In-Delta Fish Screen FacilitiesIn-Delta Fish Screen Facilities

Delta Wetlands Proposed Facilities and Basis for

Re-Engineered Facilities

Webb Tract Diversions and DischargesWebb Tract Diversions and Discharges

Bacon Island Diversions and Discharges

Bacon Island Diversions and Discharges

Two Main Locations

Re-engineered

Now

Diversion Plan and Elevation - 5/10/01

Diversion Plan and Elevation - 5/10/01

Booster Pumps Located on New Levee Section

Fish Screen

Proposed Fish Screen - 86 cfs each max.

Proposed Fish Screen - 86 cfs each max.

Hinged Pipe to Remove Screen when not in Use

No Cleaning System

Some Existing Siphons to be Screened, but Contribution is Unclear

Some Existing Siphons to be Screened, but Contribution is Unclear

Habitat Islands = 200 cfs (existing water right)

Webb Tract = 4500 cfs

32 New Siphons/Pumps = 2750 cfs

7 Existing Siphons = 1750 cfs (or 250 cfs each???)

Bacon Island = 4500 cfs

32 New Siphons/Pumps = 2750 cfs

28 Existing Siphons = 1750 cfs (or 62 cfs each??)

Typical Siphons are in the 10 -20 cfs max range…They are not proposed to be enlarged

???

DW Proposed Design Issues/Problems

DW Proposed Design Issues/Problems

• Intake Screen Unproven at this Scale• Fish Screen Criteria Not Met• Screen Structure and Support Inadequate

– Hinge, Screen, Piling, Bracing, Etc.

• Pipe/Pump Hydraulic Issues• Settlement Impacts• Levee Stability Impacts• Erosion• Cyclic Loads and Fatigue• Retrofit of Existing Siphons Uncertain

Operations and Maintenance Issues

Operations and Maintenance Issues

• Manual Cleaning is Inadequate• Sedimentation and Dredging• Corrosion Potential and Cathotic

Protection• Poor Access to Screens (cranes, boats)• Difficult Underwater Inspection• Settlement Monitoring and Adjustment• Flow Monitoring and Data Collection• Starting the Siphon• Pump Maintenance

Hinge Design Loads and FatigueHinge Design Loads and Fatigue

Cleaning System FailureCleaning System Failure

Andreotti Fish Screen9/98

Material Selection ConsiderationsMaterial Selection Considerations

Potential Environmental Issues of DW Alternative

Potential Environmental Issues of DW Alternative

• Fish Predation• Larval Fish Loss• Recreation/Boating Limitations• Aesthetics• Pump Noise• Evaluation Facilities Needed• Maintenance Activities• Construction Impacts• Water Quality at Discharge Stations

• Old Siphon Pipe Adequacy

• Electrical Requirements for Automation

• Site Issues

• Structural Adequacy

Uncertain Retrofit of Existing Facilities for Screening

Uncertain Retrofit of Existing Facilities for Screening

Siphon Screen ExampleHorseshoe Bend (30 cfs)Siphon Screen ExampleHorseshoe Bend (30 cfs)

Fish Screen Criteria Drove Alternative Facilities Design at

Intake Site

Fish Screen Criteria Drove Alternative Facilities Design at

Intake Site• Screen area inadequate for manual

cleaning

• Screen mesh is too large

• Screens over 40 cfs subject to hydraulic uniformity and siting criteria

• Not a “Distributed Intake” concept

Potential Benefits of Re-Engineered Consolidated Facility

Potential Benefits of Re-Engineered Consolidated Facility

• Operations

• Maintenance

• Structural Integrity

• Hydraulic Improvements

CCWD Los Vaqueros IntakeOld River Pump Station

CCWD Los Vaqueros IntakeOld River Pump Station

Example of Consolidated FacilityExample of Consolidated Facility

RD108

830 cfs

Sac. River

Example of Consolidated FacilityExample of Consolidated Facility