Desalination for Marin County Paul Helliker General Manager Marin Municipal Water District North Bay Watershed Association April 5, 2007 Paul Helliker General Manager Marin Municipal Water District North Bay Watershed Association April 5, 2007

2-Minute History of MMWD Water Annual Rainfall: 1879 through MMWD formed 1948 Bon Tempe 1953 Kent 1960 Nicasio 1976 First Russian River Imports 1918 Alpine 1971 Measure B Fails 1977 Richmond Bridge Pipeline 1979 Soulajule 1982 Kent Lake Raised 1990 Pilot De-Sal Plant 1991 Measure W Fails 1992 Measure V Passes 1996 Lagunitas Creek Settlement

Current MMWD Supplies Supply will decrease 25% Climate uncertainties High cost

Projected Supply and Demand Current Yield Future Yield Acre-feet 1987 Demand

Projected 2020 Scenario  Current supply deficit: 3,200AF  Demand increase: 1,560AF  Projected loss of NMWD capacity: 2,300AF  Total projected deficit: 7,060 AF  Current supply deficit: 3,200AF  Demand increase: 1,560AF  Projected loss of NMWD capacity: 2,300AF  Total projected deficit: 7,060 AF

MMWD Options  Conservation – Remains first choice – Already achieved 25% savings – BMPs implemented and very aggressive tiered rates – Additional reductions may cost more than other options  Recycling – Currently have many innovations in place – Expansion complicated by cost and water quality issues  Imports –Endangered species protection limitations –Least costly now – likely increase  Desalination –Reliable supply –Cost and energy use are major issues  Conservation – Remains first choice – Already achieved 25% savings – BMPs implemented and very aggressive tiered rates – Additional reductions may cost more than other options  Recycling – Currently have many innovations in place – Expansion complicated by cost and water quality issues  Imports –Endangered species protection limitations –Least costly now – likely increase  Desalination –Reliable supply –Cost and energy use are major issues

MMWD Plan –Proximity to infrastructure –Mix brine with wastewater in existing deep water outfall –Intake water is less saline and is warmer than ocean –No power plant impacts –Public ownership –Reduce imports

MMWD Desalination Pilot Program & EIR -Nine/Twelve month demonstration and test -Conventional/MF/UF pretreatment, 4 Reverse Osmosis makes -Chemical, biological testing of water streams -Dilution modeling -Fisheries studies -Entrainment analysis -Nine/Twelve month demonstration and test -Conventional/MF/UF pretreatment, 4 Reverse Osmosis makes -Chemical, biological testing of water streams -Dilution modeling -Fisheries studies -Entrainment analysis

Intake Screening  Designed to meet Federal and State criteria for fish protection –3/32-inch openings –<0.3 fps velocity –airburst cleaning  Located at end of existing 2000-ft pier  Multiple screens for full-scale facility  Designed to meet Federal and State criteria for fish protection –3/32-inch openings –<0.3 fps velocity –airburst cleaning  Located at end of existing 2000-ft pier  Multiple screens for full-scale facility

Reverse Osmosis (RO) Desalination  Tested four manufacturers  Three RO elements per train  Initial problems with non-standard sizes  All performed acceptably – fewer cleanings with MF/UF

Bay Fish Sampling Summary of Results  Northern anchovy & Pacific herring common in midwater trawl  Bay goby, shiner perch common in otter trawl  Dungeness crab most common invertebrate  Species composition similar to CDFG sampling  Spiny dogfish not collected by CDFG  Long-term CDFG data can be used in the environmental analysis  Northern anchovy & Pacific herring common in midwater trawl  Bay goby, shiner perch common in otter trawl  Dungeness crab most common invertebrate  Species composition similar to CDFG sampling  Spiny dogfish not collected by CDFG  Long-term CDFG data can be used in the environmental analysis

 Measurement of species composition, seasonal distribution, and densities of icthyoplankton, crab, shrimp, oysters  Twice monthly for 12 months  Use Empirical Transport Model, Adult Equivalent Loss and Fecundity Hindcast models to estimate entrainment impacts  Measurement of species composition, seasonal distribution, and densities of icthyoplankton, crab, shrimp, oysters  Twice monthly for 12 months  Use Empirical Transport Model, Adult Equivalent Loss and Fecundity Hindcast models to estimate entrainment impacts Pilot Plant Entrainment Study

*200565,866yellowfin goby N/A ,864northern anchovy ,0894,6981,860,969unidentified gobies ,45831,396229,061,594Pacific Herring ETM: Pm Estimate Annual AEL Estimate Annual 2FH Estimate Total Annual Entrainment Taxa Estimated Entrainment

Results to Date  ETM estimates range from 0.02 – 0.06%, well below sustainable harvest level of %  No northern anchovies in source water – no ETM estimate  No salmon, steelhead or sturgeon larvae were collected  ETM estimates range from 0.02 – 0.06%, well below sustainable harvest level of %  No northern anchovies in source water – no ETM estimate  No salmon, steelhead or sturgeon larvae were collected

Brine Discharge Analysis  Analyzed near- and far-field dilution of brine in sewage effluent  Brine flows stable, up to 15 MGD  Sewage highly variable flow: 2 – 100 MGD  Near field dilutions average 200:1, min. of 9:1  Far field dilutions in San Rafael Bay of 1500:1  Analyzed near- and far-field dilution of brine in sewage effluent  Brine flows stable, up to 15 MGD  Sewage highly variable flow: 2 – 100 MGD  Near field dilutions average 200:1, min. of 9:1  Far field dilutions in San Rafael Bay of 1500:1

Size of the Initial Mixing Zone Worst Case: 650m x 250m Mean: 30m x 15m

Brine Mixture Bioassays  Acute bioassays on mysid shrimp, topsmelt, marine algae at 79%, 27% and 5% brine –No significant impacts  Chronic bioassays on giant kelp, bay mussel, inland silverside at 79% and 27% brine –No significant impacts under EPA protocol (correct salinity) –Sublethal impacts for high- brine mix –No major differences from sewage effluent alone  Acute bioassays on mysid shrimp, topsmelt, marine algae at 79%, 27% and 5% brine –No significant impacts  Chronic bioassays on giant kelp, bay mussel, inland silverside at 79% and 27% brine –No significant impacts under EPA protocol (correct salinity) –Sublethal impacts for high- brine mix –No major differences from sewage effluent alone

Water Supply Analysis  Testing for: –100 Regulated compounds or compounds that require monitoring –250 non-regulated compounds –An additional 100 non-regulated compounds specific to SF Bay (incl. flame retardants, algal toxins) –E-screen bioassay  6,000 Data Points to Evaluate Water Quality and Treatment Performance  Testing for: –100 Regulated compounds or compounds that require monitoring –250 non-regulated compounds –An additional 100 non-regulated compounds specific to SF Bay (incl. flame retardants, algal toxins) –E-screen bioassay  6,000 Data Points to Evaluate Water Quality and Treatment Performance

Desalinated Water Quality Results Constituents Maximum Contaminant Level (MCL) a SF Bay Water a Desalinated Water a Existing MMWD Sources a SodiumN/A7, – 20 Chloride250 b 12, – 21 Total Organic Carbon (TOC) 2c2c 0.86ND1 – 2 Boron1d1d ND – 0.28 Ethylene Dibromide e ND Mercury0.002ND e ND a - ppm b – Federal Secondary (aesthetic) Standard c – based on MMWD source water quality d – CA DHS notification level e – 4 of 5 samples tested non-detect Detailed List of Constituent Sample Results Available

Energy for Desalting Seawater is Similar to Common Appliances At 7.15 kWh/1000 gal seawater desalination requires only 1.9 kWhr/day of power to produce 270 gallons per day. 81 Watts 1.9 kWh/day 2.4 kWh/day 140 Watts 3.4 kWh/day 75 Watts 1.8 kWh/day 100 Watts 2.4 kWh/day 100 Watts avg. On average, MMWD households use 270 gallons of water per day

Desal would be approx. 0.7% to 3% of Annual Marin Energy Use * From California Energy Commission for year 2000

Desal Energy is like an extra lightbulb in every Marin home  Average operation would be like an extra compact fluorescent bulb on all the time  Drought operation would be like a standard 100-W bulb on all the time  MMWD will be considering renewable power to supply this energy need  Average operation would be like an extra compact fluorescent bulb on all the time  Drought operation would be like a standard 100-W bulb on all the time  MMWD will be considering renewable power to supply this energy need

Desalination facility: $ million Non-construction costs (permitting, construction management, etc.): $7-10 million In-system distribution improvements (Phases IV and V): $ million Total $ million Annual operating costs: $4 – 12 million Normalized cost: $2,433 - $2,023 per acre- foot Desalination facility: $ million Non-construction costs (permitting, construction management, etc.): $7-10 million In-system distribution improvements (Phases IV and V): $ million Total $ million Annual operating costs: $4 – 12 million Normalized cost: $2,433 - $2,023 per acre- foot Cost of Desalination Option