was assumed that the frequency of
mitigation requirements would increase and that
all 436 projects due for relicensin!f7 would be
relicensed; c) the number of new projects issued
licenses was estimated at 13163•98; (d) for the
projects licensed from 1992 to 2000, a time
period of 15 years was used for annually
occurring costs (O&M and annual
reporting); (e) for the projects licensed from
2001 to 2010, a time period of 5 years was used
for annually occurring costs (O&M and annual
reporting); (f) the estimated number of future
new projects (1316) are only those estimated
future new projects that will be successfully
licensed by the FERC licensing process and in
operation, which corresponds to the target
population (Section 2) criterion; and (g) the
effects of inflation on mitigation costs were not
applied; unadjusted 1991 costs were used.
The concept of generation lost due to
mitigation requirements is controversial, and
uncertainties are unavoidable in determining the
amount of this generation loss. The cost
estimates and projections presented here did not
attempt to resolve these uncertainties. Rather, it
was chosen not to compound this uncertainty
with additional assumptions of the future
frequencies of generation losses. Instead, the
frequency of past generation losses (1980 to
1990) were simply used as the frequency of
future generation losses.
The estimated future cost of hydropower
mitigation for the period 1992 to 2010 is -$2
billion (Table 6-3). This does. not include the
. cost of lost generation which amounts to -$81
million annually if an energy value of
$0.05/k.Wh is assumed (Table 6-4). The future
Table 6-3. Future mitigation costs projected for the period 1992 to 2010, including relicensed and new
license projects (all costs in thousands of 1991 dollars). The number of relicensing projects and new
projects successfully licensed is estimated. The average project costs are based on the mitigation costs
for the time period 1980 to 1990 (see Section 4). The total costs are a function of the estimated frequency
of future mitigation requirements (see Appendix C for details).
Upstream Downstream
Instream Dissolved fish fish
flows oxygen passage passage Totals
Total costs,
1992-2000 $97,432 $13,969 $17,291 $139,589 $268,281
Total costs,
2001-2010 $255,884 $73,083 $239,679 $1,177,964 $1,746,609
Total costs,
1992-2010 $353,316 $87,052 $256,970 $1,317,553 $2,014,890
6-7
time span of interest is 19 years (1992 to 2010).
The specific years that these future projects will
come online or be· relicensed, and mitigation
generation losses incurred, is not known.
However, an 8-year average time period is
assumed for total generation losses. This
assumption means that lost generation for 1992
to 2010 is -$650 million ($81 million/yr for 8
years). It must be emphasized thatthe total cost
of future mitigation, $2.65 billion ($2 billion +
$650 million), is not the total future cost of
mitigation to the nation. This is the estimated
mitigation cost only for projects subject to FERC
licensing. Possible future rule changes such as
exempting projects < 5 MW from the FERC
licensing process may influence mitigation costs
in unknown ways.
Recommendations
One of the important objectives of examining
current trends in mitigation practices is to
identify areas deserving additional study.
Several such areas have been identified in the
past by various interests6•7•10•73•96, but the results
of this report hopefully provide a more current
and more broadly based justification for research
directions.
lnstream Flow. Overall, more research is
needed to make IFN assessment methods more
predictive and objective. A long-recognized
need in instream flow management is the
development of ways to relate physical habitat,
which is usually the focus of an instream flow
study, to fish populations. This linkage is badly
needed in the balancing decisions that FERC
must make in its licensing process. More
predictive methods would allow instream flows
to be released when they are most beneficial to
fish and conserved when such flows would be
less beneficial. Eventually, as such methods are
developed, greater flexibility in licensing
requirements would be needed to allow instream
flow releases to be varied according to measured
or modeled states of the fish population.
Many projects, especially small diversions
where instream flow costs are high, have flow
requirements set without the use of formal
studies. The mitigation costs for these smaller
projects are also disproportionately higher than
for larger projectS. Guidance for hydropower
Table 6-4. Estimated annual average generation losses for the time span 1992 to 2010 (436 relicensed
projects and 1316 new projects; energy values assumed to be $0.05/kWh; all costs in thousands of 1991
dollars). The frequency of past generation losses (1980 to 1990) was used to estimate future generation
losses. The total generation lost is a function of this frequency (see Appendix C for details).
Average annual
generation loss
(MWh per project)
Total generation lost
(MWh)
Total generation
lost ($1000)
Instream
flows
2,489
746;756
$37,338
Dissolved
oxygen
107
7,386
$369
6-8
Upstream Downstream
fish fish
passage passage Totals
1,122 6,139 2,464
28,053 847,232 1,629,426
$1,403 $42,362 $81,471
developers in selecting cost-effective studies
could help avoid arbitrary or excessively
conservative instream flow requirements that do
not provide benefits commensurate with their
costs.
Dissolved Oxygen. Continuing hydropower
development and upcoming relicense negotiations
will require adequate information on effective,
efficient DO mitigation options. For this reason,
more field applications of promising DO
mitigation technologies need to be demonstrated
and the results disseminated to the hydropower
industry through, for example, annual open
literature reviews on this subject. Field
applications at both federal and nonfederal
projects would be desirable covering a range of
project sizes, regions, and configurations.
There is a need for better biological and
physico-chemical data from which to develop an
understanding of relationships between DO
mitigation and biological response. The results
of this_ study suggest that two kinds of efforts
may be needed: (a) more extensive searches
through state and federal resource agency
technical report listings to identify suitable data
sets, if any, and (b) support for biological
monitoring at both nonfederal and · federal
hydropower project tailwaters. For example,
biological monitoring programs could be initiated
at selected new and relicensed pt:Qjects that are
required to provide DO mitigation.
Finally, the frequency of required,
post-operational release water quality monitoring
at hydropower projects with DO mitigation
requirements suggests that considerable data on
DO· concentrations below regulated hydropower
. projects is available. . Policy-level analyses of
the effects of recent hydropower mitigation
policies on tailwater resources could therefore be
performed, comparable to a study sponsored by
DOE in 1981 measuring the DO impacts of
small-and large-scale hydropower development
throughout the United States.99 The results of
such a study could be used to measure the
success or failure of new hydropower regulation
policies in balancing objectives of ongoing
6-9
power development and environmental
protection.
Fish Passage. Despite considerable efforts in
recent years to design and install fish passage
devices at hydroelectric power plants, there is
still a great need for field studies to evaluate the
biological effectiveness of these mitigative
measures. The lack of information about
biological effectiveness is a particular problem
for downstream fish passage measures, where
designs are more recent and varied, and where
there has been less practical operating experience
than, for example, at fish ladders. Fish passage
mitigation may be required at sites where the
biological benefits are uncertain (e.g., at sites
without clearly migratory fish species).
There is also a need to conduct performance
monitoring in a way that would yield
information that could be applied to the design
of fish passage measures at other sites. Most
studies of fish ladders and elevators simply count
the numbers of a target species that have
successfully used the passage device. However,
not all fish that reach the vicinity of a fish
passage device are able to use it. For example,
one study of a fish elevator indicates that an
average of 50% (and as little as 18%) of the
available fish are transported.47 Operational
monitoring studies of upstream and downstream
fish passage measures should estimate both the
numbers of fish that successfully used the device
and the numbers that failed. In large rivers it is
often difficult to even roughly quantify the fish
population available for passage. However,
some river systems have multiple mainstem dams
in close proximity, such that counts of upstream
migrating fish at the downstream ladder provide
a reasonable estimate of the fish subsequently
available for passage at the next upstream fish
ladder. It is important to use a standardized
parameter (e.g., the percent utilization of a fish
passage measure) to compare the cost-
effectiveness of different installations.
Wherever possible, the economic value of the
fish transported around a previously impassable
barrier could be estimated and compared to the
,,
'!,•
mitigative measure's construction and
·maintenance costs. This information could be
used to guide future recommendations at other
hydropower sites. Such comparisons must be
made with caution, however, because there may
not be a commercial or recreational fishery for
species that are being protected or are
undergoing restoration. In such cases the benefit
of a successful fish passage device will be
difficult to quantify in dollar terms. The value
of a mitigative measure in these circumstances
depends on the degree to which the upstream
distribution of a. fish species is extended (by
transporting adults upstream or safely passing
. juveniles downstream) or the resulting
expectation of a future fishery, neither of which
is easily predicted.
Cost and Engineering Analyses. The total
economic costs of environmental mitigation at
hydropower projects will continue to grow as
mitigation requirements become more frequent in
both relicensing and new development. Where
hydropower becomes uneconomical, generation
losses must be replaced by conseJVation or other
power sources. Replacement power sources have
their own notable environmental effects when
energy resources are extracted, transported, and
consumed and any residue waste is processed.
The hydropower developer can quantify the
hydropower mitigation costs, and like any
business person, the developer will want to know
the benefits, or payback, associated with these
costs. Unfortunately, this attempt to measure
tradeoffs can lead to confrontations between the
developer and the various agencies involved in
the regulation of hydropower operations, because
the developer is sometimes encouraged to
practice various mitigation methods with
unknown benefits. This is not to suggest that the
hydropower environmental mitigation costs are
unreasonable or that they must have an economic
payback; rather, the costs of mitigation and
substitute power generation should be rationally
measured. Additionally, greater emphasis should
be placed on attempts to quantify the benefits
derived from mitigation practices. ' This would
enable the evaluation of which methods of
mitigation provide the best usage of scare
6-10
resources, resources that can be water, land or
other commodities with economic or
noneconomic value.
This study concentrated on gathering
hydropower environmental mitigation cost data
as it relates to the hydropower developer.
Several additional mitigation costs were not
measured. These additional costs include the
expanded licensing hearings, procedures and
paperwork that is required of FERC because of
hydropower mitigation requirements. The
various state agencies' costs of studying
proposed hydropower sites and practices, and the
associated possible impacts on terrestrial and
aquatic species, and recreation also were not
measured. These costs, as well as all other
mitigation-related agency costs, should be
studied more explicitly in future volumes. All of
these costs are eventually, through one channel
or another, passed on to the consumers of this
country.
Additional effort should be placed on
understanding mitigation costs. Specifically,
future analyses should include scatter plots and
regression analysis; the investigation of potential
trends; and, the examination of potential
dependencies of, for example, DO and instream
flow costs as a function of stream flows.
Regional subgroups of the respective mitigation
methods should be studied. Projects with DO
turbine aeration or DO spill flows, for instance,
should be examined independently to determine
their. respective costs, practices and benefits.
Selected projects should be examined or. a case-
by-case basis to provide a detailed examination
of the operations, benefits and costs of
environmental mitigation. This study has
identified potential .sources of additional cost
data and future work should include obtaining
and analyzing these data. The lessons learned
obtaining information and data analysis during
this study should be applied to future volumes.
Valuation of Environmental Benefits. Two
factors limit the feasibility of monetary benefit-
cost analyses of mitigation practices: (a) the lack
of information to measure the response between
mitigation actions and natural resources87 and
(b) the fact that dollar values are often
inappropriate in evaluating natural resources like
fisheries. Nevertheless, efforts should be
increased to try to develop and demonstrate
benefit-cost applications for hydro projects. The
ECPA reinforces FERC's mandate to apply an
"equal consideration" standard in finding a
balance between power and nonpower resources
in its licensing decisions. This mandate is very
difficult to meet when all resources cannot be
evaluated in some comparable units. Further
development of generic valuation techniques for
the mitigation types studied in this report would
be very beneficial to the hydropower industry
and to its regulators.
Biological Monitoring and Analysis. The
strongest conclusion from this report is that,
although mitigation costs are measurable and
often large, mitigation benefits are essentially
unknown. Benefits are unknown because they
are difficult to measure and the necessary data
usually do not exist. Given the apparent lack of
quantitative infonnation on mitigation benefits,
the' hydropower industry is faced with an
important question: what kind of biological
infonnation would allow the effectiveness of
mitigation measures to be detennined? Some
answers can be provided based on current
knowledge, but additional study is also needed.
Three kinds of biological studies are
considered to be of clear value in addressing the
effectiveness of mitigation. First, empirical
analyses of data obtained from multiple sites can
provide a strong basis for inferring the
importance of particular factors to biological
communities, even when data from any single
site may be inadequate to support such analyses.
Second, where a single factor can be varied in
6-11
isolation from other factors, controlled
experiments can circumvent the problem caused
by interference from other factors (e.g.,
evaluating the effects of DO an<J other
environmental factors on benthic invertebrate
communities 10<). A third kind of study is one in
which detailed observations both within and
between years are incorporated into mechanistic
models that eventually can be used to make
population-level inferences of the effects of
hydropower production. All of these approaches
are data-intensive and therefore expense to
conduct
Hydropower in the U.S. is at a critical point in
its history. In 1993, the original FERC licenses
for more · than 170 projects will expire at
essentially the same time. Other federal
agencies, such as TV A20 and the Bureau of
Reclamation, are planning major operational
changes and equipment upgrades to their
hydroelectric facilities, many of which will result
in significant environmental benefits. These
imminent changes represent truly unique
opportunities to gain a broad new set of
infonnation on mitigation benefits, if the proper
monitoring is designed and conducted at these
sites. While it is certain that a large number of
site-specific monitoring programs will be
instituted in the near future, there is no evidence
that any coordination or synthesis of these
studies will take place. These activities should
be coordinated so that the infonnation content is
not lost. Consultations among FERC and other
interested parties should be held as soon as
possible to detennine the feasibility of
establishing new, coordinated monitoring
programs at relicensed projects and other federal
sites to evaluate mitigation benefits.
7. REFERENCES
1; J. S. Mattice, "Ecological Effects of Hydropower Facilities." Chapter 8, Hydropower Engineering
Handbook, McGraw-Hill, Inc., New York, 1990.
2. Computer Data Systems, Inc., Draft Hydroelectric Power Resources Assessment System User's
Manual (Revised September 1986), prepared for Office of Coal, Nuclear, Electric and Alternate
Fuels, Energy Information Administration, U.S. Department of Energy, Washington, D.C .• 1986.
3. Federal Energy Regulatory Commission (FERC), Hydroelectric Power Resources of the United
States, Report No. FERC-0070, Washington, D.C., January 1, 1988.
4. Federal Energy Regulatory Commission (FERC), PU~PA Benefits at New Dams and Diversions,
Final Staff Report, Docket No. EL87-9, Federal Energy Regulatory Commission, Office of
·Hydropower Licensing, Washington, D.C .• 1988.
5. J. M. Loar and M. J. Sale, Analysis of Environmental Issues Related to Small-Scale Hydroelectric
Development. V. lnstream Flow Needs for Fishery Resources, ORNL/fM-7861, Oak Ridge
National Laboratory, 1981.
6. J. E. Morhardt, lnstream Flow Methodologies, Project 2194-2 Final Report. EPRI EA-4819.
prepared by EA Engineering, Science, and Technology, Inc., Electric Power Research Institute.
Palo Alto, California, 1986. ·
7. D. W. Reiser, et al., "Status of Instream Flow Legislation and Practices in North America,"
Fisheries, 14, 2, 1989, pp. 22-29.
8. K. D. Bovee, A Guide to Stream Habitat Analysis using the lnstream Flow Incremental
Methodology, Instream Flow Infomiation Paper No. 12, U.S. Fish and Wildlife Service
FWS/OBS-82/26, 1982.
9. R. Milhous, et al., Physical Habitat Simulation System Reference Manual-Version II, Instream
Flow Information Paper No. 26, U.S. Fish and Wildlife Service Biological Report No. 89, 16,
1989.
10. C. L. Armour and J. G. Taylor, "Evaluation of the Instream Flow Incremental Methodology by
U.S. Fish and Wildlife Service Users," Fisheries, 16, 5, 1991, pp. 36--43.
11. Federal Register, 46 FR 15, "U.S. Fish and Wildlife Service Mitigation Policy," U.S. Fish and
Wildlife Service, January 23, 1981, pp. 7644-7663.
12. S. Reese, Hydropower Policy (draft), U.S. Fish and Wildlife Service, Washington, D.C., 1988,
3 pp.
13. M. J. Robinson, Division of Project Compliance and Administration, Federal Energy Regulatory
Corrimission, Washington, D.C., personal communication with M. J. Sale, June 4, 1990.
7-1
I;
' 14.
15.
16.
17.
18.
19.
H. H. Hannan, "Chemical Modification in Reservoir-Regulated Streams," The Ecology of
Regulated Streams, Plenum Press, New York, 1979.
T. E". Langford, Electricity Generation an4 the Ecology of Natural Waters, Liverpool University
Press, Liverpool, 1983.
S. F. Railsback, "Dissolved Oxygen Strategies for Hydro Licensing," Hydro Review, June 1988,
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R. J. Ruane, Tennessee Valley Authority, Chattanooga, letter toM. J. Sale, Oak Ridge National
Laboratory, October 30, 1991.
J. S. Gulliver, et al., "Assessing Hydro Projects' Effect on DO Concentration," Hydro Review, 9,
1990, pp. 74-87.
G. Chapman, Ambient Water Quality Criteria for Dissolved Oxygen, U.S. Environmental
Protection Agency (USEPA) Report No. EPA 440/5-86-003, USEPA Office of Water Regulations
and Standards, Criteria and Standards Division, Washington, D.C., 1986.
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Support, USACE Infonnation Exchange Bulletin, U.S. Anny Engineer Waterways Experiment
Station, Vicksburg, Mississippi, 1985-present.
24. D. L. King, Reaeration of Streams and Reservoirs: Analysis and Bibliography, U.S. Bureau of
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Springfield, Virginia, 1970, 131 pp.
25. G. E. Hauser, "Status of an Aerating Labyrinth Weir for Minimum Flow and Oxygen
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26. J. P. Holland, "Localized Mixing to Enhance Reservoir Release Quality," Environmental and
Water Quality Operational Studies, USACE lnfonnation Exchange Bulletin, E-83-1, 1983, pp.
8-12.
7-2
27. J. Gulliver, St. Anthony Falls Hydraulic Laboratory, University of Minnesota, Minneapolis, letter
toM. J. Sale, Oak Ridge National Laboratory, October 17, 1991.
28. S. C. Wilhelms, "Turbine Venting," Environmental and Water Quality Operational Studies,
USACE Infonnation Exchange Bulletin E-84-5, 1984, pp. 1-5.
29. S. E. Howington, "Simultaneous Multiple-Level Withdrawal for Reservoir Release Water Quality
Regulation," Water and Operational Technical Studies, USACE Infonnation Exchange Bulletin
E-87-4, 1987, pp. 1-4.
30. P. Rodrigue, et al., "Improvement of Dissolved Oxygen Levels at Shepaug Hydro Station,"
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31. R. E. Price, "Evaluating Commercially Available Destratification Devices," Water and Operational
Technical Studies, USACE Infonnation Exchange Bulletin E-89-2, 1989, pp. 1.,......5,
32. S. C. Wilhelms, "Reaeration at Low-Head Gated Structures: Preliminary Results," Water and
·operational Technical Studies, USACE lnfonnation Exchange Bulletin E-88-1, 1988, pp, 1-6.
33. S. C. Wilhelms, Reaeration at Navigation Locks, U.S. Anny Waterways Experiment Station,
Vicksburg, U.S. Anny Waterways Experiment Station Technical Report E-85-1, 1985, available
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37. J. Nuss, U.S. Fish and Wildlife Service, Atlanta, personal communication with L. H. Chang,
November 5, 1991.
38. M. C. Bell, Fisheries Handbook of Engineering Requirements and Biological Criteria, Contract
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39. C. H. Oay, Design of Fishways and Other Fish Facilities, The Department of Fisheries of
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Development~ II. Design Considerations for Passing Fish Upstream Around Dams,
ORNL/I'M-7396, Oak Ridge National Laboratory, 1980.
7-3
--
I,''
I
i .lj
I: '.
I:·~
41. I. F. Orsborn, "Fishways-Historical Assessment of Design Practices," American Fisheries Society
Symposium 1, 1987, pp. 122-130.
42. J. ~ruebe and M. Drooker, Modular Innovations in Upstream Fish Passage, DOE!ID/12207-1'2,
U.S. Department of Energy, Washington, D.C., 1982. ·
43. J. R. Ryckman, Effectiveness of Fish LAdders in the Grand River, Fisheries Research Report
No. 1937, Michigan Department of Natural Resources, Lansing, Michigan, 1986.
44. K. Schwalme, et al., "Suitability of Vertical Slot and Denil Fishways for Passing North-Temperate,
Nonsalmonid Fish," Canadian Journal·of Fisheries and Aquatic Sciences, 42, 1985, pp.
1815-1822.
45. S. L. Shepard, Evaluation of Upstream and Downstream Fish Passage Facilities at the West
Enfield Hydroelectric Project, Bangor Hydro-Electric Company, Bangor, Maine, 1991.
46. E. Slatick and L. R. Basham, "The Effect of Denil Fishway Length on Passage of Some
Nonsalmonid Fishes," Marine Fisheries Review, 47, 1, 1985, pp. 83-85.
47. T. Barry and B. Kynard, "Attraction of Adult American Shad to Fish Lifts at Holyoke Dam,
Connecticut River," North American Journal of Fisheries Management, 6, 1986, pp. 233-241.
48. R. Quiros, Structures Assisting the Migrations of Non-Salmonid Fish: Latin America, COPES CAL
Technical Paper No.5, Food and Agriculture Organization of the United Nations, Rome, 1989.
49. Electric Power Research Institute (EPRI), Proceedings, Fish Protection at Stream and
Hydroelectric Power Plants, EPRI CS/EA/AP-5663-SR, Palo Alto, California, 1988.
50. E. P. Taft, Assessment of Downstream Migrant Fish Protection Technologies for Hydroelectric
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51. W. S. Rainey, "Considerations in the Design of Juvenile Bypass Systems," Proceedings of the
Symposium on Small Hydropower and Fisheries, American Fisheries Society, Bethesda, Maryland,
1985, pp. 261-268.
52. D. C. Nettles and S. P. Gloss, "Migration of Landlocked Atlantic Salmon Smolts and
Effectiveness of a Fish Bypass Structure at a Small"Scale Hydroelectric Facility," North American
Journal of Fisheries Management, 7, 1987, pp. 562-568.
53. H. L. Raymond, "Effects of Hydroelectric Development and Fisheries Enhancement on Spring and
Summer Chinook Salmon and Steelhead in the Columbia River Basin," North American Journal
of Fisheries Management, 8, 1988, pp. 1-24.
54. J. Ferguson, "Relative Survival of Juvenile Chinook Salmon through Bonneville Dam on the
Columbia River," Waterpower '91, Vol. 1, Proceedings of the International Conference on
Hydropower, American Society of Civil Engineers, New York, 1991, pp. 308-317.
55. D. E. Dorratcague, et a!., "Fish Screens for Hydropower Developments," Waterpower · 85, Vol.
3, Proceedings of the International Conference on Hydropower, American Society of Civil
Engin.eers, New York, 1985, pp. 1825-1834.
7-4
56. F. C. Winchell, Evaluation of the Eicher Screen at Elwha Dam: Spring 1990 Test Results,
EPRI GS/EN-7036, Electric Power Research Institute, Palo Alto, California, 1991.
57. F. C. Winchell, Stone and Webster Engineering Corporation, personal communication with G. F.
Cada, September 13, 1991.
58. F. C. Winchell and C. W. Sullivan, "Evaluation of an Eicher Fish Diversion Screen at Elwha
Dam," Waterpower '91, Vol. 1, Proceedings of the International Conference on Hydropower,
American Society of Civil Engineers, New York, 1991, pp. 93-102.
59. R. F. Ott, et al., "Arbuckle Mountain Hydro Vertical-Axis Fish Screens," Proceedings: Fish
Protection at Steam and Hydroelectric Power Plants, Electric Power Research Institute, Palo Alto,
California, 1988, pp. 3-1 to 3-11.
60. D. Hagey, Eugene Water and Electric Board, personal communication with G. F. Cada,
December 4, 1990.
61. D. T. Michaud, "Barrier Net Perfonns Well in Test Program," Hydro Review, X, l, 1991,
pp. 117-118 .
. 62. E. P. Taft, Stone and Webster Engineering Corporation, personal communication with G. F. Cada,
November 12, 1991.
63. P. Martin, et al., "A Demonstration of Strobe Lights to Repel Fish," Waterpower '91, Vol. 1,
Proceedings of the International Conference on Hydropower, American Society of Civil
Engineers, New York, 1991, pp. 103-112.
64. E. P. Taft, Fish Protection Systems for Hydro Plants: Test Results, Interim Report, EPRI GS-
6712, Electric Power Research Institute, Palo Alto, California, 1990.
65. P. H. Loeffelman, Aquatic Animal Guidance Using a New Tuning Process and Sound System, 2nd
Edition, American Electric Power Service Corporation, Environmental and Technical Assessment
Division, Co1wnbus, Ohio, 1990.
66. P. H. Loeffelrnan, et al., "Fish Protection at Water Intakes using a New Signal Development
Process and Sound System," Waterpower '91, Vol.1, Proceedings of the International Conference
on Hydropower, American Society of Civil Engineers, New York, 1991, pp. 355-365.
67. P. H. Loeffelman, et al., "Using Sound to Divert Fish from Turbine Intakes," Hydro Review, X,
6, 1991, pp. 3o--43.
68. Federal Register, 55 FR 1, "Fish and Wildlife Service Hydropower Policy; Public Comments
Requested," U.S. Fish and Wildlife Service, January 10, 1990, pp. 923-924.
69. R. Narayanan, et al., An Economic Evaluation of Benefits and Costs of Maintaining lnstream
Flows, Water Resources Planning Series, UWRL/P-83/04, Utah Water Resource Laboratory, Utah
State University. Logan, Utah, June 1983.
7-5
i'
70. U.S. Department of Commerce, Business Consumers Digest, March 1990, March 1989, March
1990, Statistical Indicators Division of the Bureau of Economic Analysis, U.S. Government
Printing Office, Washington, D.C.
71. D. Mathur, et al., "A Critique of the Instrearn Flow Incremental Methodology," Canadian Journal
of Fisheries and Aquatic Sciences, 42, 1985, pp. 825-:-831.
72. D. Scott, and C. S. Shirvell, "A Critique of the Instrearn Flow Incremental Methodology and
Observations on Flow Determination in New Zealand," Regulated Streams: Advances in Ecology,
Plenum Press, New York, 1987, pp. 27-44.
73. M. B. Bain, "Ecology and Assessment of Warrnwater Streams: Workshop Synthesis," Biological
Report 90, 5, U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C., 1990,
44 pp. .
74. N. E. Johnson and R. M. Adams, "Benefits of Increased Streamflow: the Case of the John Day
River Steelhead Fishery," Water Resources Research, 24, 11, 1988, pp. 183~1846.
75. J. Loomis, "The Economic Value of Instrearn Flow: Methodogy and Benefit Estimates for
Optimum Flows," Journal of Environmental Mqnagement, 24, 2, 1987, pp. 169-179.
76. S. W. Wolff, et al., Brown Trout Population and Habitat Changes Associated with Increased
Minimum Low Flows in Douglas Creek, Wyoming, Biological Report 90(11), U.S. Department of
the Interior, Fish and Wildlife Service, Washington, D.C., 1990, 20 pp.
77. S. B. Weisberg, et al., "Enhancement of Benthic Macroinvertebrates by Minimum Flow from a
Hydroelectric Darn," Regulated Rivers: Research & Management, 5, 1990, pp. 265-277.
78. B. F. Waters, "A Methodology for Evaluating the Effects of Different Strearnflows on Salmonid
Habitat," lnstream Flow Needs, II, American Fisheries Society, Bethesda, Maryland, 1976,
pp. 254-266.
79. 0. T. Gorman and J. R. Karr, "Habitat Structure and Stream Fish Communities," Ecology, 59, 3,
1978, pp. 507-515.
80. I. J. Schlosser, "Flow Regime, Juvenile Abundance, and the Assemblage Structure of Stream
Fishes," Ecology, 66, 5, 1985, pp. 1484-1490.
81. J. E. Baldrige and D. Amos, "A Technique for Determining Fish Habitat Suitability Criteria: A
Comparison Between Habitat Utilization and Availability," Acquisition and Utilization of Aquatic
Habitat Inventory Information, Portland, Oregon, October 28-30, 1981, Western Division,
American Fisheries Society, 1981, pp. 251-258.
82. D. J. Orth, et al., "Considerations in the Development of Curves for Habitat Suitability Criteria,"
Acquisition and Utilization of Aquatic Habitat Inventory Information, Proceedings, Portland,
Oregon, October 28-30, 1981, Western J?ivision, American Fisheries Society, 1981, pp. 124-133.
83. D. J. Orth, "Ecological Considerations in the Development and Application of lnstrearn
Flow-Habitat Models," Regulated Rivers: Research and Management, 1, 1987, pp. 171-181.
7-6
84. P. M. Leonard and D. J. Orth. "Use of Habitat Guilds of Fish to Detennine lnstream Flow
Requirements," North American Journal of Fisheries Management, 8, 4, 1988, pp. 399--409.
85. G. C. Gannan and T. F. Waters, "Use of the Size-Frequency (Hynes) Method to Estimate Annual
Production of a Stream Fish Population," Canadian Journal of Fisheries and Aquatic Sciences,
40, 1983,pp. 203Q-2034.
86. S. F. Railsback, et al., A Computer Program for Estimating Fish Population Sizes and Annual
Production Rates, ORNL/I'M-11061, Oak Ridge National Laboratory, Oak Ridge, Tennessee,
1989.
87. A. J. Douglas and R. L. Johnson, "Aquatic Habitat Measurement and Valuation: Imputing Social
Benefits to Instream Flow Levels," Journal of Environmental Management, 32, 1991, pp.
267-280.
88. H. S. Bailey, "A New Life for the St. Croix River," Water Pollution Research Journal of Canada,
23,4, 1988,pp. 56~577.
89. S. L. Nolen, et al., "Development of Water Release Plans for Minimizing Fish Kills below Tulsa
District, Corps of Engineers Impoundments," Journal of Environmental Systems, 18, 4, 1988-1989,
pp. 353-366.
90. A. S. Weithman and M.A. Haas, "Socioeconomic Value of the Trout Fishery in Lake Taneycomo,
Missouri," Transactions of the American Fisheries Society, 111, 1982, pp. 223-230.
91. A. S. Weithman and M.A. Haas, "Effects of Dissolved-Oxygen Depletion on the Rainbow Trout
Fishery in Lake Taneycomo, Missouri," Transactions of the American Fisheries Society, 111,
1984, pp. 109-124.
92. B. L. Yeager, et al., Effects of Aeration and Minimum Flow Enhancement on the Biota of Norris
Tailwater, Tennessee Valley Authority Office of Natural Resources and Economic Development,
Knoxville, Tennessee, 1987.
93. L. H. Chang and S. W. Christensen, "Use of a Bioenergetics Model to Evaluate Effects of
Dissolved Oxygen Mitigation at Norris Dam," Proceedings, Fourth Tennessee Water Resources
Symposium, Knoxville, Tennessee, September 24-26, 1991, Tennessee Section, American Water
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95. C. Raley, et al., Maintenance of Flows Downstream from Water Development Projects in
Colorado, Montana, and Wyoming, Biological Report 88(27), U.S. Departplent of the Interior,
Fish and Wildlife Service, Washington, D.C., 1988, 73 pp. plus appendix.
96. S. G. Hildebrand and L. B. Gross, Hydroelectric Operation at the River Basin Level: Research
Needs to Include Ecological Issues in Basin-Level Hydropower Planning, EPRI WS-80-155,
Electric Power Research Institute, Palo Alto, California, 1981.
7-7
97. HCI Publications. Hydrowire's 1990-1991 Relicensing Report-FERC Project Information and
Contacts, Kansas City, Missouri, December 1990.
98. R. Hunt, Richard Hunt Associates, Annapolis, personal communication with G. Sommers. October
29. 1991.
99. Cada. G. F., et al., "An Analysis of Dissolved Oxygen Concentrations in Tailwaters of
Hydroelectric Dams and the Implications for Small-Scale Hydropower Development." Water
Resources Research, 19, 4, pp. 1043-1048.
100. T. McDonough, et al., Multivariate Analysis of Relationships between Benthic Communities and
Physicochemical Characteristics of Regulated Tailwaters in the Tennessee River Valley, draft
report prepared for the Tennessee Valley Authority, 1990.
7-8
APPENDIX A
SUMMARY OF INFORMATION
RECEIVED FROM DEVELOPERS
Table A-1. Iiems common to more than one mitigation requirement.
Items common to more than one mitigation requirement
Projects having the requiremerit/facility
Studies conducted prior to licensing:
Modeling/fisheries study by licensee
Modeling/fisheries study by resource agency
Modeling by Federal Energy Regulatory Commission
(FERC) staff .
Professional judgment by resource agency
Professional judgmentby FERC
Others
No studies
Current status of requirement/facility:
Implemented/completed
In process/under constr,uction
In operation
Postproject monitoring stUdies/reports done
Postproject monitoring studles/reports not done
~ ·., ·' ' : . . . ' • "·· ~ i. •.·. ,.• .•
Project unconstructed
Timing of need identification or imposition of requirement:
During licensing
After license issued
Other
DO = dissolved oxygen ·
IFR = instream flow requirement
UFP = upstream fish passa~e : .. · ·-. .• . ·
DFP = downstream fish passagew.1"~~~~~~o,,.:1;~;~,, ·
Mitigation requirement type
DO
59
10
4
2
11
3
3
6
32
11
20
IFR
185
39
22
74
66
36
UFP .DFP
34 85
7
6
17
8
2
29
12
17
4
17
5
9
19
8
43
1
22
17
5
58
14
. 52
19
36
16
20
Table A-1 .. (continued).
Items common to more than one mitigation requirement
Point of requirement/facility application/intended effect:
Immediately below project
At a specified distance downstream
Over a length of stream
Other
Objectives of mitigative measure:
Meet state water quality standards
Meet state antidegradation standards
Meet state site-specific water quality standards
Meet other resource agency objectives
Meet FERC parameter levels required by FERC
indt:pendently from other agencies
Objectives not stated or clarified during license process
Protect/ enhance fish population
-Sport/commercial species, adults
-Sport/commercial species, all life stages
-Anadromous fish. all life stages
-Anadromous fish, adults
,.. Anadromous fish, juveniles
-Migratory resident fish, all ~fe stages
-Migratory resident fish, adults
-Migratory resident fish, juveniles
-Migratory resident fish, egg or larval
-Nongame species
DO = Dissolved oxygen
IFR = Instream flow requirement
UFP =Upstream fish passage
DFP = Downstream fish passage
A-2
Mitigation requirement type ·
DO IFR UFP DFP
20 68
13
5 97
4 16
43
5
5
21
6
2 14
111
8
101
23
17
21
13
47
35
7
48
Table A-1. (continued).
Items common to more than one mitigation requirement
-Threatened/endangered species
-Others
Fish habitat
Nonfisheries objectives:
-Protect/enhance water temperature
-Protect/enhance water quality
-Protect/enhance recreation
-Protect/enhance riparian vegetation
-Flushing of sediments
-Other objectives
Postproject study types:
Monitoring of passage rates
Monitoring of fish populations
Measurement of mortality rates
Others
Organization conducting postproject studies:
Resource. agency
Licensee
Both agency and licensee
Others
DO= Dissolved oxygen
IFR = Instream flow requirement
UFP =Upstream fish passage
DFP = Downstream fish passage
A-3
Mitigation requirement type
DO IFR UFP DFP
13
4
144
26
52
44
26
18
3 16
12 11
7 1
10
1 1
5 2
6 13
1
1 1
Table A·2. Items particular to dissolved oxygen.
Items particular to dissolved oxygen
. DO monitoring by licensee
DO monitoring by resource agency
DO mitigation methods:
Spill flows
Spray devices
Intake level controls
Improvements to reservoir water quality
Aeration of reservoir
Aeration in the turbine
Aeration in the tailrace
Others
Water quality/biological parameters monitored:
DO
Temperature
BOD
Others
Fish populations
Benthic populations
Other biological parameters
A-4
30
6
37
3
5
3
1
16
5
8
43
39
1
8
1
1
1
Table A-3. Items particular to instream flow requirement.
Items particular to instream flow requirement
Ramping rate restrictions part of IFR
Method of detemining IFR objectives
Fish sampling by applicant
Fish sampling by resource agency
Use of existing data from resource agency
Professional judgment of resource agency
Existing agency policy
Others
Types of studies used to detemine IFR:
IFIM
HEP
Wetted perimeter
Tennant or Montana method.
Aquatic basejlow standard
Specified flow duration standard
Water temperature/quality
Other studies or assessment methods
Post-project paramete:rs mpnitored: ' · .• ' . ?_:,._ .) ~. .
Flows
•·'"\'
Habitat quali'Yc ...
:-:. ~ ' . -~ . .
Fish population by project operator
Fish population by resource agency
Fishing usage
Water quality and temperature
Sediment and substrate type and distribution
Others
21
32
29
30
116
30
21
44
11
17
.3
21
16
18
22
71
16
20
12
10
22
6
5
Table A-3. (continued).
Items particular to instream flow requirement
Performance objectives for fish passage facility
Pass specified percentage of migratory adults
Present no obvious barriers to upstream movement
Others
None Specified
Table A-4. Items particular to upstream fish passage.
Items particular to upstream fish passage
Type of facility/method in use
Trapping and hauling
Fish ladder
Fish elevator
Other
Performance objectives specified by resource agencies
Pass a specified % of migratory adults
Present no obvious barriers to upstream movement
Other
None specified
A-6
1
17
5
9
5
24
4
3
1
17
5
9
Table A-5. Items particular to downstream fish passage.
Items particular to downstream fish passage
Duration/timing of facility use
Always
Specified seasons
Specified seasons and times of day
Types of compensation for turbine passage losses of fish
Financial compensation to resource agencies
Support of stocking or hatcheries
Other
Perfonnance objectives specified by resource agencies
Specified %fish entrainment exclusion
Specified fisll monality level
Other
None specified
48
18
3
3
3
2
4
3
14
50
A-8
APPENDIX B
SUMMARY OF INFORMATION
RECEIVED FROM AGENCIES
Table B-1. Responses of state resource agencies to agency infonnation request regarding instrcam flow
mitigation.
State
AL
AK
AZ
AR
CA
co
CT
DE
FL
GA
HA
ID
IL
IN
lA
KS
KY
LA
ME
MD
MO
MT
Y= Yes
N=No
Written
mitigation
policy
NR
y
N
N
y
y
NR
NA
N
N
NR
y
N
N
N
NR
N
N
y
NR
N
y
NR =No response
NA = Not applicable
Accepts Instream
off-site flow
mitigation requirements
NR NR
y y
y N
y y
NR y
y y
NR NR
NA NA
NR NR
NA y
NR NR
y y
N NR
N y
NA N
NR NR
y y
N N
y y
NR NR
N N
y y
More than one
instream flow Operational Non-fishery
assessment · monitoring instream flow
method conducted values
NR NR NR
y y y
NR NR NR
NR N y
y y y
y y y
NR NR NR
NA NA NA
NR NR NR
N N y
NR NR NR
N N y
NR NR NR
N N y
NA NA NA
NR NR NR
N N y
NA NA NA
y y y
NR NR NR
NR NR NR
y N y
B-1
Table B-1. (continued).
More than one
Written Accepts Instream instream flow Operational Non-fishery
mitigation off-site flow assessment monitoring instream
State policy mitigation requirements method conducted flow values
NE N N NR NR NR NR
NV N NR y N N NR
NH N N y N N y
NJ y N y y y y
NM NR NR NR NR NR NR
NY NR NR NR NR NR NR
NC N N y y N y
ND NR NR NR NR NR NR
OH .N y y N N y
OK NR NR NR NR NR NR
OR NR NR NR NR NR NR
PA y N y NR NR NR
RI NR NR NR NR NR NR
sc y y y y y y
SD N N NA NA NA NA
TN N y NR y y y
TX N N y y N y
UT y y y y N y
VT NR NR NR NR NR NR
VA NR NR NR NR NR NR
WA y y y y y y
wv N y y y N y
WI NR NR NR NR NR NR
· WY NR NR NR NR NR NR
Y= Yes N=No
NR = No response NA = Not applicable
B-2
Table B-2. Responses of federal resource agencies to agency infonnation request regarding instream flow
mitigation.
Inslream flow Type of
In stream requirements study to Objectives
flow for FERC-determine of inslream Suggested Studies of
Agency, mitigation licensed need for flow mitigation mitigation
region policy? projects? mitigation? mitigation? technologies? effectiveness?
EPA, III N NA D G F,D D
EPA, VII N y (2) c G,WF,M c y (2)
FWS, TX MP y (2) D WWF IFIM NR
FWS,OK N N NA NA IFIM NR
FWS,NM N N NA NA IFIM NR
FWS,OR HP,MP Y (many) GF,NNL AF,CWF IFIM,T,OT N
FWS, VI HP,MP Y (many) IFIM,D,ETS, WWF,CWF, IFIM,OT,FS, N
FWS,III HP,MP Y (many)
FWS.GA HP,MP Y (many)
FWS,MA MP,NFP NR
FWS, PA N Y (many)
NMFS,SE N NA
NMFS,CA N NR
ABF = Aquatic Base Flow method
AF = Anadromous fish
C = Consultation with other state/federal agencies
CWF = Coldwater fish
D = Defer to other state/federal agencies
ETS = Endangered or threatened species
F =Flow data
FS = Fish survey
G = General aquatic life
GF = General fiSheries
HP =Hydropower Policy of the U.S. FWS
IFIM = Inslream Flow Incremental Methodology
M = Macroinvertebrates
MP = Mitigation Policy of the U.S. FWS
N=No
GF,F,ROR M,WF F,O
ss G,SS IFIM,T,O N
SS,FS,F G,AF,ETS IFIM,WP,T ,F y (2)
NFP,SS GF,AF IFIM,F NR
NNL,ROR G,GF WP,ABF N
NA
D
B-3
NA NA NA
SS,AF IFIM NR
NA = Not Applicable
NFP =New England Flow Policy of the U.S. FWS,
Region 5
NNL = No net Joss of aquatic habitat
NR = No Response
0 = Other instream flow methods
OT = Other transect methods
ROR = Run-of-River requirement
SS = Site-specific studies
T = Tennent or Montana Method
WF =Waterfowl
WP =Wetted perimeter method
WWF = Warmwater fish
Y=Yes
B-4
Table B-3. (continued).
DO
Written requirements
DO for
mitigation FERC-Iicensed
State policy projects
LA N N
ME y NR
MD NR NR
MA N y
MI y y
MN y y
MS N NA
MO N NA
MT N N
NE N y
NV N y
NH N N
NJ y y
NM NR NR
NY NR NR
NC N y
ND NR NR
AD= Antidegradation standards
BIOL = Biological monitoring/studies
FW = Other fish and wildlife objectives
I = Intake level control
MD = Modeling
MN = Monitoring
N=No
NA = Not applicable
NR = No response
0 =Other
Type of
study to
determine
need for
mitigation
NA
MN,MD
NR
NR
:MN
MN,MD
NA
0
NR
0
PJ
0
MN,MD
NR
NR
MN
NR
B-5
Suggested
Objectives DO Studies of
of DO mitigation mitigation
mitigation technologies effectiveness
NA NA
SWQ S, SP, I. R
NR NR
FW NR
SWQ,FW s.o
SWQ,AD S, T, 1,0
NA NA
FW S, T
NR NR
0 SP
FW NONE
AD,SWQ S. R
SWQ S, T
NR NR
NR NR
SWQ S. I
NR NR
OP = Method determined by operator
PJ = Professional judgment
NA
NR
NR
N
N
N
NA
BIOL, WG
NR
WQ,BIOL
N
N
y
NR
NR
y
NR
R = Improvements to reservoir water quality
S = Spill flows
SP = Spray devices
SWQ = State water quality standards
T = Turbine aeration
WQ =Water quality monitoring/studies
Y =Yes
Z = Cease operating
II!
Table B-3. (continued).
DO
Written requirements
DO for ·
mitigation PERC-licensed
State policy projects
OH N y
OK NR NR
OR NR NR
PA y y
RI NR NR
sc N N
SD N NA
TN N NA
TX N y
UT N NR
VT NR NR
VA NR NR
WA y NR
wv N y
WI NR NR
WY NR NR
AD = Antidegradation standards
BIOL = Biological monitoring/studies
FW = Other fish and wildlife objectives
I = Intake level conlrol
MD = Modeling
MN = Monitoring
N=No
NA = Not applicable
NR = No response
0 =Other
Type of
study to
detennine
need for
mitigation
0
NR
NR
NR
NR
MN
NA
MD
PJ,MN,
MD.O
NR
NR
NR
NR
MN
NR
NR
B-6
Suggested ·
Objectives DO Studies of
of DO mitigation mitigation
mitigation technologies effectiveness
AD,FW s.o
NR NR
NR NR
SWQ,AD NR
NR NR
SWQ R, I,O
NA NA
SWQ NONE
SWQ,AD OP. I,
T,S
NR NR
NR NR
NR NR
NR NR
AD.SWQ S. SP, I,
T,O
NR NR
NR NR
OP = Method determined by operator
PI = Professional judgment
N
NR
NR
NR
NR
y
NA
y
WQ
NR
NR
NR
NR
WQ
NR
NR
R = Improvements to reservoir water quality
S = Spill flows
SP = Spray devices
SWQ = State water quality standards
T = Turbine aeration
WQ = Water quality monitoring/Studies
Y =Yes
Z = Cease operating
Table B-4. Responses of federal resource agencies to agency infonnation request regarding dissolved
oxygen mitigation.
Dissolved
oxygen
Dissolved requirements
oxygen for
Agency, mitigation FERC-licensed
region policy? projects?
EPA, III N NR
EPA, VII N y
FWS, TX N y
FWS,OK N y
FWS, NM N y
FWS,OR N y
FWS, VI N y
FWS, III N y
FWS,GA N y
FWS, MA N NR
FWS, PA N y
NMFS, SE N NA
NMFS, CA N NR
AD = Antidegradation Standards
BIOL = Biological Monitoring/Studies
FW = Other Fish and Wildlife Objectives
I = Intake Level Control
MD == Modeling
MN == Monitoring
N =No
NA = Not Applicable
NR =No Response
0 =Other
OP = Method Determined by Operator
Type of study Objectives of
to determine dissolved Suggested DO Studies of
need for oxygen mitigation mitigation
mitigation? mitigation? technologies? effectiveness?
REVIEW SSS, AD S, SP, I, R, 0 NR
REVIEW SWQ.AD S, SP, I, R, 0 N
REVIEW, PJ SWQ,FW 0 NR
REVIEW SWQ OP N
REVIEW SWQ S, I, 0 N
REVIEW SWQ SP,O N
NR NR I, SP, 0 WQ
REVIEW FW,O s NR
MN, BIOL, FW SP, 0, OP N
REVIEW
REVIEW FW S, T NR
REVIEW AD S, SP, I, R, 0 N
NA NA NA NA
REVIEW AD,O 0 NR
PI = Professional Judgment
R = Improv.ements to Reservoir Water Quality
REVIEW = Reviews existing studies
B-7
S = Spill Rows
SP = Spray Devices
SSS = State Site-Specific
SWQ =State Water Quality Standards
T = Turbine Aeration
WQ =Water Quality Monitoring/Studies
Y =Yes
Z = Cease Operating
Table B-5. Responses of state resource agencies to agency infonnation request regarding upstream fish
passage.
Passage Required Required
Written Accept requirements for for for Performance Operational
mitigation off-site FERC-licensed anadromous resident objectives performance
State policy mitigation projects fish fiSh quantified monitored
AL N N NR NR NR NR NR
AK y y N NR NR NR NR
AZ N NR NR NA NR NR NR
AR N y N NA N N N
CA y NR NR NR NR NR NR
co y y N NA y N N
CT NR NR NR NR NR NR NR
DE NA NA NA NA NA NA NA
FL N NR NR NR NR NR N
GA N NR NR NR NR NR NR
HA NR NR NR NR NR NR NR
'i':
l,l i
ID y y y y y N N
l IL NR NR NR NR NR NR NR
!, IN N N y NA y N N I
I'
lA N NA N NA NR NR NR
KS NR NR NR NR NR NR NR
i! i KY N y N NA NR NR NR 11! I! LA N N N NA NA NA NA I' I ,I
r!i ME y y y y N y y ji,'
':11
:1'
MD NR NR NR NR NR NR NR
MA N N y y N y y
MI y y y y N N y
i
i1
1 MN :11 NR NR NR NR NR NR _NR
MS NA NA NA NA NA NA NA
'" MO N N N NA NA NA NA !!
Y= Yes
N =No
NR = No response
NA = Not applicable
B-8
Table B·S. (continued).
State
MT
NE
NV
NH
NJ
NM
NY
NC
ND
OH
OK
OR
PA
RI
sc
SD
TN
TX
UT
VT
VA
WA
wv
WI
WY
Y =Yes
N =No
Written
mitigation
policy
N
N
N
N
y
NR
NR
N
NR
N
NR
NR
y
NR
N
N
N
N
N
NR
NR
y
N
NR
NR
NR = No response
NA = Not applicable
Accept
off-site
mitigation
y
N
NR
N
N
NR
NR
N
NR
y
NR
NR
NR
NR
y
N
y
N
y
NR
NR
N
y
NR
NR
Passage
requirements for
PERC-licensed
projects
N
NR
N
y
N
NR
NR
NR
NR
NR
NR
NR
NR
NR
y
NR
NR
N
NR
NR
NR
y
N
NR
NR
Required Required
for for Performance Operational
anadromous resident objectives performance
fiSh fish quantified monitored
N N N N
NR NR NR NR
NA N N N
y N y y
N N N NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
NR NR NR NR
y N y y
NR NR NR NR
NR NR NR NR
NA NA NA NA
NR NR NR NR
NR NR NR NR
NR NR NR NR
y N y y
NA NA NA NA
NR NR NR NR
NR NR NR NR
B-9
Y =Yes
N =No
NR =No response
NA = Not applicable
B-10
Table B-6. (continued).
Passage Required Required
Written Accept Requirements for for for Performance Operational
mitigation off-site FERC-licensed anadromous resident objectives performance
State policy mitigation projects fish fish quantified monitored
MT N y N N N N N
NE N N NR NA NR NR NR
NV N NR N NA N N N
NH N N y y y N y
NJ y N y N y N NR
NM NR NR NR NR NR NR NR
~'Y NR NR NR NR NR NR NR
NC N N NR NR NR NR NR
ND NR NR NR NR NR NR NR
OH N y NR NR NR NR NR
OK NR NR NR NR NR NR NR
OR NR NR NR NR NR NR NR
PA y NR NR NR NR NR NR
RI NR NR NR NR NR NR NR
sc N y y y N NR NR
SD N N NR NR NR NR NR
TN N y NR NR NR NR NR
TX N N N NA NA NA NA
UT N y NR NR NR NR NR
VT NR NR NR NR NR NR NR
VA NR NR NR NR NR NR NR
WA y N y y y y y
wv N y y NR NR YA N
WI NR NR NR NR NR NR NR
WY NR NR NR NR NR NR NR
Y =Yes
N=No
NR = No response
NA = Not applicable
B-11
[I':
rj·
\'I
Table B-7. Responses of federal regulatory and resource agencies to agency infonnation request
regarding fish passage mitigation.
Fish How were
passage needs and Studies of
Agency, mitigation objectives mitigation
region/state policy? detennined? effectiveness?
EPA, III N
EPA, VII N
FWS, TX N
FWS, OK N
FSW, NM N
FWS, OR N
FWS, VI N
FWS, III N
FWS, GA N
FWS, MA N
FWS, PA N
NMFS, SE N
NMFS, CA N
ANAD = Anadromous species
ALL = All species
CONS NR
CONS y
NA NA
NA NA
NA NA
REV y
CONS N
REV NA
REV NA
REV y
REV y
NA NA
REV NR
BAR= No obvious barrier to upstream fish movement
CONS = Consultation with other agencies
EXC =Exclude a specified percentage of fish from entrairunent
MOR = Limit mortality to a specified level
N= No
NA =Not applicable
NR = No response
0 =Other
RES = Resident, migratory species
REV = Reivew of existing infonnation and plans
Y =Yes
B-12
· Type of fish Perfonnance
protected objectives
ANAD, RES BAR, EXC, MOR
ALL BAR, MOR
NA NA
NA NA
NA NA
ALL BAR. MOR
RES EXC
ANAD, RES N
ANAD BAR·
ANAD.RES BAR, EXC
ALL BAR, MOR
NA NA
ANAD BAR, EXC
APPENDIX C
MITIGATION COST SUMMARY WORKSHEETS
-----~----"'!!!!!~
Estimated Yearly Generation Losses 1980·1990
280 SAMPU! SIZE 707 POPULA'fiON SIZE
Estimated No. F!Htimaled Estimated Estimated F!Hlimatt•d ~!stimated J,:stimnled
No. of of Projects Avf'rag:t• 'l'otal Gent'rntion Gem·rntion <:enernlion Gent•ration Generation Generation
Mitigation Projects %of In 1'arget Gentarnllon Generation $0.04 $0.0ii $0.06 $0.011 SO.IO $0.15
M .. thod in Sample Snmples Population l..cw;s (kWh I Loss!kWhl per kWh pNkWh per kWh per kWh pl'r kWh per kWh
DO II 3.93% 28 107,047 2,997,:116 $119,89:1 $149.866 $17!1,8:19 $239,785 $299,732 $44!1,!i!l7
Jnstream Flow 4!1 17.14% 121 2,4119,186 :101,1!11,506 $12,047,66() $15.0W,575 5111,071,490 $24,095,:1211 S:I0,119,151 $45,1711,726
Upstream ~'ish Passage 4 1.43% I() 1,122.120 11,221.200 $4411,11411 5561,060 $67:1,272 $897,6!16 Sl,l22,120 $1,683,180
Downstream Fish Passage 22 7.86% 56 6,1:19,:164 :143,-804,384 S1:1,7fi2.175 Sl7. Hl0,219 $20.6211,26:1 $27,504,:151 S:l4,:180,43H S51.570.651!
Yearly l..a;t Generation Tot.~ Is ul Various per kWh Cosl~ $26.:168,576 $:12.960,720 S:l9.552,86·1 $52,7:17,152 565,921,441 $98,882,161
5 Yt'ars Total Lo~<s Sl:ll.ll42.8111 SI64.Ho:um2 $197.764,:122 $26:!.6115.762 5:129,607,20:1 $494.41 0,80fi
Estimated Yearly Generation Losses 1992-2010
4:16 No. of Re licenso•N
1316 No. of New l.ico•nst's
280 S,\MPLE SIZB 1752 TOTAL
E!slimated ~:~hnHIIt'd B~timatPd l~stimatcd Eshmah·d ~!&limatrrl
No. of Estimated No. Avo•nrg<• Total Gt'ncrntion Gt•n«•ratJon Generation <:t'nf'ration (;(•ncrntion Gem•ratiun f) . Mitif,'lllion Projects %of Projt·cts Gnl'rnhon Generation $0.04 SO.llii $0.06 $0.08 $0.10 SO. Iii
Method 1n Sample Sam ph• Future l..osstkWhl Loss1k\Vhl JX'r kWh per k\\'h per kWh per kWh pl'r kWh per kWh
IJO II :1.9:1'#-69 107,047 7,386,243 $295.450 S:lti!l,:ll2 S443,17ii Sfi!l0,899 $7!18,624 $1, J()j ,!1:16
lnstream Flow 48 17.14'?1· 300 2.411!1,1116 746. 7!".5,800 $2!1,870,232 5:17.:1:17,7!1() $44,805,3411 $59.740,46-1 $74,675,580 $112,01:1,:170
Upstream Fish Pas.quge 4 1.4:1'.:1. 25 1,121!.120 28,053,000 $1.122,120 Sl.402,6ii0 $1,683,180 $2,244.2•10 $2,805,:100 S4,207,!!ii0
Downstream Fish Pu ... ~agt' 22 7.86'.;· 138 6,1:1!1,:164 847.232.232 $:1:1,889,28!1 542.:161,612 $50,833,934 $67,778,579 Sli4, 12:1.22:1 s 121 .OII4.11:1n
Yt'arly Lost Generation Totals at Various per kWh Costs $65.1 77,091 581.471,:164 $97.765,637 $130,:154, 182 s 162.942, 72!! $244.414,091
7 Years Total Loss $456,239,637 $:'i70.~!1!1,546 S684,359,4r>fi $912,479,274 $1,140,599,093 $1.710,11!18,6:19
Estimated Yearly Generation Losses 1980-1990 and 1992-2010
(Includes 198!1-1990 Projects for 5 Years + I !I Future Years, and l!:l!12-2010 Projects for 7 Future Years)
t:stimated Eshmated Estim11ll•d Bstimaled Bstimated Estimated
Generation neneration GenPrlllion Generation <Jeneration Generation
$0.04 $0.05 $!1.06 $0.011 $0.10 $0.15
per kWh per kWh pPr kWh per kWh per kWh per kWh
1980-1990 Licensed Projt'Cts@ 24 Years $632,845,1130 $791,057,287 $949,268,745 $1,265,6!11,660 $1,582,114,574 $2,373,171,862
1992-2010 Licensl'd Projects@ 7 Years $456,2:19,637 $570.299,546 $684,359,456 $912,479.274 $1,140,59!1,093 $1,710,8911,6:1!1
$1,089,085,467 $1,:161,3f>6,833 $1,633,628,200 $2, I 711,170,934 $2,722,713,667 $4,084,070,500
Environmental Mitigation Costs 1980·1990 (1991 Constant Dollar Analysis)
Target Population Size 707 Years for Annual Costs 5
Sample Size 280
Averuge No. of 5 Yt•nr.<
No. Sample Average AvPrnKe Average Annuul Target Tnrgct Target t\nnunl Tnrg~t. Target
Projrcl.q Capital Study 0&~ lie porting Population Populntiun Population Population Population
2RO Costs Costs Cool.~ Costs 707 Capital Cru;l.~ Study Costs O&M Costs Rt•purt Costs 'rotnl Cost.•
DisHOived Oxygen
<IMW 13 $1,099 SI,OOO $706 $1,413 :13 $:16,267 $:1:1,000 $116,490 $2:1:1,145
1&<10 17 $29,926 $:1:1,940 $1,420 $1,941 4:1 $1,2116,818 $1.459,420 $305,300 $417,31;)
10 & <50 21 $19,375 $25.6il4 $4,204 $3,556 5:1 SI,026,87!i $1,:159,662 $1,114,060 $9-'2.:140
50 &<100 2 Sll,919 Sir\ $4,610 S512 s $59,595 so 8115,250 Sl2,t1UO
IOOMW &< 3 $1,079,:152 $307.328 $5,396 $19,668 II $8,634,816 S2,4ilt1,624 $215.840 $7116,720
56 Total Co~l.~ 142 SII,044.3il Sf>,:ll 0,706 SI,Btl6,940 $2,:192,:120 S20,614.:1:17
lnstreum Flow ;; Years Annual Cost.•
< IMW 48 $411,008 $14.279 $1,8:1:1 $1,305 121 $5,808,968 $1,727.759 SI,IOS,965 $7119,525
I&< 10 71) $:18,731 $46,636 $5,4:16 $2,121 1119 $7,320,159 $11,1114.20·1 S5.137,020 $2,UU4,34:i
() 10& <ilO 26 Slll.'l,689 $231.452 $11,9ii6 Sll.600 66 $12,123,474 Slii.275.sa2 S2.9ii1i,480 S:l,828,000
,!.:;. 50 & <IOU 3 $1.2ii5,378 $1,01!:1.5:10 Sfi.l~2 so II $10,043,024 $11, 66S. 2•10 $204.880 so
IOOMW &< 5 $0 X/A $0 so t:l so so su so
157 Total Costs: 397 S:l5.295,62:i $:14,486,0:15 S9,406,34ii $6,621,870 $8!i,80!l,t17fi
Upstream Fish Passage 5 Years Annual CosLq
<IMW 5 $42,721 $:1.238 $2,1511 $1.619 1:1 $555,:17:1 $42,094 $140,270 Sl05,23ii
1&<: Ill 14 $82,614 $36.2110 $9,:\0fl $3.85!1 35 $2,891.490 $1.269.1100 $1,6211,91)() $674.275
10 & <EiO 7 $653,997 $97,7116 $!1,911! $7,964 18 Sll,771,946 $1,760,1411 $11!12,620 $716.760
50 & <:J()() 0 N/A ":\/A t--:1.\ N/,\ 0 $0 $0 so $0
IOOMW&< 3 $24,745,007 ~I.\ $717,0110 $78,536 II $197 ,960,()56 so S2t1,6t1:1.200 $3,141,440
29 Total Cost.• i4 $21:1.1711,1165 $3,072,042 83 I ,:144,990 $4,637,710 $252,233.607
Downstream Fish Passage 5 Years Annual Costs
<:IMW 24 $25,912 S9,1\48 $4,4!16 St,Oii8 61 Sl.580,6:12 $600,728 S1.:16ti,230 $:122,6HO
I&< 10 38 $277,125 $80,047 $11,1112 $1,640 96 $26.604,00() $7,684,512 S5,367.:II;O $787,200
10& <50 16 $650,025 $198.824 $31,44:1 $4,157 40 $26,001,000 $7,952,960 $6,288,6()() $831,400
50 & <100 0 N/A !\lA N/A N/A 0 $0 $0 $0 so
IOOMW &< I $12,900,020 $5,8fl0.713. N/A N/A :1 $38,700,060 $17,552,139 so $0
79 'rolul Costs 200 $92,885,692 $3:1,790,339 $13,024.190 Sl,941.290 $141,641,:ilt
'l'ot.al CooL• · r\11 Projects 1980-1990 $500,2!19,:1:10
r
(") .
'.,..)
1992-2000
Relicensea
New J.icenst's
Dissolved Oxygtm
<IMW
I&< 10
10& <50
50 & <100
IOOMW&c
Instream Flow
<1MW
I&< 10
10 & <50
SO&<IOO
JOOMW &<
Upstream Fish Pnssage
< IMW
I&< 10
10 & <50
50& <100
IOOMW &<
........ , ... _. ... -
Environmental Mitigation Costs 1992-2000 (1991 Constant Dollar Analysis)
< IMW I & <10 10&< 50&< 100 IOOMW&<
39 131 51 13 4
83 67 15 2
No. of No. of New Total 1991 1991
Total
238
168
1991 1991
15 Years of Annual Costs
Estimated Mitigation Requir"ments
31'l· DO 12% Upstream Fish Passagt>
7:1% lnstream Flow 48% Downl!trt'anl Fish Pnssng"
Totnl Total Tntnl Total
RelicenRed Licensed No. of Avc•rnge Averngl' Average Average Annual Capital
Costs
Study
CosL~
O&M Annual Annual
Proj~cts Projecl~ Projects Capill1l Costs Study CosL~ O&M Costs Ht'porting Costs Cas!.~ Rc•porting Co.•l•
12
41
16
4
74
28
96
37
9
3
173
5
16
6
2
0
29
26
21
5
0
53
61
49
II
I
12:1
10
8
2
0
0
20
38
62
21
5
127
1!9
145
48
10
4
296
15
24
8
2
0
49
51.099
$29,!)26
Sl9.:1iii
$11,919
S I ,079,:152
541!,()()11
S:l8,'i:ll
Sll!:I.6H9
$1.255.:l.iH
so
542,721
$82,61•1
$653,997
N/,\
$24.745,007
$1,000
$33;940
$25,654
NIA
$307,321!
514,27!1
$46,6:16
$2:ll,4ii2
$1,083,530
N/A
$3,238
$36,280
$97,786
NIA
N/A
5706
$1.420
$4.204
54.610
$5,396
51,413 $41,762 $38,000 $402,420 $805,410
Sl,941 81.855,412 $2.104,21!0 $1,320,600 $1,805,1:10
53,556 $406,875 $538,7:14 $1,:124,260 $1,120,140
5512 $S9,595 SO $:145,7ii0 $:11!,400
$19,6611 51,079,352 $307,:128 $80,940 $295,020
'l'ntlol CosL• $:1.442,996 $2.988,:142 1\:1,47:1,970 $4,064,100
51.833 Sl,30ii 54.272,712 Sl,2i0,11:11 $2,447.05ii $1.742,175
55.4:16 $2,121 $5,615,99ii $6,762,220 $11.82:1,:100 $4,61:1.175
$8,9.)6 $11.600 $11,817,072 511,109.696 56,4411.:120 $8,352,000
55.122 SO SI2.55:1,711U $10,83:3,:100 Si611,:1UO $0
so so so $0 $0 so
$2.158
$9.:10!!
$9,918
NIA
$717,080
Total Costs $:11.259,559 $29,978.047 $21,4!!6.975 $14,707,:150
$1,619 $640,815 548.570 $485,550 $364.275
$3,8;)3 $1,982,736 Sll70.i:l0 $~1.:150,8110 $1,387,080
$7,964 $5,231,976 $782:21111 s 1.190,16() $955,680
1:\IA $0 SO SO SO
$78,536 $0 so so so
Totul Cosl.q $7,8S5,527 SI,70Uii8 $5,026.f>fl0 $2,707,035 .....
S( Downstream Fish Passage
~ . < IMW 19 40 59 $25,912 $9,848 $4,486 $1,0511 $1.528,8011 $581,0:12 S:l,970,110 $936,330
·;p-';!> 1 & < 10 63 32 95 $277,125 $80,047 $11,182 $1,640 $26,326,875 $7,604,465 $15,9:14.350 $2.:.137,000
~ ~ ~ > 10 & <50 24 7 31 $650,02i> $198,824 $31.443 $4, 157 $20,150.775 $6,16:1,544 s 14,620.99[, $1 ,933.005
'l'otnl
CosL~
51:1,969,408
$97,4:11.9:11
$17.290,730
~-E:f ?:" ~ 50 & <100 6 I 7 N/A N/A N/A NIA SO SO $0 SO ·~ ~ ~ 100MW & < 2 0 2 $12,900,020 $5,850,713 N/A NtA S2fi,800,040 $11,701,426 $0 $0
·~ S 0 114 80 194 'l'olal Co&L~ $73,806,498 $26,1150,467 s:l4,525,45f> $5,206,335 $139,588,755
• ~ f/l ~~ .... o ~ ;I> ,.... ¢ Tl\ _. 0 ~ \,JIA. ~~g
?rfflfll ~~
'0
~
A
./'
,'f.
,,
I)
~
Environmental Mitigation Costs 2001-2010 (1991 Constant Dollar Analysis)
2001·2010
RelicensPK
New LicenKes
< 1!'.1\\1
29
li08
No. of
I &<10
68
483
10&< 50&.<100
34 10
125 22
No. of New Tulnl 1!1!11
IOOMW & <Total
44
tO
19!11
185
t 148
1991 1991
5 Years of Annual Costs
Estimall>d Mitigation RNtuirt'mt'nts
49~ DO 14'ii· Upstrenm Fish Passage
!lf>'l-lnstream Flow ·S2'h• J)ownstreant Fish Passage.•
Total Total Total
Relicensed l.ict•nsed No. of Averngt• Avcrltgc• Avcragl' Average Annu:>l
Total
Capital
Costs
Sutdy O&M Annual Annual Total
CO>ots
DiHsolved Oxygen
<IMW
I&.< 10
10 &. <50
50 & <100
tOOMW &<
ln!llream Flow
< 1:-.1\V
I & < 10
10& <50
fit)& <100
lOOM\\'&<
Upstream Fish Passage
<IMW
I&< 10
10 & <50
50 &<IOU
IOOMW&<
Downstream Fish PuHsage
< IMW
I&< 10
10 & <50
50 & <100
IOOMW&<.
ProjecL~ Projl'jcts ProjecL~ Co pi tal l:usL~ Study Co~L~. O&M CoKL'I Hc•porling Co.< I.:. CosL~ co.,ls Ht•purling CosL•
14
3:1
l'i
5
249
237
61
II
26:1 $1,0!1!1
210 S2ll.!l26
it! s 1!),;1 i.i
16 Stl.!ll!l
22 5 2'i $1,0itl,:lf,2
91 56:\ 6:14
28
IJ:j
:12
10
42
177
4
10
5
6
26
48:1
4G9
lltl
21
10
1092
71
68
18
3
1
161
24 417
56 396
2f! 103
8 18
511
524
If> I
:n
fi2
1269
15
78
23
4
7
187
441
452
131
26
S.JH.OOII
S:lll.i:ll
Sl:l3.nll!l
Sl.2:iii.:l7!1
so
S42,721
$112,61•1
S65:1,997
N/,\
$24,745,007
$25,912
$277, 12:i
$6.';0,025
N/A
$1,000
5:13,940
S25,6.i4
I'/,\
$:107,328
$14,27!1
$46,6:16
$2:!J,4ii2
SJ.OH:I.ii:IO
to:/,\
$:1.2:18
$36,2110
S!I7.7H6
N/A
N/A
$9,848
$110,047
$1911,824
N/A
36 8 44 $12,900.020 $5,850,713
152 942 10!14
$706
51.420
S.J,204
$4,610
S5.:l96
S1,11:1:1
Sii,4:16
SK.ll;i6
$5,122
so
$2.15H
$9,:10H
$9,91:!
:.It\
$717,01!0
$4,486
$1l,IH2
$:11,443
N/A
$1,41:1 $289,0:17 $26:1.000 $!1211,390
S 1.941 511,0110,020 $9.16:1,1100 $1,!117,00{)
sa.5:if> s t,;; 1 t.2:io $2.001.012 S t,6:19.G!ill
S:i 12 $190,704 SO S:l6ll.l;t~O
$19.6till $2!1,142.504 $11.297 .115l'l Si211.4HO
Total CosL~ s:l!!.2t3,!it:i st9,72:i,t>ml s:;.,;x~.2to
$1,858,0!l5
$2,620,350
SI,31!6,H.JO
S40.91i0
S2.ti!if>,JIIO
Sll.f>tll ,42.;
Si,:JOr, 524,532,0!1!1 S7,29fi,ii69 $4.61!:1.31:. $3,33·1,275
52,1?.1 $20,295,044 $24.4:!7,264 Sl4.2·12,:121l $f>.ii57,020
Sl 1.600 $27,7:17,0:1!1 $:1·1,!l.Jll,21i2 S6.itil.7~0 $8,7!ili,Oll0
~tl $38,916,7111 ~33,ri!!H,ol:t0 Si9:1.!llll SO
Sll SO SO SO SO
Si:I.0!12,H I H
'T'otal Costs $111,480,889 $100.272./ilf• s;26.4111,:12fi s J7,64tl,295 $25:i,!!84,024
$1,til9 S:l,204,075
S:l.llf•;l $6,443,11!12
57 ,!!ti4 s 15,041,!1:11
Nl,\ $0
S711,1i:lti $17:1,215,1149
Total Costs $197,904,947
SJ,05!1 $11.427,192
$242,115()
$2,fi29,114U
$2.249,()71!
so
$0
$5.:121,768
S809,2fill
s:l.6:lO.I2n
st.l40.r.7n
sn
$2ii.09i,!IOO
$:10,677,740
$4.:142,968 $9.8!11,6:!0
$1.640 SJ25,260,500 $36,1111,244 $2ii,271,:120
$4,157 $85.153,275 $26,04fi.944 $20,595,165
N/,\ $0 $0 SO
$607.125
St,502,67tl
$!l15,1!6t)
$0
52,7411,760
$5.77 4,4l!i
$2.3:12,H90
$3,706,400
$2,722,1!:11i
$0
$239,6711,1170
N/A N/A $567,600,81!0 $257,431.:172 $0 $0
'l'olnl CosL~ $789,441,647 $324,001,li211 S!i!i,758,1tii $8,762,12.'\ $1,177,96:1,61/i
'T'otal CosL~. All Projects 2001-2010 $1,746.609,327
'T'otal Costs· All Projects 19!11-2010 $2,014,800,151
. ·'-"
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