oRIGlru,qL

lJnited States Department of the

FISH AND WILDLIFE SERVICE

UTAH FIELD OFFICE

2369 WEST ORTON CIRCLE, SUITE 50

WEST VALLEY CITY, UTAH 84II9

May 14,2013

Gnîr

l"rdr #

Sate

Director, Upper Colorado Region, Bureau of Reclamation

Chair, Flaming Gorge Technical V/orking Group, Bureau of Reclamation

This letter describes our recommendations for 2013 spring and base flows in Reach 2 of

the Green River for discussion by the Flaming Gorge Technical V/orking Group

(FGTV/G) in development of recommendations for Flaming Gorge Dam operations. Our

intent is to work with other FGTWG members to ensure consistency with the 2005

biological opinion (BO; U.S. Fish and Wildlife Service 2005) and 2006 record of

decision (ROD; U.S. Department of Interior 2006), which recommend flows to protect

and assist in recovery of endangered fishes.

The following recommendations are subject to forecasted and real-time May - July

hydrologic conditions in the upper Green River drainage, with recognition that trade-offs

of spring and base flows should be considered and used to adjust operations as deemed

appropriate.

Spring-peak Research FIow

We support the Upper Colorado River Endangered Fish Recovery Program's (Recovery

Program) 2013 Spring Flow Request, as explained in their February 26,2013letter. The

primary objective as presented in their letter is to time Flaming Gorge releases and

resultant floodplain connection with the presence of wild produced nzorback sucker

larvae. The Recovery Program's objective is consistent with the intent of the Flow and

Temperature Recommendations for Endangered Fishes in the Green River Downstream

of Flaming Gorge Dam (Flow Recommendations; Muth et al. 2000), the 2005 BO, and

the 2006 ROD, and uses the best available science to guide Flaming Gorge operations

and recovery actions in an adaptive management framework. Timing Flaming Gorge r

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In Reply Refer To

FWSiR6

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08-FA-0180

Memorandum

To:

From:

Subject:

FieldSupervisor,UtahFieldofftce,U.S.FishandWildlifeService{ey

2013 Green River Spring and Base Flows to Assist in Recovery of the

Endangered Fishes
eleases concurrently with wild produced larvae is a major step in re-establishing a stable

population of razorback sucker in the Green River basin.

The Recovery Program, in an effort to scientifically evaluate the results of operating

Flaming Gorge Dam concurrent with the presence of larval razorback sucker, developed

the Study Plan to Examine the Effects of Usi_ng Larval Sucker Occurrence in the Green

River ai a Triggerþr Flamirg Gorg" DamI (Larval Trigger Study Plan or LTSP)' The

Study Design matrix (Table 2 in the LTSP) details the range of experimental conditions

the Recovery Program would like to assess, with recognition that more than one set of

flow conditions of that matrix could be accomplished in a single year. Because the LTSP

describes a systematic analysis for evaluating the success of operating Flaming Gorge

concurrently with wild producedrazorback sucker larvae, we conclude it is very

important to follow its recommendations whenever possible.

The Bureau of Reclamation (Reclamation) proposes to operate peak releases

conservatively and exercise the flexibility in the ROD by operating one classification

lower than indicated in the forecasts. As a result, Reclamation will operate under a dry

classification for the spring peak, despite both the Upper Green and Yampa River Basins

being in the moderately dry classification as of the April mid-month forecast. We

understand that a &y 2012 and a moderately dry 2013 have reduced much of the

flexibility Reclamation has for reservoir operations.

Under this operation proposal, the LTSP advises providing flows between 8,300 and

14,000 cubic feet per second (cfs) for one to six days in order to connect floodplain

habitats such as Stewart Lake, Old Charley Wash, and Above Brennan. Last year these

same operational criteria were targeted and achieved (5 days above 8,300 cfs). Sampling

indicated thatrazorback suckers were entrained into Stewart Lake, demonstrating

success. However, because of operational constraints those larval fish were not refurned

to the river as planned, as Stewart Lake desiccated during a very dry year.

We support Reclamation targeting one to six days above 8,300 cfs under the LTSP. V/e

believe that2012 conditions did not fulfill the intent of the LTSP because of the

desiccation of Stewart Lake, and therefore a repeat of the efforts in20l2 is warranted. In

20T3,Program partners believe that Stewart Lake will remain wetted before being

drained in late summer to support selenium remediation. This selenium remediation effort

is consistent with endangered fish recovery. As a result of these coordinated management

actions, we believe we can provide a meaningful data point for the LTSP this year.

'We request that Reclamation attempts to provide connection at targeted floodplain

habitats for six consecutive days (or as many as possible). Because hydrologic conditions

are in the moderately dry category, but Reclamation is operating one classification drier,

we believe that operating towards a longer duration of connection is warranted. Also, we

request that Reclamation work the FGTWG to determine if floodplain habitats besides

Stewart Lake and Old Charley Wash can be connected during larval drift. We understand

1 Can be found online ¿¡; http://www.coloradoriverrecoverv.org/documents-publications/technicalreports/i sf/l arvaltri egerstudyplan.pdf
flows to connect these floodplain habitats will largely be based on Yampa flows

coincident with Flaming Gorge releases.

Justificationfor the LTSP under the Flaming Gorge BO and ROD

The LTSP is an important document that is assisting in the consistent evaluation of how

Flaming Gorge operations are benefitingruzorback sucker. The LTSP and updated flow

release is supported by the most recent scientific research into endangered fish ecology

and floodplain management (Bestgen et al.20ll). As the Recovery Program described in

the LTSP, the Bestgen et al. (2011) report synthesized long term data, evaluated the

ability to operate Flaming Gorge Dam for the purpose of entraining wild razorback larvae

into floodplain habitats, and created a set of conclusions and recommendations to guide

future management. The Flow Recommendations recommended utilizing up-to-date

research and monitoring, such as the Bestgen et al. (20I l) draft report:

"the collection ofadditional data on endangered fishes and their habitats should focus on the

evaluation and possible modification of our recommendations by following an adaptivemanagement process" (Muth et al. 2000, p. 5-39);

as well as biological information to guide the onset of spring peak flow:

"Examples of real-time and other year-specific information to be considered in determining

annual patterns ofreleases . . .

¡ Initial appearance oflarval suckers in established reference sites in Reach 2 (e.g.,

CliffCreek)" (Muth et al. 2000, p. 5-9, Table 5.3).

Similarly, the 2005 BO calls for adaptive management in implementing the proposed

action (operations of Flaming Gorge Dam) (U.S. Fish and Wildlife Service 2005,p. 16)

and set forth this process as a conservation measure:

"The adaptive management process will rely on the Recovery Program for monitoring and

research studies to test the outcomes of implementing the proposed action and proposing

refurements to dam operations" (U.S. Fish and Wildlife Service 2005, p. 17);

and

"[Bweau of] Reclamation, Westem [Area Power Administration], and the [U.S. Fish and

Wildlife] Service will use any new information collected in these studies to determine the

need for management actions or modification of operations as determined appropriate"

(U.S. Fish and'ù/ildlife Service 2005,p.17)

Therefore, we believe that the Recovery Program's 2013 Spring Flow Request and

implementation of the LTSP are supported by the 2005 BO and we support

Reclamation's implementation of this request. The Recovery Program has determined

that a minimum of six study years are needed to meet the objectives of the LTSP. Unless

otherwise specifically stipulated, this letter conveys the Service's interpretation of ESA

compliance under the 2005 BO as it relates to Reclamation's future LTSP-related spring

operations. We recognize that Reclamation's targeting of a biological trigger þresence
of larval razorback sucker) rather than a hydrological one (Yampa River flows) deviates

from past operations and may require greater volumes of water in some years. However,

we conclude that this experiment is consistent with the intent of the Flow

Recommendations and will assist in the recovery of the endangered f,rsh.

We further recognize that timing releases from Flaming Gorge Dam consistent with the

Recovery Program's 2013 Spring Flow Request and the LTSP may require the

hydrologic tradeoff of not meeting the 2000 Flow and Temperature Recommendations

for Reach 2. Nevertheless, we support Reclamation following the Recovery Program's

2013 Spring Flow Request and LTSP, and consider that doing so will meet Reclamation's

responsibility to the ROD objectives in 2013.

Operations of Stewart Lake

As previously mentioned, we believe water management for selenium remediation at

Stewart Lake is consistent with endangered fish recovery. Past operations of Stewan

Lake (independent of endangered flrsh considerations) have focused on a 'fill and drain'

operation. This operation followed the general procedure of an initial intake of water into

Stewart Lake with Green River spring peak flows, a complete fill of the lake with Red

Fleet water, and a draining of the lake after months of inundation. This operational plan

has been utilized consistently2 and successfully over the majority of the past decade and

has improved the selenium levels in Stewart Lake.

Recent work demonstrated that the most effective operation for selenium remediation

would be a single fill and drain operation3 with a total duration of inundation of about 90

days. To be consistent with past operations and to follow the most effective remediation

process, UDWR's proposed 2013 operations are to allow Green River connection flows

to first enter the lake, use Red Fleet water to completely fill the lake, and tentatively drain

the lake on August 15 (Stewart Lake Working Group 2013). We support this proposal.

Our office believes that operating Stewart Lake for selenium remediation under this

consistent operation plan will benefit endangered fish without affecting the selenium

remediation efforts that have been underway for many years. We find no reason to adjust

selenium remediation operations from past procedures and support the UDWR's plan to

drain the lake near the end of the summer. In fact, we believe that the LTSP request to

consistently connect Stewart Lake in all years will continue to provide selenium

remediation benefrts by providing a consistent supply of water for initial filling.

Recently, some concern has been raised about the legal and biological ramifications for

entraining larval fish into Stewart Lake before selenium levels are completely

remediated. However, we believe that any larval fish entrained into Stewart Lake are

2 This plan has been used each year between 2003 and 2010. Historically high flows in 20l l altered

operations in 201I (no Red Fleet water needed because of large input of Green River water) and 2012 (no

Red Fleet water used in order to dry the lake bed sufficiently from the 2011 flows) (Stewart Lake

Working Group 2013)

3 rather than fill and drain twice a year
more likely to survive in Stewart Lake than in the main channel habitats. We base this on

continued improvement of selenium levels in Stewart Lake and years of unsuccessful

recruitment of the species in main channel habitats that contain non-native predators.

Although Stewart Lake selenium levels have not been completely remediated, Stewart

Lake offers larval fish better habitat than the main channel because larval fish can grow

more quickly and in a predator free environmenta. While some impacts to endangered

fish from selenium exposure may still occur (reduced survival, physiological

abnormalities, etc.), these impacts are much less than the likely predation effects in the

main channel.

As a result, we believe that entraining larval razorback sucker into Stewart Lake (via

Flaming Gorge operations) and harboring them over the summer (via Stewart Lake

remediation efforts) offer a net benefit to the species. While there may be some level of

incidental takes from selenium levels in the lake, this take is covered in the 2005 BO for

operation of Flaming Gorge. We would like to compliment Reclamation, the UDWR, and

other partners for improving conditions of Stewart Lake and are confident complete

remediation will occur in the near future.

Base Flow Request

Because of projected drier than average year conditions, we believe that base flow

augmentation is a very important consideration for 2013. Base flows are important for a

variety of ecological reasons, such as increased resource and habitat availability. We

propose the following approach to base flow operations in 2013, which mirrors our

recommended approach in 2010 and20l2. The 2010 and20l2 proposals relied on the

most up-to-date research available. Biological data collected those years indicated that

numbers of Colorado pikeminnow continue to improve.

Our understanding is that Reclamation will identifu a Reach I base flow target

commensurate with the April - July hydrologic condition in accordance with the ROD

and the BO. The Reach I targetwill create a flow condition in Reach 2that falls within

the appropriate base flow range when coupled with projected Yampa River base flows

(Muth et al. 2000). For reasons mentioned below, we request that Reclamation does not

operate under a classification drier than the off,rcial base flow classif,rcation and also

releases higher flows than the scheduled base flow target through September 30,2012.

We understand that Reclamation may need to release less than the base flow target

through the remainder of the base flow period (October to March) to balance annual

operations.

Specifically, we request that Reclamation augment the Reach I calculated base flow

target by as much as 40%o. For example, if Reclamation determines that a release of

1,100 cfs is necessary to comply with the ROD and BO, then we request that up to

1,540 cfs be released through Sept 30, 2012. This augmentation is in accordance with the

o UDWR is operating a weir to prevent large bodied fish from entering Stewart Lake in 2013

5 As defined under the Endangered Species Act
Reach 2 summer - autumn seasonal flow variability recognized in the Flow

Recommendations.

We believe that the Flow Recommendations intended that seasonal variability be

incorporated into dam operations to assist in the recovery of the species and

accommodate natural variability, but not allow for manipulation that targets a specific

operational pattern. Ow 2012 base flow proposal, which complies with the ROD and the

BO, is consistent with the intent of the flow recommendations, is based on information

gathered by the Recovery Program, and responds to current biological conditions in the

Green River system.

Our rationale for requesting elevated base flows through September 30 is similar to our

requests in 2008, 2009,2010,2011, and20l2, and is intended to accomplish two goals:

1) provide improved nursery conditions for age-O (young-of-year) Colorado

pikeminnow in Reach 2; and

2) hinder nonnative smallmouth bass in Reaches I and2 by delaying their

spawning time and decreasing growth of the age-0 cohort.

Goal l: Habitat conditions for age-} Colorado pikeminnow

Since 2000, there has been a wide range of base flow conditions in Reach 2. Many of the

lower base flow years coincided with low age-0 Colorado pikeminnow catch rates as

determined each autumn via Recovery Program Project 1386 - Interagency Standardized

Monitoring Program (Table 2). For example, during the summers of 2001, 2002,2003,

2006, and2007 base flows in Reach 2 dropped below 1,000 cfs for varying periods of

time and age-0 Colorado pikeminnow catch rates were in the single digits (Badame et al.

2010, p. 8).

Contrastingly, in 2009 and 2010, Reach 2 experienced average base flows that exceeded

2,000 cfs for the second and third consecutive years, and for only the second and third

time in the most recent eleven year period. Those same years, Utah Division of Wildlife

Resources (UDWR) biologists reported the highest catches of age-O pikeminnow since

1991 (Badame et al. 2010, p. 8; Table 2). We understand that there are many variables

that could have contributed to the increased catch of age-0 CPM, such as numbers of

spawning adults, densities of nonnative fish throughout the larval drift zone, densities of

nonnatives in backwaters, productivity of baclnvaters, and sampling efficiency.

However, we believe that the higher base flows (approximately 2,400 to 2,600 cfs) in

Reach 2 in2008,2009, and 2010 played an important role in this increase by providing

consistent high-qualify backwater habitat throughout the summer growing season.

In response to our 2012 request, Reclamation augmented flows in Reach 2 before

September 30ú, as much as water supply allowed (Table l). At the Jensen gauge

(Reach 2) average flows decreased from approximately 1700 cfs on July 15tr to 1280 on

6 Can be found online ¿1 ; http://www.coloradoriverrecoverv.org/documents-publications/work-plandocuments/arpts/20 I 2/rsch/1 3 8.pdf
September 30ú. Augmented flows were highest in early summer, with releases from

Fúming Gorge being approximately 1300 cfs until Seitember 7ú. From September l0ú

until September 30ú, releases averaged approximately 1120 cfs as the water supply

outlook worsened. Overall, the summer base flow period had an average flow of

approximately 1443 cfs at the Jensen Gauge.

Table l. 2012 Flows in Reach 2 of the Green River.

Base flow

period

Comparison of augmented

flow throughout season

Julv 15* to

Sept. ¡0ft

July 20'' to

Seot. eú

Sept. 10"'to

Sept. 30ú

Typical Flaming Gorge

releases (Reach 1)

nJa 1330 cfs I 120 cfs

Average flow at Jensen

Gause (Reach 2) 1443 cfs 1490 cfs 1280 cfs

September samplingT in the middle Green River, when flows were close to 1300 cfs at

Jensen, demonstrated that backwater habitats were reduced in area and depth - likely due

to decreased base flows (Skorupski et al.2012, p. 3). UDWR captured 2 age-D Colorado

pikeminnow and 0 juvenile pikeminnow in backwater habitats, representing the second

lowest catch rates since 1990 (Skorupski et aL.2012, p.3 & p. 9). Contrastingly,

sampling in the Yampa River in June through August of 2012 indicated that it was a

relatively strong year for reproduction for Colorado pikeminnow as many larvae were

captured and the spawning season was very long (Bestgen et al. 2012, p. 6). These

results likely indicate that Colorado pikeminnow spawning was strong throughout the

Green River basin in early summer (June and July) but as backwater habitat dried

throughout the summer, young fish were forced to main channel habitats.

Predicted 2013 conditions are again drier than average, indicating that this year the

FGTWG should again attempt to provide adequate base flow conditions for Colorado

pikeminnow and prevent the base flows from dropping to levels not compatible with

age-0 Colorado pikeminnow survival. Results ftom20l2 suggest that low base flows in

September prematurely reduced backwater habitat quality and likely forced any juvenile

or age-O Colorado pikeminnow into the mainstem channel before the growing season

ended. Maintaining consistent base flows throughout September allows young fish to

reach adequate size before entering the main channel habitat'

Most above-average Colorado pikeminnow recruitment events in the middle and lower

Green River occurred when suÍtmer flows ranged from about 1,800 to 2,700 cfs (Bestgen

1997; inMuth et al. 2000). Similarly, most below-average Colorado pikeminnow

recruitment events occurred when flows were below 1350 cfs. The relationship between

base flow elevations and quality of nursery habitat is an information need identified in the

Green River Study Plan (Green River Study Plan ad hoc group 2007) and is currently

7 Annual monitoring for YOY Colorado pikeminnow began 17 September 2012 and was completed on27

September 2012.
being investigated through a Recovery Program project entitled "Historical assessment of

factors affecting young Colorado pikeminnow abundance and physical habitat

availability in the Green River, Utah."

Table 2. Age-0 Colorado pikeminnow (CPM) standardized catch and corresponding flow

conditions in Reach 2 as measured by the USGS at their Jensen, Utah gage. Green rows indicate

successful Colorado pikeminnow reproduction, blue rows indicate flows exceeding the Colorado

pikeminnow ecological threshold, red lines indicate years where flows were below 1000 cfs.

Goal 2: Hinder smallmouth bass reproduction

Smallmouth bass have become a problematic nonnative species in the Upper Colorado River

Basin, preying on native species & competing for resources. Understanding smallmouth bass

spawning periodicity and adjusting flow releases from Flaming Gorge Dam accordingly will

likely help with disruption of the species' reproduction and lead to a reduction in the overall

population. Smallmouth bass spawning and recruitrnent is often favored by lower flows

and associated warmer water temperatures (Graham and Orth 1986, Swenson et aI.2002),

thus higher flows coupled with lower water temperatures may prove detrimental to

smallmouth bass reproduction. Studies in other parts of the range of smallmouth bass have

shown that weather-related water temperature reductions or increased flow events reduce

their spawning success and number of ofßpring. Specifîcally, high flows can be associated

with year-class failures (Smith et al. 2005) and may sweep eggs or fry from nursery aÍeas

(Mason et al. 1991). Reduced water temperatures often result in abandonment of spawning

I In 2011, the Green River and its tributaries had very wet conditions, which in some cases were the wettest on record.

While these flows facilitated ecological function for floodplains and la¡val sucker production, they likely exceeded

the ecological threshold for successful Colorado pikeminnow recruitment. Average flows during the base flow period

were 8,660, which is much higher than those in years with high age-0 Colorado pikeminnow collections

(approximately four times higher).
nests by the guarding male bass, after which developing eggs and just-hatched young are

susceptible to predation and other mortality factors. Smallmouth bass may also be

susceptible to increased turbidity or siltation which can disrupt spawning or feeding

(Berkman and Rabeni 1987; Sweka and Hartman 2003). Further, smallmouth bass often

inhabit regulated rivers where static, stable flow regimes provide favorable habitat and

managing flows to provide a more variable flow regime may make it more difficult for

this species to persist (Mims and Olden 2012).

Information from the Upper Colorado River Basin continues to indicate that higher and

cooler base flows delay smallmouth bass spawning and reduce growth of the age-O

smallmouth bass cohort. The effect of flow and temperature on the onset of smallmouth

bass spawning is clearly demonstrated with data collected in Lodore Canyon, Green

River (Figure l). Smallmouth bass in the Green River-Lodore Canyon study area first hatch

11

2û 9000

7000

tJl

o 5000 tr

10

5

3000

1 000

o o

0 -1000

5/21 6/1 0 6/20 7 /10 7/20 7 /30

Figure l. Comparison of flow (green), water temperature (purple), and onset of 16" C

water temperature (gray arrow) in Lodore Canyon (Green River - Reach 1), 2010 & 2011.

Distributions ofhatching dates of, including first hatching in 2010 and 201 I and hatch duration

in 2010. Bass were collected from t}re Green River in Lodore Canyon. Left vertical axis is the

frequency of fish in histograms or water temperature; right vertical axis is Green River

discharge (in cubic feet per second).

well after spring peak releases decline and just slightly after (usually within one week) mean

daily water temperatures regularly exceed l6'C. During years with relatively wet or cool

springtime periods (2011), smallmouth bass spawning occurred nearly three weeks later

than during ayear with drier, wanner conditions (2010). The same relationship has been

¡t,

o

o

9|

G

o

!,

i5

30

(J"

(¡) F15

o

c lfJ

o

(t :J

c,

lt0

4500

4000

3500

3000

2500

2000

1 500

1 000

500

0

5í21 5/31 6/1 0 7 /20 7 /30
observed on the Yampa River. Hatching date and the extent of the reproductive season was

much shorter in2011 when high flows were relatively cool. The 2012 water temperatures

suggest a relatively late initiation of hatching as well, and that is supported by capture of very

few and relatively small bass in Lodore Canyon in late-July. High flows and associated cool

temperatures appear to not only delay spawning but also slow the growth rates of age-0

smallmouth bass which decreases their likelihood for overwinter survival (Shuter at al.

I 980; Lawrence et al. 2012).

Conclusion

In summary, we request that Reclamation:

o Time spring flow releases from Flaming Gorge to correspond with the

presence of wild produced ruzorback sucker larvae according to the LTSP

in order to improve entrainment success;

o Attempt to meet connection at Stewart Lake for 6 consecutive days and

targel.wetlands with higher connecting flows if Yampa River flows allow;

. Work with the UDWR to operate Stewart Lake water supplies for selenium

remediation efforts equivalent to the past, by filling the lake following a

Green River connection and draining later in the summer; and

o Enhance summer base flows in Reach 2 of the Green River at the expense

of winter base flows to continue to improve Colorado pikeminnow nrüsery

conditions, support age-0 Colorado pikeminnow, and disadvantage

smallmouth bass.

We believe that datagathered by the Recovery Program make a strong case for these

proposed operations in 2013 and should benefit young life stages of endangered fish. We

hope that hydrology conditions in the Upper Green and Yampa River drainages will

supply sufficient water to meet these needs. Furthermore, we believe that these

operations are consistent will the existing BOs for Flaming Gorge and Stewart Lake and

the Flaming Gorge ROD.

We thank Reclamation for the opportunity to provide this input and look forward to

participating in the Flaming Gorge Technical Working Group process. If you have any

questions or concerns, please contact Kevin McAbee at 801-975-3330 ext. 143.

10
Literature Cited

Badame, P., K. Creighton, T. Hedrick, L. Monroe, and K. Bestgen. 2010. Young-of-the-year

Colorado pikeminnow monitoring. FY 2010 Annual Project Report, Colorado River

Recovery Program Project Number 138.

Berkman, H.E. and C.F. Rabeni. 1981. Effect of siltation on stream fish communities.

Environmental Biology of Fishes. 18:285-294.

Bestgen, K. R. lggT.Interacting effects of physical and biological factors on recruitment of age-O

Colorado squawfish. Doctoral Dissertation. Colorado State University, Fort Collins, CO.

Bestgen, K.R., G.B. Haines, and A.A. Hill. 201l. Synthesis of floodplain wetland information:

timing of razorback sucker reproduction in the Green River, Utah, related to streamflow,

water termperature, and floodplain wetland availability. Final Report to the Upper

Colorado River Endangered Fish Recovery Program. Larval Fish Laboratory

Contribution 163.

Bestgen, K.R., A. Webe¡ and T. Jones. 2Ùl2.Interagency Standardized Monitoring Program

Assessment of Endangered Fish Reproduction in Relation to Flaming Gorge Operations

in the Middle Green and Lower Yampa Rivers-Yampa and Middle Green River

Assessment of Colorado Pikeminnow and Razorback Sucker Larvae. FY 2012 Annual

Project Report, Colorado River Recovery Program Project Number 22f.

Graham, R.J., and D.J. Orth. 1986. Effects of temperature and streamflow on time and duration of

spawning by smallmouth bass. Transactions of the American Fisheries Society. I l5:693-

702.

Green River Study Plan ad hoc Group. 2007. Study plan for the implementation and evaluation

of flow and temperature recommendations for endangered fishes in the Green River

downstream of Flaming Gorge Dam. Upper Colorado Basin Endangered Fish Recovery

Program, Lakewood, CO.

Lawrence, D. J., J. D. Olden, and C. E. Torgersen. Spatiotemporal patterns and habitat

associations of smallmouth bass (Micropterus dolomieu) invading salmon-rearing habitat.

Freshwater Biology 57 :1929-19 46.

Mason, J. W., D. J. Graczyk, and R. A. Kerr, 1991. Effects of runoff on smallmouth bass

populations in four southwestern Wisconsin sffeams. Pages 28-38 inD. C. Jackson,

editor. First lnternational Smallmouth Bass Symposium. Mississippi State University,

Mississippi State.

Mims, M. C., and J. D. Olden. 2012. Life history theory predicts fish assemblage response to

hydrologic regimes. Ecology 93:35-45.

Montgomery,J.C., D. H. Fickeisen, and C. D. Becker. 1980. Factors influencing smallmouth

bass production in the Hanford area, Columbia River. Northwest Science 54:296-305.

l1
Muth, R.T., L.W. Crist, K.E. LaGory, J.W. Hayse, K.R. Bestgen, T.P. Ryan, J.K. Lyons, R.A.

Valdez. 2000. Flow and temperature recommendations for endangered fishes in the

Green River downstream of Flaming Gorge Dam. Upper Colorado River Endangered

Fish Recovery Program, Denver, CO.

Shuter, 8.J., J.A. Maclean, F.E.J. Fry, and H.A. Regier. 1980. Stochastic simulation of

temperature effects of first-year survival of smallmouth bass. Transactions of the

American Fisheries Society 109:l-34.

Skorupski, J.4., M.J. Breen, B.J. Kiefer, and K. Creighton. 2012. Young-of-the-year Colorado

pikeminnow monitoring. FY 2012 Annual Project Report, Colorado River Recovery

Program Project Number 138.

Smith, S. M., J. S. Odenkirk, and S. J. Reeser. 2005. Smallmouth bass recruiûnent variability

and its relation to stream discharge in three Virginia Rivers. North American Journal of

Fisheries Management 25 :l I l2-l l2l .

Sweka, J.4., and K.J. Hartrnan. 2003. Reduction of reactive distance and foraging success in

smallmouth bass, Micropterus dolomieu, exposedto elevated turbidity levels.

Environmental Biology of Fishes 67:341-347.

Swensen, W. 4., B. J. Shuter, D. J. Orr, and G. D. Heberling. 2002. The effects of stueam

temperature and velocity on first-year growth and year-class abundance of smallmouth

bass in the upper Mississippi River. American Fisheries Society Symposium 3l:101-113.

Stewart Lake Working Group. 2013. Stewart Lake Annual Meeting Minutes (Draft).

U.S. Department of the Interior. 2006. Record of Decision on the operation of Flaming Gorge

Dam Final Environmental Impact Statement. U.S. Department of the Interior, Bureau of

Reclamation, Salt Lake City, Utah.

U.S. Fish and Wildlife Service. 2005. Final Biological Opinion on the operation of Flaming

Gorge Dam. U.S. Fish and Wildlife Service, Denver, Colorado.

l2