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Susitna-Watana Hydroelectric Project Document
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Title:
Technical memorandum: Characterization and mapping of aquatic habitats SuWa 200
Author(s) – Personal:
Author(s) – Corporate:
HDR
AEA-identified category, if specified:
Final study plan
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 200
Existing numbers on document:
Published by:
[Anchorage : Alaska Energy Authority, 2013]
Date published:
July 2013
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Study plan Section 9.9A
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Document type:
Pagination:
17 p. in various pagings
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Notes:
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
July 1 5, 2013
Ms. Kimberly D. Bose
Secretary
Federal Energy Regulatory Commission
888 First Street, NE
Washington, DC 20426
Re: Susitna-Watana Hydroelectric Project, FERC Project No. 14241-000;
Characterization and Mapping of Aquatic Habitats Technical
Memorandum
Dear Secretary Bose:
On April 1, 2013, the Federal Energy Regulatory Commission (Commission or FERC)
issued its Study Plan Determination (April 1 SPD) for 14 of the 58 proposed individual
studies in the Alaska Energy Authority’s (AEA) Revised Study Plan (RSP) for the
Susitna-Watana Hydroelectric Project, FERC Project No. 14241 (Project).
When approving the Characterization of Aquatic Habitats Study, RSP Section 9.09,
FERC recommended that AEA consult with the Technical Workgroup (TWG) and file
the following information to quantify small and low-order tributaries in the Upper River
study area:
1. A detailed description of the specific methods to be used for selecting a
representative sample of small and low-order Upper River tributaries for
aquatic habitat mapping.
2. Documentation of consultation with the TWG, including how its comments
were addressed.
Consistent with the Commission’s recommendations within the April 1 SPD, AEA is
filing the attached Characterization and Mapping of Aquatic Habitats Technical
Memorandum (attached as Attachment A).
Although the April 1 SPD recommended that this document be filed by June 30, 2013,
this recommended deadline was extended by Commission Staff to allow AEA to seek
additional consultation from TWG participants.
The draft version of this document was made available for review on July 3, 2013.
2
On Saturday, July 1 3, 2013, via email, AEA received written comments on this document
from U.S. Fish and Wildlife Service and National Marine Fisheries Service. Attached as
Attachment B is a comment response table that includes a response to these written
comments, and an explanation for why comments were not incorporated into the final
plan.
As always, AEA appreciates the participation and commitment to this licensing process
demonstrated by Commission Staff, federal and state resource agencies, and other
licensing participants. AEA looks forward to working with licensing participants and
Commission Staff in implementing the approved studies, which AEA believes will
comprehensively investigate and evaluate the full range of resource issues associated
with the proposed Project and support AEA’s license application, scheduled to be filed
with the Commission in 2015.
If you have questions concerning this submission please contact me at wdyok@aidea.org
or (907) 771-3955.
Sincerely,
Wayne Dyok
Project Manager
Alaska Energy Authority
Attachments
cc: Distribution List (w/o Attachment)
Attachment A
Characterization and Mapping of Aquatic Habitats Technical Memorandum (July 2013)
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Technical Memorandum:
Characterization and Mapping of Aquatic Habitats
Prepared for
Alaska Energy Authority
Prepared by
HDR
July 2013
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i July 2013
TABLE OF CONTENTS
1. Background ............................................................................................................................ 1
2. FERC Staff SPD Recommendations to RSP Section 9.9 .................................................... 1
3. Selection of Small and Low-order Tributaries for Habitat Mapping within the
Reservoir Inundation Zone ................................................................................................... 2
4. Summary ................................................................................................................................ 5
5. References ............................................................................................................................... 5
LIST OF TABLES
Table 1. List of primary and secondary tributaries proposed for fish population
sampling and habitat mapping within the proposed inundation zone. .................................... 6
Table 2. Inventory of low-order (secondary or tertiary) tributaries in the proposed
reservoir inundation zone............................................................................................................. 7
APPENDICES
Appendix A: Map of Tributaries in the Upper Susitna River Showing Low-order
Tributaries within the Proposed Reservoir Inundation Zone
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii July 2013
LIST OF ACRONYMS AND ABBREVIATIONS
Abbreviation Definition
AEA Alaska Energy Authority
AWC Anadromous Waters Catalog
FDAIP Fish Distribution and Abundance Implementation Plan
FERC Federal Energy Regulatory Commission
HRM historic river mile
ISR Initial Study Report
PRM Project river mile
Project Susitna-Watana Hydroelectric Project
RSP Revised Study Plan
TM Technical memorandum
ZHI zone of hydraulic influence
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 1 July 2013
1. BACKGROUND
On December 14, 2012, Alaska Energy Authority (AEA) filed with the Federal Energy
Regulatory Commission (FERC) its Revised Study Plan (RSP), which included 58 individual
study plans (AEA 2012). Included within the RSP was the Characterization of Aquatic Habitats
Study, Section 9.9. This study focuses on the characterization and mapping of aquatic habitats
with the potential to be altered and/or lost as a result of construction and operation of the
proposed Susitna-Watana Hydroelectric Project (Project).
On February 1, 2013 FERC issued its Study Plan Determination (February 1 SPD) for 44 of the
58 studies, approving 31 studies as filed and 13 with modifications (FERC 2013a). A decision
on the remaining 14 studies was deferred until AEA filed additional information and held
meetings with licensing participants to discuss the new information. RSP Section 9.9 was one of
the 14 deferred studies.
On April 1, 2013, FERC issued its SPD (April 1 SPD) for the remaining 14 of the 58 proposed
individual studies in the RSP (FERC 2013b). When approving the Characterization of Aquatic
Habitats Study, RSP Section 9.9, FERC included certain recommendations. This Technical
Memorandum addresses one of the FERC recommended modifications to RSP Section 9.9.
Specifically, in the April 1 SPD (B-211), FERC stated:
We recommend that AEA consult with the TWG and file no later than June 30, 2012, the
following information to quantify small and low-order tributaries in the Upper River
study area:
1. A detailed description of the specific methods to be used for selecting a representative
sample of small and low-order Upper River tributaries for aquatic habitat mapping.
2. Documentation of consultation with the TWG, including how its comments were
addressed.
This memo provides a detailed description of the methodology for selecting a representative
sample of small primary tributaries and low-order (secondary and tertiary) tributaries within the
proposed inundation zone of the Upper River.
2. FERC STAFF SPD RECOMMENDATIONS TO RSP SECTION 9.9
In its April 1 SPD, in addition to the above mentioned FERC recommendation, FERC included
other recommended changes to RSP Section 9.9, which AEA is implementing.
AEA addressed the other FERC SPD recommendations as follows:
a. We recommend that AEA remove the level 5 calculation of edge habitat from the
habitat classification system. See April 1 SPD at 208.
AEA Response: AEA will remove the Level 5 edge habitat from the classification
system described in RSP Section 9.9.5.4 and Table 9.9-4.
b. We recommend changing the classification of backwater, beaver complex, and
clearwater plume habitats from level 3 (mainstem habitat) to level 4 (mainstem and
tributary mesohabitats). See April 1 SPD at 210.
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 2 July 2013
AEA Response: AEA will revise the classification of mainstem backwater, beaver
complex, and clearwater plume habitats in the mainstem as described in RSP Section
9.9.5.4 and Table 9.9-4 from Level 3 to Level 4.
c. We recommend modifying the study plan to have AEA identify and give specific
consideration to backwater habitats, as defined by the agencies (i.e., the confluence
of off-channel habitats with main channel habitats), as a unique habitat feature and
ensure a representative subsample of these locations when selecting transect
locations for one-dimensional or two-dimensional aquatic habitat modeling within
Middle River and Lower River instream flow study sites. See April 1 SPD at 212.
AEA Response: AEA will revise RSP Section 9.9.5.4 and Table 9.9-4 to identify
backwater as a unique habitat feature and to ensure modeling of backwater habitat in
Focus Areas.
d. We recommend modifying the study plan to have AEA classify Middle River tributary
reaches within the zone of hydrologic influence into geomorphic reaches based on
tributary basin drainage area and stream gradient to provide a general
understanding of the relative potential value to fish and aquatic resources, and report
on these attributes in the initial and updated study reports. See April 1 SPD at 213.
AEA Response: AEA will revise the study to state that Middle River tributary
reaches within the zone of hydrologic influence will be classified into geomorphic
reaches based on tributary basin drainage area and stream gradient and that these
attributes will be reported in the Characterization of Aquatic Habitats Study Initial
Study Report (ISR) to be filed with FERC in February 2014.
e. We recommend that AEA provide a detailed description of methods and results of
2012 and 2013 habitat mapping in the initial study report, including a complete set of
photographic base maps delineating macrohabitats (level 3) and mesohabitats (level
4) for all mapped locations. See April 1 SPD at 214.
AEA Response: AEA will revise the study plan to state that a detailed description of
methods and results of 2012 and 2013 habitat mapping will be provided in the
Characterization of Aquatic Habitats Study ISR to be filed with FERC in February
2014.
3. SELECTION OF SMALL AND LOW-ORDER TRIBUTARIES FOR
HABITAT M APPING WITHIN THE RESERVOIR INUNDATION ZONE
The reference of “small and low-order” tributaries are interpreted by AEA to mean small
tributaries emptying directly into the mainstem Susitna River and tributaries to tributaries. For
the purpose of this technical memorandum a tributary that confluences directly with the Susitna
River is referred to as a primary tributary. A tributary that confluences with a primary tributary
is referred to as a secondary tributary and a tributary that confluences with a secondary tributary
confluences is referred to as a tertiary tributary. Also, for the purposes of this technical
memorandum the nomenclature primary, secondary, and tertiary is more definitive than the term
“low-order” that generally refers to any tributary ranging from the smallest of headwater stream
(first-order) to a tributary emptying directly into the Susitna.
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 3 July 2013
The methodology used for selection of tributaries within the inundation zone that will be habitat
mapped incorporates three independent steps. Step 1 describes tributaries selected as proposed in
the RSP Section 9.9. These tributaries represent primarily larger primary and secondary
tributaries. Steps 2 and 3 described below are in response to Item 3 of FERC’s April 1 SPD that
recommends the selection of additional small and low-order tributaries within the proposed
inundation zone.
Step 1: Select all tributaries within the reservoir inundation zone that are proposed for
Fish Distribution and Abundance Sampling (Study 9.05 Implementation Plan).
The tributaries that were previously selected as Step 1 and proposed in RSP Section 9.9 are listed
in Table 1 and include:
• The largest of the primary tributaries - Jay Creek, Kosina Creek, Watana Creek, and
Deadman Creek;
• Four smaller primary tributaries - Unnamed tributaries 206.2, 204.3, 197.6, and 194.8;
• Two large secondary tributaries - Tsisi Creek and Watana Tributary (RB 8.7).
Habitat mapping in tributaries also selected for the Fish Distribution and Abundance Study
sampling provides for synergy across studies and allows for more robust characterization of
these important aquatic habitats. In addition to habitat mapping at low flow events, fish
sampling teams will describe habitats where fish are collected, gaining an understanding of how
habitat conditions and fish-habitat associations in these tributaries change seasonally.
Step 2: Selection of small primary tributaries within the reservoir inundation zone that are
not targeted for fish surveys.
AEA will also habitat map a representative proportion of primary tributaries smaller than those
selected in Step 1. As shown in Appendix A, there are approximately 37 small primary
tributaries that have some distance of channel length within the inundation zone, none of which
have been targeted for fish sampling. Many of t hese tributaries range in length from 1 to 2 miles
with some exceeding 3 miles. Many can be characterized as having a lower gradient reach
located within the inundation zone, followed by a high gradient reach within, or beyond, the
upstream limit of the inundation zone. For most of these tributaries, less than 25% of the total
length of the stream is within the inundation zone. Several of these tributaries may be seasonal
streams or have barriers very near their confluences with the Susitna River. A review of the
aerial video shows that some tributaries may only have subsurface flow in late summer and fall,
as they cross the lateral cobble bars along the Susitna River.
AEA will rely on existing data and GIS analyses to select a subset of these small primary
tributaries for habitat mapping. AEA will determine morphological metrics for each tributary
and then categorize the tributaries into similar groupings (e.g. larger drainage basin with higher
gradient inundation zone; smaller drainage basin with lower gradient inundation zone) based on
the results of the GIS analysis and professional judgment. The morphological metrics that may
be used in categorization include the following:
• Stream length
o total stream length
o reach length in the inundation zone
o reach length upstream of the inundation zone
• Average gradient
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 4 July 2013
o for the entire stream length
o for the reach in the inundation zone
o for the reach upstream of the inundation zone
• Drainage basin area
AEA will randomly select 25% of the tributaries within each category for a total of
approximately 10 additional small primary tributaries to be habitat mapped within the inundation
zone. Habitat mapping methods will be consistent with methods described in RSP Section
9.9.5.3.2.
Step 3: Selection of secondary and tertiary tributaries located within the reservoir
inundation zone.
In addition to large fish-bearing tributaries selected in Step 1 and smaller primary tributaries
selected in Step 2, AEA proposes to habitat map a subset of secondary and tertiary tributaries
that have a section of their stream channel located within the inundation zone. Using available
topographic maps and Project aerial imagery, AEA has identified 21 secondary and tertiary
tributaries having any reach within the proposed inundation zone. Table 2 is a list of these
tributaries and Appendix A is a map of their locations.
As can be seen in Appendix A and Table 2, 15 of the 21 secondary and tertiary tributaries are
within the watersheds of two primary tributaries; unnamed tributary 194.8 and Watana Creek,
both of which fall within the boundaries of geomorphic reach UR-6. The remaining 6 low-order
tributaries are contained within the watersheds of 5 other primary tributaries, all in geomorphic
reaches UR-6, UR-5, and UR-4.
Table 2 provides relative estimates of gradient and rough calculations of stream length for each
of the 21 tributaries. Drainage basin area is unknown at this time. Morphological metrics of all
21 low-order tributaries will be determined using the best available GIS data sets.
A subset of these secondary and tertiary tributaries will be selected for habitat mapping based on
physical characteristics of the tributaries using the methods described below.
1) The initial filter of tributaries to be habitat mapped will be based on those with reach
lengths in the inundation zone that are equal to or exceed one-half mile and 50% of their
total stream length. This minimum stream length is necessary to ensure that there will be
adequate stream length to represent the range of habitat types potentially present in non-
mapped streams.
2) From among the initial cut of secondary and tertiary tributaries a second filter will be
applied to obtain a general representation of streams with similar gradients and drainage
areas.
Applying criteria from 1) above, 9 tributaries are filtered out as candidates for habitat mapping of
low-order tributaries in the inundation zone. Six of these nine are located in the Watana Creek
watershed. Since the other 3 candidates are each in a different watershed, all three of these will
be habitat mapped. Applying criteria 2) in Watana Creek watershed, a sub-set of the six
secondary and tertiary tributaries will be selected based on stream typing using similarities in
gradient and drainage basin size.
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 5 July 2013
At this time the physical data on stream gradient and drainage area are not available for filtering
at the second criteria level. Regardless, we propose that a minimum of 33 percent of the low-
order tributaries identified in Watana Creek (or two tributaries) will be selected for habitat
mapping.
In summary, AEA will field habitat map at least five secondary and tertiary tributaries from a
population of 21 low-order tributaries (24 percent) in the inundation zone. Three of these are
197.6 RB-1, 198.4 LB-1, and 207.4 RB-1 and two will be selected in the Watana watershed as
described above. Habitat mapping methods will be consistent with methods described in RSP
Section 9.9.5.3.2.
4. SUMMARY
In this technical memorandum AEA has described a proposed method that will result in the
selection of 25 tributaries within the proposed reservoir inundation zone for habitat mapping.
Ten of these tributaries are large primary and secondary tributaries known to support fish
populations and are targeted for fish sampling under RSP Section 9.5. In addition, AEA
provides a systematic approach to grouping smaller primary, secondary, and tertiary tributaries
based on physical characteristics and random selection of tributaries within categories. This will
result in selection of an additional 10 primary tributaries and at least 5 secondary or tertiary
tributaries for habitat mapping.
5. REFERENCES
ADF&G (Alaska Department of Fish and Game). 2012. Anadromous Waters Catalog.
http://www.sf.adfg.state.ak.us/SARR/AWC/index.cfm. Accessed May 2013.
AEA (Alaska Energy Authority). 2012. Susitna-Watana Hydroelectric Project No 14241-000.
Revised Study Plan (RSP) submitted to FERC December 2012.
AEA. 2013. Susitna River Fish Distribution and Abundance Implementation Plan: Susitna-
Watana Hydroelectric Project FERC Project No. 14241. March 31, 2013.
FERC (Federal Energy Regulatory Commission). Office of Energy Projects. 2013a. February 1,
2013 Study Plan Determination for the Susitna-Watana Hydroelectric Project No 14241-
000. Federal Energy Regulatory Commission.
FERC. Office of Energy Projects. 2013b. April 01, 2013 Study Plan Determination for the
Susitna-Watana Hydroelectric Project No 14241-000. Federal Energy Regulatory
Commission.
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 6 July 2013
Table 1. List of primary and secondary tributaries proposed for fish population sampling and habitat mapping within the proposed inundation zone.
Primary
Tributary
Secondary
Tributary
Geomorphic
Reach
Project
River
Mile
Total
Stream
Length
Drainage
Area Mi
Approximate
Elevation and
River Mile of
Anadromous
Barrier
Habitat Mapping
Study Area1
Documented
Chinook in
Watershed
Tributary Proposed for
FDA Sampling
Mapping
Method
Species Known to be Present in Tributary or Plume2 Chinook Dolly Varden Lake Trout Arctic Grayling Round Whitefish Humpback Whitefish Whitefish spp. Salmonid spp. Burbot Longnose Sucker Slimy Sculpin Sculpin spp. Rainbow Trout Sampled [NO FISH} Jay Creek - RB UR-4 211.0 19.6 61.8 None PRM 0.0 to 2,200 ft NI Yes Aerial and
Ground X X X X X X X X
Kosina Creek - LB UR-4 206.8 39.5 400.2 None PRM 0.0 to 3,000 ft Yes Yes Aerial and
Ground X X X X X X X X X
Tsisi Creek1 - LB UR-4 7.4 (LB) NI NI None PRM 0.0 to 3,000 ft Yes Yes Aerial and
Ground
Unnamed Tributary - LB UR-5 206.2 7.43 <31 None PRM 0.0 to 2,200 ft NI Yes Ground only X X
Unnamed Tributary - LB UR-5 204.3 6.2 <31 Possible – PRM
0.5 PRM 0.0 to 2,200 ft NI Yes Ground only X X X
Unnamed Tributary - LB UR-6 197.6 5.4 <31 PRM 1.3 PRM 0.0 to 2,200 ft NI Yes Ground only X X X X
Watana Creek - RB UR-6 196.8 26.9 174.8 None PRM 0.0 to 3,000 ft Yes Yes Aerial and
Ground X X X X X X X X
Watana Tributary
– RB UR-6 8.7 (RB) UNI NI None PRM 0.0 to 3,000 ft Yes Yes Aerial and
Ground
Unnamed Tributary - RB UR-6 194.8 7.1 124 None PRM 0.0 to 2,200 ft NI Yes Ground only X X X X X X X
Deadman Creek - RB UR-6 189.3 41.9 175.1 ≈1,700 ft - PRM
0.4 PRM 0.0 to 2,200 ft NI Yes Aerial and
Ground X X X X X
1 For streams in watersheds known to support Chinook salmon, the habitat mapping study area will extend to 3,000 feet unless there is a confirmed Chinook barrier between 2,200 and 3,000 feet elevation; in which case the study area will terminate at the impassable barrier. For streams
in watersheds not known to support Chinook salmon, the habitat mapping study area will terminate at 2,200 feet elevation..
2 Fish species presence based on historical and current surveys. Streams between the low the proposed dam
NI: No information available at this time.
TECHNICAL MEMORANDUM CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS TM
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 7 July 2013
Table 2. Inventory of low-order (secondary or tertiary) tributaries in the proposed reservoir inundation zone.
(Green shading indicates preliminary selection for habitat mapping consideration based on Criteria 1, above.)
Primary
Tributary
Secondary
or Tertiary
Tributary1
Geomorphic
Reach
Estimated
Total
Tributary
Length2 (mi)
Estimated Stream
Length in
Inundation2
Zone (mi)
Percent of Estimated
Total Stream
Length in
Inundation
Zone
Relative Estimated
Gradient in
Inundation
Zone3
Total Drainage
Basin Area4 Perennial5
Anadromous
Barrier Downstream
Documented
Chinook in
Watershed
Aerial Video
Available
Primary Tributary
Proposed for
Habitat Mapping
or FDA
194.8
RB-1
UR 6
3.1 1.2 40.0 M-H
UK
UK
No No No Yes
RB-2 3.7 0.8 21.7 M-H UK
RB-3 1.2 0.2 12.5 L UK
LB-1 0.9 0.2 20.0 M-H UK
LB-2 1.6 0.2 12.0 L UK
LB-3 1.6 0.1 4.0 L UK
Sub-total 6 12.1 2.6 21.8
Watana
Creek
RB-1
UR-6
0.6 0.6 100.0 H
UK
UK
No
Yes No Yes
RB-2 1.2 1.2 100.0 L UK
RB-3 6.2 2.2 35.0 L-M Likely
RB-4 7.5 0.6 8.3 H Likely
LB-1 5.0 3.7 75.0 L-H Likely
LB-1.1 2.2 1.6 71.4 M-H UK UK
LB-1.1.1 1.1 1.1 100 M-H UK UK
LB-2 2.5 1.2 50.0 M UK No
LB-2.1 4.3 0.3 7.1 M-H UK UK
LB-3 5.0 0.9 18.8 M Likely No
Sub-total 9 34.5 13.5 38.0
197.6 RB-1 UR 6 3.1 1.9 60.0 H UK UK No No No Yes
Sub-total 1
198.4 LB-1 UR 6 0.9 0.6 66.7 M-H UK UK No NI No No
Sub-total 1
207.4 RB-1 UR 5 0.8 0.6 77.7 M-H UK UK No NI No No
Sub-total 1
Kosina RB-1 UR 4 5.0 0.2 3.8 M UK Likely No Yes No Yes
Sub-total 1
Jay RB-1 UR 4 2.2 0.2 7.1 M-H UK UK No No No Yes RB-2 2.5 0.3 12.5 M-H UK
Sub-total 2 4.7 0.5 10.0
Total 21 62 19.9 32
1 Unnamed secondary and tertiary tributaries in the Upper River have not been assigned a Project name at this time. The alpha-numeric naming system applied in this TM is for the purposes of this TM only.
2 Digitized GIS lengths not yet available.
3 Relative gradients are: H = high, M= moderate, L=low. Digitized GIS gradient data not yet available.
4 Digitized GIS drainage basin area not yet available.
5 Likelihood of tributary being perennial is attributed to any tributary greater than 5 miles in length. There is no other basis for this determination. Field reconnaissance in later summer required.
UK = Unknown,
NI = No information available; UK= Unknown
1
ATTACHMENT B
Alaska Energy Authority Response to the July 15, 2013 Comments of National Marine Fisheries Service and
U.S. Fish and Wildlife Service on the Technical Memorandum; Characterization and Mapping of Aquatic Habitats,
the Susitna-Watana Hydroelectric Project, FERC Project No. 14241 1
Comment AEA Response
1. Paragraphs 1, 2, 3, 6, and 7.
Consistent with the FERC April 1, 2013 Study Plan Determination, this technical
memorandum is limited to providing a detailed description of the methodology for selecting
a representative sample of small primary tributaries and low-order (secondary and tertiary)
tributaries in the within the proposed inundation zone of the Upper River. The
NMFS/USFWS recommendations provided within these paragraphs pertain to other aspects
of RSP Section 9.9 and are therefore beyond the scope of this technical memorandum.
2. Paragraphs 4 and 5
Recommendation:
“….it may be prudent, given the
uncertainty of the eventual dam height, to
include the Oshetna River in the list of
tributary rivers within the inundation zone -
in addition to Jay, Kosina, Watana and
Deadman Creeks. Similarly, Goose Creek
should be included.”
These tributaries will be mapped per RSP Section 9.9.5.3.2 and RSP Table 9.9.2.
3. Paragraph 8 Recommendation:
“The relationship to this study and the fish
habitat and abundance study has been
alluded to in this study plan, the
interactions of these two studies should be
explicitly described: what information
feeds into which study, when, and how.”
The relationship between RSP Section 9.9 and other studies is described in RSP Section
9.9.8 and RSP Figure 9.9-20.
1 A PDF copy of the July 13, 2013 comments is attached as Exhibit 1 to this attachment.
1
EXHIBIT 1
From: Susan Walker - NOAA Federal [susan.walker@noaa.gov]
Sent: Saturday, July 13, 2013 4:23 PM
To: Betsy McGregor; Matt Cutlip; Jeffrey Davis; Buntjer, Michael; eric Rothwell; Berg,
Catherine; Haught, Stormy B (DFG); <jan@hydroreform.org>; joe.klein@alaska.gov
Subject: Review of Technical Memo: Characterization and Mapping of Aquatic Habitats
Hi Betsy -
I apologize for getting this review to you late. Receiving the draft at COB on Wednesday, July 3
did not allow much time for review.
As discussed during the Fish and Aquatics TWG meetings on June 24, NMFS agrees with the the
manner with which AEA has addressed FERC's SPD recommendations a and b (edge habitat
reclassification removal and reclassification of backwater, beaver complex and clearwater plume
habitats from level 3 - mainstem, to level 4 - main stem and tributary mesohabitats).
In regard to FERC SPD recommendation c, we still have concerns over the representativeness
of the subsamples of backwater habitats given the influence of flows on the presence and
extent of this habitat type, and the low-flow (about 12,000 cfs) aerial photography used to
classify these important habitats. We expect that AEA will address the representativeness issue
in its ISR.
We also expect that AEA will address and describe the relative potential value of tributary
reaches in the middle river to fish and aquatic resources, based upon tributary basin drainage
area and stream gradient and report this assessment in the ISR, per FERC SPD
recommendation d. Similarly, we expect that the photographic base maps delineating meso-
and macro-habitats will be field-verified and corrected given the limitations and errors inherent
in the original aerial photography based mapping, per FERC SPD recommendation e and as
explained and discussed during the TWG meeting.
The major issue AEA is seeking to consult with the Services and TWG with is the selection of
small and low-order tributaries for habitat mapping within the reservoir inundation zone. We
agree that the nomenclature AEA proposes: primary, secondary and tertiary, is more definitive
than "low-order". AEA prposes to select all tributaries within the reservoir inundation zone that
are proposed for fish distribution and abundance sampling, Study 9.05. We generally concur
with the methods AEA proposes to select these tributaries. We would like to see more detail on
how these tributaries are determined to be representative the lotic habitats that will be lost or
altered by reservoir flooding and fluctuation in the ISR. However, we question whether the
current inundation zone, based on a dam height of 730 feet, is accurate. The height of the
dam, and thus the elevation of the reservoir inundation zone, is not set. We have seen
proposed ams heights ranging from 730' to 750' with plans for expanding the dam height to as
high as 885'. As there is one very major anadromous fish-bearing tributary, the Oshtna River,
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located less than one mile with an outlet less than 50' higher in elevation above the current low
dam and reservoir elevation of 2050', it may be prudent, given the uncertainty of the eventual
dam height, to include the Oshetna River in the list of tributary rivers within the inundation zone
- in addition to Jay, Kosina, Watana and Deadman Creeks. Similarly, Goose Creek should be
included.
Related to the unknown dam and reservoir heights and elevations, the fluctuation of the head
of the reservoir is not described here (it may be elsewhere). Based on personal conversations
with Bryan Carey and Wayne Dyok, we understand that the head, or upstream-most extent of
the reservoir may fluctuate over a five-mile longitudinal distance as the reservoir is drawn down
and refilled; the interaction of that fluctuation will undoubtably have significant effects on the
two fish-bearing rivers within or near to that fluctuating zone of hydraulic influence, Goose
Creek and the Oshetna Rver. Thus this is another reason to include these tributaries in the
initial assessment.
"Missing" from the assessment of quantification and description of project effects to tributaries
to the reservoir is an assessment of the mainstem Susitna River above the proposed reservoir
and its tributary rivers and streams. The mainstem river could be considered the largest
"tributary" to the reservoir, and no assessment is proposed of the characterization and mapping
of this habitat is proposed. It should be. The effects, loss or change in habitat values and
ecosystem functions from the project on the upper 100 miles of river habitat or the 100s of
miles of the upper river tributaries (from the head of the reservoir to the glacial headwaters
should be quantified. There seems to be an unstated assumption that the project effects will
not extend upstream from the head of the reservoir, yet, creating a 40+ mile long lentic habitat
in place of existing logic river is certain to have effects on the upper river. The effects of the
project need to consider the river system in its entirety, as opposed to assessment of small
isolated patches.
AEAs use of the proposed selection of small and low-order tributaries for habitat mapping
within the reservoir inundation zone is not clearly stated. It is implied that the selected habitats
will be mapped to document fish habitat values that will be lost, and that this information will
be extrapolated to result in a total amount of lost habitat and lost habitat value for purposes of
mitigation, compensatory or otherwise. But this is not stated or described. It should be
explicit. In addition to the amount of habitat lost due to inundation, the amount and type of
habitat lost to inundation, affected by reservoir fluctuation and the amount and value of habitat
remaining needs to be mapped, described as to function and quantified. The quality of lost
stream habitat as well as the quality of remaining stream habitat above the reservoir fluctuation
zone and inundation zone should be assessed for its current and post-project values to support
fish and other flora and fauna and contributions to ecosystem functioning.
The relationship to this study and the fish habitat and abundance study has been alluded to in
this study plan, the interactions of these two studies should be explicitly described: what
information feeds into which study, when, and how. Similarly, the relationship between
information gathered in this study with information useful to other studies should be
described. At a glance it appears that this study is inter-related to at least the Fish Passage
Feasibility Study (quality and quantity and connectivity of stream habitat accessibile from the
reservoir and upstream in the main stem, and ability of that altered habitat to support
anadromous, resident and adfluvial species), several terrestrial wildlife studies, the Future
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Reservoir Fish Study, avian studies (for shorebirds, raptors, and other piscivorous species as
well as those feeding upon other aquatic invertebrate species), and Water Quality (especially
mercury). This study plan should identify other studies which will or could use this information
on how and wen that information will be provided to those investigations.
Thank you for this opportunity to comment on this important technical memorandum. Please
contact me if you have any questions.
--
Sue Walker
NMFS Hydropower Coordinator
Alaska Region
P.O. Box 21668
709 W. 9th Street
Juneau, Alaska 99802-1668
907-586-7646
FAX: 907- 586-7358