Study for Fish Screens at

Existing Delta Facilities

Study for Fish Screens at

Existing Delta Facilities

Dr. Leah OrloffWater Resources Manager

CUWA Board Meeting July 24, 2009

- 2 -July 24, 2009

Study ObjectiveStudy Objective

Analyze the feasibility of pilot fish screens in the Delta for existing export facilities.

- 3 -July 24, 2009

Near-term and long-term benefits– Existing Delta exports are adaptively Existing Delta exports are adaptively

managed based on salvage of delta smelt and managed based on salvage of delta smelt and salmon salmon

– Existing Delta facilities are still necessary Existing Delta facilities are still necessary with any size Isolated Facility, including with any size Isolated Facility, including 15,000 cfs 15,000 cfs

2,000 cfs pilot screens will provide water 2,000 cfs pilot screens will provide water supply reliabilitysupply reliability

The Need for Fish ScreensThe Need for Fish Screens

- 4 -July 24, 2009

Current Operations Current Operations

No screening means no reliability

• In 2009, FWS adaptively restricted exports based on combined delta smelt salvage.

– FWS tightened constraints from mid-May through June because of high salvage levels.

– Despite the restrictions, pumps were shut down for 1-2 days at the end of May to avoid exceeding take limits.

• 2,000 cfs pilot screens would have prevented almost all salvage in spring 2008 and 2009.

- 5 -July 24, 2009

2009: 2,000 cfs screens would have prevented nearly all salvage

2009: 2,000 cfs screens would have prevented nearly all salvage

- 6 -July 24, 2009

2008: Fish screens would have saved up to 186 TAF

2008: Fish screens would have saved up to 186 TAF

Number of days in this month when cumulative salvage exceeded FWS take limit

Acre-feet pumped at Banks this month when cumulative salvage exceeded FWS take limit

If current FWS smelt take limits had been in place in spring 2008, they would have been exceeded in May, June, and July.

Date Take Limit Exceeded

Banks Pumping after Take Limit Exceeded

May 24 22 TAF

June 10 30 TAF

July 1 134 TAF

TOTAL: 186 TAF

- 7 -July 24, 2009

Long- term, fish screens are needed for dual conveyance

Long- term, fish screens are needed for dual conveyance

BDCP modeling shows– Continued reliance on existing Delta exports– Over 50% of supply from existing facilities in drier years

20%

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

AverageExports

(TAF/year)

Wet Above Normal Below Normal Dry Critical

Comparison of Water Supply Diversion Locationfor Different Hydrological Conditions

BDCP Modeling for DRERIP Analysis (1/11/09)

Scenario 1 (mid-level bypass flows)

75%

30%

50%

40%

Ave

rage

Exp

orts

(T

AF

/yea

r)

Wet Above Below Dry Critical Normal Normal

- 8 -July 24, 2009

Pilot Project StudyPilot Project Study

• Project Management:

– Funding partners will enter into an MOU

– Two-tier management: Policy Team and Technical Team

• Schedule: All work to be completed within 6 months of consultant selection.

• Budget: $200,000

- 9 -July 24, 2009

Pilot Project StudyPilot Project Study

Objective: Analyze the feasibility of pilot fish screens in the Delta for existing export facilities. Determine the best:

– location– way to limit predation– way to ensure sweeping velocity– way to move fish out of the South Delta– way to avoid indirect impacts – improvement in water supply reliability

- 10 -July 24, 2009

Scope of WorkScope of Work

Task 1: Review previous studies

Task 2: Develop conceptual alternatives

Task 3: Assess alternatives for feasibility and benefits

Task 4: Perform a blocking analysis

Task 5 Prepare materials for scientific review panel

- 11 -July 24, 2009

Potential Screen LocationsPotential Screen Locations

• Feasibility studies will examine the best placement and design of fish screens to limit predation

• Positive barrier fish screens and tidal barriers provide sweeping velocities for fish survival

North Canal West Canal Italian Slough

ScreenScreenTidal BarriersTidal Barriers

ScreenScreen

Tidal BarriersTidal Barriers

ScreenScreen

Channel ModificationChannel Modification

- 12 -July 24, 2009

Extra SlidesExtra Slides

- 13 -July 24, 2009

2008: 2,000 cfs screens would have prevented nearly all salvage

2008: 2,000 cfs screens would have prevented nearly all salvage

- 14 -July 24, 2009Apr May Jun Jul Aug

0

200

400

600

800

1000

1200

1400

1600

1800

2008

Num

ber

of D

elta

Sm

elt

Delta SmeltWhat if FWS Take Limits were in place in Spring 2008?

0

8

18,343

21

29,970

31

134,067

Take Limit (FWS OCAP BO 2008)Concern Level (FWS OCAP BO 2008)Cumulative Historical Salvage

In the near term, fish screens may ensure water supply reliability

In the near term, fish screens may ensure water supply reliability

Number of days in this month when cumulative salvage exceeded FWS take limit

Acre-feet pumped at Banks this month when cumulative salvage exceeded FWS take limit

If current FWS delta smelt take limits had been in place in spring 2008, take limits would have been exceeded in May, June, and July, costing up to 182 TAF at Banks Pumping Plant.

2008 Data

- 15 -July 24, 2009

Tides provide sweeping velocity in the South Delta

Tides provide sweeping velocity in the South Delta

0 1 2 3 4 5 6 7

100

90

80

70

60

50

40

30

20

10

0

Absolute Value of Sweeping Velocity [ft/s]

Per

cent

Exc

eede

nce

Cummulative Distribution of Sweeping VelocityOld River at Highway 4

1999-2005

JanFebMarAprMayJunJulAugSepOctNovDec

0.4 ft/s

- 16 -July 24, 2009

Screens WorkScreens Work

CCWD’s Old River Intake screen prevents CCWD’s Old River Intake screen prevents fish entrainment fish entrainment – 12 years of operation 12 years of operation

– 982 TAF diverted982 TAF diverted

– Negligible effect on listed fishNegligible effect on listed fish Collected 1 delta smelt (June 2000, 18mm)Collected 1 delta smelt (June 2000, 18mm) Collected 1 longfin smelt (April 2002, 22mm)Collected 1 longfin smelt (April 2002, 22mm) Collected 0 Chinook salmon and 0 steelheadCollected 0 Chinook salmon and 0 steelhead

- 17 -July 24, 2009

Fish Screens May Provide Benefit now and in the future

Fish Screens May Provide Benefit now and in the future

Source: Wim J. Kimmerer, Matthew L. Nobriga. Investigating Particle Transport and Fate in the Sacramento-San Joaquin Delta Using a Particle Tracking Model. San Francisco Estuary and Watershed Science, Vol. 6, Issue 1 (February 2008), Article 4.

• Now: OMR restrictions limit South Delta exports

• Future: Dual conveyance will lower South Delta exports

Fish that are successfully screened from exports have a greater likelihood of escaping the Delta during low export conditions.

- 18 -July 24, 2009

• Drafting a review report – synthesis of previous Drafting a review report – synthesis of previous studies is a first step studies is a first step

• However …However …– DWR report is not examining current conditionsDWR report is not examining current conditions

Outmoded technologyOutmoded technology OMR restrictions have changed Delta hydrodynamics - may OMR restrictions have changed Delta hydrodynamics - may

increase fish screen effectiveness increase fish screen effectiveness Fish screens may prevent SWP from reaching take limitsFish screens may prevent SWP from reaching take limits

– DWR may not have resources to do further studiesDWR may not have resources to do further studies

Current DWR EffortsCurrent DWR Efforts

- 19 -July 24, 2009