HomeMy WebLinkAboutChenega Bay Hydroelectric Reconnaissance Report - Mar 2011 - REF Grant 7030010Chenega Hydroelectric Project
Reconnaissance Report
FINAL
This project was financed by the Denali Commission and its partners:
Prepared for:
Chenega Corporation
3000 C Street, Suite 301
Anchorage, Alaska 99503
Prepared by:
HDR Alaska, Inc.
2525 C Street, Suite 305
Anchorage, Alaska 99503
March, 2011
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Table of Contents
1 Introduction ..............................................................................................................................1
1.1 Project Area ..................................................................................................................1
1.2 Previous Studies ............................................................................................................3
2 Field Reconnaissance ...............................................................................................................3
2.1 July Field Reconnaissance ............................................................................................3
2.1.1 Anderson Creek Reconnaissance Summary ....................................................4
2.1.2 South Lake Reconnaissance Summary ............................................................4
2.2 October Field Reconnaissance ......................................................................................5
2.2.1 Anderson Creek Reconnaissance Summary ....................................................5
3 Hydrology ................................................................................................................................6
3.1 Streamflow Data Collection ..........................................................................................6
3.2 Estimates of Long-Term Streamflow ............................................................................9
3.3 Peak Flow Analysis ......................................................................................................9
4 Project Arrangement ................................................................................................................9
4.1 Project Description .....................................................................................................10
5 Energy Generation .................................................................................................................12
6 Cost Estimates .......................................................................................................................13
7 Economic Evaluation .............................................................................................................13
8 Environmental Considerations ...............................................................................................15
8.1 Fish Resources ............................................................................................................15
8.1.1 Background and Purpose ...............................................................................15
8.1.2 Field Methods ................................................................................................16
8.1.3 Results ............................................................................................................16
8.1.4 Discussion ......................................................................................................20
8.2 Wetlands .....................................................................................................................22
8.3 Permits ........................................................................................................................24
9 Land Ownership, and Water Rights .......................................................................................25
9.1 City Water Supply ......................................................................................................26
10 Conclusions and Recommendations ......................................................................................26
11 References ..............................................................................................................................28
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List of Tables
Table 1. Characteristics of Anderson Creek at City Intake ..............................................................6
Table 2. Streamflow, Anderson Creek at City Intake, April 2009 – September 2010 .....................7
Table 3. Comparison of Nearby Precipitation and Streamflow to 50-Year Averages .....................8
Table 4. Peak Discharge Estimates for Anderson Creek at City Intake ...........................................9
Table 5. Key Project Parameters ....................................................................................................10
Table 6. Average Annual Energy ...................................................................................................13
Table 7. Economic Analysis, all Energy Sold ................................................................................14
Table 8: Economic Analysis, with Present Energy Sales ...............................................................15
List of Figures
Figure 1. Vicinity Map .....................................................................................................................2
Figure 2. Mean Daily Discharge, Anderson Creek at City Intake, April 2009 – September 2010 ..7
Figure 3. Preliminary Project Design .............................................................................................11
Figure 4. Energy Utilization with Present Energy Sales ................................................................14
Figure 5. Fisheries Resources .........................................................................................................18
Figure 6. Office-Based Wetland Mapping .....................................................................................23
List of Appendices
Appendix A. 1992 Chenega Bay Hydroelectric Study and 1982 USCOE Reconnaissance Study
Appendix B. July 2009 and October 2009 Field Reconnaissance Trip Reports
Appendix C. Anderson Creek Flow Data
Appendix D. Energy Calculation
Appendix E. Cost Calculation
Appendix F. Fisheries Resource Information
Appendix G. Office-Based Preliminary Jurisdictional Determination
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1 Introduction
The Chenega Corporation (Chenega) contracted with HDR Alaska, Inc. to evaluate the potential
of a small-scale hydroelectric project to service the village of Chenega Bay on Evans Island,
Alaska (Figure 1). This reconnaissance report examines the viability of small-scale hydroelectric
energy generation primarily at the creek that provides the water source for the community. A
second site was evaluated during the reconnaissance but was not considered viable due to access
constraints.
The scope of work defined for this project included:
Data collection and review.
Field reconnaissance and field reconnaissance memorandum.
Evaluation of hydrology and collection of streamflow data.
Development of conceptual project layout.
Estimation of energy production and project costs.
Permit assessment and wetlands evaluation.
Preparation of this reconnaissance report.
This report is a high-level overview intended to identify projects which demonstrate a basic
measure of feasibility and to eliminate projects that have evident fatal flaws from an engineering
and environmental perspective. This report also provides information to enable Chenega to
determine the economic feasibility of a project and to pursue funding for future phases of the
project.
1.1 Project Area
The project is located within the community of Chenega Bay Alaska (pop. 79). Chenega Bay is
located on Evans Island at Crab Bay, 42 miles southeast of Whittier in Prince William Sound. It
is 104 air miles southeast of Anchorage and 50 air miles east of Seward. It lies at approximately
60.065710 North Latitude and 148.010380 West Longitude (Sec. 24, T001S, R008E, Seward
Meridian.)
The community of Chenega Bay has an average community load of 28 kilowatt (kW), an
estimated peak load of 62 kW and annual community energy sales of 244,187 kilowatt hours
(kWh)/year. Power is presently produced using diesel generators. The annual diesel electricity
generated is 273,610 kWh/year, with a diesel fuel consumption of 23,374 gallons per year
(AEA).
The primary creek investigated for this project was a small creek that flows into Sawmill Bay at
the community of Chenega Bay. At the start of this report the name of this creek was unknown,
but was later identified as Anderson Creek. The main body of this report uses the name
Anderson Creek but memorandum included in the appendices may use other names. A small
creek issuing from a lake on the south side of Evans Island was also investigated during the site
reconnaissance. This creek is called South Lake Creek for the purposes of this report.
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Figure 1. Vicinity Map
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The Anderson Creek watershed drains steep terrain from the ridgeline of Evans Island, contains
no lakes, and has no major tributaries. There is an existing water supply dam and intake
approximately 0.6 miles upstream of the mouth of the creek at elevation 248 feet. This water
system is owned by the community of Chenega Bay, was constructed in 1984 by the U.S. Public
Health Service (PHS), and the water treatment plant was recently renovated by the Alaska Native
Tribal Health Corporation (ANTHC). The drainage area at the city intake is 0.45 square miles in
area. Between the city intake and the community of Chenega there is a large waterfall and three
abandoned timber dams constructed atop smaller natural falls. Between the community of
Chenega and the mouth of the creek there is another small waterfall.
South Lake is at an elevation of approximately 600 feet above sea level and has a 0.54-square
mile drainage area. The outlet creek that drains South Lake flows through steep terrain,
primarily across bedrock, before reaching sea level roughly one mile from the lake. A steep
waterfall is located approximately 0.3 miles upstream from the mouth. A wetland complex is
located on the east side of the stream near the mouth. The South Lake watershed has no major
tributaries.
1.2 Previous Studies
The hydroelectric potential at Chenega was evaluated in 1992 (Phukan Consulting Engineers and
Associates, 1992). This investigation concluded that a project on Anderson Creek was
technically feasible and would generate power at a unit cost of $0.61 per kWh (1992 dollars).
The main body (excluding photograph attachments) of the 1992 report is included in Appendix
A.
The hydroelectric potential at South Lake was evaluated in 1982 (USACE, 1982). This
investigation estimated that a project on Section 22 Lake (South Lake) would generate power at
a unit cost of $0.72 per kWh (1982 dollars). The section of the 1982 report pertaining to Section
22 Lake is also included in Appendix A.
2 Field Reconnaissance
2.1 July Field Reconnaissance
A field reconnaissance was done on July 14 to 15, 2009. The purpose of the field reconnaissance
was to evaluate the feasibility of constructing a small hydroelectric project to service the village
of Chenega Bay. Reconnaissance was done for two sites that had been identified as potential
project locations: Anderson Creek and the South Lake drainage. Anderson Creek drains into
Sawmill Bay, while the South Lake drainage is located on the opposite side of the island and
empties into Prince of Wales Passage. A separate memorandum included in Appendix B
describes the field reconnaissance and provides an overview map of the two areas visited.
The field team evaluated the following engineering aspects during the field reconnaissance:
site access
potential intake and tailrace locations
existing and potential pipeline routes
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potential powerhouse locations
potential transmission line locations
Fisheries-related reconnaissance included recording existing fish passage barriers, documenting
fish species presence and distribution, and characterizing general fish habitat within each system.
The field team relied on minnow traps, hand nets, and visual observations to document fish
presence.
2.1.1 Anderson Creek Reconnaissance Summary
Engineering.Constructing a small hydroelectric project at Anderson Creek appears to be
technically feasible, mainly due to ease of access at the Chenega Bay site and existing
infrastructure. Preliminary findings indicate the intake for the hydroelectric project could be
located at the city water supply intake, and the powerhouse could be located adjacent and to the
north of the existing diesel generator powerhouse. A viable route to connect the powerhouse
back to the stream (i.e. a tailrace) was identified from the proposed powerhouse to the adjacent
stream channel. The primary technical challenge for the site will be the construction of the upper
portion of the pipeline within the narrow confines of the creek ravine.
Fisheries.At a point approximately 0.1 miles upstream from its mouth, the stream flows through
relatively steep bedrock, thereby creating a small bedrock cascade/waterfall. The field team
observed young-of-the-year coho salmon (Oncorhynchus kisutch)in the lower portion of the
stream, downstream from the bedrock falls. Dolly Varden char (Salvelinus malma) was the only
fish species observed upstream from the bedrock falls. The small falls appears to preclude fish
movement past this point; based on local knowledge, salmon have not been observed upstream
from the falls (Vigil 2009).
The field team walked the entire length (approximately 0.45 miles) of the creek between the
intake and the proposed tailrace. Multiple manmade dams (typically constructed at natural falls)
and natural falls considered to be fish passage barriers were documented in the upstream portion
of this reach. The most downstream fish passage barrier encountered was approximately 0.65
miles upstream from the mouth (i.e., approximately 0.2 miles upstream from the proposed
tailrace or 0.25 miles downstream from the city intake).
The farthest upstream Dolly Varden char was observed approximately 0.35 miles upstream from
the mouth. Although not documented at this time, the presence of Dolly Varden char upstream
from this point, but downstream of the fish passage barrier (noted above), was considered likely
and was later documented (see Section 8.1).
2.1.2 South Lake Reconnaissance Summary
Engineering.Constructing the pipeline and road corridor would be difficult due to the steep
terrain in the area. Access is also complicated because of the lack of an existing road connection
to the village of Chenega Bay. An access road or a pipeline would not be possible up the stream
channel or to its west side, due to steep terrain. It may be possible to divert the lake water to the
north and construct a route east of the creek, if the lake level was raised and a dam was
constructed at the natural outlet channel. However, the terrain east of the creek may be too steep
for an access road. Although constructing a small hydroelectric facility is possible in this
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location, the project would be neither economically justifiable nor easily operated, primarily due
to access issues. The village of Chenega has indicated that it is considering a road connection to
the south side of Evans Island via the saddle at the existing runway. If this connection were
constructed it may be worth revisiting the feasibility of this hydroelectric project.
Fisheries.A steep waterfall in bedrock located approximately 0.3 miles upstream from the
mouth precludes fish migration past this point. Minnow traps were fished in the creek
downstream of the waterfall. Dolly Varden char was the only species captured or observed
during the stream survey. Although fish presence was not considered likely in the lake (i.e.,
primarily due to the steep nature of the creek), one trap was fished in the lake. No fish were
captured from or observed in the lake. A wetland complex located along the east of the channel
near its mouth appears to drain into the stream. The team visually inspected a small portion of
the wetland complex; no fish were observed.
2.2 October Field Reconnaissance
2.2.1 Anderson Creek Reconnaissance Summary
A second field reconnaissance was done on October 14 to 15, 2009. The purpose of the field
reconnaissance was to collect additional, site-specific information for Anderson Creek related to
engineering and fish resources. The field team collected streamflow and elevation data; installed
an additional staff gage lower in the drainage; and identified the upstream extent of fish presence
in Anderson Creek. A separate memorandum included in Appendix B describes the field
reconnaissance.
Engineering.The primary technical challenge for the site will be the construction of the upper
portion of the pipeline within the narrow confines of the creek ravine, but this is not seen as
insurmountable and could be accomplished with HDPE pipe. Streamflow data was downloaded
and along with more accurate elevation information will provide a basis for reevaluating the
potential energy from the project. Permitting for the flow modification of the creek in the reach
between the intake and the tailrace will need to be done to finalize evaluation of the potential
energy.
Fisheries.The purpose of the reconnaissance was to further assess fish presence within the reach
of the creek between the intake and the tailrace, and to determine the upstream extent of fish
presence in Anderson Creek. The team set a total of 21 traps within reach of the creek between
the intake and the tailrace. Traps were fished overnight throughout this reach. Dolly Varden char
was the only fish species captured. The farthest upstream Dolly Varden char was captured in a
pool at the base of the most downstream fish passage barrier approximately 0.65 miles upstream
from the mouth
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3 Hydrology
Characteristics of Anderson Creek at the city intake are summarized in Table 1.
Table 1. Characteristics of Anderson Creek at City Intake
Site Characteristics Anderson Creek
(at City Intake)
Drainage Area (sq. mi) 0.45
Main Channel Length (mi) 0.77
Main Channel Slope (ft / mi) 1625
Mean Basin Elevation (ft) ~600
Range of Basin Elevation (ft) 248 to ~1500
Basin Aspect Southeast
Area of Lakes and Ponds (%) 0%
Area of Forest (%) 46%
Mean annual precipitation (in) 200
Mean min. January temp. (°F) 18
Area of Glaciers (%) 0
3.1 Streamflow Data Collection
At the time of the July 2009 field reconnaissance, streamflow in Anderson Creek at the city
intake was 1.5 cubic feet per second (cfs) (3.3 cfs/square mile), and at South Lake was measured
at 2.7 cfs (5.0 cfs per square mile). As the two basins are of similar size, this difference in runoff
per square mile can likely be attributed to the variation in basin aspect. The Anderson Creek
basin faces southeast and was generally free of snow while the South Lake basin faces northwest
and snowmelt was still contributing to flow in the basin at the time of this reconnaissance.
A stream gage was installed at the city intake on April 2, 2009 at the existing city weir. Data
from the recorder was downloaded on October 14, 2009 and again on September 22, 2010
providing 18 months of streamflow data. Mean monthly flow for this period is shown in Table
2, and a graph of daily flows is shown in Figure 2. Appendix C provides mean daily discharge
data and a flow duration curve for the period of record from April 2, 2009 to September 22,
2010. Flow records were averaged for overlapping days during the 18 month period of record.
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Table 2. Streamflow, Anderson Creek at City Intake, April 2009 – September 2010
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean
Monthly
Flow (cfs) 2.6 9.7 4.2 5.9 11.6 5.1 3.8 3.9 6.8 6.7 5.2 6.7
Runoff
(cfs/square
mile) 5.7 21.6 9.4 13.1 25.9 11.3 8.5 8.7 15.0 15.0 11.6 14.9
Figure 2. Mean Daily Discharge, Anderson Creek at City Intake, April 2009 – September 2010
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Storms happen any season of the year in Prince William Sound, thus there is not a consistent
seasonal pattern of streamflow at Anderson Creek, except during snowmelt in the spring.
Between mid-April and late June, flow is higher than the mean (5 cfs) for 40 to 50 days. Other
months of the year, Anderson Creek is flashy, with rainfall events typically causing flow to rise
above the mean for 48 hours or less. Low flow (lower than 5 cfs) occurs between storms during
the summer and during cold spells in the winter. The longest low-flow period on record is 31
days in the summer of 2009, but typical low-flow periods last 7 to 14 days. During more typical
(wetter) years, storms happen more frequently, shortening the period of time when flow is below
average. A wetter winter may also increase the duration of the spring snowmelt period.
To gain insight as to whether the gaged period was representative of a wet, dry, or average
period, precipitation records from the National Weather Service stations at Cordova (80 miles to
the east) and Seward (50 miles to the west) were obtained along with the 50-year averages.
These data are shown in Table 3 along with the monthly departure from the average. Also shown
is the discharge at Nicolet Creek near Cordova, a gaged stream with similar basin characteristics
to Anderson Creek. Most months, the period of record was drier than average, and this is
reflected in lower-than-average flows in Nicolet Creek for 14 of the 18 months (all but August
and July of 2009 and June and July of 2010). Based on these data, recorded flows at Anderson
Creek represent generally dry conditions.
Table 3. Comparison of Nearby Precipitation and Streamflow to 50-Year Averages
Month
Cordova
Precipitation
(inches)
Deviation
from 50-
Year
Average
(inches)
Seward
Precipitation
(inches)
Deviation
from
Average
(inches)
Nicolet
Creek
Flow (cfs)
Deviation
from
Average (cfs)
Apr-09 1.85 -3.5 1.93 -2.09 3.10 -12.90
May-09 1.56 -4.42 1.25 -2.77 8.91 -3.09
Jun-09 4.32 -0.75 1.67 -0.63 2.84 -1.16
Jul-09 5.85 -0.36 9.95 7.32 6.20 1.20
Aug-09 13.19 4.11 3.67 -1.47 12.96 4.96
Sep-09 10.68 -2.88 3.51 -6.55 9.76 -0.24
Oct-09 6.64 -5.57 7.81 -1.96 5.81 -9.19
Nov-09 4.88 -3.28 7.26 0.29 3.95 -11.05
Dec-09 8.27 -0.23 5.69 -1.86 8.99 -6.01
Jan-10 2.98 -3.23 1.45 -4.65 9.84 -4.16
Feb-10 5.55 -0.98 10.09 4.32 7.66 -6.34
Mar-10 6.51 1.11 2.66 -1.12 6.54 -5.46
Apr-10 7.75 2.4 5.35 1.33 8.91 -7.09
May-10 3.64 -2.34 1.94 -2.08 9.40 -2.60
Jun-10 5.87 0.8 1.83 -0.47 6.93 2.93
Jul-10 8.21 2 4.54 1.91 9.47 4.47
Aug-10 8.36 -0.72 3.97 -1.17 6.37 -1.63
Sep-10 1.57 -11.99 0.67 -9.39 1.73 -8.28
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3.2 Estimates of Long-Term Streamflow
A number of USGS stream gages in the Western Prince William Sound area were considered to
select a station for estimating a long-term streamflow record for Anderson Creek at the city
intake. Nicolet Creek near Cordova was selected as the most comparable station to Anderson
Creek. Nicolet Creek has a 0.76-square mile drainage area and was gaged continuously by the
USGS from September 9, 1999 until the present (11 years). Although seasonal differences
between the creeks were apparent when comparing the first 6 months of streamflow data, it
seemed appropriate to use Nicolet long-term daily means adjusted by drainage area to fill in
missing months. This correlation was revisited when a full 18 months of hourly streamflow data
had been collected at Anderson Creek and found to be inconsistent. For example, in 2009
snowmelt was a full month earlier at Nicolet Creek than at Anderson Creek, but in 2010
snowmelt peaks were concurrent. Short-duration storm peaks occurred with similar frequency
but different timing between the two gages. The most appropriate record on which to base daily
energy estimates is the 18 months of data at Anderson Creek. The energy estimate will likely be
conservative because of persistent dry conditions during the period of record described above.
3.3 Peak Flow Analysis
Applying the USGS regression equation for Region 3 yields the discharge estimates summarized
in Table 4. (Curran 2003). This regression equation applies the following basin characteristics:
drainage area, the percent of the drainage basin that is lake storage, annual precipitation, and
average January temperature. The peak hourly flow recorded for the period of record of April 2,
2009 to September 22, 2010 was 117 cfs on September 24, 2009.
Table 4. Peak Discharge Estimates for Anderson Creek at City Intake
Recurrence
Interval
Peak Discharge
Estimates
(years)(cfs)
2 158
5 210
10 245
25 288
50 320
100 350
200 382
500 422
Note: Based on USGS Regression Equation (Curran 2003)
4 Project Arrangement
This section of the report describes arrangement of a project for hydroelectric generation at
Anderson Creek. The alternative described in this report would be a stand-alone project that
would discharge its water back into Anderson Creek. This project would be run-of-the-river
because the Anderson Creek basin is too steep to create a significant amount of storage.
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4.1 Project Description
The intake for Anderson Creek would be located at the existing city intake at elevation 248 feet
mean sea level (MSL); Figure 3. Water would be conveyed to the powerhouse via a 12-inch
diameter 2,000-foot-long HDPE or steel pipeline. This pipeline would be either above ground
HDPE pipe supported either by cables or steel pipe supported on concrete saddles through the
upper 350 feet of canyon area and shallow buried HDPE pipe once it exits the canyon. The
pipeline would follow and could potentially be combined with the water supply pipeline.
The powerhouse would be located adjacent to the existing diesel powerhouse at a finish floor
elevation of 63.5 feet (MSL) and would be a pre-engineered structure containing a combination
of three 1-cfs and one 2-cfs pumps running in reverse as turbines, induction generators, and
associated switchgear and controls. This type of generating system would need to run in parallel
with the existing diesel generating units. This configuration was selected due to the small size of
the system and the simplicity of the equipment and operations. It was assumed that a small
control weir would be required to supply back pressure on the pumps to reduce cavitation.
Alternatively, the use of a single turbine may also be applicable. The use of a reaction-type
Francis turbine was also evaluated but not selected due to concerns about operational flexibility,
high installed costs, and poor efficiency at low flows. It is recommended that pipeline material
and equipment selection should be revisited in future feasibility study work.
Water would be returned to Anderson Creek though a 400-foot long rock lined channel (tailrace).
The existing city intake access road would be used for access to the intake and for construction
of the new pipeline. No new electrical transmission line is required as the hydro powerhouse
would be located adjacent to the existing diesel powerhouse.
Key project parameters are presented in Table 5 below. Net head for this run-of-the-river project
would be approximately 169 feet at the design flow of 5 cfs, resulting in a capacity of 54 kW.
Average annual inflow was estimated to be 4.9 cfs.
For determining turbine size, the rated flow of the turbine was sized at 30% on the annual flow
duration curve.
Table 5. Key Project Parameters
Parameter Value
Max. HW, ft 248
Centerline Elev., ft 66
Gross Head, ft 182
Net Head, ft 169
Design Flow, cfs 5
Capacity, kW 54
Avg. Inflow, cfs 4.9
Active Storage, AF 0
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Figure 3. Preliminary Project Design
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5 Energy Generation
Energy generation was estimated using a spreadsheet model. If pump turbine equipment was
selected for this project, the individual units would run in either an “on” or “off” type of
operation. There would be no flow regulation by the unit. As such, the energy generation for
this alternative configuration was estimated by integrating the flow duration curve, net head and
equipment performance data. See Appendix D, Energy Calculation, for more detail.
The following assumptions were used in modeling energy production:
Use of hourly flow data from Anderson Creek for the period of record of April 2, 2009 to
September 22, 2010.
A quantity of 40 gallons per minute (0.09 cfs) on a continuous basis was assumed as the
amount of flow used by the water treatment plant (telephone conversation with Rebecca
Poolis of USPHS, April 16, 2009).
Plant capacity sized for the optimum power available from the stream.
Diesel generators will run continuously, and the hydroelectric system will offset a portion
of the diesel requirements.
Losses for station service, transformers, and unscheduled downtime were estimated to
reduce gross generation by 3%.
Using these assumptions the average annual energy generation was estimated at 224 megawatt-
hours (MWh) corresponding to an annual plant factor (the average percentage of full capacity
used over a given period of time)
From FY 2004 to 2008 Chenega had average annual community energy sales of 250 MWh. This
is approximately the capacity of the project. However, due to the need to operate a diesel
generator in conjunction with the hydroelectric project for voltage and frequency control, the full
output of the hydropower project would not be used until the load grows.
of 48%.
Fisheries studies conducted for this project (Section 8.1) found resident Dolly Varden char in a
portion of Anderson Creek between the intake and the proposed tailrace. The State of Alaska
Fishway Act requires that a “sufficient quantity of water be maintained in the stream to admit
freely the passage of fish” (AS 16.05.841). Satisfying the intent of this statute may require an
environmental flow allowance in the creek to provide fish passage during periods of low natural
stream flows. To evaluate the effect of environmental flow on the project, various minimum
flow allowances at the intake were analyzed and could be expected to reduce generation
proportionately as shown in Table 6. This reduction would occur primarily in the times of low
natural inflow. Environmental flows, if required, would be supplemented by local flows from
tributary streams and spill during time when inflow exceeded turbine capacity.
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Table 6. Average Annual Energy
Environmental
Flow
(cfs)
Average Annual
Energy Generation
(MWh)
0.0 224
0.25 209
0.5 194
0.75 182
1.0 171
6 Cost Estimates
An opinion of probable construction costs was derived for the Anderson Creek project presented
above. The following assumptions were used in the cost estimate:
Indirect construction costs associated with engineering, construction management,
permitting, and the owner’s internal costs were added to the direct construction cost
estimate as lump sum amounts.
A contingency of 30% was added to the total of the direct and indirect construction costs
to reflect uncertainties of layout and design that would not be resolved until later in the
development process.
Interest accrued during a 1-year construction period was assumed to be 5% and was
added to the total of the direct and indirect construction costs.
The estimate assumed first-year operations and maintenance (O&M) expenses were
comprised of the following:
o Total labor, expenses, and owner’s general and administrative (G&A) expenses
were estimated at $5,000/yr.
o A repair and replacement fund of $5,000.
Cost estimates assumed that the project would be operated as part of the overall electrical
generation system; therefore labor to operate the project was not included.
It is estimated that a run-of-the-river project on Anderson Creek would have a construction cost
$850,000 in 2010 dollars. (Appendix E, Cost Information).
7 Economic Evaluation
A detailed economic evaluation was not included in the scope of this work. However, in order to
provide a conceptual view of the economics, a general analysis was done. Results are presented
as the first year estimated annual cost per kWh in 2010 dollars. In deriving these costs, it was
assumed that 100% of the debt would be financed at 5% for 30 years. Annual O&M costs
assume that the diesel power plant operator maintains the hydroelectric plant. Using these
assumptions, the stand-alone project would have a 2010 price of energy of $0.29 per kWh.
Stipulation of environmental flows would increase the cost of this energy. Grant funding would
reduce this cost of energy.
Table 7 provides a simple economic analysis of the project.
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Table 7. Economic Analysis, all Energy Sold
Project Annual Energy (MWh/yr), 0 cfs environmental flow 224
Estimated Project Cost $850,000
Annual Debt Service (30 yr @ 5%, 100% financing of entire project cost) $55,294
Annual O&M Allowance $10,000
Energy Cost per kWh $0.29
Estimated Diesel Efficiency (kWh/gallon) 11.7
Displaced Diesel Fuel (gallons) 19,145
2010 Value of Diesel Fuel ($/gallon) $6
Energy Cost per kWh for Diesel Generation $0.51
Annual Value of Displaced Diesel Fuel at $6.00 per gallon $115,000
The present average annual community energy sales are approximately 250 MWh. Running in
conjunction with a diesel generator, the amount of energy that could be utilized from a
hydroelectric project would be less than its theoretical capacity. Assuming no load growth and
that 30% of the community’s needs would be met with diesel generation, the hydroelectric
project would integrate into the existing system as shown in Table 8.
Figure 4. Energy Utilization with Present Energy Sales
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Table 8: Economic Analysis, with Present Energy Sales
Project Annual Power Sales (MWh/yr), 0 cfs environmental flow 164
Estimated Project Cost $850,000
Annual Debt Service (30 yr @5%, 100% financing of entire project cost) $55,294
Annual O&M Allowance $10,000
Energy Cost per kWh $0.40
Estimated Diesel Efficiency (kWh/gallon) 11.7
Displaced Diesel Fuel (gallons) 14,017
2010 Value of Diesel Fuel ($/gallon) $6
Energy Cost per kWh for Diesel Generation $0.51
Annual Value of Displaced Diesel Fuel at $6.00 per gallon $84,000
8 Environmental Considerations
The following section presents a general overview of potential expected environmental
considerations for a hydroelectric project at Anderson Creek. This section describes fish
resources and wetlands which are considered to be the primary considerations. For the purposes
of this reconnaissance report, HDR Alaska did not conduct any environmental work beyond the
two reconnaissance visits described in Section 2.
8.1 Fish Resources
8.1.1 Background and Purpose
Anderson Creek is listed by the Alaska Department Fish and Game (ADF&G) Anadromous
Waters Catalog (AWC) as providing habitat for sockeye salmon (O. nerka) to a point
approximately 0.45 miles upstream from its mouth (ADF&G 2009a). According to Mr. Vigil, a
resident of the village, pink (humpy; O. gorbuscha) and chum salmon (dog; O. keta) spawn in
the lower reaches of the creek; however, sockeye (red) salmon do not enter Anderson Creek.
1
Figure 4
Mr. Vigil also indicated that salmon do not migrate upstream of a small waterfall approximately
0.1 miles upstream from the mouth and downstream of the road crossing ( ).
The purpose of the fisheries-related reconnaissance level field surveys was to document fish
species presence and distribution, record existing fish passage barriers, and characterize general
fish habitat in Anderson Creek. Information contained in this report is based on the
reconnaissance level field work (July 14 to 15 and October 14 to 15, 2009); interviews with a
local resident Michael Vigil of Chenega Village; and correspondence with ADF&G biologists
Samuel Hochhalter (2009) and Steve Moffitt.
Study methods were reviewed by ADF&G, and fish resource permit (FRP) SF2009-219d-1 was
issued by ADF&G prior to the team conducting fieldwork. The sampling plan, FRP application,
and FRP are provided in Appendix F.
1 Personal communication with Michael Vigil, August 14, 2009.
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8.1.2 Field Methods
The field team relied on minnow traps, hand nets, underwater observations, and visual (ground)
observations to document fish presence. The field team set ¼-inch mesh minnow traps baited
with commercially processed salmon eggs. Traps were set in Anderson Creek from its mouth
upstream to the city intake structure. Traps were fished for varying periods of time, ranging
from less than one hour to overnight; most traps were fished overnight.
The field team relied on visual observations and hand nets in areas where habitat conditions
precluded the effectiveness of minnow traps and underwater observations (i.e., shallow areas).
Polarized sunglasses were used to maximize the effectiveness of this approach. Captured fish
were identified by species and counted before being returned live near the point of capture. The
field team also recorded fish fork lengths (i.e., fork of the tail to the nose) for most of the fish
captured. The field team recorded global positioning system (GPS) locations for each sample
site and documented general habitat and stream channel characteristics. Field photographs
representative of habitat conditions in Anderson Creek are shown in Figure 4.
8.1.3 Results
In July, the field team set a total of 14 minnow traps in Anderson Creek and visually inspected
the stream for fish presence from the mouth to the city intake site. Traps were fished from the
mouth of Anderson Creek to just downstream of the proposed tailrace, and upstream of a fish
barrier (Figure 4). The traps captured Dolly Varden char (n=39) and Sculpin (n=1), and the field
team used hand nets to capture young-of-the-year coho salmon. All coho salmon (i.e., estimated
n=100) and the Sculpin were observed in the downstream portion of Anderson Creek, near or
within the limits of tidal influence. Dolly Varden char fork lengths ranged from 76 mm to 170
mm (mean=124 mm). Fish capture results are presented in Appendix F. The team also identified
probable fish passage barriers: one in the lower portion of Anderson Creek (i.e., downstream
from the road crossing) and a series of falls between the tailrace and the intake, as discussed
below.
In October, the field team returned to further assess fish presence within the reach between the
intake and the tailrace and to determine the upstream extent of fish presence in Anderson Creek.
The team set a total of 21 traps within the reach between the intake and the tailrace. Traps were
fished overnight in the vicinity of the tailrace site, upstream throughout the reach between the
intake and the tailrace, and downstream and upstream of a series of manmade dams and natural
falls (Figure 4). The traps captured Dolly Varden char (n=84) exclusively. The field team
measured Dolly Varden char fork lengths; fork lengths ranged from 63 mm to 160 mm
(mean=103 mm).
In the upstream portion of the reach between the intake and the tailrace, the team recorded GPS
locations for a series of manmade dams (typically constructed at natural falls) and natural falls.
The field team set traps upstream and downstream of each manmade dam and/or falls to confirm
whether or not any of the falls act as passage barriers to fish and to determine the upstream
extent of fish use in Anderson Creek. The traps captured Dolly Varden char immediately
downstream of the lower falls; however, no fish were captured in any of the traps (n=6) set
upstream from this point in October. Additionally, no fish were captured from traps (n=8) set
above this point in July.
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The base of the downstream (i.e., nearest to the tailrace) falls and associated dam in the reach
between the intake and the tailrace was found to be the upstream extent of fish in Anderson
Creek (Figure 4). The natural falls and associated timber dam, measured to be approximately 14
feet high, is located approximately 0.65 miles upstream from the mouth (i.e., approximately 0.2
miles upstream from the tailrace or 0.25 miles downstream from the city dam).
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Figure 5. Fisheries Resources
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The field team also recorded general habitat characteristics observed in Anderson Creek during
both survey events. Overall, Anderson Creek provides good habitat for rearing and resident fish.
Anderson Creek flows through a forested area for most of its length, and therefore has a high
recruitment potential for large woody debris. The creek provides abundant overhanging
vegetation, woody debris, undercut banks, and small pools, all of which provide suitable cover
for fish. Throughout its length, the stream channel varies from approximately 2 feet to 30 feet
wide (i.e. average 12 feet) and just a few inches to over 4 feet deep. All four depth and flow
combinations (i.e., shallow-slow, shallow-fast, deep-slow, deep-fast) are present.
The lower portion of the creek (i.e., just upstream from the mouth) is primarily riffle habitat
dominated by a cobble and gravel substrate. Just upstream from the tidally influenced area,
rearing habitat was considered good with abundant overhanging vegetation, woody debris,
undercut banks, and small pools, all of which presumably provide suitable cover for juvenile
fish. Juvenile coho salmon, Dolly Varden char, and Sculpin occupied this portion of Anderson
Creek. Habitat in the lower section appears suitable for salmon spawning in places although no
spawning was observed.
At a point approximately 0.1 miles upstream from its mouth, the stream flows through relatively
steep bedrock, thereby creating a bedrock cascade/waterfall. Boulders and exposed bedrock
dominate the substrate in the vicinity of the bedrock falls. In July, the field team observed young-
of-the-year coho salmon in the lower portion of the stream, downstream from the bedrock falls.
The field team did not capture or observe coho salmon upstream from this point during either
sampling event. Local knowledge also indicates salmon do not migrate upstream from the falls.
Dolly Varden char, captured during both survey events, was the only fish species observed
upstream from the bedrock falls.
Upstream from the road crossing, the stream flows through a low-gradient slow meandering
channel with variable habitat types including runs, small pools, and riffles. Coarse angular
cobbles and organics/fines are the dominant substrate in this section. Abundant overhanging
vegetation, woody debris, undercut banks, and small pools appear to provide good habitat for
rearing or resident fish.
The length of the stream between the proposed tailrace and the intake is roughly 0.45 miles in
length. In the lower 0.2 miles of this reach, substrate is dominated by variable size gravels (i.e.,
ranging from fine to coarse). All four depth and flow combinations are present throughout the
reach.
In the upstream 0.25 miles of this reach, the stream channel is confined by steep bedrock.
Multiple natural falls and manmade dams preclude fish passage. The upstream extent of fish
presence was identified within a relatively deep (3.5 to 4 feet) plunge pool located at the base of
a waterfall (Barrier Falls 2, Figure 3). Substrate in this area is dominated by small, angular
cobble. The width of the stream channel from this point downstream varies from approximately
5 feet (i.e., higher gradient areas confined by bedrock) to approximately 15 feet (i.e., deep, slow
pools created by downed large wood debris).
In most areas the stream channel appears relatively stable. However, the field team identified
areas where the stream channel recently shifted its course. One such area was located near the
middle portion of the reach between the intake and the tailrace, where the stream has shifted to
Chenega Hydroelectric Project
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the east and is actively cutting through compressed organic material. The stream flows fast
through this moderately incised and narrow (1 to 2 feet) channel (i.e., approximately 250 feet in
length). Canopy cover in this area is significantly less than the majority of the stream. This
section has relatively faster flow and provides a lesser variety of habitats used by Dolly Varden
than the former channel.
8.1.4 Discussion
According to the AWC, streams draining Evans Island into Sawmill Bay primarily provide
spawning habitat for pink salmon, with the exception of Anderson Creek (ADF&G 2009a). The
AWC lists Anderson Creek as anadromous for the presence of sockeye salmon (ADF&G 2009a).
However, according to local knowledge, sockeye (red) salmon do not enter Anderson Creek but
do spawn in O’Brien Creek.2
Pink salmon typically return to their natal streams beginning mid-July through late August
(ADF&G 2009b). Mr. Vigil indicated that large numbers of pink salmon are typically visible
near the mouth of Anderson Creek in mid-late July. He reported that chum (dog) salmon
typically enter the creek at the same time as pink (humpy) salmon (Vigil 2009). The team did not
observe any pink or chum salmon during the survey. It is possible that adult pink and chum
salmon had not yet moved into the creek at the time of the survey. Pink and chum salmon fry
generally emerge in late winter and out migrate in the spring so their presence at the time of this
survey was not expected (Heard 1991).
Local knowledge indicates that pink (humpy) and chum (dog)
salmon spawn in the lower reaches of the Anderson Creek, but do not migrate upstream of a
waterfall located below the road crossing (Vigil 2009). The small waterfall is located
approximately 0.1 miles upstream from the mouth. Based on local knowledge, none of the
salmon species has been observed upstream from the falls.
In Prince William Sound, sockeye salmon return to their natal streams from late May through
August (ADF&G 2009b). Local knowledge indicates that sockeye (red) salmon enter O’Brien
Creek from May through June. Based on local knowledge, sockeye salmon do not enter
Anderson Creek (Vigil 2009). The field team did not observe sockeye salmon in Anderson
Creek. However, in this area (i.e., based on run timing for O’Brien Creek), the peak run of
sockeye salmon would have already occurred by the time of the July 15 survey.
Coho salmon was the only salmon species observed in Anderson Creek. The field team observed
young-of-the-year coho salmon in the lower portion of Anderson Creek during the July survey.
The farthest upstream coho salmon was observed near the base of the small waterfall, located
approximately 0.1 miles upstream from the mouth. The presence of young-of-the-year coho
salmon suggests that adult coho salmon may spawn in the lower portion of Anderson Creek.
Typically adult coho salmon return to their natal streams in late summer through early fall in
Alaska. Run timing in Prince William Sound varies from mid-late July through late September
2 O’Brien Creek, which flows past the airport and drains into Crab Bay, is located approximately one mile to the
northeast. Mr. Vigil counted 28 adult red salmon in 2008. A recent report (McLaughlin 2004) confirmed that
sockeye salmon spawn in O’Brien Creek, and also found coho, pink, and chum salmon. In addition to pink
salmon, AWC lists O’Brien Creek as anadromous for the presence of chum salmon.
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with the peak of the run in late August (ADF&G 2009b). The team did not observe any adult
coho salmon during either survey event
3
In Alaska, Dolly Varden char typically spawn in streams from mid-August through November
(ADF&G 2007). Dolly Varden char is one of the most widely distributed salmonids in Alaska
(DeCicco 2005). Coastal areas throughout the state support both anadromous and resident (i.e.,
potamodrous
. The lack of spawning adults was not surprising, due to
the natural timing of spawning for this species in this area. However, the locals noted the
presence of spawning coho salmon in O’Brien Creek up until early October 2009; the locals
indicated this was later than usual.
4
Dolly Varden char was the most widely distributed species observed and/or captured from
Anderson Creek, and was the only fish species observed upstream from the bedrock falls (i.e.,
located below the road crossing). The upstream extent of Dolly Varden char was recorded at the
base of a large waterfall and associated dam structure, located approximately 0.65 miles
upstream from the mouth.
) forms (DeCicco 2005; ADF&G 2007). The resident form is most often found
upstream from barriers (i.e., natural falls, manmade dams) that prevent the upstream migration of
anadromous fish (Ihlenfeldt 2005). Resident forms typically have smaller body lengths (i.e.,
average 135 mm) than anadromous forms (i.e., average 321 mm) and are darker in color
(Ihlenfeldt 2005). The sea-run Dolly Varden char is typically silver with numerous red to orange
spots (ADF&G 2007). The field team did not observe larger, silvery Dolly Varden char typical
of the sea-run (i.e., anadromous) form during either survey.
The presence of Dolly Varden char upstream from the passage barrier in the lower portion of the
creek; the small body size of fish observed (i.e., min=63; max=170; average=114 mm); and the
lack of larger spawning Dolly Varden presence indicates that Anderson Creek supports a resident
form of Dolly Varden char (i.e., upstream of the small waterfall).
The small waterfall located approximately 0.1 miles upstream from the mouth currently acts as a
barrier to fish movement. Based on preliminary local knowledge and information gained through
the field surveys, the small waterfall marks the upstream extent of anadromous fish use in
Anderson Creek, while the large waterfall and associated dam structure located approximately
0.65 miles upstream of the mouth marks the upstream extent of the resident population of Dolly
Varden in Anderson Creek.
Based on preliminary project design concepts, the intake for the potential hydroelectric project
would be located at the existing city intake site. Water would be conveyed to the powerhouse via
a pipeline; the powerhouse would be located adjacent to the existing diesel powerhouse. Water
would be returned to the stream via a rock-lined channel (i.e. a tailrace).
The project as proposed would divert up to a maximum of 5 cfs from Anderson Creek at the
existing city intake. It is expected that flow from the local drainage basin will supplement the
reach downstream of the intake. This flow will increase with distance downstream. Flows
3 The field team visually inspected the lower portion of Anderson Creek for fish presence in July 2009; however, the
field team did not include the lower 0.1 miles during the October field event.
4 Potamodrous fish migrate within freshwater only
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greater than 5 cfs would pass through the spillway and flow through the stream. Flows greater
than 5 cfs are expected about 30 percent of the time, primarily from snowmelt from April
through June and from rainfall in August and September. Bedload would be released during
high flow events to maintain sediment transport in the creek.
Dolly Varden char was the only fish species observed to occupy habitat in the reach between the
intake and the tailrace during the surveys. Dolly Varden char were observed throughout the
stream to a point approximately 0.65 miles upstream from the mouth, at the base of a waterfall
and dam structure.
Based on preliminary project design concepts, local knowledge, and information gained through
the field surveys, Dolly Varden char is the only species occupying habitat in the reach between
the intake and the tailrace and would therefore be the only species affected by the project.
8.2 Wetlands
A consideration for the siting and selection of any new hydroelectric facilities is the presence of
wetlands and other waters of the U.S. An office-based preliminary jurisdictional determination
(PJD) was prepared for the project area (Appendix G). The attached PJD report describes
locations within a 25.4-acre area that are preliminarily determined to be subject to the
jurisdiction of the U.S. Army Corps of Engineers (USACE) under authority of Section 404 of the
Clean Water Act. By federal law (Clean Water Act) and associated policy, it is necessary to
avoid project impacts to wetlands wherever practicable, minimize impacts where impacts are not
avoidable, and in some cases compensate for impacts.
The PJD report is an office-based study; no formal field verification was conducted. Off-site
identification of wetlands and other waters of the U.S. were completed using readily available
aerial photographs, natural resource mapping, and existing documentation. Based on the findings
of the PJD, it has been preliminarily determined that areas displayed as wetlands on Figure 5 meet
the USACE criteria for being classified as wetland. Approximately 55 percent (13.9 acres) of the
mapped 25.4 acres are wetland and therefore subject to jurisdiction under Section 404.
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Figure 6. Office-Based Wetland Mapping
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The proposed hydroelectric pipeline would be located along the same alignment as the existing
domestic water pipeline. Based on the findings of the PJD and the approximate location of the
existing domestic pipeline, approximately 200 feet of the proposed pipeline would traverse
through wetlands. All three wetland types (i.e., emergent, scrub-shrub, and forested) mapped in
the project area would likely be traversed. The existing pipeline intersects with wetlands at a
point approximately 150 feet downstream from the point at which it is buried underground.
Based on the PJD, the upper portion of the existing access road is also shown to intersect
wetlands. Figure 5 displays the findings of the office-based PJD overlain by existing features and
the preliminary project design.
The remainder of the project area, approximately 45 percent (11.5 acres) of the mapped area,
appears to lack characteristics to support classifying those areas as wetland. This includes the
steep canyon walls of Anderson Creek, developed areas, and mature forested areas situated on
the terrace above Anderson Creek. These areas would not be subject to jurisdiction under
Section 404, subject to the confirmation of the U.S. Army Corp of Engineers.
8.3 Permits
Typically hydroelectric project are regulated under Federal Energy Regulatory Commission
(FERC) guidelines. The jurisdiction granted to FERC to issue licenses and exemptions was
established by Section 23(b) of the Federal Power Act of (1976)5
“…requires that waterpower projects be licensed if they are located on
navigable waters of the United States, occupy any part of the public lands or
reservations of the United States, use surplus water or waterpower from a
Federal Government dam, or, if constructed after August 26, 1935 are located
on any part of a non-navigable water subject to Congress’ Jurisdiction under
the Commerce Clause and affect the interests of the interstate or foreign
commerce.”
which:
The proposed Chenega Bay hydroelectric project appears to lack the specific criteria that would
necessitate any license or exemption from FERC because the project:
1. does not involve any waterbody having known current or historic navigational uses such
as the passage of people or goods, and so is located on non-navigable waters,
2. would not use surplus water or water power from a federal dam,
3. would be located on non-navigable waters, and is not subject to the authority of Congress
under the Commerce Clause, or
4. would not occupy lands or reservations of the United States.
The finding that no FERC license is required for the Anderson Creek hydropower project is
based on the lack of FERC jurisdiction and not on an exemption granted by that agency.
Consultation with FERC should be done to verify and document that this project is not under
FERC jurisdiction.
5 Section 23(b), 16 USC subpart 817.
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The Chenega Bay hydroelectric project would go through the State of Alaska permitting process,
and the following permits would be required for the proposed project:
Alaska Department of Fish and Game (ADF&G) Division of Habitat Title 16 Fish
Habitat Permit
US Army Corps of Engineers Section 404 permit
Alaska Department of Environmental Conservation (ADEC) Section 401 Water Quality
Certification in support of Section 404 permits
Alaska Department of Natural Resources (ADNR) Division of Coastal and Ocean
Management (DCOM) Coastal Consistency Determination
ADNR Water Rights Permit
The lower portion of Anderson Creek is classified as an anadromous fish stream; therefore, a
Fish Habitat Title 16 permit will be required for the construction of the proposed project because
there would be impacts to the creek. Dolly Varden char were found in a portion of the creek in
which flows will be altered. ADF&G will need to be consulted regarding requirements for
environmental flow in this reach of the creek.
The construction of the project would require a Section 404 permit because the project would
involve fill within waters of the United States, including wetlands. In addition, an ADEC
Section 401 Water Quality Certification in support of the Section 404 permit would be required.
The project is located within the coastal boundaries of the State of Alaska, and a consistency
determination from the Alaska Coastal Management Program and Coastal Zone Questionnaire
would be required for this project.
A water right is a legal right to use surface or ground water under the Alaska Water Use Act (AS
46.15). A water right allows a specific amount of water from a specific water source to be
diverted, impounded, or withdrawn for a specific time. The proposed project would require a
water right for the use of water from Anderson Creek.
9 Land Ownership, and Water Rights
The proposed project area includes Sections 23 and 26, and Sections 24 and 25 are adjacent to
the project area. The land within the project area has been conveyed from the Bureau of Land
Management (BLM) to the Chenega Corporation/Chugach Natives, Inc.
6
There are two ADNR interests in Section 26: a lease on the school and a Temporary Water Use
Permit (TWUP) issued to Chenega Bay Indian Reorganization Act (IRA) Village Council for
temporary use of water from Anderson Creek for a road construction project. This TWUP does
not grant rights to the water in Anderson Creek, and the water rights permit for the proposed
hydroelectric project would take precedence. The IRA permit expires in November 2009.
6 Interim conveyances (IC) 208-207 in Section 26 and ICs 1216/1215 in Section 23.
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9.1 City Water Supply
The City of Chenega Bay currently diverts a small amount of water (up to 40 gallons per minute,
0.09cfs) from Anderson Creek to provide drinking water for the community.
7
The Chenega Corporation would coordinate with the City of Chenega Bay throughout the
project, and initial consultation with the City of Chenega Bay regarding the proposed project has
taken place (Poolis 2009). The City of Chenega Bay water supply would have priority regarding
the use of the water in Anderson Creek. The existing drinking water pipeline is in disrepair, and
the Chenega Corporation is proposing to replace the pipeline. Ideally both the drinking water
facility and the hydroelectric facility would be served by a single shared pipeline and the cost of
the pipeline shared between the two users. Further details would be determined during project
design.
The water is
diverted from the creek into a 4-inch diameter pipeline where it is conveyed to the water
treatment plant and is distributed to the community. The proposed hydroelectric project would
use the remainder of the water in the creek that is in excess of the amount required for the
community’s drinking water to generate energy. The pipeline for the hydroelectric facility
would be built in the same corridor as the existing drinking water pipe and ideally would be
combined with this pipeline.
10 Conclusions and Recommendations
The feasibility of a small hydroelectric project on Anderson Creek is aided because access roads
and an intake have already been constructed as part of the existing water facility, no electrical
transmission line is required due to co-location of the hydroelectric powerhouse with the diesel
powerhouse, and hydroelectric operations costs are minimized because there is already a
powerhouse operator who could handle this function. Assuming all hydropower generated could
be sold and that no environmental flows are required, the project would be able to produce power
at $0.29/kWh. If annual power sales remains similar to that used in Chenega today, less
hydropower will be sold and the hydropower generation costs will increase to $0.40/kWh.
Environmental flows to accommodate resident Dolly Varden char in the affected reach of
Anderson Creek would further reduce hydropower generation and raise the unit costs of
hydropower.
Non-economic benefits of the project are that a reduced amount of diesel fuel would be shipped
in Prince William Sound and less atmospheric carbon would be produced. A further benefit of
the project is that because it is renewable it will help stabilize the future cost of power for the
City of Chenega Bay.
If a decision is made to pursue this project the next steps are to:
Pursue additional grant funding.
Continue stream gaging of Anderson Creek through the winter and until design is
complete.
Initiate discussions with ADF&G regarding requirements for environmental flow.
7 Approximately 40 gallons/minute are diverted to meet the drinking water needs of the community.
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Prepare and submit permit applications.
Survey plan and profile of the pipeline route.
Perform soils exploration along pipeline and tailrace route.
Prepare preliminary design criteria and preliminary design of project.
Refine estimate of cost.
Prepare final design documents.
Bid the project
Construct the project.
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11 References
Alaska Department of Fish and Game (ADF&G). 2007.Dolly Varden – ADF&G Wildlife
Notebook Series. (last updated November 2007). Available at:
(http://www.adfg.state.ak.us/pubs/notebook/notehome.php as) as viewed on 26 October
2009.
_____. 2009a. Catalog of Waters Important to the Spawning, Rearing or Migration of
Anadromous Fishes –Evans Island. Available at:
(http://gis.sf.adfg.state.ak.us/AWC_IMS/viewer.htm) as viewed on 14 August 2009.
_____. 2009b. Run Timing – Cordova, Whittier, Valdez and other Prince William Sound
destinations. Available at:
(http://www.sf.adfg.state.ak.us/Static/Region2/pdfpubs/pws_runtime.pdf) as viewed on
14 August 2009.
Alaska Energy Authority (AEA). 2010.Community Information Summary, Chenega Bay 2010).
Available at:
(ftp://ftp.aidea.org/2010AlaskaEnergyPlan/2010%20Alaska%20Energy%20Plan/Commu
nity%20Deployment%20Scenarios/Chenega%20Bay%20-
%20Community%20Deployment%20Scenario.pdf) as viewed on 18 November 2010.
Curran, 2003.Estimating the Magnitude and Frequency of Peak Streamflows for Ungaged Sites
on Streams in Alaska and Conterminous Basins in Canada. USGS Water Resources
Investigations Report 03-4188.
DeCicco, F. 2005. Dolly Varden: Beautiful and Misunderstood; Dolly Varden's Reputation as
Varmint Undeserved - ADF&G Wildlife News.Sport Fish Division. Available at:
(http://www.wildlifenews.alaska.gov/index.cfm?adfg=wildlife_news.view_article&articl
es_id=147) as viewed on 26 October 2009.
Heard, William R. 1991. Life History of Pink Salmon (Oncorhynchus gorbuscha). Auke Bay
Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National
Oceanic and Atmospheric Administration, Auke Bay, Alaska 99821, pg 121 in Pacific
Salmon Life Histories, University of British Columbia, Vancouver, B.C., edited by C.
Groot and L. Margolis, 1991.
Hochhalter, Samuel. 2009. Personal Communication with Sam Hochhalter, Division of Sport
Fish, Cordova. Phone and email correspondence (Re: timing of fish runs – Evans Island)
with Erin Cunningham, HDR Alaska, on August 14, 2009.
Ihlenfeldt, Nancy J. 2005. An Annotated Bibiolography: Above Barrier Resident Dolly Varden
(Salvelinus malma) and Related Studies. Alaska Department of Natural Resources Office
Chenega Hydroelectric Project
Reconnaissance Report
29
of Habitat Management and Permitting; Technical Report No. 05-05, by Nancy J.
Ihlenfeldt, November 2005.
McLaughlin, Andrew T. 2004. O’Brien Creek Anadromous Stream Enhancement Project
Proposal and Report.
Moffit, Steve. 2009. Personal Communication with Steve Moffit and Samuel Holter, Division of
Sport Fish, Cordova. Phone and email correspondence (Re: timing of fish runs – Evans
Island) with Erin Cunningham, HDR Alaska, on August 18, 2009.
Phukan Consulting Engineers and Associates, Inc. 1992. Chenega Bay Hydro-Electric Study.
Prepared for Alaska Energy Authority. October 1992 (W.O. 92466).
Poolis, Rebecca. USPHS, Personal Communication, April 16, 2009.
U.S. Army Corps of Engineers Environmental Laboratory (USACE). 1982. Regional Inventory
and Reconnaissance Study for Small Hydropower Projects Southcentral Alaska.
_____. 1995. Corps of Engineers: Alaska District List of Navigable Waters (in addition to all
Tidal Waters). Available at: (http://www.poa.usace.army.mil/reg/NavWat.htm).
_____. 1987. Corps of Engineers Wetlands Delineation Manual. Vicksburg, MS.
_____. 2007. Regional Supplement to the Corps of Engineers Wetlands Delineation Manual:
Alaska Region. Vicksburg, MS.
Vigil, Michael. 2009. Personal Communication with Michael Vigil, Chenega Corporation (Re:
timing of fish runs – Evans Island Region) with Erin Cunningham, HDR Alaska, on July
14, 2009 and August 14, 2009.
Chenega Hydroelectric Project
Reconnaissance Report
Appendix A
1992 Chenega Bay Hydroelectric Study and
1982 USCOE Reconnaissance Study
Chenega Hydroelectric Project
Reconnaissance Report
Appendix B
July 2009 and October 2009 Field Reconnaissance Trip Reports
Diesel
Powerhouse
Station
Chenega PHS
Water Supply Inake
0 500 1,000 1,500 2,000250
Feet
0 140 280 420 56070
Meters
1:9,600Scale=
Figure 1. Study Sites: July 2009 Reconnaissance
Trip Report
South Lake
Chenega PHS
Water Suppy Creek
South Lake's
Outlet Creek
Mouth of
South Lake
Outlet Creek
Submitted to: The Chenega Corporation
Created by: HDR Alaska, Inc.
Project: Chenega Bay Hydroelectric Feasibility Study
South Lake Site
INDEX MAP
Chenega Site
HDR Alaska, Inc.
2525 C Street, Suite 305
Anchorage, AK 99503-2632
Phone (907) 644-2000
Fax (907) 644-2022
www.hdrinc.com
Appendix
Cover
Memo
To: Brian Pillars, Chenega Corporation
From: Bob Butera, HDR Alaska, Inc. Project: Chenega Hydro Reconnaissance
CC:
Date: October 23, 2009 Job No: 107232
Re: Field Reconnaissance Trip Report: Chenega PHS Water Supply Creek (October)
Purpose of Field Reconnaissance
The purpose of the October field reconnaissance trip was to further evaluate the feasibility of
constructing a small hydroelectric project on Anderson Creek to service the village of Chenega
Bay (Figure 1). The field team collected additional site specific data for Anderson Creek related
to engineering and fish resources.
Field Team and Logistics
Bob Butera and Erin Cunningham (HDR Alaska, Inc.; HDR) arrived in Chenega Bay via Alaska
Air Transit at approximately 6:00 pm on Tuesday, October 13, 2009. Brian Pillars (Chenega
Corporation), provided transportation from the airstrip to the Corporation office, where the team
received keys to the apartments.
Anderson Creek Reconnaissance Summary
At approximately 7:00 pm on October 13, the field team set minnow traps in the lower portion of
the bypass reach in Anderson Creek lower portion of the creek to verify fish presence in the
reach upstream of the proposed tailrace location.
The morning of October 14th, field team started the day by pulling traps set the previous night,
and setting additional traps upstream of the previous traps, then returned to the tailrace site and
measured the flow in Anderson Creek.
In the afternoon of October 14th the intake site was visited. At the intake site the field team
downloaded and reinstalled the two HOBO U-20 pressure transducers/data loggers; removed
the plywood obstructing the weir; measured the volume of water flowing through the leaking
sluice gate; and verified the elevation datum at the gage site using standard survey equipment.
Streamflow measurements were made upstream and downstream of the weir to verify the
amount of flow removed from the system by the WTP and to verify the weir equation.
The morning of October 15th, field team started the day by pulling traps set the previous night.
Locations of fish barriers were collected using an accurate GPS. The field team then returned
to the intake site and obtained a stage reading. Peat probes were done along the segment of
the pipeline between the canyon and the access road. The WTP was visited and the pressure
gage noted at 82 psi, with typical average daily flows of 40 to 50 gpm. A topographic survey
was done from a benchmark at the clinic to the potential powerhouse site to verify the elevation
at this location. A flow measurement was made at the road crossing of Anderson Creek and a
staff gage installed that could potentially be read through the winter.
HDR Alaska, Inc.
2525 C Street, Suite 305
Anchorage, AK 99503-2632
Phone (907) 644-2000
Fax (907) 644-2022
www.hdrinc.com
Appendix
Cover
The field team departed from the Chenega Bay airstrip at approximately 2:15 pm via Alaska Air
Transit on October 15, 2009 and arrived in Anchorage at approximately 3:30 pm.
Preliminary Findings:
Engineering Aspects. Streamflow data was downloaded and along with more accurate elevation
information will provide a basis for reevaluating the potential energy from the project. The
primary technical challenge for the site will be the construction of the upper portion of the
pipeline within the narrow confines of the creek ravine, but this is not seen as insurmountable
and could be accomplished with HDPE pipe. The primary challenge for the project will be
permitting the flow modification of the bypass reach.
Fisheries Aspects. Traps were set throughout the potential bypass reach, both downstream and
upstream of a series of falls (natural falls, and manmade dams constructed at natural falls).
Traps placed downstream of the dams/falls captured Dolly Varden char; no fish were captured
upstream of the downstream most falls. The farthest upstream Dolly Varden was captured in a
pool at the base of the first series of falls. Dolly Varden char was the only fish species captured.
Chenega Hydroelectric Project
Reconnaissance Report
Appendix C
Anderson Creek Flow Data
2009 Streamflow at Anderson CreekDateDailyAverageDateDailyAverageDateDailyAverageDateDailyAverageDateDailyAverageDateDailyAverageDateDailyAverageDateDailyAverageDateDailyAverage4/2/2009 0.2 5/1/2009 7.8 6/1/2009 7.3 7/1/2009 2.0 8/1/2009 2.3 9/1/2009 1.5 10/1/2009 1.4 11/1/2009 1.2 12/1/2009 29.64/3/2009 0.2 5/2/2009 11.1 6/2/2009 7.3 7/2/2009 1.8 8/2/2009 1.6 9/2/2009 1.6 10/2/2009 1.1 11/2/2009 1.1 12/2/2009 11.94/4/2009 0.3 5/3/2009 12.8 6/3/2009 8.0 7/3/2009 1.6 8/3/2009 1.2 9/3/2009 2.8 10/3/2009 3.3 11/3/2009 1.2 12/3/2009 3.44/5/2009 0.3 5/4/2009 9.2 6/4/2009 8.7 7/4/2009 1.6 8/4/2009 1.6 9/4/2009 1.4 10/4/2009 8.9 11/4/2009 19.8 12/4/2009 2.04/6/2009 0.3 5/5/2009 7.0 6/5/2009 10.7 7/5/2009 1.5 8/5/2009 9.0 9/5/2009 1.1 10/5/2009 8.5 11/5/2009 27.5 12/5/2009 1.64/7/2009 0.3 5/6/2009 6.6 6/6/2009 8.7 7/6/2009 1.4 8/6/2009 2.5 9/6/2009 0.8 10/6/2009 2.7 11/6/2009 4.2 12/6/2009 1.34/8/2009 0.3 5/7/2009 9.9 6/7/2009 8.7 7/7/2009 1.3 8/7/2009 1.4 9/7/2009 0.8 10/7/2009 9.0 11/7/2009 2.2 12/7/2009 1.14/9/2009 0.4 5/8/2009 10.0 6/8/2009 7.9 7/8/2009 1.1 8/8/2009 1.2 9/8/2009 1.1 10/8/2009 8.5 11/8/2009 2.9 12/8/2009 1.04/10/2009 0.4 5/9/2009 9.4 6/9/2009 7.7 7/9/2009 1.0 8/9/2009 1.0 9/9/2009 1.6 10/9/2009 5.0 11/9/2009 4.3 12/9/2009 0.94/11/2009 0.5 5/10/2009 8.6 6/10/2009 6.6 7/10/2009 0.8 8/10/2009 0.9 9/10/2009 14.5 10/10/2009 10.4 11/10/2009 1.9 12/10/2009 0.84/11/20090.55/10/20098.66/10/20096.67/10/20090.88/10/20090.99/10/200914.510/10/200910.411/10/20091.912/10/20090.84/12/2009 0.6 5/11/2009 10.3 6/11/2009 5.2 7/11/2009 0.7 8/11/2009 0.7 9/11/2009 9.8 10/11/2009 20.8 11/11/2009 1.5 12/11/2009 0.84/13/2009 0.5 5/12/2009 11.9 6/12/2009 4.6 7/12/2009 0.7 8/12/2009 0.6 9/12/2009 25.2 10/12/2009 4.5 11/12/2009 0.8 12/12/2009 0.74/14/2009 0.5 5/13/2009 10.6 6/13/2009 4.8 7/13/2009 0.6 8/13/2009 0.6 9/13/2009 8.9 10/13/2009 2.7 11/13/2009 1.0 12/13/2009 0.64/15/2009 0.6 5/14/2009 7.4 6/14/2009 3.9 7/14/2009 0.5 8/14/2009 1.6 9/14/2009 3.9 10/14/2009 2.0 11/14/2009 0.7 12/14/2009 0.64/16/2009 0.9 5/15/2009 6.0 6/15/2009 4.2 7/15/2009 0.5 8/15/2009 6.2 9/15/2009 2.3 10/15/2009 1.6 11/15/2009 0.7 12/15/2009 0.64/17/2009 1.7 5/16/2009 8.2 6/16/2009 3.9 7/16/2009 0.4 8/16/2009 9.1 9/16/2009 17.8 10/16/2009 1.4 11/16/2009 0.6 12/16/2009 0.64/18/2009 2.9 5/17/2009 9.3 6/17/2009 3.8 7/17/2009 0.3 8/17/2009 2.9 9/17/2009 5.2 10/17/2009 1.1 11/17/2009 0.6 12/17/2009 0.44/19/2009 6.1 5/18/2009 9.4 6/18/2009 5.8 7/18/2009 0.2 8/18/2009 1.6 9/18/2009 2.9 10/18/2009 1.0 11/18/2009 0.6 12/18/2009 1.44/20/2009 3.5 5/19/2009 8.6 6/19/2009 4.4 7/19/2009 0.4 8/19/2009 1.2 9/19/2009 1.7 10/19/2009 1.0 11/19/2009 0.6 12/19/2009 1.94/21/2009 3.2 5/20/2009 7.6 6/20/2009 3.9 7/20/2009 1.4 8/20/2009 1.0 9/20/2009 11.3 10/20/2009 2.7 11/20/2009 0.5 12/20/2009 0.84/22/2009 3.2 5/21/2009 8.0 6/21/2009 4.6 7/21/2009 5.1 8/21/2009 0.8 9/21/2009 35.8 10/21/2009 8.8 11/21/2009 0.5 12/21/2009 0.94/23/2009 2.8 5/22/2009 14.5 6/22/2009 8.8 7/22/2009 13.4 8/22/2009 0.6 9/22/2009 4.0 10/22/2009 12.3 11/22/2009 0.7 12/22/2009 4.34/24/20092 65/23/200915 46/23/20094 17/23/20097 28/23/20090 79/23/20091 910/23/200912 611/23/200913 812/23/20099 24/24/20092.65/23/200915.46/23/20094.17/23/20097.28/23/20090.79/23/20091.910/23/200912.611/23/200913.812/23/20099.24/25/2009 2.6 5/24/2009 26.6 6/24/2009 3.1 7/24/2009 4.9 8/24/2009 2.3 9/24/2009 26.2 10/24/2009 10.6 11/24/2009 4.5 12/24/2009 8.84/26/2009 3.5 5/25/2009 13.7 6/25/2009 3.0 7/25/2009 3.8 8/25/2009 2.4 9/25/2009 26.2 10/25/2009 8.8 11/25/2009 3.1 12/25/2009 21.14/27/2009 4.9 5/26/2009 12.7 6/26/2009 2.9 7/26/2009 18.3 8/26/2009 4.8 9/26/2009 4.4 10/26/2009 3.8 11/26/2009 3.8 12/26/2009 11.84/28/2009 5.5 5/27/2009 9.0 6/27/2009 2.8 7/27/2009 5.2 8/27/2009 11.1 9/27/2009 2.8 10/27/2009 2.4 11/27/2009 9.7 12/27/2009 8.74/29/2009 6.7 5/28/2009 6.8 6/28/2009 2.8 7/28/2009 8.0 8/28/2009 23.2 9/28/2009 1.7 10/28/2009 2.2 11/28/2009 3.9 12/28/2009 5.24/30/2009 7.2 5/29/2009 6.8 6/29/2009 2.7 7/29/2009 10.4 8/29/2009 9.6 9/29/2009 1.5 10/29/2009 1.6 11/29/2009 4.0 12/29/2009 3.75/30/2009 6.9 6/30/2009 2.3 7/30/2009 6.1 8/30/2009 4.1 9/30/2009 2.5 10/30/2009 1.3 11/30/2009 2.6 12/30/2009 2.35/31/2009 6.5 7/31/2009 5.6 8/31/2009 2.1 10/31/2009 1.0 12/31/2009 1.8APPENDIX C: STREAMFLOW DATA
2010 Streamflow at Anderson Creek.DateDailyAverage DateDailyAverage DateDailyAverage DateDailyAverage DateDailyAverage DateDailyAverage DateDailyAverage DateDailyAverage DateDailyAverage1/1/2010 1.5829236 2/1/2010 1.610587 3/1/2010 12.8 4/1/2010 4.0 5/1/2010 4.9 6/1/2010 9.1 7/1/2010 1.5 8/1/2010 4.0 9/1/2010 0.91/2/2010 3.8422175 2/2/2010 1.562401 3/2/2010 13.4 4/2/2010 2.6 5/2/2010 4.5 6/2/2010 9.9 7/2/2010 1.6 8/2/2010 2.5 9/2/2010 0.71/3/2010 1.6869937 2/3/2010 1.30095 3/3/2010 4.4 4/3/2010 2.0 5/3/2010 5.4 6/3/2010 7.2 7/3/2010 3.2 8/3/2010 2.1 9/3/2010 0.61/4/2010 1.641149 2/4/2010 1.082167 3/4/2010 3.1 4/4/2010 2.0 5/4/2010 8.2 6/4/2010 6.5 7/4/2010 1.9 8/4/2010 10.0 9/4/2010 0.81/5/2010 1.5238143 2/5/2010 1.011303 3/5/2010 2.9 4/5/2010 2.0 5/5/2010 7.5 6/5/2010 8.3 7/5/2010 3.5 8/5/2010 4.3 9/5/2010 4.21/6/2010 2.0696949 2/6/2010 5.426924 3/6/2010 2.6 4/6/2010 1.4 5/6/2010 7.1 6/6/2010 5.3 7/6/2010 2.4 8/6/2010 2.7 9/6/2010 1.41/7/2010 10.530891 2/7/2010 1.961815 3/7/2010 3.0 4/7/2010 1.0 5/7/2010 6.1 6/7/2010 4.9 7/7/2010 7.0 8/7/2010 2.3 9/7/2010 3.21/8/2010 6.1486831 2/8/2010 1.12403 3/8/2010 2.2 4/8/2010 0.9 5/8/2010 5.5 6/8/2010 4.8 7/8/2010 6.3 8/8/2010 2.4 9/8/2010 2.21/9/2010 6.3241213 2/9/2010 1.582694 3/9/2010 5.3 4/9/2010 0.9 5/9/2010 6.0 6/9/2010 4.7 7/9/2010 2.4 8/9/2010 2.6 9/9/2010 1.31/10/2010 3.7639672 2/10/2010 9.40279 3/10/2010 16.7 4/10/2010 0.9 5/10/2010 5.8 6/10/2010 3.6 7/10/2010 2.6 8/10/2010 2.8 9/10/2010 1.01/11/2010 1.9971891 2/11/2010 12.97266 3/11/2010 19.3 4/11/2010 1.1 5/11/2010 29.9 6/11/2010 6.4 7/11/2010 1.9 8/11/2010 2.4 9/11/2010 0.91/12/2010 1.5102857 2/12/2010 8.402642 3/12/2010 18.7 4/12/2010 1.2 5/12/2010 31.3 6/12/2010 7.4 7/12/2010 1.4 8/12/2010 2.2 9/12/2010 0.81/13/2010 1.470525 2/13/2010 3.85226 3/13/2010 0.9 4/13/2010 1.8 5/13/2010 7.8 6/13/2010 5.2 7/13/2010 2.3 8/13/2010 10.6 9/13/2010 0.71/14/2010 1.5147916 2/14/2010 10.7957 3/14/2010 1.1 4/14/2010 4.4 5/14/2010 28.0 6/14/2010 3.9 7/14/2010 2.7 8/14/2010 6.0 9/14/2010 0.71/15/2010 1.6010368 2/15/2010 15.27755 3/15/2010 12.0 4/15/2010 3.3 5/15/2010 15.3 6/15/2010 7.2 7/15/2010 1.5 8/15/2010 3.2 9/15/2010 0.61/16/2010 3.582325 2/16/2010 14.96681 3/16/2010 2.7 4/16/2010 2.4 5/16/2010 7.5 6/16/2010 4.4 7/16/2010 1.4 8/16/2010 3.2 9/16/2010 0.61/17/2010 3.1576666 2/17/2010 12.24485 3/17/2010 1.2 4/17/2010 4.3 5/17/2010 5.1 6/17/2010 4.4 7/17/2010 1.1 8/17/2010 3.7 9/17/2010 0.51/18/2010 2.0887224 2/18/2010 39.98469 3/18/2010 1.6 4/18/2010 16.3 5/18/2010 5.9 6/18/2010 3.8 7/18/2010 1.5 8/18/2010 2.5 9/18/2010 0.51/19/2010 1.4008921 2/19/2010 19.58795 3/19/2010 4.7 4/19/2010 8.5 5/19/2010 7.7 6/19/2010 3.8 7/19/2010 2.6 8/19/2010 1.8 9/19/2010 0.51/20/2010 2.0721605 2/20/2010 9.591183 3/20/2010 2.8 4/20/2010 4.4 5/20/2010 10.3 6/20/2010 4.3 7/20/2010 1.8 8/20/2010 1.5 9/20/2010 0.41/21/2010 1.4314797 2/21/2010 4.828183 3/21/2010 1.7 4/21/2010 5.9 5/21/2010 6.3 6/21/2010 3.5 7/21/2010 2.1 8/21/2010 1.3 9/21/2010 0.51/22/2010 0.8320539 2/22/2010 3.562504 3/22/2010 1.2 4/22/2010 4.3 5/22/2010 6.1 6/22/2010 3.2 7/22/2010 1.4 8/22/2010 1.5 9/22/2010 0.51/22/20100.83205392/22/20103.5625043/22/20101.24/22/20104.35/22/20106.16/22/20103.27/22/20101.48/22/20101.59/22/20100.51/23/2010 0.7140557 2/23/2010 3.285649 3/23/2010 1.1 4/23/2010 3.0 5/23/2010 5.1 6/23/2010 3.0 7/23/2010 1.1 8/23/2010 1.51/24/2010 0.6668832 2/24/2010 2.729168 3/24/2010 2.2 4/24/2010 2.6 5/24/2010 4.6 6/24/2010 3.1 7/24/2010 1.1 8/24/2010 1.01/25/2010 0.5999489 2/25/2010 2.21556 3/25/2010 1.4 4/25/2010 9.6 5/25/2010 6.3 6/25/2010 3.1 7/25/2010 2.9 8/25/2010 0.91/26/2010 0.5722742 2/26/2010 1.782979 3/26/2010 1.2 4/26/2010 45.1 5/26/2010 8.5 6/26/2010 2.9 7/26/2010 11.6 8/26/2010 0.81/27/2010 0.8404856 2/27/2010 1.394207 3/27/2010 1.6 4/27/2010 29.3 5/27/2010 9.6 6/27/2010 2.2 7/27/2010 4.0 8/27/2010 1.01/28/2010 3.4557759 2/28/2010 1.430996 3/28/2010 2.5 4/28/2010 12.9 5/28/2010 8.6 6/28/2010 2.4 7/28/2010 2.8 8/28/2010 1.61/29/2010 6.3336088 3/29/2010 3.9 4/29/2010 12.0 5/29/2010 10.1 6/29/2010 2.0 7/29/2010 2.4 8/29/2010 1.21/30/2010 2.6378359 3/30/2010 3.6 4/30/2010 8.3 5/30/2010 9.4 6/30/2010 1.7 7/30/2010 2.0 8/30/2010 1.11/31/2010 1.5238039 3/31/2010 3.6 5/31/2010 8.7 7/31/2010 7.7 8/31/2010 0.8APPENDIX C: STREAMFLOW DATA
Appendix C. Flow Duration Curve for Discharge Below 20 cfs
0
2
4
6
8
10
12
14
16
18
20
0 10 20 30 40 50 60 70 80 90 100Anderson Creek Discharge (cfs)
% of Time Exceeded
Flow Duration Curve
APPENDIX C: STREAMFLOW DATA
Chenega Hydroelectric Project
Reconnaissance Report
Appendix D
Energy Calculation
Alt 1 WithdrawalsHW 248 Water Supply 40 gpm 0.089 cfsPH Floor 63.5 Env. Flow 0 0.25 cfsTW 65.5PipelineLength 2000Months to run (1=yes, 0=no, only select ONE month at a time)Dia 12 Jan 31 1Area 0.79 Feb 28 2f 0.011 Mar 31 3Apr 30 4Qmax 5 cfs May 31 5Vmax 6.37 fps Jun 30 6HL max 13.85 ft Jul 31 7Aug 31 8Sep 30 9Net Head 168.7 Oct 31 10Capacity 53.6 Nov 30 11Dec 31 12 1Total Days 31 - 0.25 0.50 0.75 1.00 744 Jan 13,366 12,386 10,024 8,676 7,595 Energy from using 4 pumps Nov 2010 Feb 20,162 18,722 17,473 16,554 158012 @ 1 cfs W2W Mar 17,617 15,830 14,206 12,787 11,760 2 @ 3 cfs Q % Exceed Eff Hours HL kW Energy Apr 16,253 15,406 14,354 13,351 123031.0 55.38 0.75 134.0 0.6 11.6 1,548 kWh May 37,916 37,556 37,133 36,718 36,226 2.0 37.37 0.75 42.0 2.2 22.9 962 kWh Jun 28,035 26,698 25,367 23,952 225413.0 31.72 0.75 34.0 5.0 33.8 1,150 kWh Jul 14,618 13,178 11,565 10,155 9,215 4.0 27.15 0.75 39.0 8.9 44.1 1,720 kWh Aug 13,949 12,098 10,748 9,695 86955.0 21.91 0.75 163.0 13.8 53.6 8,729 kWh Sep 12,631 11,498 10,459 9,537 8,826 6.0 0.00 0.75 0.0 19.9 - - Oct 21,491 19,991 18,531 17,459 166977.0 0.00 0.75 0.0 27.1 - - Nov 13,345 12,233 11,359 10,561 9,743 8.0 0.00 0.75 0.0 35.4 - - Dec 14,595 13,686 12,923 12,086 1134114,109 223,978 209,282 194,142 181,531 170,743Losses -3% (423) 13,686 3%Alternative 3MIF
30% diesel
FY 2010 kWh Sold Hydro Potenti Usable Hydro
09 J 15,620 14,618 10,934
A 17,766 13,949 12,436
S 19,789 12,631 12,631
O 15 446 21 491 10 812O15,446 21,491 10,812
N 21,907 13,345 13,345
D 25,079 14,595 14,595
J 26,259 13,366 13,366
F 21,598 20,162 15,119
M 22,887 17,617 16,021
A 21,662 16,253 15,163
M 23,399 37,916 16,379M23,399 37,916 16,379
J 18,695 28,035 13,087
250,107 223,978 163,888
48%
Chenega Energy Profile
15,000
20,000
25,000
30,000
35,000
40,000
kWhChenega Energy Profile
kWhSold
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
J A S O N D J F M A M JkWh
FY 2010
Chenega Energy Profile
kWhSold
Hydro Potential
Usable Hydro5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
J A S O N D J F M A M JkWh
FY 2010
Chenega Energy Profile
kWhSold
Hydro Potential
Usable Hydro
Chenega Hydroelectric Project
Reconnaissance Report
Appendix E
Cost Calculation
Item Quantity Unit Unit Cost Amount
330 LAND AND LAND RIGHTS
.1 Land Rights - Generation Plant LS -$
.2 Special use permits LS -$
.3 Surveying 1 LS 7,500$ 7,500$
331 STRUCTURES AND IMPROVEMENTS
.1 POWERHOUSE -$
.1 Excavation 15 CY 50$ 733$
.2 Concrete (incl. reinforcement) 9 CY 1,200$ 11,316$
.3 Pre-engineered metal building 400 SF 125$ 50,000$
.4 Misc. Metals 0 LS 1,000$ -$
.5 HVAC, Plumbing & Electrical (included) 0 LS 2,500$ -$
.6 Grounding Grid 1 LS 1,000$ 1,000$
.7 Fire Protection (included) 0 LS 500$ -$
332 RESERVOIRS, DAMS AND WATERWAYS
.1 SITE WORK -$
.1 Clearing/Drainage/Erosion Control 1 LS 2,500$ 2,500$
.3 INTAKE -$
.1 Excavation 20 CY 50$ 1,000$
.2 Care of Water/Diversion 1 LS 2,000$ 2,000$
.3 Trash racks LS -$
.4 Control Gates/Valve w/operator 1 LS 25,000$ 25,000$
.5 Concrete (structural) 1 CY 1,200$ 1,200$
.6 Concrete (mass) CY -$
.7 Misc. Metals 1 LS 750$ 750$
.5 WATER CONDUCTORS AND ACCESSORIES
.1 PENSTOCK (Buried and supported on saddles) -$
.a Clearing 0.9 ACRE 25,000$ 23,674$
.b Penstock material (steel) 2000 LF 45$ 90,000$
.c Concrete (thrust blocks and supports) 3 CY 1,200$ 3,600$
.d Penstock installation 2000 LF 25$ 50,000$
.e Bifurcation/inlet piping 0 LS 15,000$ -$
.2 TAILRACE
.a Clearing 0.2 ACRE 25,000$ 5,739$
.b Excavation 1 LS 5,000$ 5,000$
.c Support and lining 1 LS 4,000$ 4,000$
333 WATERWHEELS, TURBINES AND GENERATORS
.1 54 kW pump/turbine, generator, guard valve 54 kW 750$ 40,500$
.2 Install 1 EA 30,000$ 30,000$
334 ACCESSORY ELECTRICAL EQUIPMENT
.1 Switchgear 1 LS 25,000$ 25,000$
.2 Station Service 1 LS 1,000$ 1,000$
.3 Control Panel 1 LS 7,500$ 7,500$
.4 Conduit/wires/cables 1 LS 5,000$ 5,000$
CHENEGA
OPINION OF PROBABLE COST
335 MISC. POWER PLANT EQUIPMENT
.1 Powerhouse crane 1 LS 2,500$ 2,500$
336 ROADS, RAILROADS AND BRIDGES
.1 Road Grading 1 LS 2,000$ 2,000$
.3 Clearing/Drainage/Erosion Control 1 LS 2,000$ 2,000$
353 STATION EQUIPMENT
.1 Main transformer 1 LS 4,000$ 4,000$
.2 Accessory switchgear equipment 1 LS 2,000$ 2,000$
Total Direct Construction Costs 406,513$
Survey and Geotechnical 1 LS 30,000$
Design Engineering 1 LS 120,000$
Permitting 1 LS 30,000$
Owner's General Administration & overhead 1 LS 10,000$
Construction Management 1 LS 20,000$
Subtotal 616,513$
Contingency 30% 185,000$
Interest during construction 5% 41,000$
2010 Estimated Project Cost (rounded) 850,000$
Annual Energy, MWh 224
Debt Service (5%, 30 yr) 55,294$
O&M 10,000$
2010 Cost of Energy, $/kWh 0.29$
Chenega Hydroelectric Project
Reconnaissance Report
Appendix F
Fisheries Resource Information
Chenega Hydroelectric Project
Reconnaissance Report
Appendix G
Office-Based Preliminary Jurisdictional Determination
- 1 -
Office Based Preliminary Jurisdictional Determination
Chenega Bay Hydroelectric Project
Chenega, Alaska
1. APPLICANT:ChenegaCorporation
2. WATERWAY:SawmillBay
3. LOCATION:
A. Narrative: The project area is located along Anderson Creek, immediately northwest of the
community of Chenega Bay on Evans Island, Alaska. Wetland mapping was completed for a
25.4 acre area surrounding a proposed hydroelectric project intake site on Anderson Creek and
a proposed tailrace corridor located near the communitys existing power facilities (Graphic 1,
Figure 1).
B.Legal Description:
Section: 23 and 26 Township: 1S Range: 8E Meridian: Seward
Latitude/Longitude (WGS84 Datum): N60.069/W148.016
4. SOURCE(S):
USGSMaps:Seward A 3 (Figure 1)
NWIMaps:Seward A 3 (Figure2)
Soil Maps: None
Corps Wetland Maps: None
Aerial Photographs: Stereoscopic pairs of color aerial photography from Aerometric, Inc. taken on
June 28, 2005 at 1=1,500scale and two 2005 orthorectified aerial images (2 foot and 1 foot pixel
resolution (1=800scale)).
Other: Photographs of the surrounding area from two site visits conducted by a project engineer
and fisheries scientistover July14 15 andon October 15, 2009.
5. PRELIMINARYJURISDICTIONAL DETERMINATION:
The Chenega Corporation is currently evaluating alternatives to provide a reliable source of electricity to
the community of Chenega Bay through hydroelectric power generation. A consideration for the siting
and selection of any new hydroelectric facilities is the presence of wetlands and other waters of the U.S.
This report describes locations within a 25.4 acre area that are preliminarily determined to be subject to
the jurisdiction of the U.S. Army Corps of Engineers (USACE) under authority of Section 404 of the Clean
Water Act. By federal law (Clean Water Act) and associated policy, it is necessary to avoid project
impacts to wetlands wherever practicable, minimize impact where impact is not avoidable, and in some
cases compensate for the impact.
This preliminary jurisdictional determination (PJD) is an office based study. No formal field verification
was conducted. Off site identification of wetlands and other waters of the U.S. were completed using
readily available aerial photographs, natural resource mapping, and existing documentation. The focus
of this PJD is on identification of wetlands and other regulated waters; project design and impacts are
not discussed in this report. Wetlands, waters of the U.S., and uplands (non wetlands), as referenced in
this report, are defined as:
- 2 -
Wetlands:Those areas that are inundated or saturated by surface or groundwater at a
frequency and duration sufficient to support, and that under normal circumstances do support,
a prevalence of vegetation typically adapted for life in saturated soil conditions(33 Code of
Federal Regulations [CFR] Part 328.3(b)). Wetlands are a subset of waters of the U.S.Note
that the wetlandsdefinition does not include unvegetated areas such as streams and ponds.
As described in the 1987 Wetlands Delineation Manual and in the Alaska Regional Supplement
to the 1987 Wetland Delineation Manual (USACE 1987, USACE 2007), wetlands must possess the
following three characteristics: (1) a vegetation community dominated by plant species that are
typically adapted for life in saturated soils, (2) inundation or saturation of the soil during the
growing season, and (3) soils that are saturated, flooded, or ponded long enough during the
growing season to develop anaerobic conditions.
Waters of the U.S.:Waters of the U.S. include other waterbodies regulated by the USACE,
including navigable waters, lakes, ponds, and streams, in addition to wetlands.
Uplands:Non water and non wetland areas are called uplands.
Aerial photographs, topography, and existing U.S. Fish and Wildlife Service National Wetland Inventory
(NWI) mapping were combined into a Geographic Information Systems (GIS) database and analyzed to
identify probable wetlands or other regulated waters occurring within the mapping area. Delineating
wetlands from aerial photography includes looking for vegetation clues, evidence of soil saturation, and
Graphic 1. Approximate area mapped for this desktop study (photo courtesy of the Alaska Division of Community and Regional Affairs)
- 3 -
evaluating topographic features. On aerial photography, scientists look for saturation adapted
vegetation communities, low plant height, open canopy structure, and presence of hydrophytic plant
species. A common example is the presence of stunted spruce trees, which are indicative of a limitation
to growth such as excessively wet soils. Visible evidence of wetland hydrology is also sought, including
surface water and darker areas of photos indicating surface saturation. A sites proximity to streams,
open water habitat, and marshes can be indicative of shallow subsurface water. Lastly, evidence of
topographic high points and sloped surfaces that would allow soils to drain is used to support classifying
those areas as upland. Topographic depressions, toes of slopes, and flat topography serve as indicators
of potentially poor soil drainage.
Photographs taken during two site visits (on July 14 15 and October 15, 2009) were also used to identify
apparent wetland areas and wherever possible, those photo locations were located on the aerial
photography. Photo signatures (color, texture) seen on aerial photography matched with the on the
ground photographs were then extrapolated to similar locations throughout the mapping area and
wetland/upland boundaries were digitized into the GIS database.
In addition to examining aerial photograph features and ground photographs, NWI wetland mapping
was reviewed for this office based study. NWI mapping is generally an effective tool for large scale
planning and analysis of wetlands but not suitable for smaller site specific projects such as this study.
NWI mapping is primarily based on high altitude aerial photographic interpretation with limited ground
truthing, and therefore wetland boundaries tend to be oversimplified with many smaller wetlands not
included in the mapping. According to the NWI, emergent and scrub shrub wetlands occur within the
mapping limits of this office based PJD (USFWS 1996) (Figure 2).
All available datasets were reviewed collectively to complete digitizing of wetland upland boundaries
using GIS. GIS polygons were attributed with NWI mapping codes based on the USFWS Classification of
Wetlands and Deepwater Habitats of the U.S.(Cowardin et al.1979). A map of wetland boundaries
overlaid on the 2005 orthorectified aerial photograph base is shown on Figure 3. Descriptions of each
mapped wetland type, their jurisdictional status, and acreage are included below. Three wetland types
are likely to occur in the mapped area, these include:
Emergent Wetlands. Emergent wetlands are characterized by a plant community dominated by
graminoids and forbs. Within the mapped area, this community type is seen in both wetland
and non wetland areas. Areas mapped as emergent wetlands on Figure 3 are locations where
surface saturation (i.e., darker areas) is seen on aerial photographs and where emergent
communities are situated along topographically flat or low lying areas that may be conducive to
retaining water. Plant species often encountered in this common Prince William Sound wetland
type include deer cabbage (Fauria crista galli FACW), calthaleaf avens (geum calthifolium
FACW), crowberry (Empetrum nigrum FAC), and luetka (Luetka pectinata UPL) (DeVelice et
al.1999 and Viereck et al.1992). Graphic 2 shows a site photograph of emergent wetlands
taken nearby the project area. Approximately 2 acres of emergent wetlands were identified in
the mapping area.
Areas with similar emergent vegetation signatures that were determined to be non wetland
include developed and disturbed areas near the existing power generation facilities and along a
small access road corridor extending to the north. Plant communities in these areas are
typically early successional communities that are resilient to frequent disturbances, likely
dominated by non native and weedy species.
- 4 -
Graphic 2. Typical view of emergent and scrub shrub wetlands.
Graphic 3. Existing water pipeline along Anderson Creek.
Graphic 4. Steep sideslopes along Anderson Creek.
Scrub shrub wetlands. Scrub shrub
wetlands were identified on aerial
photographs along the fringes of and
within drier areas of the widespread
emergent wetland complexes. Common
plant species likely include mountain
hemlock (Tsuga mertensiana FAC),
Stellers cassiope (Cassiope stelleriana
FACW), crowberry (FAC), and early
blueberry (Vaccinium ovalifolium FAC)
(DeVelice et al.1999 and Viereck et al.
1992). Small areas of scrub shrub
wetland can be seen intermixed with
emergent wetlands on Graphic 2.
Approximately 2.7 acres of scrub shrub
wetlands were delineated in the mapping
area.
Differences in shrub height were also
used to determine wetland from non
wetland scrub shrub sites; where stunted
shrub growth is visible on the aerial
photography, this may be an indication
of wetter soils and an overall suppression
of growth. Non wetland scrub shrub
communities occur along steep
sideslopes (Graphics 3 and 4) and along
roadway corridors.
Forested wetlands. Forested wetlands
are often the most difficult wetland type
to delineate from aerial photograph
interpretation. According to NWI maps,
forested wetlands are ubiquitous
throughout Prince William Sound. Given
the maritime climate of the project area,
it is likely that many of the forested areas
situated along flat or low lying landforms
are wetland and were mapped as such
for the office based PJD. Tree height was
also used a key indicator of wetland
presence or absence; tall, mature trees
are often good indicators of non hydric
soils and stunted trees are often good
indicators of saturated hydric soils.
Common plant species likely include mountain hemlock (FAC), Sitka spruce (Picea sitchensis
FACU), tall blueberry (Vaccinium alaskaense FAC), and Sitka alder (Alnus sinuata FAC)
(DeVelice et al.1999 and Viereck et al.1992).
- 5 -
Forested areas situated on steep slopes and topographic high points that are not conducive to
retaining water are likely non wetland. Accordingly, field photographs indicate that many of the
forested areas along the Anderson Creek riparian corridor are too steep to be wetland (Graphics
3 and 4). Approximately 9.2 acres of forested wetlands were delineated in the mapping area.
The project area also includes the waters and floodplain of Anderson Creek, a small perennial stream
approximately 1 mile in length from source to sea. The creek flows through the mapping area and then
enters the marine waters of Sawmill Bay, a Section 10 water. The creek is generally confined to narrow
channel surrounded by steep canyon walls in its upper half. The creek channel meanders through
relatively low gradient, forested terrain in its middle portion, flows through a narrow constricted
bedrock channel (i.e., downstream of the road crossing) before draining into Sawmill May.
6. SUMMARY:
Based on the findings above, it has been preliminarily determined that areas displayed as wetlands on
Figure 3 meets the USACE criteria for being classified as wetland. Approximately 55 percent (13.9 acres) of
the mapped 25.4 acres are wetland; and therefore subject to jurisdiction under Section 404. The NWI
mapping codes used to classify these wetlands include PEM1C (seasonally flooded emergent wetland),
PSS4/EM1C (seasonally flooded mixed needleleaf scrub shrub/emergent wetland), and PFO4B (saturated
needleleafforestwetland).
Within the mapped area, the USACE also has jurisdiction over Other Waters of the U.S.,including streams.
Anderson Creek would be subject to jurisdiction under Section 404. Anderson Creek is not listed on 1995
U.S. Army Corps of Engineers list of navigable waters of Alaska; however, Anderson Creek is a tributary of
SawmillBay, which issubject tojurisdiction under Section 10.
The remainder of the project area, approximately 45 percent (11.5 acres) of the mapped area appears to
lack characteristics to support classifying those areas as wetland. This includes the steep canyon walls of
Anderson Creek, developed areas, and mature forested areas situated on the terrace above Anderson
Creek. These areas would not be subject to jurisdiction under Section 404, subject to the confirmation
of the USACE.
OFFICE BASEDDETERMINATION MADE BY:
JeffSchively, PWS
Biologist/Professional Wetland Scientist
HDR Alaska, Inc.
Date:October 2009
Attachments:
Figure 1. Vicinity Map
Figure 2. NWI Mapping
Figure 3. Office Based Wetland Determination
- 6 -
REFERENCESCITED
Cowardin, L. M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater
Habitats of the United States. Office of Biological Services, U.S. Fish and Wildlife Service,
Washington, D.C.
DeVelice, R.L., C.J. Hubbard, K. Boggs, S. Boudreau, M. Potkin, T. Boucher, and C. Wertheim. 1999. Plant
community types of the Chugach National Forest, southcentral Alaska. USDA Forest Service,
Chugach National Forest, Alaska Region Technical Publication R10 TP 76. Anchorage, Alaska.
375 pp.
U.S. Army Corps of Engineers Environmental Laboratory (USACE). 2007. Regional Supplement to the
Corps of Engineers Wetlands Delineation Manual: Alaska Region. Vicksburg, MS.
U.S.Army Corps of Engineers Environmental Laboratory (USACE). 1995. Corps of Engineers: Alaska
District List of Navigable Waters (in addition to all Tidal Waters). Available online at:
http://www.poa.usace.army.mil/reg/NavWat.htm.
U.S. Army Corps of Engineers Environmental Laboratory (USACE). 1987. Corps of Engineers Wetlands
Delineation Manual. Vicksburg, MS.
U.S. Federal Register. November 13, 1986 Part II. Rules and Regulations, Vol. 51, No. 219. U.S.
Department of Defense. Corps of Engineers, Department of the Army. 33 CFR Parts 320 330,
Regulatory Programs of the Corps of Engineers; Final Rule.
U.S. Fish and Wildlife Service (USFWS). 1996. National Wetland Inventory Mapping for USGS
Quadrangles Seward A 3. Available online at:
http://enterprise.nwi.fws.gov/shapedata/alaska/
Viereck L. A., C. T. Dyrness, A.R. Batten, and K.J. Wenzlick. 1992. The Alaska Vegetation Classification. U.
S. Department of Agriculture.
Mapping Area
0 0.5 1 1.50.25
Miles
Chenega Bay Hydroelectric Project
Preliminary Jurisdictional Determination
Vicinity Map
Figure 1
MAP NOTES:
1. USGS topographic map Seward A-3
shown as base map.
LEGEND
Mapping Area
PEM1/SS4B
PEM1/SS4B
0 200 400100
Feet
Chenega Bay Hydroelectric Project
Preliminary Jurisdictional Determination
NWI Mapping
Figure 2
MAP NOTES:
1. National Wetland Inventory (NWI)
mapping prepared by the U.S. Fish and
Wildlife Service (Sewardd A-3)
2. Base aerial image from Aerometric, Inc. taken
June 28, 2005.
LEGEND
Mapping Area
Chenega Creek
NWI Mapped Wetlands
PEM1/SS4B Saturated Mix Needleleaf Scrub-Shrub/Emergent Wetland
Mapping Codes
PEM1C
PFO4B
PFO4B
PSS4/EM1C
PSS4/EM1C
PEM1C
PEM1C
PSS4/
EM1C
PFO4B
PFO4B
PSS4/
EM1C
PEM1C
PEM1C
PSS4/
EM1C
PFO4B
PSS4/
EM1C
PSS4/EM1C
PSS4/
EM1C
PSS4/
EM1C
PSS4/
EM1C
PSS4/
EM1C
0 200 400100
Feet
Chenega Bay Hydroelectric Project
Preliminary Jurisdictional Determination
Office-Based Wetland Mapping
Figure 3
MAP NOTES:
1. Wetland mapping based on a review
of aerial photographs, available resource
mapping, and topographic information. No
fieldwork has been conducted to verify
boundaries.
2. Base aerial image from Aerometric, Inc. taken
June 28, 2005.
LEGEND
Mapping Area
Anderson Creek
Wetlands
PEM1C Seasonally Flooded Emergent Wetland
PSS4/EM1C Seasonally Flooded Mix Needleleaf Scrub-Shrub/Emergent Wetland
PFO4B Saturated Needleleaf Forest Wetland
Mapping Codes