Baker River Hydroelectric Project
(FERC No. 2150)
AQUATIC RESOURCES WORKING GROUP
FUTURE POTENTIAL AQUATIC HABITATS
OF THE BAKER RIVER PROJECT AREA
(STUDY A-37)
Prepared by:
R2 Resource Consultants, Inc.
15250 NE 95th Street
Redmond, Washington 98052-2518
DRAFT REPORT
Unpublished Work, Copyright 2004, Puget Sound Energy, Inc.
May 2004
CONTENTS
1.
INTRODUCTION.............................................................................................................1-1
2.
STUDY APPROACH .......................................................................................................2-1
2.1
FUTURE SCENARIO ASSUMPTIONS................................................................2-1
2.1.1
Scenario 1 – Project Decommissioning ......................................................2-1
2.1.2 Scenario 2 – Flood-Control-Only without Lake Shannon ..........................2-4
2.2
3.
4.
PREDICTION OF AQUATIC HABITAT TYPES AND ATTRIBUTES
UNDER FUTURE SCENARIOS ...........................................................................2-6
RESULTS..........................................................................................................................3-1
3.1
EXTENT OF POTENTIALLY AVAILABLE AQUATIC HABITATS
UNDER HYPOTHETICAL WITHOUT PROJECT OPERATIONS
SCENARIOS...........................................................................................................3-1
3.2
PREDICTED AQUATIC HABITAT CONDITIONS AT THE END OF
THE UPCOMING LICENSE PERIOD UNDER HYPOTHETICAL
WITHOUT PROJECT OPERATIONS SCENARIOS. ..........................................3-1
LITERATURE CITED......................................................................................................4-1
APPENDIX A:
APPENDIX B:
APPENDIX C:
Fluvial Process Groups
Reference Conditions and Channel Recovery Rates for Riverine Habitats in
the Baker River Basin
Aquatic Habitat Availability by Channel Size and Type for Baker River
Subbasin
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
ii
Future Aquatic Habitat –A-37
LIST OF FIGURES
Figure 1-1. Baker River location map. .................................................................................................... 1-2
Figure 2-1. Lake Shannon future potential aquatic habitat types (current conditions)............................ 2-2
Figure 2-2. Baker Lake future potential aquatic habitat types (current conditions). ............................... 2-3
Figure 3-1. Lake Shannon future potential aquatic habitat types (Scenario 1, Project
Decommissioning)................................................................................................................ 3-2
Figure 3-2. Baker Lake future potential aquatic habitat types (Scenario 1, Project
Decommissioning)................................................................................................................ 3-3
Figure 3-3. Lake Shannon future potential aquatic habitat types (Scenario 2, Flood-Control-Only
without Lake Shannon)......................................................................................................... 3-5
Figure 3-4. Baker Lake future potential aquatic habitat types (Scenario 2, Flood-Control-Only
without Lake Shannon)......................................................................................................... 3-6
Figure 3-5. Total length of riverine habitat in the Baker River watershed potentially accessible to
anadromous fish under alternate planning scenarios developed for Baker Relicensing
Studies T-7b and A-37. The length of accessible habitats under Scenarios 1 and 2 was
derived by adding habitats available above the current reservoir high pool level under
current conditions to the amount of additional habitat that would become available
under Scenario 1 (Project Decommissioning) or Scenario 2 (Flood-Control-Only
without Lake Shannon)......................................................................................................... 3-8
Figure 3-6. Additional wetland habitats in the Baker Project Area that would be potentially
accessible to anadromous fish under alternate planning scenarios developed for Baker
Relicensing Studies T-7b and A-37. Wetlands identified as potentially accessible to
anadromous fish are defined as non-forested wetland types that are located
immediately adjacent to streams or water bodies and that could become temporarily
inundated during the high flow season. These wetland areas are the same as areas
identified in study T-7b and do not represent additional wetland habitat above and
beyond that identified in Study T-7b. Under ongoing operations, no wetland habitat
would be available because the entire A-37 study area would be inundated by the
project reservoirs. ................................................................................................................. 3-9
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
iii
Future Aquatic Habitat –A-37
LIST OF TABLES
Table 2-1.
Channel type and physical characteristics associated with channel types delineated in
the Baker River study area.................................................................................................... 2-9
Table 2-2.
Habitat conditions characteristic of streams within the drawdown zone (Year 0). ............ 2-12
Table 2-3.
Site potential habitat conditions characteristic of streams at Year 100. ............................. 2-13
Table 3-1.
Length of additional riverine habitat by gradient classification in the Baker River
basin that would be available for return to reference conditions under Scenario 1,
Project Decommissioning. .................................................................................................... 3-4
Table 3-2.
Area of open water and potentially accessible wetland habitat that would be available
in the Baker River watershed at typical summer pool elevation under future
hypothetical Without Project Scenario 1, Project Decommissioning. .................................. 3-4
Table 3-3.
Length of additional riverine habitat by gradient classification in the Baker River
basin that would be available for return to reference conditions under Scenario 2,
Flood-Control-Only without Lake Shannon. ........................................................................ 3-7
Table 3-4.
Area of open water and wetland habitat that would be available at typical summer
pool elevation in the Baker River watershed under future hypothetical Without Project
Scenario 2, Flood-Control-Only without Lake Shannon. ..................................................... 3-7
Table 3-5.
Predicted habitat conditions by channel type at the end of the upcoming license period
(year 40) under Scenario 1, Project Decommissioning, and average habitat conditions
over the 40-year period....................................................................................................... 3-10
Table 3-6.
Predicted habitat conditions by channel type at the end of the upcoming license period
and average conditions over the 40-year period (year 40) under Scenario 2, FloodControl-Only without Lake Shannon.................................................................................. 3-11
Table 3-7.
Lake habitat characteristics in the Baker River study area under hypothetical future
Without Project scenarios as compared to existing conditions........................................... 3-12
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
iv
Future Aquatic Habitat –A-37
1. INTRODUCTION
The Baker River Hydroelectric Project is owned and operated by Puget Sound Energy, Inc.
(PSE). The Baker River Project (FERC No. 2150; hereafter referred to as the Baker Project)
consists of the Lower Baker Development (completed in 1925) and the Upper Baker
Development (completed in 1959). The Baker Project is located in Skagit County, Washington,
about 50 miles (80 km) north of the city of Seattle, and 50 miles (80 km) south of the Canadian
border (Figure 1-1). The Project was licensed for 50 years, effective May 1, 1956, by the
Federal Power Commission, now known as the Federal Energy Regulatory Commission (FERC).
The Project’s current license expires on May 1, 2006, and PSE has filed its notice of intent to
seek relicense of the Project.
As a prerequisite to filing a new license, the applicant must consult with federal, state and local
agencies, affected Indian Tribes, non-governmental agencies and the general public. The FERC
allows an applicant for a new license to engage in a “traditional” or “alternative” pre-filing
process. In March 2000, PSE began efforts to engage all potentially interested parties, including
resource agencies and tribes, in a collaborative approach to relicensing. Under the Alternative
Licensing Procedures (ALP) established by FERC in 1997, the licensee consults with the
agencies, tribes and other interested parties from the outset of the process and seeks to obtain
agreement on licensing issues to be addressed in the new license. Participants cooperatively
examine environmental issues and design scientific studies as needed. As part of this process,
PSE established five primary working groups focusing on the following resource areas: aquatic
resources; terrestrial/wildlife; recreation/aesthetics; cultural/historical; and economics and
operation. The purpose of these working groups is to identify issues and review available
information, select studies that need to be completed, and make recommendations about the
resource area.
The goal of the Aquatic Resources Working Group (ARWG) is to identify issues and develop
solutions and recommendations addressing fish and aquatic resource interests related to the
Baker Project and its operations, leading to a settlement agreement. The ARWG has requested a
series of studies to be undertaken in support of the relicensing process, and has numbered those
studies consecutively.
A number of the collaborating parties expressed the desire to consider a “future without Project”
scenario as a measure of the long-term effects of the Project on the ecological resources of the
Baker River Basin. In response to this request, Study T-7b was initiated by the Terrestrial
Resources Working Group (TRWG). Following initiation of Study T-7b, ARWG participants
requested that a similar evaluation of aquatic habitats be conducted as Study A-37.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
1-1
Future Aquatic Habitat –A-37
The goal of Study A-37 was to predict the types of aquatic habitats that could occur in the
Project Area in the future if the Project were not relicensed. Discussions among the ALP
participants in the TWG and ARWG identified two potential sets of future scenarios that could
result if the project were not relicensed: 1) removal of the dams and other project facilities; and
2) retention of project facilities at Upper Baker Lake and operation to provide ongoing flood
control.
Since the Project Area is currently dominated by reservoirs, the ARWG chose to use pre-Project
channel morphologic types as indications of site potential (i.e., the capacity of the site to produce
certain types of habitat in the future). Study A-37 describes the historic type and distribution of
river, stream and stream associated wetlands located within the Project Area prior to construction
of the Baker Project Developments. The length of stream reaches historically represented by
specific habitat types is considered to be a reasonable approximation of the area of similar
habitats that would be present in the future, even if the specific location of the various habitats
changed. This study was designed to provide information that may be used to support
development of protection, mitigation and enhancement measures (PMEs) that would be
implemented under the new license.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
1-3
Future Aquatic Habitat –A-37
2. STUDY APPROACH
The A-37 study area consists of 2,278 acres within the Lake Shannon basin that are currently
inundated by Lake Shannon (Figure 2-1) and 4,980 acres within the Baker Lake Subbasin that
are currently inundated by Baker Lake (Figure 2-2). Lands within the Project Boundary that lie
outside the reservoirs were excluded from Study A-37 study because it was assumed there would
be no net change in habitat value on these lands under any of the potential future scenarios.
Removal of the dams would have associated impacts to upland and upstream and downstream
aquatic habitats, but assessment of these impacts is beyond the scope of Study A-37.
The first step in determining potential future aquatic habitat conditions was to make a series of
assumptions about: a) the retention and management of project facilities in the future; and b) the
recovery of aquatic habitats within the study area subsequent to the end of the current license
term.
2.1
FUTURE SCENARIO ASSUMPTIONS
Assumptions about future Project management and operation were developed by the Terrestrial
Working Group in support of Study T-7b Potential Future Vegetation of the Baker River Project
Area (Vaughn and Zablotney, 2003). That study is referred to hereafter as “Study T-7b”. Two
hypothetical future “Without Project” scenarios were identified.
Scenario 1 (Project
Decommissioning) calls for complete removal of both dams and reclamation of the lands beneath
both reservoirs. Scenario 2 (Flood-Control-Only without Lake Shannon) acknowledges the need
to retain flood control within the Baker River basin in the future, and assumes that if the Baker
River Hydroelectric Project were not relicensed, the Lower Baker Development would be
removed and operation of the Upper Baker Project facilities would be taken over by the USACE.
Specific assumptions for each scenario are described in detail below. Scenario 2 was developed
under the explicit assumption that future flood control would be limited to 74,000 acre-feet,
which was identified as the working hypothesis for all Baker relicensing workgroups.
2.1.1 Scenario 1 – Project Decommissioning
Under Scenario 1, Both Upper and Lower Baker Dams would be removed. Upper Baker Dam
would be removed first so that Lake Shannon could act as a temporary sediment trap during the
re-establishment of the upper Baker River channel. It was assumed the original (pre-Project)
Baker Lake, with an outlet at elevation 660 ft NAVD 88, would reappear in its historic location
and configuration. Study A24 Hydrology and Geomorphology of the Baker Project Area Part 2:
Sediment transport and Channel Response (R2 Resource Consultants, 2004) suggests that
sedimentation since construction of the Baker Project in 1959 has not been sufficient to
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-1
Future Aquatic Habitat –A-37
appreciably alter the volume of historic Baker Lake. The sequence of decommissioning under
Scenario 1 would be as follows:
1. Local, state and federal permitting would require 5 years to complete, starting after the
end of the current license.
2. Upper Baker Dam removal would begin in Year 6 after the end of the current license, and
conclude in Year 10.
3. The Baker River would be routed around Upper Baker Dam in Year 7.
4. The area inundated beneath existing Baker Lake would be planted to expedite recovery of
native vegetation communities (see Study T-7b for details).
5. Forestlands established on lands owned by the U.S. Forest Service in the area beneath
existing Baker Lake would be managed as Late Successional Reserves.
6. Sediment yield from Baker Lake reservoir would be assessed in Years 7 through 10.
7. The Baker River would be routed around Lower Baker Dam in Year 11.
8. Lower Baker Dam would be removed in Years 12 through 15.
9. The area currently occupied by Lake Shannon would be planted to expedite recovery of
native vegetation communities (see Study T-7b for details).
10. The area currently occupied by Lake Shannon would be managed for commercial timber
production.
11. Analysis period focuses on the 40 years subsequent to the end of the current license, to
facilitate comparison to future with-project operations.
2.1.2 Scenario 2 – Flood-Control-Only without Lake Shannon
Under Scenario 2 it was assumed that if the Baker River Project were not relicensed for
hydropower production, the USACE would retain Upper Baker Dam to provide the
congressionally mandated flood storage capacity of 74,000 acre-feet from 15 November through
1 March. At the time the Terrestrial Working Group was originally developing assumptions
regarding a future Flood-Control-Only Scenario for Study T-7b, work group members agreed to
move forward using the assumption that the USACE would not increase the amount or seasonal
duration of flood storage. A number of proposals for additional flood storage were considered
when study T-7b was prepared, but no single proposal could be identified for purposes of
analysis. It was further assumed that the USACE would make no structural modifications to
Upper Baker Dam that would significantly modify flood storage capacity or operation.
Structural modifications are feasible, but they would likely precipitate additional flood storage
and violate the assumption of no increased flood storage.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-4
Future Aquatic Habitat –A-37
Under Scenario 2, Lower Baker Dam would be removed. While retention of Lower Baker Dam
could increase overall flood storage capacity in the Baker River, this would be inconsistent with
the previous assumption that existing flood storage capacity would be limited to 74,000 acrefeet. It is assumed that the USACE would be required to maintain upstream and downstream
passage for anadromous fish at Upper Baker Dam, and to manage for specific fish flows
downstream of the dam. Methods of fish passage and target instream flows would be determined
by the USACE, along with interested resource agencies and tribes. An assessment of the effect
of future instream flows on downstream habitats was beyond the scope of Study A-37.
The sequence of implementation for the Scenario 2, Flood-Control-Only without Lake Shannon
would be as follows:
1. Local, state and federal permitting for the removal of Lower Baker Dam would take 5
years after the end of the current license.
2. The Baker River would be routed around Lower Baker Dam in Year 6.
3. Lower Baker Dam would be removed in Years 7 through 10.
4. The area inundated by existing Lake Shannon would be planted to expedite recovery of
native vegetation communities (see Study T-7b for details).
5. The area currently occupied by Lake Shannon would be managed for commercial timber
production.
6. Analysis period focuses on the 40 years subsequent to the end of the current license, to
facilitate comparison to future with-project operations.
Operation of Upper Baker Development project facilities under the Flood-Control-Only without
Lake Shannon Scenario would be as follows:
Flood storage behind Upper Baker Dam would occur between elevations of 677.77 feet and
703.24 feet (NAVD 1988). The lower elevation of 677.77 feet is considered the minimum
generating pool level and represents the minimum elevation at which water can be passed
through Upper Baker Dam using the existing turbine as energy dissipates. The physical structure
of the dam potentially would allow water to be released down to elevation of 637.77 feet, but
there would be no way to reliably dissipate the energy of this water without significant structural
modifications. The upper elevation of 703.24 feet represents the area needed to store 74,000
acre-feet above 677.77 feet.
From March 1 through early November, the reservoir would be held at or near 703.24 feet,
fluctuating only in response to changes in inflow and to permit releases of water for downstream
fisheries. While it is feasible that the reservoir could be held at 677.77 feet from 1 March to
early November to allow seasonal vegetation to develop, the TRWG rejected this operational
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-5
Future Aquatic Habitat –A-37
regime for two reasons: a) recreation and aesthetic concerns in the watershed would favor a full,
stable pool during the summer months; and b) inclusion of seasonal vegetation in Scenario 2
would be inconsistent with the assumptions upon which Scenario 1 is based. Seasonal
vegetation and seasonally available aquatic habitat were not considered in Study A-37 or T-7b,
even though a considerable amount of vegetation and riverine habitat currently exists in the
drawdown zones of both Baker Lake and Lake Shannon and would exist in the future under
Scenario 2.
2.2
PREDICTION OF AQUATIC HABITAT TYPES AND ATTRIBUTES
UNDER FUTURE SCENARIOS
The amount and type of aquatic habitat that would become available under each scenario was
predicted based on an assessment of channel morphologic type and the topography of the
inundation zone. Wetland habitats that could provide periodic refugia when inundated by high
flows are also discussed in this report, based on information provided in Study T-7b. Wetland
habitats identified as potentially accessible future aquatic habitats in this report do not represent
areas that would provide year-round aquatic habitats that would contribute to fish production.
Seasonally inundated wetland habitats are the same as those identified in Study T-7b, and do not
represent additional wetland area.
Channel morphology is a useful tool for classifying streams and rivers because it: 1) dictates
habitat conditions used by the various life-history stages of salmonid species (Beechie and
Sibley, 1997); 2) directly influences the productive capacity of each habitat type (Vannote et al.,
1980; Naiman et al., 1992; Paustian et al., 1992); and 3) varies in terms of sensitivity and
response to changes in inputs of water, sediment and wood from natural or anthropogenic
disturbances (Paustian et al., 1992; Montgomery and Buffington, 1993; Rosgen, 1997).
The amount of aquatic habitat (i.e., channel length, channel type, low flow wetted area) available
under future without project evaluation scenarios was estimated by identifying the historical
length and channel morphologic type of streams located within the study area prior to
development of the Baker River Project. Information sources used to evaluate stream length and
channel types included:
•
General Land Office (GLO) notes dating from 1880 and 1892;
•
A 1:31,680 scale topographic map of the Baker River valley from the confluence with
the Skagit River up to and including Baker Lake produced by the USGS in 1915
(Herron, 1916);
•
1:24,000 scale topographic quadrangle maps produced by the USGS dated 1952;
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-6
Future Aquatic Habitat –A-37
•
1:4,800 scale topographic maps of the proposed Baker Lake reservoir area with a 510 foot contour interval (NAVD 1929) dating from 1959 (Stone and Webster, 1959);
and
•
1:23,280 scale black and white aerial photographs taken in 1959 that depict the
cleared Baker Lake reservoir area immediately prior to filling the reservoir.
The dams that comprise the Upper Baker Development and Lower Baker Development were
constructed several decades apart, and thus information on pre-project aquatic habitat types were
derived from different sources and different time periods. The most recent and accurate
available map/photo set was used to quantify aquatic habitats for each part of the study area. In
the case of Lake Shannon, the primary data source used to quantify pre-Project conditions was
the 1915 topographic map (Herron, 1916). In the case of Baker Lake, the primary data source
used to quantify pre-Project conditions was the 1959 photo set, supplemented by topographic
information from the 1959 topographic maps (Stone and Webster, 1959).
Channel segments with consistent geomorphic characteristics and response potential were
delineated based on stream gradient, landform, channel confinement, and channel planform.
Channel segments were classified using a modified version of the system developed by the USFS
Region 10 (Paustian et al., 1992). The USFS system is based on identification of “fluvial
process groups” that describe the interrelationship between watershed processes such as the flow
regime, fluvial erosion and mass wasting, and large woody debris (LWD) recruitment and the
role of wood in habitat formation. Channel gradient and confinement were measured from
topographic maps. Landforms were identified using a combination of topographic maps,
geology maps and aerial photo analysis.
Side channels associated with low gradient channel segments were easily identifiable on the
aerial photographs taken after the reservoir area had been cleared. Side channels were noted
only in association with alluvial floodplain channel types. Aerial photos covering the Lake
Shannon area before construction of the reservoirs were not available and existing maps were not
an appropriate scale for identifying side channels. As a result, the ratio of side channel length to
the length of alluvial floodplain channel measured in Baker Lake was assumed to be the same for
the Lake Shannon area.
Wetland area that could periodically provide aquatic habitat during highwater events in the fall
and winter was assumed to consist of those wetlands that are located adjacent to open
waterbodies (streams, ponds, lakes) or within the floodplain (i.e., wet meadows and shrub
wetlands). The distribution, type, and area of wetland and open water habitats that would
develop under Future Without-Project operational scenarios were identified in Study T-7b.
Wetlands considered to provide potential habitat during the winter season are a subset of those
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-7
Future Aquatic Habitat –A-37
identified for Study T-7b, and do not represent additional wetland areas or habitats within the
seasonal drawdown zone. A complete description of the general characteristics (area, type,
depth) of wetland habitats identified in Study T-7b is provided in this report.
Study T-7b also provides an estimate of the historic amount of lake and pond habitat within the
study area. Those estimates are applied in Study A-37. The area of open water habitats (lakes
and ponds) was derived from a combination of aerial photo interpretation, topographic maps and
GIS analysis. Historic Baker Lake, and other small natural lakes and ponds that existed prior to
Project development were delineated on the 1959 aerial photographs and quantified for Study
T-7b. It was assumed that natural Baker Lake would have the same depth and configuration in
the future when the reservoir (if present) was drawn down below elevation 660. It was further
assumed that the overall area of small lakes and ponds (e.g., beaver ponds) would be the same
under hypothetical without project operational scenarios as historically, although the location of
such features within the study area could change.
The area and volume of lake features formed by project facilities under future without project
scenarios was estimated using GIS data on existing lake topography (Walker and Associates,
2001). The 2001 topographic layers only extend to elevation 685 feet NAVD 88 and 380 feet
NAVD 88 respectively in Upper Baker Lake and Lake Shannon. Topography below the
minimum elevation of the 2001 Walker and Associates contours was estimated by digitizing
contours on older topographic maps (e.g., USGS, 1952; Herron, 1916) and extrapolating the
elevation of interest between existing contours.
Channels depicted on historic maps and photos were classified as side channel, mainstem river
(i.e., Baker River), large tributary (low flow wetted width > 5.5 m) or small tributary (low flow
wetted width < 5.5 m) based on the wetted width of the existing segment of each stream located
just above the current reservoir high pool elevation. Data on the current low flow wetted width
upstream of the reservoir for each channel is presented in Appendix B of Habitat Conditions of
Tributary Reached Accessible to Anadromous and Adfluvial Salmonids and Estimated Salmonid
Production Potentials: Baker River Basin (R2, 2003). The low flow wetted width of the reach
located immediately upstream of the existing full pool elevation was assumed to be
representative of the future low flow wetted width within the study area. Low flow habitat area
under each scenario was estimated by multiplying the length of each channel times the low flow
wetted width.
Channels were further classified by gradient. Gradient classes used for this analysis are
consistent with those used for Studies A01 and A26b, as well as with those of commonly used
channel geomorphic classification systems (Montgomery and Buffington, 1993; Paustian et al.,
1992).
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-8
Future Aquatic Habitat –A-37
To assess future habitat conditions, channels identified within the Baker River study area were
classified into one of eight geomorphic types: palustrine; alluvial floodplain; canyon, moderate
gradient mixed control, alluvial fan; steep alluvial fan, mountain or steep mountain. These
channel types correspond with seven channel process groups (Paustian et al., 1992) and six
Rosgen channel types (Rosgen, 1997). A summary of geomorphic inputs and channel
responsiveness is provided in Table 2-1. A detailed description of the morphologic
characteristics and fluvial processes associated with each channel process group is provided in
Appendix A.
Table 2-1.
Channel type and physical characteristics associated with channel types delineated
in the Baker River study area.
Paustian
Process
Group
Rosgen
Type
Palustrine
DA
Cobble/
gravel
Glacial
Outwash/
Floodplain
C3-D3
single thread
(1.0)
Boulder
Large
Contained
F2
2-4
single thread
(varies)
Cobble/
gravel
Moderate
gradient
mixed control
B3
2-4%
>4
multiple
thread
(<1.2)
Mixed
Alluvial Fan
variable
Steep alluvial fan
4-8%
>4
multiple
thread
(<1.2)
Mixed
Alluvial Fan
variable
Mountain
4-8%
<2
single thread
(<1.2)
Boulder/
Cobble
High
Gradient
Contained
A2
Steep Mountain
8-20%
<2
single thread
(<1.2)
Boulder/
Cobble
High
Gradient
Contained
A2a
Planform
(sinuosity)
meandering/
anastomosing
Dominant
Substrate
sand/small
gravel
>4
meandering/
braided
(>1.2)
2-4%
<2
Moderate gradient
mixed control
2-4%
Alluvial fan
Gradient
(%)
Entrenchment1
Palustrine
0-0.5%
>4
Alluvial floodplain
0.5-2%
Canyon
Channel Type
1
Entrenchment equals the ratio of valley width to channel width.
The recovery and evolution of aquatic habitat conditions over the future license period was
evaluated in a semi-quantitative manner. There are currently few empirical data available
describing channel recovery following the removal of large dams. Although over 480 dams have
been removed over the past century, most of the dams that have been removed are small; fewer
than 10 percent were greater than 20-feet tall, and only seven were greater than 50-feet tall
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-9
Future Aquatic Habitat –A-37
(Friends of the Earth et al., 1999). Perhaps the best available information that can be used to
evaluate channel recovery from catastrophic disturbances such as removal of a large dam comes
from research conducted at Mount Saint Helens in the aftermath of the 1980 eruption that sent
massive mudflows down many river channels. Channels there continued to experience high rates
of erosion 10-years after the eruption and associated mudflows. Trout populations were about 20
percent of those observed in undisturbed streams, although populations of sculpin and
macroinvertebrates recovered rapidly (Hawkins et al., 1994). In general, flushing of fine
sediments and recovery was faster in streams with confined channels (Lucas, 1986).
Given the uncertainty surrounding the future rate of channel recovery, several simplifying
assumptions were made. The rate of recovery was assumed to vary by channel type (Figure 2-3).
Canyon, mountain and steep mountain channels that have high confinement, steep gradient
and/or high stream power were assumed to recover the most rapidly. These channels generally
have banks that are highly resistant to erosion, and can transport out more sediment than is
supplied to them in most years. In contrast, alluvial floodplain, side channels and palustrine
channels were assumed to have the slowest recovery rate. The sediment supply generally
exceeds the transport rate of these channel types, thus it will take longer for sediment that has
accumulated since the dams were constructed to be transported downstream. In addition, bank
materials in alluvial floodplain and palustrine channels tend to be unconsolidated, and will be
highly susceptible to erosion until vegetation with stabilizing root systems becomes fully
established. Other channel types were assumed to have an intermediate recovery rate.
Because of the dependence of many aquatic habitat attributes on LWD, complete recovery for all
channel types was assumed to occur only after a period sufficient for development of mature
forest stands. Potential vegetation zones surrounding existing Baker Lake consist primarily of
Western Hemlock and Pacific Silver Fir vegetation zones; mature seral stages for these forest
types develop when the forest is between 80 and around 250 years old (USFS, 2002). To
simplify this analysis, mature forest conditions were assumed to become established at the end of
100 years. This does not mean to suggest that the entire riparian zone adjacent to each channel
segment would consist of late successional forest at that time, but rather that a sufficient time had
passed that the entire spectrum of age and size classes typical of Pacific Northwest Forests (with
the exception of old growth) would potentially be represented in floodplain communities. Old
growth conditions such as those reported to be present in the Baker River valley prior to the
development of the Baker River Project may take more than 250 years to become established
(USFS, 2002).
Channel recovery in supply-limited canyon and mountain channels was assumed to begin
immediately and continue at a rapid rate initially (logarithmic curve), becoming slower towards
the end of the estimated period required for recovery to the reference state. Transport-limited
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-10
Future Aquatic Habitat –A-37
alluvial floodplain channels were assumed to remain highly unstable for the first 10-years
following dam removal. After 10-years, channel recovery was assumed to progress slowly at
first, then more rapidly towards the end of the recovery period (exponential curve). Other
channel types were assumed to have an intermediate recovery rate (linear). In all cases,
complete channel recovery was assumed to occur once the time required for development of
mature forest conditions had occurred.
Habitat Condition
End of license Period
Similar to
reference
Canyon, Mountain
Alluvial Floodplain, Palustrine
Similar to
drawdown
Other
Dam
removed
Figure 2-3.
Time
Late successional
forest developed
Conceptual pathways of channel recovery following dam removal.
Since no scientifically defensible models predicting channel recovery were available,
assumptions regarding recovery rates and changes in channel conditions over time should be
considered rough estimates at best.
Data from existing channels within the Baker River basin were used to represent the habitat conditions
that would occur at each end of the recovery period. Habitat data from channels within the existing
drawdown zone were used to represent conditions that would be present immediately following removal
of the dam (Scenario 1) or in the former drawdown zone above the new high pool (Scenario 2). There are
currently data on existing habitats within the drawdown zone for all channel types except for Canyon and
Moderately confined channels (Table 2-2), although in some cases the range of channel sizes represented
was limited. Data on conditions in individual reference reaches used to develop Table 2-2 are presented
in Appendix B.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-11
Future Aquatic Habitat –A-37
Data describing habitat conditions in streams in the upper Baker subbasin were used to represent
“site potential” habitat conditions that would occur at the end of the recovery period. The upper
Baker subbasin consists of lands managed as Late Successional Reserve (LSR) by the USFS, or
as wilderness by the National Park Service. There are currently no roads into the upper Baker
subbasin, and timber harvest and other human activities that could affect channel conditions in
the subbasin are limited. Data from lightly managed basins in the Baker River subbasin were
used to supplement upper Baker subbasin information. Data describing reference habitat
conditions for fully recovered channels are presented in Table 2-3. Data on conditions in
individual reference reaches used to develop Table 2-3 are presented in Appendix B.
Table 2-2.
Habitat conditions characteristic of streams within the drawdown zone (Year 0).
Channel Type
Gradient
Class
Low Flow wetted
width (ft/m)
Pools/1000 ft
Key LWD/1000 ft
Mainstem Alluvial Floodplain
0-1
>66 ft (>20 m)
0.5
0
Side Channel2
0-1
18-66 ft (5.5-20 m)
0.5
0
Mainstem Canyon1
1-2
>66 ft (>20 m)
0.3
0
Mainstem MGMC2
2-4
>66 ft (>20 m)
0.5
0
0-1
18-66 ft (5.5-20 m)
0.5
0
Large Alluvial Fan
2-4
18-66 ft (5.5-20 m)
1.3
0
Large Steep Alluvial Fan3
4-8
18-66 ft (5.5-20 m)
1.3
0
Large Mountain
4-8
18-66 ft (5.5-20 m)
0
0
Large Steep Mountain4
8-20
18-66 ft (5.5-20 m)
0
0
Small Palustrine2
0-1
<18 ft (<5.5 m)
0.5
0
Small Alluvial Fan
2-4
<18 ft (<5.5 m)
0
0
Small Steep Alluvial Fan5
4-8
<18 ft (<5.5 m)
0
0
Small Mountain
4-8
<18 ft (<5.5 m)
3.8
1.1
Small Steep Mountain
8-20
<18 ft (<5.5 m)
4.6
0
Large Palustrine
2
1
No drawdown data available; # of pools assumed to be equivalent to reference state; LWD frequency assumed to
be zero
2
No drawdown data available; conditions assumed to be similar to mainstem alluvial floodplain
3
No drawdown data available; conditions assumed to be similar to large alluvial fan
4
No drawdown data available; conditions assumed to be similar to large mountain
5
No drawdown data available; conditions assumed to be similar to small alluvial fan
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-12
Future Aquatic Habitat –A-37
Table 2-3.
Site potential habitat conditions characteristic of streams at Year 100.
Channel Type
Gradient
Class
Low Flow wetted
width (ft/m)
Pools/1000 ft
Key LWD/1000 ft
Mainstem Alluvial Floodplain
0-1
>66 ft (>20m)
1.8
3.7
Side Channel
0-1
18-66 ft (5.5-20m)
5.0
5.7
Mainstem Canyon
1-2
>66 ft (>20m)
0.3
0.9
Mainstem MGMC
2-4
>66 ft (>20m)
2.7
1.8
Large Palustrine
0-1
18-66 ft (5.5-20m)
7.3
10
Large Alluvial Fan
2-4
18-66 ft (5.5-20m)
2.2
2
Large Steep Alluvial Fan
4-8
18-66 ft (5.5-20m)
9.6
2.4
Large Mountain
4-8
18-66 ft (5.5-20m)
8.7
6.9
Large Steep Mountain
8-20
18-66 ft (5.5-20m)
10.9
2
Small Palustrine
0-1
<18 ft (<5.5m)
16.3
1.8
Small Alluvial Fan
2-4
<18 ft (<5.5m)
2.0
0.1
Small Steep Alluvial Fan
4-8
<18 ft (<5.5m)
4.0
1.7
Small Mountain
4-8
<18 ft (<5.5m)
9.8
4.9
Small Steep Mountain
8-20
<18 ft (<5.5m)
16.6
2.4
Habitat characteristics at the end of the 40-year license period were derived by applying the
equation associated with each curve presented in Figure 2-3 to the appropriate channel type. The
time available for recovery varied between management scenarios and within the analysis area
(i.e., Baker Lake versus Lake Shannon) as a result of the assumption that dam removal would be
accomplished in stages.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
2-13
Future Aquatic Habitat –A-37
3. RESULTS
3.1
EXTENT OF POTENTIALLY AVAILABLE AQUATIC HABITATS
UNDER HYPOTHETICAL WITHOUT PROJECT OPERATIONS
SCENARIOS.
All of the aquatic habitat types that existed in the study area prior to Project construction are
represented in each of the two hypothetical without project management scenarios. The extent
and approximate distribution of aquatic habitats under Scenario 1: Project Decommissioning are
depicted in Figures 3-1 and 3-2. The approximate additional length of riverine habitats, and area
of lake and wetland habitats that would become available under Scenario 1 were estimated based
on the extent and distribution of historic habitats (Tables 3-1, 3-2). The actual location of stream
channels and wetlands that would develop in the future under Scenario 1 could differ
substantially from the locations depicted in Figures 3-1 and 3-2. Detailed information on the
length and characteristics of each habitat type that would become available are presented for
each scenario by subbasin in Appendix C.
The extent and approximate distribution of aquatic habitats under Scenario 2, Flood-ControlOnly without Lake Shannon are depicted in Figures 3-3 and 3-4. The approximate additional
length of riverine habitat, and area of lake and wetland habitat that would become available
under Scenario 2 were estimated based on the extent and distribution of historic habitats (Tables
3-3, 3-4). The actual location of stream channels and wetlands that would develop in the future
under Scenario 2 could differ substantially from the locations depicted in Figures 3-3 and 3-4.
Detailed information on the length and characteristics of each habitat type that would become
available are presented for each scenario by subbasin in Appendix C.
Figures 3-5 and 3-6 present the total amount of aquatic habitat that would be potentially be
accessible to anadromous and adfluvial fish in the Baker River basin under each scenario
compared to the amount of habitat that currently exists.
3.2
PREDICTED AQUATIC HABITAT CONDITIONS AT THE END OF
THE UPCOMING LICENSE PERIOD UNDER HYPOTHETICAL
WITHOUT PROJECT OPERATIONS SCENARIOS.
Given the relatively short time-frame of the upcoming license period (relative to the time
required for recovery of geomorphic process), none of the riverine habitats attained conditions
representative of unmanaged reference conditions within the 40-year analysis period. Habitat
conditions that would be expected to occur for various channel types in the Lake Shannon and
Baker Lake study areas at the end of the 40-year license period are presented in Tables 3-5 and
3-6.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
3-1
Future Aquatic Habitat –A-37
Table 3-1.
Length of additional riverine habitat by gradient classification in the Baker River
basin that would be available for return to reference conditions under Scenario 1,
Project Decommissioning.
Available Habitat in miles
Gradient
0%-1%
1%-2%
2%-4%
4%-8%
8%-20%
Subtotal
Lake Shannon Subbasin
Small Tributary
0.0
0.0
0.8
2.2
0.6
3.6
Large Tributary
0.0
0.0
0.6
1.1
0.0
1.7
Baker River
9.6
0.5
0.0
0.0
0.0
10.1
Side Channel
6.0
0.0
0.0
0.0
0.0
6.0
15.6
0.5
1.4
3.3
0.6
21.4
Subbasin Total
Baker Lake Subbasin
Small Tributary
10.5
0.0
9.7
1.1
0.3
21.6
Large Tributary
3.0
1.9
0.8
2.8
0.4
8.9
Baker River
7.4
3.3
0.0
0.0
0.0
10.7
Side Channel
6.2
0.0
0.0
0.0
0.0
6.2
Subbasin Total
27.1
5.2
10.5
3.9
0.7
47.4
Grand Total
42.7
5.7
11.9
7.2
1.3
68.8
Table 3-2.
Area of open water and potentially accessible wetland habitat that would be
available in the Baker River watershed at typical summer pool elevation under
future hypothetical Without Project Scenario 1, Project Decommissioning.
Area in Acres
Lake Shannon
Baker Lake
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Lake
Pond
Wet Meadow
Shrub wetland
0
4
10
16
549
15
40
133
3-4
Future Aquatic Habitat –A-37
Table 3-3.
Length of additional riverine habitat by gradient classification in the Baker River
basin that would be available for return to reference conditions under Scenario 2,
Flood-Control-Only without Lake Shannon.
Available Habitat in miles
Gradient
0%-1%
1%-2%
2%-4%
4%-8%
8%-20%
Total
Lake Shannon Subbasin
Small Tributary
0.0
0.0
0.8
2.2
0.6
3.6
Large Tributary
0.0
0.0
0.6
1.1
0.0
1.7
Baker River
9.6
0.5
0.0
0.0
0.0
10.1
Side Channel
6.0
0.0
0.0
0.0
0.0
6.0
15.6
0.5
1.4
3.3
0.6
21.4
Subbasin Total
Baker Lake Subbasin
Small Tributary
2.1
0.0
2.4
0.2
0.1
4.8
Large Tributary
2.1
1.1
0.5
1.0
0.0
4.7
Baker River
0.8
0.0
0.0
0.0
0.0
0.8
Side Channel
0.8
0.0
0.0
0.0
0.0
0.8
Subbasin Total
5.8
1.1
2.9
1.2
0.1
11.1
21.4
1.6
4.3
4.5
0.7
32.5
Grand Total
Table 3-4.
Area of open water and wetland habitat that would be available at typical summer
pool elevation in the Baker River watershed under future hypothetical Without
Project Scenario 2, Flood-Control-Only without Lake Shannon.
Area in Acres
Lake Shannon
Baker Lake
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Lake
Pond
Wet Meadow
Shrub wetland
0
4
10
16
3,589
1
4
7
3-7
Future Aquatic Habitat –A-37
45
Ongoing Operations
40
Scenario 1- Project Decommissioning
Miles of Potentially Accessible Habitat
35
Scenario 2- Flood Control Only
30
25
20
15
10
5
0
Side Channel
0-1%
1-2%
2-4%
4-8%
8-20%
Gradient Class
Figure 3-5.
Total length of riverine habitat in the Baker River watershed potentially
accessible to anadromous fish under alternate planning scenarios
developed for Baker Relicensing Studies T-7b and A-37. The length of
accessible habitats under Scenarios 1 and 2 was derived by adding
habitats available above the current reservoir high pool level under
current conditions to the amount of additional habitat that would become
available under Scenario 1 (Project Decommissioning) or Scenario 2
(Flood-Control-Only without Lake Shannon).
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
3-8
Future Aquatic Habitat –A-37
160
8,000
Ongoing Operations
140
7,000
Scenario 1- Project Decommissioning
120
6,000
100
5,000
80
4,000
60
3,000
40
2,000
20
1,000
0
0
Pond
Figure 3-6.
Lake area (acres)
Pond/wetland area (acres)
Scenario 2- Flood Control Only
Wet Meadow
Shrub wetland
Lake
Additional wetland habitats in the Baker Project Area that would be
potentially accessible to anadromous fish under alternate planning
scenarios developed for Baker Relicensing Studies T-7b and A-37.
Wetlands identified as potentially accessible to anadromous fish are
defined as non-forested wetland types that are located immediately
adjacent to streams or water bodies and that could become temporarily
inundated during the high flow season. These wetland areas are the same
as areas identified in study T-7b and do not represent additional wetland
habitat above and beyond that identified in Study T-7b. Under ongoing
operations, no wetland habitat would be available because the entire A-37
study area would be inundated by the project reservoirs.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
3-9
Future Aquatic Habitat –A-37
Table 3-5.
Predicted habitat conditions by channel type at the end of the upcoming license
period (year 40) under Scenario 1, Project Decommissioning, and average habitat
conditions over the 40-year period.
Channel Type
Potentially
Accessible
Stream
Length
(mi)
Year 40
Gradient
Class
Low Flow Wetted
Width
Average
Pools/
1000 ft
Key
LWD/
1000 ft
0.6
0.1
Pools/
1000 ft
Key
LWD
1000 ft
Lake Shannon1
Mainstem Alluvial Floodplain
8.4
0-1
>66 ft (>20 m)
0.55
0.05
Side Channels
6.0
0-1
18-66 ft (5.5-20 m)
0.7
0.2
0.60
0.10
Mainstem Canyon
1.7
1-2
>66 ft (>20 m)
0.3
0.8
0.30
0.40
Mainstem MGMC
0.1
2-4
>66 ft (>20 m)
1.2
0.5
0.70
0.25
Large Palustrine
0.0
0-1
18-66 ft (5.5-20 m)
0.8
0.4
0.65
0.20
Large Alluvial Fan
0.5
2-4
18-66 ft (5.5-20 m)
1.6
0.6
1.45
0.30
Large Steep Alluvial Fan
0.0
4-8
18-66 ft (5.5-20 m)
3.8
0.7
2.55
0.35
Large Mountain
1.1
4-8
18-66 ft (5.5-20 m)
7.3
5.8
3.65
2.90
Large Steep Mountain
0.0
8-20
18-66 ft (5.5-20 m)
9.2
1.7
4.60
0.85
Small Palustrine
0.0
0-1
<18 ft (<5.5 m)
0.7
0.1
0.60
0.05
Small Alluvial Fan
0.5
2-4
<18 ft (<5.5 m)
0.6
0.03
0.30
0.02
Small Steep Alluvial Fan
0.2
4-8
<18 ft (<5.5 m)
1.2
0.5
0.60
0.25
Small Mountain
2.3
4-8
<18 ft (<5.5 m)
9
4.3
6.40
2.70
Small Steep Mountain
0.6
8-20
<18 ft (<5.5 m)
14.6
2
9.60
1.00
1
Baker Lake
Mainstem Alluvial Floodplain
6.8
0-1
>66 ft (>20 m)
0.6
0.2
0.55
0.10
Side Channel
6.2
0-1
18-66 ft (5.5-20 m)
0.8
0.3
0.65
0.15
Mainstem Canyon
2.3
1-2
>66 ft (>20 m)
0.3
0.8
0.30
0.40
Mainstem MGMC
1.6
2-4
>66 ft (>20 m)
1.3
0.6
0.90
0.30
Large Palustrine
3.0
0-1
18-66 ft (5.5-20 m)
0.9
0.6
0.70
0.30
Large Alluvial Fan
0.8
2-4
18-66 ft (5.5-20 m)
1.6
0.7
1.45
0.35
Large Steep Alluvial Fan
4.6
4-8
18-66 ft (5.5-20 m)
4.2
0.8
2.75
0.40
Large Mountain
0.1
4-8
18-66 ft (5.5-20 m)
7.7
6.1
3.85
3.05
Large Steep Mountain
0.4
8-20
18-66 ft (5.5-20 m)
9.6
1.8
4.80
0.90
Small Palustrine
10.5
0-1
<18 ft (<5.5 m)
1.3
0.1
0.90
0.05
Small Alluvial Fan
9.7
2-4
<18 ft (<5.5 m)
0.7
0.04
0.35
0.02
Small Steep Alluvial Fan
0.5
4-8
<18 ft (<5.5 m)
1.4
0.6
0.70
0.30
Small Mountain
0.5
4-8
<18 ft (<5.5 m)
9.4
4.6
6.60
2.85
Small Steep Mountain
0.3
8-20
<18 ft (<5.5 m)
15.6
2.2
10.10
1.10
1
Under Scenario 1, recovery of channels currently inundated by Baker Lake begins in year 7 when the Baker River is routed
around lower Baker Dam. Recovery of channels currently inundated by Lake Shannon begins in year 12 when the Baker
River is routed around lower Baker Dam
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
3-10
Future Aquatic Habitat –A-37
Table 3-6.
Predicted habitat conditions by channel type at the end of the upcoming license
period and average conditions over the 40-year period (year 40) under Scenario 2,
Flood-Control-Only without Lake Shannon.
Channel Type
Potentially
Accessible
Stream
Length
(mi)
Year 40
Gradient
Class
Low Flow Wetted
Width
Average
Pools/
1000 ft
Key
LWD/
1000 ft
Pools/
1000 ft
Key
LWD
1000 ft
Lake Shannon1
Mainstem Alluvial Floodplain
8.4
0-1
>66 ft (>20 m)
0.6
0.1
0.55
0.05
Side Channels
6.0
0-1
18-66 ft (5.5-20 m)
0.7
0.2
0.60
0.10
Mainstem Canyon
1.7
1-2
>66 ft (>20 m)
0.3
0.8
0.30
0.40
Mainstem MGMC
0.1
2-4
>66 ft (>20 m)
1.2
0.5
0.70
0.25
Large Palustrine
0.0
0-1
18-66 ft (5.5-20 m)
0.8
0.4
0.65
0.20
Large Alluvial Fan
0.5
2-4
18-66 ft (5.5-20 m)
1.6
0.6
1.45
0.30
Large Steep Alluvial Fan
0.0
4-8
18-66 ft (5.5-20 m)
3.8
0.7
2.55
0.35
Large Mountain
1.1
4-8
18-66 ft (5.5-20 m)
7.3
5.8
3.65
2.90
Large Steep Mountain
0.0
8-20
18-66 ft (5.5-20 m)
9.2
1.7
4.60
0.85
Small Palustrine
0.0
0-1
<18 ft (<5.5 m)
0.7
0.1
0.60
0.05
Small Alluvial Fan
0.5
2-4
<18 ft (<5.5 m)
0.6
0.03
0.30
0.02
Small Steep Alluvial Fan
0.2
4-8
<18 ft (<5.5 m)
1.2
0.5
0.60
0.25
Small Mountain
2.3
4-8
<18 ft (<5.5 m)
9
4.3
6.4
2.7
Small Steep Mountain
0.6
8-20
<18 ft (<5.5 m)
14.6
2
9.6
1.0
1
Baker Lake
Mainstem Alluvial Floodplain
0.8
0-1
>66 ft (>20 m)
0.6
0.3
0.55
0.15
Side Channel
0.8
0-1
18-66 ft (5.5-20 m)
0.9
0.5
0.70
0.25
Mainstem Canyon
0.0
1-2
>66 ft (>20 m)
0.3
0.8
0.30
0.40
Mainstem MGMC
0.0
2-4
>66 ft (>20 m)
1.4
0.7
0.95
0.35
Large Palustrine
2.1
0-1
18-66 ft (5.5-20 m)
1.0
0.8
0.75
0.40
Large Alluvial Fan
0.5
2-4
18-66 ft (5.5-20 m)
1.7
0.8
1.50
0.40
Large Steep Alluvial Fan
2.0
4-8
18-66 ft (5.5-20 m)
4.6
1
2.95
0.50
Large Mountain
0.0
4-8
18-66 ft (5.5-20 m)
8.0
6.3
4.00
3.15
Large Steep Mountain
0.1
8-20
18-66 ft (5.5-20 m)
10.0
1.8
5.00
0.90
Small Palustrine
2.2
0-1
<18 ft (<5.5 m)
1.3
0.1
0.90
0.05
Small Alluvial Fan
2.4
2-4
<18 ft (<5.5 m)
0.8
0.04
0.40
0.02
Small Steep Alluvial Fan
0.0
4-8
<18 ft (<5.5 m)
1.6
0.7
0.80
0.35
Small Mountain
0.0
4-8
<18 ft (<5.5 m)
9.4
4.6
6.60
2.85
Small Steep Mountain
0.1
8-20
<18 ft (<5.5 m)
15.6
2.2
5.50
1.00
1
Under Scenario 2, recovery of channels inundated by Baker Lake begins in year 0 when Flood-Control-Only without Lake
Shannon operations are implemented. Recovery of channels in Lake Shannon begins in year 6 when the Baker River is routed
around lower Baker Dam.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
3-11
Future Aquatic Habitat –A-37
Physical characteristics known to influence the productivity of lake habitats are presented for each
hypothetical without project scenario in Table 3-7. No information is available regarding the recovery
rate of natural lakes following dam removal. Turbidity would likely be higher than for unmanaged
reference conditions for at least the first decade following implementation of either without project
scenario, as stream channels cut through lacustrine sediment deposits in the former reservoir pool and
experienced elevated rates of bank erosion until vegetation became established.
Recovery and vegetation characteristics of wetland habitat are described in Study T-7b.
Table 3-7.
Lake habitat characteristics in the Baker River study area under hypothetical
future Without Project scenarios as compared to existing conditions.
Surface Area
at Full Pool
(acres)
Euphotic
Zone Area
(lake area
with depth
< 34 feet)
(acres)
Scenario 1, Project
Decommissioning1
550
Scenario 2, FloodControl-Only without
Lake Shannon2
Current Conditions3
Scenario
1
2
3
Volume at
Full Pool
(acre-feet)
Euphotic
Zone
(volume of
depth < 34
feet)
(acres)
Wetted
Perimeter at
Full Pool
(ft)
118
55,275
16,687
25,702
3,589
1,806
167,216
90,668
205,217
7,258
2,476
420,500
204,187
332,824
Natural Baker Lake elevation at full pool is approximately 666 feet NAVD 88; pool areas derived from digitizing
lake area on historic aerial photographs.
Under Scenario 2, Baker Lake full pool elevation is 703.77 ft NAVD 88. Lower Baker Dam would be removed,
and no natural lake would be present in the area currently inundated by Lake Shannon.
Includes data for both Baker Lake and Lake Shannon.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
3-12
Future Aquatic Habitat –A-37
4. LITERATURE CITED
Beechie, T. J. and T. H. Sibley. 1997. Relationships between channel characteristics, woody
debris and fish habitat in northwestern Washington streams. Trans. Amer. Fish. Soc.
126: 217-229.
Friends of the Earth, American Rivers, and Trout Unlimited. 1999. Dam Removal Success
Stories: restoring rivers through removal of dams that don’t make sense.
Hawkins, C.P., J. Sedell, and S. Gregory. 1994. Recovery of stream ecosystems following
catastrophic disturbances. In Frenzen, P.M., A.M. Delano and C.M. Crisafulli (compilers)
Mount St. Helens: biological research following the 1980 eruptions. U.S. Forest Service
Pacific Northwest Research Station. Publication PNW-GTR-342. Portland, Oregon.
Herron, W.H. 1916. Profile surveys in 1915 in Skagit River basin, Washington, prepared under
the direction of W. H. Herron, acting chief geographer, prepared in cooperation with the
state of Washington. U.S. Geological Survey Water Supply Paper 419. Washington
Government Printing office. 8p. plus fold out maps.
Lucas, R.E. 1986. Recovery of gamefish populations impacted by the May 18 1980 eruption of
Mount St. Helens: winter run steelhead in the Toutle River watershed in Keller, S.A.C.,
editor, 1986. Mount St. Helens: 5 years later. Eastern Washington University press.
Cheney, Washington. 441 p.
Montgomery, D. R. and J. M. Buffington. 1993. Channel classification, prediction of channel
response, and assessment of channel condition. Timber Fish and Wildlife Report TFWSH10-93-002. 84 pp.
Naiman, R. J., T. Beechie, L. E. Benda, D. R. Berg, P. A. Bisson, L. H. MacDonald, M. D.
O’Connor, P. L. Olsen, and E. A. Steele. 1992. Fundamental elements of ecologically
healthy watersheds in the Pacific Northwest Coastal Ecoregion. Pages 127-188 in R. J.
Naiman, editor. Watershed management: balancing sustainability and environmental
change. Springer-Verlag, New York.
Paustian, S. J., K. Anderson, D. Blanchet, S. Brady, M. Cropley, J. Edgington, J. Fryxell, G.
Johnejack, D. Kelliher, M. Kuehn, S. Maki, R. Olson, J. Seesz and M. Wolanek. 1992. A
channel type users guide for the Tongass National Forest, Southeast Alaska. U.S. Forest
Service, Alaska Region R10-TP-26. 179 pp.
R2 Resource Consultants Inc. (R2). 2003. Habitat conditions of tributary reaches accessible to
anadromous and adfluvial salmonids and estimated salmonid production potentials: Baker
River basin. Consultant report prepared for Puget Sound Energy, Inc. Bellevue,
Washington.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
4-1
Future Aquatic Habitat –A-37
R2 Resource Consultants, Inc. (R2). 2004. Hydrology and geomorphology of the Baker and
middle Skagit Rivers. Part 2: sediment transport and channel response. Consultant report
prepared for Puget Sound Energy, Inc. Bellevue, Washington. February 2004.
Rosgen, D. 1997. Applied River Morphology. Wildland Hydrology, Pagosa Springs, Colorado.
Stone and Webster Engineering Corporation (Stone and Webster). 1959. Aerial topographic
survey, 1″ = 400′ scale map, 10′ contour interval with 5′ supplemental contours
(NGVD 29).
U.S. Geological Survey (USGS). 1952. Lake Shannon Quadrangle, Washington. 1:15,000 scale
15-minute series topographic map. U.S. Geological Survey, Denver, Colorado.
U.S. Forest Service (USFS). 2002. Baker River watershed analysis. Mount Baker Snoqualmie
National Forest, Pacific Northwest Region. ~200 p. + Appendices
Vannote, R. L, G. W. Minshall, K. W. Cummins, J. R. Sedell, and C. E. Cushing. 1980. The
river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences 37:130-137.
Vaughn, M.E. and J.J. Zablotney. 2003. Potential future vegetation of the Baker River Project
Area. Relicense Study T-7b Final Report FERC Project No. 2150. Consultant Report
prepared for Puget Sound Energy Inc. August 2003. 31 p.
Walker and Associates. 2001. Aerial topographic survey, 5′ digital contours (NAVD 88). The
lowest Lake Shannon elevation available from this dataset is 380′ (NAVD 88).
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
4-2
Future Aquatic Habitat –A-37
APPENDIX A
Fluvial Process Groups
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Future Aquatic Habitat –A-37
Alluvial Floodplain Channels
Alluvial floodplain channels in the Baker River study area are mainstem streams that occupy
broad valley bottoms with extensive floodplains composed of alluvial material. Alluvial
floodplain channels commonly support abundant off-channel habitats including side channels
and wetlands.
Planform: Sinuous, multiple secondary and side channels. Anastomosing to braided under high
sediment supply conditions.
Gradient: 0-1%
Confinement: Low
Bankfull width: >30m
Bedform: Pool-riffle. Pools free-formed by hydraulics or associated with stable LWD and
obstructions.
Sediment transport: Bed substrate consists of mobile sediment (primarily gravel and cobble).
Bedload is stored as bars and islands within the channel, while suspended sediments deposit in
overbank areas during high flows. The floodplain serves as a long-term sediment storage site;
sediment stored within the floodplain is mobilized as the channel migrates laterally or avulses to
form new channels.
LWD Distribution and Function: Alluvial floodplain channels in the study area are large, with
a bankfull width that is greater than one site potential tree height. Individual pieces of LWD may
provide some channel complexity if they become lodged along the bank, but wood is generally
transported downstream, and either accumulates as debris jams, or is mobilized through the
system. Accumulations of LWD have a strong influence on channel morphology, creating pools,
bars and other habitat features. Accumulation of LWD may also cause channel avulsions (rapid
shifts in the thalweg) that are responsible for forming side channel habitats. Wood of a sufficient
size to influence channel morphology is recruited to large alluvial floodplain channels primarily
through bank erosion. Smaller pieces are delivered by fluvial transport from upstream reaches.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
A-1
Future Aquatic Habitat –A-37
Palustrine Channels
Palustrine channels in the Baker River study area are small tributary streams or groundwater fed
channels that are located within or flow across the floodplain formed by larger rivers.
Planform: Sinuous, multiple threaded.
Bankfull Width: <10m
Gradient: 0-1%
Confinement: Low
Bedform: Dune-ripple; pools rare, formed by LWD or undercut banks where present. Long
deep glides more typical.
Substrate: Silt and sand to small gravel. Sediment delivery to these streams is limited, as they
drain small areas that may lie almost entirely within the floodplain of larger rivers. In cases
where palustrine channels are fed by steep mountain streams, bedload from upstream reaches
deposits in small alluvial fans and is rarely transported through the lower gradient reaches. The
main sediment source is bank erosion. Bank stability is maintained by the roots of riparian or
wetland vegetation along the banks. Unvegetated banks are unstable and susceptible to erosion.
LWD Distribution and Function: Palustrine channels are small, and frequently occupy nonforested wetlands. Individual pieces of LWD may provide some channel complexity if they
break and enter the channel, but intact fallen trees typically span the channel above the bankfull
margin. Accumulation of wood fragments or beaver dams may block the channel and cause
channel avulsions (rapid shifts in the thalweg) that are responsible for forming side channel
habitats.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
A-2
Future Aquatic Habitat –A-37
Moderate Gradient Mixed Control Channels
Moderate gradient mixed control channels may occur throughout the drainage basin. Offchannel habitat or side channels may occur where valley bottoms are relatively wide, but are not
common in this channel type.
Planform: single thread, weakly sinuous with occasional side channels.
Bankfull Width: Up to 50m
Gradient: 2-4%
Confinement: Moderate
Bedform: plane bed or forced pool riffle; pools formed by LWD or other stable obstructions.
Substrate: Highly variable, depends on gradient and LWD loading. Channels without LWD
have bed material that consists primarily of cobble to boulder size clasts. Moderate gradient
mixed control channels with abundant LWD have bed materials that consists primarily of sand,
gravel and cobbles.
LWD Distribution and Function: Moderate gradient mixed control channels are very
responsive to LWD, the presence of which can substantially increase the number of pools. Both
individual pieces and jams affect channel morphology. Large woody debris is delivered from
stream banks, small bank failures where the channel impinges directly on steep sideslopes, or by
fluvial transport from upstream reaches.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
A-3
Future Aquatic Habitat –A-37
Canyon Channels
Canyon channels are large mainstem streams that are tightly confined by bedrock. The Baker
River within the Project area formerly contained a number of canyon sections.
Planform: single thread
Bankfull Width: 10-30m
Gradient: 2-4%
Confinement: High
Bedform: Planebed to step-pool. Deep, bedrock controlled pools.
Substrate: Boulder and cobble, with frequent bedrock outcrops. Mobile sediments accumulate
in patches associated with stable obstructions.
LWD Distribution and Function:
Large woody debris is rapidly transported through these channels. Wood that does lodge in the
canyon is subject to extreme hydraulic forces and tends to break down and remobilize rapidly.
Where accumulations of LWD do occur in smaller canyon channels, substantial amounts of
gravel and cobble may also be retained.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
A-4
Future Aquatic Habitat –A-37
Alluvial Fan Channels
Alluvial fans are depositional features that form as a result of the rapid change in sediment
transport capacity that occur where steep mountainous streams enter wide valleys. Many of the
alluvial fan channels in the Baker River study area cross very large alluvial fans formed by
Holocene glacial outwash and lahars originating from volcanic activity at Mount Baker.
Planform: weakly sinuous, multiple divergent distributaries.
Bankfull Width: Up to 50m
Gradient: 2-6%
Confinement: Low
Bedform: plane bed or forced pool riffle to step-pool; pools formed by LWD or other stable
obstructions.
Substrate: Highly variable. Sediment delivery to these channels occurs almost entirely from
upstream reaches. Coarse material is deposited on the upstream portion of the alluvial fan.
Substrate becomes finer in a downstream direction.
LWD Distribution and Function: Alluvial fan channels are very responsive to LWD, which
may block the channel and force channel avulsions or act to form bed steps that trap and store
smaller sediments and create plunge pools. Riparian areas are often narrow at the fan apex,
becoming wider as the fan and associated distributary channels spread out. Off-channel habitats
or side channels are common in this channel type.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
A-5
Future Aquatic Habitat –A-37
Mountain Channels
Tributary streams typically originate as mountain channels. Mountain channels are areas of net
sediment export, delivering sediment to downstream segments. Off-channel habitat or side
channels are uncommon.
Planform: straight, single thread
Bankfull Width: Up to 30 m
Gradient: 4-8%
Confinement: High
Bedform: Step-pool
Substrate: Stable cobble and boulder; mobile sediments accumulate in patches associated with
stable obstructions. Sediment storage is typically associated with LWD.
LWD Distribution and Function: LWD stores sediment and contributes to formation of
plunge pools. Large woody debris is delivered from adjacent sideslopes through wind throw,
tree fall or mass wasting. Larger mountain channels (width >10 m) may deliver substantial
amounts of LWD to downstream reaches via fluvial transport. Mountain channels with widths
less than about 10 meters are assumed to deliver few pieces of wood that qualify as LWD
(Martin and Benda 1998). Wood originating from these channels would be expected to consist
primarily of fragments.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
A-6
Future Aquatic Habitat –A-37
APPENDIX B
Reference Conditions and Channel Recovery
Rates for Riverine Habitats in the Baker River Basin
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Future Aquatic Habitat –A-37
Table B-1. Drawdown zone stream conditions in Baker Lake subbasin (data from R2 2003)
Stream/Reach
Name
1
Size Channel Type
Reach
Length
(ft)
Map
Gradient
(%)
Low Flow
Wetted
Width
(ft)
Pools/1000 ft
Key Pieces/1000
ft
Sandy
Park
Anderson
Noisy
Swift
Baker
Little Sandy
Beaver
Little Park
Welker
536
Silver
Chadwick
L
Alluvial Fan
1,575
4
28
8.3
0.0
L
Alluvial Fan
2,330
2
99
0.0
0.0
L
Mountain
558
8.5
27
0.0
0.0
L
Mountain
1,083
3
35
0.0
0.0
M
Alluvial Floodplain
5,053
1.5
335
1.3
0.0
M
Alluvial Floodplain
9,121
0.5
43
2.2
0.0
S
Alluvial Fan
2,494
1.5
36
6.6
1.3
S
Alluvial Fan
755
1.5
11
8.7
0.0
S
Alluvial Fan
2,756
1.5
13
4.8
0.0
S
Mountain
558
4
7
5.9
0.0
S
Mountain
492
6
15
40.0
0.0
S
Mountain
262
9
15
0.0
0.0
S
Mountain
230
6
15
14.3
14.3
539 S
Steep Mountain
262
11
18
12.5
0.0
1
Stream size assigned based on low flow wetted width of first reach upstream of existing reservoir high pool elevation
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
B-1
Future Aquatic Habitat –A-37
Table B-2. Reference stream conditions from unmanaged channels in the Baker River basin (data from R2 2003).
Stream/Reach
Name
Baker River - R2
Baker River - R3
Baker River - R6
Side Channel 4A
Side Channel 4B
Side Channel 4C
Side Channel 4E
Side Channel 4F
Side Channel 5A
Side Channel 5B
Side Channel 5C
Baker River - R4
Baker River - R7
Channel
Bald Eagle - R1
Size
M
M
M
L
L
L
L
S
L
L
L
M
M
L
L
1
Channel Type
Alluvial Floodplain
Alluvial Floodplain
Alluvial Floodplain
Side Channel
Side Channel
Side Channel
Side Channel
Side Channel
Side Channel
Side Channel
Side Channel
Canyon
MGMC
Palustrine
Alluvial Fan
Reach
Length
(ft)
8,727
2,559
7,809
295
1,247
1,181
2,953
164
1,739
1,837
4,187
7,448
3,379
2,822
4,298
Map
Gradient
(%)
0.5
0.8
1.4
<1
0.5
1
1
1
2
1
1
1.2
3
<1
3
Low Flow
Wetted
Width
Key
(ft)
Pools/1000 ft Pieces/1000 ft
61
0.6
0.2
56
2.0
5.9
60
2.8
4.9
23
0.3
0.0
22
9.2
13.3
20
7.5
8.3
19
5.3
0.0
5
0.0
0.0
31
8.2
2.9
38
5.6
12.8
23
3.8
8.8
68
0.3
0.9
48
2.7
1.8
24
3.5
2.1
35
2.3
3.0
Sulphide - R1 and
L
Alluvial Fan
6,660
3.5
41
R2
Pass - R1
L
Steep Alluvial Fan
689
6
31
Crystal - R1
L
Steep Alluvial Fan
1,509
8
22
Bald Eagle - R2
L
Mountain
459
6
33
Pass - R1
L
Mountain
689
6
47
Sulphide
L
Mountain
1,411
8
41
Crystal
L
Mountain
755
7
26
Blum
L
Steep Mountain
2,658
10
28
Scramble
L
Steep Mountain
1,969
12
18
Silver Creek
L
Steep Mountain
1,214
12
18
Pass - R2
L
Steep Mountain
1,050
14
47
0563B
S
Palustrine
1,102
1
10
Lake Creek - R1
S
Steep Alluvial Fan
1,739
6
4
452
S
Mountain
3,478
5
9
Hidden
S
Mountain
427
8
9
Morovitz - R4
S
Mountain
4,954
3.8
23
Lake
S
Steep Mountain
1,706
17
9
Ermine
S
Steep Mountain
427
19
3
539
S
Steep Mountain
1,608
20
7
1
M=Mainstem Baker River; L=large (low flow width > 5.5m); S=Small (low flow
wetted width <5.5m)
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
B-2
2.1
0.9
16.0
3.3
6.5
16.0
7.1
5.3
12.0
8.6
6.6
16.2
16.3
4.0
5.2
14.1
10.1
21.7
18.8
9.3
1.5
3.3
0.0
1.5
5.0
21.2
4.9
2.0
0.0
1.0
1.8
1.7
10.1
4.7
0.0
3.5
0.0
3.7
Future Aquatic Habitat –A-37
Table B-3. Channel characteristics by decade for Mainstem - Alluvial Floodplain channels.
Gradient Class
0-1
0-1
0-1
0-1
0-1
0-1
0-1
Year
0
10
20
30
35
40
100
Pools/1000 m
0.5
0.5
0.5
0.6
0.6
0.6
1.8
Key/1000 ft Comment
0
Reference=Drawdown
0
0.1
0.1
0.2
0.3
3.7
Reference=Undisturbed
Table B-4. Channel characteristics by decade for side channels associated with Alluvial Floodplain channels.
Gradient Class
0-1
0-1
0-1
0-1
0-1
0-1
0-1
Year
0
10
20
30
35
40
100
Pools/1000 m
0.5
0.5
0.6
0.7
0.8
0.9
5
Key/1000 ft Comment
0
Reference=Drawdown
0
0.1
0.2
0.3
0.5
5.7
Reference=Undisturbed
Table B-5. Channel characteristics by decade for Mainstem - Canyon channels.
Gradient Class
2-4
2-4
2-4
2-4
2-4
2-4
2-4
Year
0
10
20
30
35
40
100
Pools/1000 m
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Key/1000 ft Comment
0
Reference=Drawdown
0.3
0.6
0.8
0.8
0.8
0.9
Reference=Undisturbed
Table B-6. Channel characteristics by decade for Mainstem - Moderate Gradient Mixed Control channels.
Gradient Class
2-4
2-4
2-4
2-4
2-4
2-4
2-4
Year
0
10
20
30
35
40
100
Pools/1000 m
0.5
0.7
0.9
1.2
1.3
1.4
2.7
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Key/1000 ft Comment
0
Reference=Drawdown
0.2
0.4
0.5
0.6
0.7
1.8
Reference=Undisturbed
B-3
Future Aquatic Habitat –A-37
Table B-7. Channel characteristics by decade for Large Palustrine channels.
Gradient Class
0-1
0-1
0-1
0-1
0-1
0-1
0-1
Year
0
10
20
30
35
40
100
Pools/1000 m
0.5
0.5
0.6
0.8
0.9
1.0
7.3
Key/1000 ft Comment
0
Reference=Drawdown
0.0
0.2
0.4
0.6
0.8
10
Reference=Undisturbed
Table B-8. Channel characteristics by decade for Large Alluvial Fan channels.
Gradient Class
2-4
2-4
2-4
2-4
2-4
2-4
2-4
Year
0
10
20
30
35
40
100
Pools/1000 m
1.3
1.4
1.5
1.6
1.6
1.7
2.2
Key/1000 ft Comment
0
Reference=Drawdown
0.2
0.4
0.6
0.7
0.8
2
Reference=Undisturbed
Table B-9. Channel characteristics by decade for Large Steep Alluvial Fan channels.
Gradient Class
4-8
4-8
4-8
4-8
4-8
4-8
4-8
Year
0
10
20
30
35
40
100
Pools/1000 m
1.3
2.1
3.0
3.8
4.2
4.6
9.6
Key/1000 ft Comment
0
Reference=Drawdown
0.2
0.5
0.7
0.8
1.0
2.4
Reference=Undisturbed
Table B-10. Channel characteristics by decade for Large Mountain channels.
Gradient Class
4-8
4-8
4-8
4-8
4-8
4-8
4-8
Year
0
10
20
30
35
40
100
Pools/1000 m
0
3.1
5.9
7.3
7.7
8.0
8.7
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Key/1000 ft Comment
0
Reference=Drawdown
2.5
4.7
5.8
6.1
6.3
6.9
Reference=Undisturbed
B-4
Future Aquatic Habitat –A-37
Table B-11. Channel characteristics by decade for Large Steep Mountain channels.
Gradient Class
8-20
8-20
8-20
8-20
8-20
8-20
8-20
Year
0
10
20
30
35
40
100
Pools/1000 m
0
3.9
7.4
9.2
9.6
10.0
10.9
Key/1000 ft Comment
0
Reference=Drawdown
0.7
1.4
1.7
1.8
1.8
2
Reference=Undisturbed
Table B-12. Channel characteristics by decade for Small Palustrine channels.
Gradient Class
0-1
0-1
0-1
0-1
0-1
0-1
0-1
Year
0
10
20
30
35
40
100
Pools/1000 m
0
0
0.3
0.7
1.0
1.3
16.3
Key/1000 ft Comment
0
Reference=Drawdown
0
0.0
0.1
0.1
0.1
1.8
Reference=Undisturbed
Table B-13. Channel characteristics by decade for Small Alluvial Fan channels.
Gradient Class
2-4
2-4
2-4
2-4
2-4
2-4
2-4
Year
0
10
20
30
35
40
100
Pools/1000 m
0
0.2
0.4
0.6
0.7
0.8
2.0
Key/1000 ft Comment
0
Reference=Drawdown
0.01
0.02
0.03
0.04
0.04
0.10
Reference=Undisturbed
Table B-14. Channel characteristics by decade for Small Steep Alluvial Fan channels.
Gradient Class
4-8
4-8
4-8
4-8
4-8
4-8
4-8
Year
0
10
20
30
35
40
100
Pools/1000 m
0
0.4
0.8
1.2
1.4
1.6
4
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Key/1000 ft Comment
0
Reference=Drawdown
0.2
0.3
0.5
0.6
0.7
1.7
Reference=Undisturbed
B-5
Future Aquatic Habitat –A-37
Table B-15. Channel characteristics by decade for Small Mountain channels.
Gradient Class
4-8
4-8
4-8
4-8
4-8
4-8
4-8
Year
0
10
20
30
35
40
100
Pools/1000 m
4.6
6.5
8.1
9.0
9.2
9.4
9.8
Key/1000 ft Comment
1.1
Reference=Drawdown
2.5
3.7
4.3
4.4
4.6
4.9
Reference=Undisturbed
Table B-16. Channel characteristics by decade for Small Steep Mountain channels.
Gradient Class
8-20
8-20
8-20
8-20
8-20
8-20
8-20
Year
0
10
20
30
35
40
100
Pools/1000 m
3.8
8.4
12.5
14.6
15.1
15.6
16.6
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Key/1000 ft Comment
0
Reference=Drawdown
0.9
1.6
2.0
2.1
2.2
2.4
Reference=Undisturbed
B-6
Future Aquatic Habitat –A-37
APPENDIX C
Aquatic Habitat Availability by Channel Size and
Type for Baker River Subbasin
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
Future Aquatic Habitat –A-37
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Alluvial
Floodplain
10.9
21.2
30.9
Side Channel
5.0
11.8
17.2
5.1
Canyon
3.4
5.7
2.7
Channel Type
Moderate
Gradient
Mixed
Control
2.7
4.2
3.0
4.3
3.5
Alluvial Fan Steep Alluvial
Fan
14.9
19.2
Mountain
11.7
15.7
17.6
Steep
Mountain
25.6
25.0
24.3
Scenario28.7
2 - Flood-Control-Only w/out Lake Shannon
Scenario 1 - Project Decommissioning
Ongoing operations
Riverine Habitat Types
Baker River Watershed
1440.19_A-37Report_FuturePotentialAquaHab_05.04
C-1
Future Aquatic Habitat –A-37
Total length of riverine habitat in the Baker River watershed potentially accessible to anadromous fish under alternate
planning scenarios developed for Baker Relicensing Studies T-7b and A-37. The length of accessible habitats under Scenarios
1 and 2 was derived by adding habitats available under current conditions to the amount of additional habitat that would
become available under Scenario 1 (Project Decommissioning) or Scenario 2 (Flood-Control-Only without Lake Shannon).
Palustrine
6.3
10.5
16.8
Baker River Project Relicensing
Figure C1.
Miles of stream
Riverine Habitat Types, Baker River Watershed
Mainstem Baker River
25.0
Ongoing operations
21.2
Scenario 1 - Project Decommissioning
20.0
Scenario 2 - Flood-Control-Only w/out Lake
Shannon
Miles of stream
15.3
15.2
15.0
9.9
10.0
6.0
5.1
5.0
3.1
3.4
2.8
1.7
1.1
2.0 2.0
1.8
0.9
0.7 0.7 0.7
0.0
Side Channel
Alluvial Floodplain
Canyon
Moderate Gradient
Mixed Control
Mountain
Steep Mountain
Channel Type
Riverine Habitat Types, Baker River Watershed
Large Tributary (>5.5m wide)
7.0
6.5
Ongoing operations
6.0
Scenario 1 - Project Decommissioning
Scenario 2 - Flood-Control-Only w/out
Lake Shannon
5.0
Miles of stream
4.2
4.0
3.9
4.0
3.8
3.4
3.1
3.0
2.7 2.7
2.3 2.3 2.3
2.2
1.8 1.9 1.8
2.0
1.0
0.8
1.0
0.3 0.3 0.3
0.0
Palustrine
Alluvial Floodplain
Canyon
Alluvial Fan
Steep Alluvial Fan
Mountain
Steep Mountain
Channel Type
Riverine Habitat Types, Baker River Watershed
Small Tributary (<5.5m wide)
Ongoing operations
16.0
Scenario 1 - Project Decommissioning
14.8
14.4
Scenario 2 - Flood-Control-Only w/out Lake
Shannon
14.0
12.412.2
12.0
11.5
Miles of stream
10.0
9.1
8.6
8.0
7.3
6.1
6.0
6.0
4.4
4.0
3.8
2.0
0.7
0.0 0.0 0.0
0.0 0.0 0.0
Alluvial
Floodplain
Canyon
0.2
0.2
0.0
Palustrine
Alluvial Fan
Steep Alluvial
Fan
Mountain
Steep Mountain
Channel Type
Figure C2.
Length of riverine habitat in the Baker River watershed potentially accessible to anadromous
fish under alternate planning scenarios developed for Baker Relicensing Studies T-7b and A37 habitats by channel size and type. The length of accessible habitats under Scenarios 1 and 2
was derived by adding habitats available under current conditions to the amount of additional
habitat that would become available under Scenario 1 (Project Decommissioning) or Scenario
2 (Flood-Control-Only without Lake Shannon).
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
C-2
Future Aquatic Habitat –A-37
Lake Shannon Subbasin
Mainstem Baker River
9.0
8.4 8.4
Ongoing operations
8.0
Scenario 1 - Project Decommissioning
Scenario 2- Flood-Control-Only
7.0
6.0 6.0
Miles of stream
6.0
5.0
4.0
3.0
2.0
1.7 1.7
1.1 1.1
1.0
0.0
0.0
0.0 0.1 0.1
0.0
0.0
0.0 0.0 0.0
0.0
Side Channel
Alluvial Floodplain
Canyon
Moderate Gradient
Mixed Control
Mountain
Steep Mountain
Channel Type
Lake Shannon Subbasin
Large Tributary (>5.5 m wide)
3.0
Ongoing operations
2.7 2.7 2.7
Scenario 1 - Project Decommissioning
2.5
Scenario 2- Flood-Control-Only
Miles of stream
2.0
1.5 1.5
1.5
1.1 1.1
1.0
1.0
0.8 0.8 0.8
0.7 0.7 0.7
0.5
0.0 0.0 0.0
0.0 0.0 0.0
0.0
0.0
Palustrine
Alluvial Floodplain
Canyon
Alluvial Fan
Steep Alluvial Fan
Mountain
Steep Mountain
Channel Type
Lake Shannon Subbasin
Small Tributary (<5.5 m wide)
10.0
9.3 9.3
9.0
Ongoing operations
8.7
Scenario 1 - Project Decommissioning
8.0
Scenario 2- Flood-Control-Only
Miles of stream
7.0
5.8 5.8
6.0
5.0
4.0
3.6 3.6
3.5
3.1
3.0
2.0
1.3 1.3 1.3
1.0
0.0 0.0 0.0
0.0 0.0 0.0
Alluvial
Floodplain
Canyon
0.0
0.2 0.2
0.0
Palustrine
Alluvial Fan
Steep Alluvial
Fan
Mountain
Steep Mountain
Gradient/Channel Type
Figure C3.
Length of riverine habitats in the Lake Shannon subbasin potentially accessible to
anadromous fish under alternate planning scenarios developed for Baker Relicensing Studies
T-7b and A-37 by channel size and type. The length of accessible habitats under Scenarios 1
and 2 was derived by adding habitats available under current conditions to the amount of
additional habitat that would become available under Scenario 1 (Project Decommissioning)
or Scenario 2 (Flood-Control-Only without Lake Shannon). Note that Lower Baker Dam
(Lake Shannon) would be removed under both Scenarios 1 and 2.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
C-3
Future Aquatic Habitat –A-37
Baker Lake Subbasin
Mainstem Baker River
8.0
Ongoing operations
6.8
7.0
Scenario 1 - Project Decommissioning
6.2
Scenario 2 - Flood-Control-Only
6.0
Miles of stream
5.0
4.0
3.0
2.3
2.0
1.6
0.8
1.0
0.0
0.8
0.0
0.0
0.0
0.0
0.0
0.0 0.0 0.0
0.0 0.0 0.0
Mountain
Steep Mountain
0.0
Side Channel
Alluvial Floodplain
Canyon
Moderate Gradient
Mixed Control
Channel Type
Baker Lake Subbasin
Large Tributary (>5.5 m wide)
Ongoing operations
6.0
Scenario 1 - Project
Decommissioning
5.3
5.1
5.0
Scenario 2- Flood-ControlOnly
4.8
4.3
4.0
Miles of stream
3.6
3.2
3.0
3.0
3.3
2.7
2.1
2.0
1.6 1.6 1.6
1.0
0.7
0.0
0.0 0.0 0.0
0.0
0.1
0.0
0.0
Palustrine
Alluvial Floodplain
Canyon
Alluvial Fan
Steep Alluvial Fan
Mountain
Steep Mountain
Channel Type
Baker Lake Subbasin
Small Tributary (<5.5 m wide)
16.0
Ongoing operations
14.3
Scenario 1 - Project Decommissioning
14.0
Scenario 2- Flood-Control-Only
12.6
Miles of stream
12.0
10.0
8.0
4.0
6.4
6.3
6.2
5.8
6.0
6.7 6.5
5.8
5.3
3.8
2.9
2.0
0.5
0.0 0.0 0.0
0.0 0.0 0.0
Alluvial
Floodplain
Canyon
0.0
0.0
0.0
Palustrine
Alluvial Fan
Steep Alluvial
Fan
Mountain
Steep Mountain
Channel Type
Figure C4.
Length of riverine habitats by channel size in the Baker Lake subbasin potentially accessible
to anadromous fish under alternate planning scenarios developed for Baker Relicensing
Studies T-7b and A-37. The length of accessible habitats under Scenarios 1 and 2 was derived
by adding habitats available under current conditions to the amount of additional habitat that
would become available under Scenario 1 (Project Decommissioning) or Scenario 2 (FloodControl-Only without Lake Shannon).
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
C-4
Future Aquatic Habitat –A-37
Upper Baker Subbasin
Mainstem Baker River
9.0
8.1 8.1 8.1
Ongoing operations
8.0
Scenario 1 - Project Decommissioning
Scenario 2- Flood-Control-Only
7.0
Miles of stream
6.0
5.0 5.0 5.0
5.0
4.0
3.4 3.4 3.4
3.0
2.7 2.7 2.7
2.0
1.5 1.5 1.5
1.0 1.0 1.0
1.0
0.0
Side Channel
Alluvial Floodplain
Canyon
Moderate Gradient
Mixed Control
Mountain
Steep Mountain
Channel Type
Upper Baker Subbasin
Large Tributary (>5.5 m wide)
3.0
Ongoing operations
2.6 2.6 2.6
2.5
Scenario 1 - Project Decommissioning
Scenario 2- Flood-Control-Only
2.0 2.0 2.0
Miles of stream
2.0
1.6 1.6 1.6
1.5
1.0
0.5 0.5 0.5
0.5
0.0 0.0 0.0
0.0 0.0 0.0
0.0 0.0 0.0
0.0
Palustrine
Alluvial Floodplain
Canyon
Alluvial Fan
Steep Alluvial Fan
Mountain
Steep Mountain
Channel Type
Upper Baker Subbasin
Small Tributary (<5.5 m wide)
1.4
1.2
Ongoing operations
Scenario 1 - Project Decommissioning
1.2 1.2 1.2
Scenario 2- Flood-Control-Only
1.1 1.1 1.1
1.0
Miles of stream
0.9 0.9 0.9
0.8
0.6
0.4
0.3 0.3 0.3
0.2
0.0 0.0 0.0
0.0 0.0 0.0
Alluvial Floodplain
Canyon
0.0 0.0 0.0
0.0
Palustrine
Alluvial Fan
Steep Alluvial Fan
Mountain
Steep Mountain
Channel Type
Figure C5.
Length of riverine habitats in the upper Baker subbasin potentially accessible to anadromous
fish under alternate planning scenarios developed for Baker Relicensing Studies T-7b and A37 by channel size and type. Note that neither Scenario 1 (Project Decommissioning) or
Scenario 2 (Flood-Control-Only without Lake Shannon) changes the amount of accessible
habitat in the upper Baker subbasin as compared to current conditions.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
C-5
Future Aquatic Habitat –A-37
Lake Habitat Characteristics
Entire Study Area
Ongoing operations
8,000
Scenario 1 - Project Decommissioning
Scenario 2 - Flood-Control-Only
450,000
420,500
7,258
400,000
7,000
350,000
6,000
5,000
250,000
4,000
204,187
200,000
167,216
Area (acres)
Volume (acre-feer)
300,000
3,000
2,476
150,000
2,000
90,668
100,000
55,275
1,000
50,000
550
550
16,687
118
118
0
0
Total Volume
Euphotic volume
Total Area
Euphotic Area
Lake Habitat Characteristics
Baker Lake Subbasin
Ongoing operations
6,000
Scenario 1 - Project Decommissioning
Scenario 2 - Flood-Control-Only
300,000
274,221
4,980
250,000
5,000
4,000
3,589
167,216
150,000
3,000
136,943
100,000
1,891
90,668
1,806
Area (acres)
Volume (acre-feet)
200,000
2,000
55,275
50,000
1,000
550
16,687
118
0
0
Total Volume
Euphotic volume
Total Area
Euphotic Area
Lake Habitat Charateristics
Lake Shannon Subbasin
160,000
146,279
2,278
Ongoing operations
2,500
Scenario 1 - Project Decommissioning
Scenario 2 - Flood-Control-Only
140,000
2,000
100,000
1,500
Area (acres)
Volume (acre-feet)
120,000
80,000
67,244
1,000
60,000
585
40,000
500
20,000
0
0
Total Volume
Figure C6.
Euphotic volume
Total Area
Euphotic Area
Characteristics of lake habitats in the Baker River watershed that would be available to
anadromous fish under alternate planning scenarios developed for Baker Relicensing Studies
T-7b and A-37. The area of accessible lake habitats represents only those areas within the
A-37 Study Area, defined as the area below the full pool level of the existing Baker Lake
(elevation 727.77 NAVD 88) and Lake Shannon (elevation 442.35 feet NAVD 88) reservoirs.
Lake area outside the study area is present (e.g., Everett Lake) but is small compared to the
lake area within the Baker Project Area.
Baker River Project Relicensing
1440.19_A-37Report_FuturePotentialAquaHab_05.04
C-6
Future Aquatic Habitat –A-37