Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
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STUDY DESCRIPTION FA-S5
STREAM FISH POPULATION STUDY
September 2014
STUDY GOAL AND OBJECTIVE
The Bucks Creek Project (Project) Pre-Application Document (PAD) (November 2013)
reviewed the existing, relevant, and reasonably available information associated with fish and
aquatic resources and identified the following issues:

FA-1 Condition of fisheries in Project reservoirs

FA-2 Potential effect of entrainment at Project diversions and intakes on fish
populations

FA-3 Condition of Benthic Macroinvertebrate Communities in Project creeks

FA-4 Effects of Project operations on common amphibian and aquatic reptile species

FA-5 Effects of the Project on instream habitat in Project-affected streams

FA-6 Potential spread of invasive mussels to Project reservoirs
In addition to the issues identified in the PAD, in their April 2014 comments on the PreApplication Document, FERC Scoping Document 1, and requests for new studies, the SWRCB,
USFS, and CDFW requested a new study to assess stream fish populations.
Information required to address issues FA-1, FA-2, FA-3, and FA-4 will be collected in studies
FA-S1, FA-S2, FA-S3, and RTE-S1, respectively. The Licensees included information needed to
address FA-5 and FA-6 within the PAD (see Sections 5.3.3–5.3.5 and 5.3.9, respectively), and
anticipate no additional information will be necessary to assess flow/habitat relationships or the
extent or the potential spread of invasive mussels to Project reservoirs; however, additional
information will be collected in study FA-S4 to assess current stream habitat conditions in
Project-affected streams for comparisons to prior studies and to provide information on
spawnable gravel availability and passage barriers.
The goal of this study is to develop the essential additional information necessary to supplement
the existing information to address fish populations in Project-affected stream reaches. To address
the condition of fisheries in Project affected streams (FA-5), a stream fish population study will be
conducted in perennial tributary streams with unscreened diversions to the Milk Ranch Conduit.
Data are already available for Bucks Creek, Milk Ranch Creek, and Grizzly Creek, and are
presented in the PAD (Section 5.3.2). The specific objectives are to determine and quantitatively
describe: (1) fish species composition and distribution, (2) total or relative abundance of fish by
species, (3) fish population size and age-class distributions, and (4) fish condition.
Additionally, if fish are captured in the perennial tributaries to the Milk Ranch Conduit during
this study, the Licensees will sample the outlet from the Milk Ranch Creek Conduit as part of
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©2014, Pacific Gas and Electric Company and the City of Santa Clara
Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
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Study Description FA-S2 (Fish Entrainment Risk Assessment). Specifically, FA-S2 would
sample water exiting the conduit using an appropriate net system, or similar device, where it
empties into Lower Bucks Lake at the north end of the dam. The net would be set in place for
one 48-hr sample period in each of three seasons (late spring, summer, and early fall), and
checked roughly every 12 hours at dawn and dusk to discern the time period when fish were
captured (i.e., daytime versus nighttime).
EXISTING INFORMATION
Sampling in lower Bucks Creek, Grizzly Creek, and Milk Ranch Creek was conducted in 2002,
prior to implementing changes in the Project minimum instream flow releases, and sampling was
repeated in Bucks and Grizzly creeks in fall 2006, 2009, 2011, and 2013 following the 2006
increases to the Project minimum flows (Salamunovich 2007, 2009, 2012, 2014; Thomas R.
Payne & Associates 2002). Additional spawning surveys were conducted in Milk Ranch Creek
from 2003 through 2009.
The lower Bucks Creek trout fishery today is comprised primarily of rainbow trout with brown
trout contributing to only a small proportion of the fish populations. Since 2006, trout abundance
and biomass have increased in the lower sections of Bucks Creek, but have decreased upstream
near the dam. In 2011, trout abundance in the downstream section of lower Bucks Creek was
estimated to be 2,481 trout/mile, with a biomass of 42.5 kg/hectare (37.9 pounds/acre). The trout
populations in the downstream section of lower Bucks Creek continue to be composed of
multiple age classes that exhibit a length-to-weight relationship (condition factor) that suggests a
healthy fishery. Rainbow trout abundance and biomass in the lower section of Bucks Creek is
three to five times higher now compared to levels noted in 1983; however, in the upstream
section of lower Bucks Creek, immediately downstream of Lower Buck Lake Dam, trout
populations showed a decline across the three years of surveys since implementation of the new
flow schedule (Salamunovich 2007, 2009, 2012). No rainbow trout were captured in the
upstream section of lower Bucks Creek during surveys conducted in 2009 and 2011. The most
recent survey (2011) estimated trout abundance in the upstream section of lower Bucks Creek at
251 trout/mile, with a biomass of 12.9 kg/hectare (11.5 pounds/acre), which is less than the 2002
estimates prior to the Project flow increases (Salamunovich 2012).
In lower Grizzly Creek, rainbow trout were more abundant in the downstream section of the
reach, whereas brown trout were more abundant in the upstream section prior to the instream
flow changes in 2006. Following implementation of the new flow schedule in 2006, rainbow
trout populations have increased, while brown trout populations have declined. However, despite
this shift, the overall trout abundance has remained relatively stable while overall trout biomass
has declined. The 2011 overall trout abundance estimate was 1,660 trout/mile at the upstream
lower Grizzly Creek site, which was 89 percent of the 2002 abundance estimate. The 2011 total
trout biomass estimate was 47.4 kg/hectare (42.3 pounds/acre), or 63 percent of the 2002
biomass estimate. Despite these changes, the trout populations in upper Grizzly Creek still
possess multiple size/age classes and good condition factors.
The lower Milk Ranch Creek fishery consists of rainbow trout (Thomas R. Payne & Associates
2002). The 2002 abundance estimate for rainbow trout was 243 fish/100 m (3,908 fish/mile),
with four to five size/age classes represented in the population. The 2002 biomass estimate for
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©2014, Pacific Gas and Electric Company and the City of Santa Clara
Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
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rainbow trout in the lower Milk Ranch Creek basin was 61.7 kg/hectare (55.0 pounds/acre). In
2006, PG&E created a new 1,100-foot-long spawning channel along lower Milk Ranch Creek to
enhance spawning habitat. Late winter and spring surveys for rainbow trout spawning activity in
lower Milk Ranch Creek were conducted periodically from 2003 through 2009. Spawning
rainbow trout from the NFFR appear to spawn in lower Milk Ranch Creek and in the constructed
spawning channel (PG&E 2006a, 2006b; Kossow 2010).
The existing composition of fish populations in tributary streams diverted into the Milk Ranch
Conduit is not known.
NEXUS BETWEEN PROJECT AND RESOURCE TO BE STUDIED AND HOW THE
RESULTS WILL BE USED
Project operations have the potential to affect environmental conditions within tributary streams
downstream of Project diversions, including: water temperature, quantity, and quality; transfer of
water from one hydrologic basin to another; and entrainment at diversions. The Project diverts
steam flow at 8 unscreened diversions to the Milk Ranch Creek Conduit. These diversions are
therefore capable of entraining fish. Water from the Milk Ranch Conduit is released (via direct
release) from into Lower Bucks Lake. Although fish are expected to survive the release into
Lower Bucks Lake, the effect of the emigration of fish at the diversion points on stream
populations is unknown.
Entrainment, as well as changes in these environmental conditions, can affect the abundance,
distribution, and structure of the local fish communities.
The Licensees and resource agencies will use the information obtained from this study in
combination with existing information to evaluate (1) the effects of the Project’s water
diversions on the local fish communities, and (2) various management options when balancing
resource uses.
STUDY AREA AND SITES
The study area includes the Project-affected reaches of up to eight perennial tributaries that are
diverted (and the diversions maintained) where they cross Milk Ranch Conduit. These tributaries
include Grouse Hollow and three unnamed tributaries to Milk Ranch Creek, and Bear Ravine,
Slide Ravine, Bear Trap Creek, and one unnamed tributary to Bucks Creek.
A portion of these tributaries do not have surface flow year-round. A total of 16 sites are possible
for this study (including 1 site upstream of each diversion, and 1 site downstream of each
diversion) (Table 1). Streams included in the survey must have year-round surface flow both
upstream and downstream of each diversion. Proposed sample sites along tributary streams to
Milk Ranch Conduit may be eliminated from the study based on accessibility and hydrologic
conditions (i.e., presence of sufficient water). The Licensees will propose up to 5 streams (10
sites) of the total sites possible for sampling, and will consult with the agencies regarding the
which tributaries to sample.
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©2014, Pacific Gas and Electric Company and the City of Santa Clara
Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
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Table 1
Possible Tributary Stream Sampling Sites and Project-Affected Streams
Approximate Sample Site
Location2
Stream Name1
Approximate Location on Conduit
(mi from downstream terminus)
Milk Ranch Creek Watershed
Downstream of Milk Ranch Conduit
Unnamed Tributary
Upstream of Milk Ranch Conduit
Downstream of Milk Ranch Conduit
Grouse Hollow
Upstream of Milk Ranch Conduit
Downstream of Milk Ranch Conduit
Unnamed Tributary
Upstream of Milk Ranch Conduit
Unnamed Tributary below Bald
Eagle Lake
Downstream of Milk Ranch Conduit
Upstream of Milk Ranch Conduit
7
6.5
5
5
Bucks Creek Watershed
Unnamed Tributary
Slide Ravine
Bear Ravine
Bear Trap Creek
Downstream of Milk Ranch Conduit
Upstream of Milk Ranch Conduit
Downstream of Milk Ranch Conduit
Upstream of Milk Ranch Conduit
Downstream of Milk Ranch Conduit
Upstream of Milk Ranch Conduit
Downstream of Milk Ranch Conduit
Upstream of Milk Ranch Conduit
3
2
1
0.25
1
The Licensees will select up to 5 streams (10 sites) of the total sites possible for sampling.
2
Specific sample locations will be identified in the field based on site-specific conditions, including access.
Agency staff will be invited to participate in study site selection. Specifically excluded from the
study are areas where access is unsafe (very steep terrain or high water flows) or private property
for which the Licensees have not received approval from the landowner to enter the property to
perform the study. Licensees will make a good faith effort to obtain access to private property to
conduct the study.
METHODS
Backpack electrofishing will conducted at up to 10 sites in tributary streams to Milk Ranch
Creek using a multiple-pass depletion method. Block nets will be used to prevent migration in
and out of the sample site and to facilitate an accurate assessment of the sample population.
Sample sites may be separated into segments to improve sampling efficiency. Electrofishing will
be conducted following procedures identified by Reynolds (1996). Specifically, the
electrofishing crew will consist of one backpack shocker and approximately two net/live-car
crew members, depending on the size of wetted stream channel. The electrofishing crew will
began at the downstream block net and proceed slowly and deliberately upstream working
closely together. As fish are captured (netted), they will be placed in buckets and periodically
transferred to a live-car to be held until the completion of the pass. Upon completion of each
pass, the captured fish will be processed. During processing, fish data recorded included species
identification, total length (TL mm), fork length (FL mm), weight (g), and, if applicable, notes
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Bucks Creek Hydroelectric Project, FERC Project No. 619
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on the general condition of the fish, including any parasites that may be present. At each sample
location, scale samples will be collected from up to ten fish of each game species (e.g., rainbow
trout, brown trout, brook trout) at a variety of sizes and aged for comparison to confirm age/size
class determinations. Fish will be held in a live-car outside the boundary of the sample site until
the completion of the final pass. Once the fish from the final pass are processed, all fish will be
returned to the sample unit from which they were captured.
To minimize the potential to spread of invasive species (e.g., New Zealand Mud Snail [NZMS],
quagga/zebra mussel), appropriate decontamination protocols will be followed prior to each
aquatic-based field effort or moving between watersheds. Procedures may include, but not be
limited to, freezing or soaking with a commercial 409 cleaner all field gear (including waders,
boots, wetsuits) to kill NZMS, spraying equipment with a bleach and water solution to prevent
spread of quagga/zebra mussel, and inspecting all field equipment (including boats).
Incidental observations of other species of interest will be documented on field data sheets or
specific incidental species observation forms, and compiled into a single database of incidental
observations that can be used as a reference for other studies and analyses.
ANALYSIS
Data will be entered into an Excel spreadsheet for reduction, tabulation, and summary. Species
composition estimates will be calculated for all species captured using the total count of fish
observed. Age class will be estimated for all species captured using length-frequency analysis
and comparisons to available literature; length-frequency histograms will be developed for all
fish species observed and breaks or modalities within the histogram will be evaluated to
determine approximate age classes. The size ranges for age classes will be used for trout species
to determine the young-of-year (YOY)/juvenile/adult age classes.
Trout abundance, density, and biomass estimates will be calculated for each sample segment for
all trout species combined, as well as for individual species.
Estimation of Trout Densities
Trout density estimates (number of fish per surface acre of stream) will be calculated for age
classes including YOY and juvenile/adult trout using the Zippin estimator within the multiple
pass regression analysis software developed by Van Deventer and Platts (1989). Estimates of
trout density (number per surface acre of stream) will be calculated from the abundance
estimates divided by the unit area:
Density (trout/acre) = Population Estimate (N)
Area
In some instances where trout populations are in low abundance or strong depletions for an
individual species life stage are not obtained, the trout abundance estimate (ỹJ) will be computed
using the Jackknife estimator (Pollock and Otto 1983, as recommended by Mohr and Hankin, in
press):
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Bucks Creek Hydroelectric Project, FERC Project No. 619
©2014, Pacific Gas and Electric Company and the City of Santa Clara
Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
FA-S5
r 1
~
y J   ci  rc r ,
i 1
where r is the number of removal and ci denotes the number of trout observed on pass i.
Trout Biomass and Condition
Biomass estimates (kg per surface acre) will be computed for each species at each site segment
using multiple pass regression analysis software developed by Van Deventer and Platts (1989).
Biomass estimates will be made for all trout species combined as well as individual species.
Biomass per acre (B.ac) will be calculated as:
Bˆ.ac  w  dˆ ,
where w is the average fish weight and d̂ is the estimated density for the segment.
To assess trout condition at each site, the weight-to-length relationship of individual trout will be
assessed as a method of identifying the nutritional state or health of the fish related to size and
growth. Fulton’s condition factor (Ricker 1975), a measure of this nutritional state, will be
calculated for each trout. Individual condition factors (k) will be calculated by the following
formula:
Individual condition factors (k) = Wet Weight (grams) x 105
[Total Length (mm)]3
The typical mean condition factors for wild trout range from approximately 0.80 to 1.20 (Beak
1991, EA 1986, Ebasco Environmental 1993, Wilcox 1994), although condition is dependent on
the time of sampling, the species, and strain of trout.
STUDY-SPECIFIC CONSULTATION
Study-specific consultation for this study includes the following:

Notification of dates for field sampling and an invitation to participate

Study site selection

Review of Year 1 study results
CONSISTENCY WITH GENERALLY ACCEPTED SCIENTIFIC PRACTICE
Backpack electrofishing is widely accepted methods for sampling fish populations in small
streams. The sampling methods described here are from Fisheries Techniques (2nd Edition), a
special project publication by the American Fisheries Society (Murphy and Willis 1996). This
textbook is a comprehensive reference volume of modern sampling and data collection methods
in fisheries science used by students and professionals.
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PRODUCTS
A summary of the information and findings will be included in the Application for New License,
Exhibit E. A stand-alone Technical Memo will be produced with the methods and results of the
study. Licensees will provide relevant data as appendices to the Technical Memo, and in
electronic format upon request. Study results will be provided to the Relicensing Participants as
soon as possible after the data are collected, tabulated, summarized, and checked for quality
(i.e., Quality Assurance/Quality Control). The Licensee intends to have study results, to the
degree complete, available in sufficient time to allow collaborative development of possible
PM&E measures for inclusion in its Draft License Application. Data gathered as part of the study
will be included as an appendix to the License Application. Study products may include a
presentation to resource agency personnel and other relicensing participants. Inventory forms
(e.g., CNDDB) will be provided to the appropriate resource agency. Any standard GIS shapefiles
produced will be provided upon request; any custom formats or ancillary GIS data manipulation
will be the responsibility of the party receiving the data.
RELATIONSHIP TO OTHER STUDIES
Data from this study will be used in support of Study Description FA-S2 (Fish Entrainment Risk
Assessment). Specifically, if fish are captured in the perennial tributaries to the Milk Ranch
Conduit, the Milk Ranch Creek Conduit will be sampled for entrained fish at the elevated outlet
pipe as part of Study FA-S2.
SCHEDULE
Fish population sampling in tributary streams to the Milk Ranch Conduit will include a single
season of surveys and commence in late summer or early fall 2015. Data analysis will occur
during the fall–winter of 2015–2016. Reporting of the 2015 survey data will be completed by
spring 2016. Preliminary assessments will be included, as available, in the Initial Study Report in
fall 2015 and subsequent ILP documents, as updated to allow for early discussions of the data
and need for additional surveys.
LEVEL OF EFFORT AND COST
The preliminary estimated cost (2014 dollars) for the study subtotaled by major tasks is as
follows:
Office Work ......................................................$
Field Work ........................................................$
Analysis.............................................................$
Products.............................................................$
Total (2014 dollars) .........................................$
6,000
28,000
14,500
18,000
66,500
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Bucks Creek Hydroelectric Project, FERC Project No. 619
©2014, Pacific Gas and Electric Company and the City of Santa Clara
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Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
REFERENCES
Beak Consultants Incorporated. 1991. Instream flow requirements for brown trout, Rush Creek,
Mono County. California Department of Fish and Game Stream Evaluation Report
91-1. Sacramento, California. California Department of Fish and Wildlife (CDFW).
2013. Fish planting records for Bucks Lake, Plumas County. Statewide Hatchery
Database Records for 2001–2012.
EA (EA Engineering, Science, and Technology, Inc.). 1986. Instream flow and fisheries studies
for the Mill Creek Hydroelectric Project. Prepared for Southern California Edison
Company. Lafayette, California.
Ebasco Environmental (currently Foster-Wheeler Environmental). 1993. North Fork Stanislaus
River Basin 1992 fish population surveys. Prepared for Northern California Power
Agency. Sacramento, California.
Kossow, M.C. 2010. 2009 adult spawner survey report, Rock Creek-Cresta Project (FERC No.
1962). March 2010 final report prepared by Meadowbrook Conservation Services for
Pacific Gas and Electric Company.
Mohr, M.S., and D.G. Hankin. In press. Two-phase survey designs for estimation of fish
abundance in small streams. NOAA Technical Memorandum NMFS-SWFSC.
Murphy, B.R., and D.W. Willis (eds). 1996. Fisheries techniques. Second Edition. American
Fisheries Society. Bethesda, Maryland.
PG&E (Pacific Gas and Electric Company). 2006a. Fishery habitat improvements, tributary
monitoring data report, 2004. Bank-side and snorkeling observations of rainbow
trout spawning activity, 2004 final report. Rock Creek-Cresta Project FERC Project
No. 1962, License Condition No. 11. TES Report No. 026.11.06.3.
PG&E (Pacific Gas and Electric Company). 2006b. Fishery habitat improvements, tributary
monitoring data report. Bank-side and snorkeling observations of rainbow trout
spawning activity, 2005 draft report. Rock Creek-Cresta Project FERC Project No.
1962, License Condition No. 11. TES Report No. 026.11.06.13.
Reynolds, J.B. 1996. Electrofishing. Fisheries Techniques. Second Edition. B.R. Murphy and
D.W. Willis (eds). American Fisheries Society, Bethesda, Maryland. pp. 83–120.
Ricker, W.E. 1975. Computation and interpretation of biological statistics of fish populations.
Fisheries Research Board of Canada. Bulletin 191.
Salamunovich, T. 2007. Bucks Creek Project (FERC No. 619) 2006 fish population report for
Bucks and Grizzly creeks. April 2007 report prepared for Environmental Services
Department, Pacific Gas and Electric Company, San Ramon, California.
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Bucks Creek Hydroelectric Project, FERC Project No. 619
©2014, Pacific Gas and Electric Company and the City of Santa Clara
Bucks Creek Hydroelectric Project, FERC Project No. 619
Revised Study Plan
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Salamunovich, T. 2009. Bucks Creek Project (FERC No. 619) 2009 fish population report for
Bucks and Grizzly creeks. December 2009 report prepared for Land and
Environmental Management Services Department, Pacific Gas and Electric
Company, San Ramon, California.
Salamunovich, T. 2012. Bucks Creek Project (FERC No. 619) 2011 fish population report for
Bucks and Grizzly creeks. January 2012 report prepared for Land and Environmental
Management Department, Pacific Gas and Electric Company, San Ramon,
California.
Thomas R. Payne & Associates. 2002. Bucks Creek Project 2002 fish population report, FERC
Project No. 619, Article 103. December 2002 report prepared for Technical and
Ecological Services Department, Pacific Gas and Electric Company, San Ramon,
California.
Van Deventer, J.S., and W.S. Platts. 1989. Microcomputer software system for generating
population statistics from electrofishing data, user’s guide for MicroFish 3.0. General
Technical Report INT-254. U.S. Department of Agriculture, Forest Service,
Intermountain Research Station.
Wilcox, S.D. 1994. South Fork Power Project fish population monitoring 1993. Prepared by
Ebasco Environmental for Oroville-Wyandotte Irrigation District. Sacramento,
California. January.
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