Developing Brackish Water Desalination in the San Francisco Bay Area
CA/NV AWWA
Annual ConferenceOctober 1, 2013
Strategies for Developing Water Supply Projects
1. Use Less, Conserve More
- By 2035, conservation savings are projected to be
equivalent to the water needs of 450,000 households
2. Recycle and Reuse
- By 2035, use of recycled water is projected to free up
drinking water supplies for 180,000 households;
other non-potable reuse is also being developed
3. Acquire New Supplies
- Focus on regional partnerships
- Maximize use of existing facilities/assets (unused
capacities)
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EBMUD
CCWD
SFPUC
Zone 7
SCVWD
48,000 acre-feet
200,000 people
330,000 acre-feet
1.8M people
300,000 acre-feet
2.6M people
200,000 acre-feet
1.3M people
120,00 acre-feet
500,000 people
A partnership between
Bay Area’s 5 largest
water supply agencies.
Bay Area Regional Desalination Project
Together, our
agencies serve over
5.6 million residents
and businesses in the
Bay Area.
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Study Site: East Contra Costa County
Mallard Slough site in East
Contra Costa (ECC) selected
for Pilot Test/further analysis.
Benefits of Mallard Slough:
• Brackish water source
- Less power
- Less cost
• Permitted CCWD water intake
(Mallard Slough Pump Station)
- Existing intake facilities
(w/permitted fish screen)
• Ability to connect to CCWD or
EBMUD networks
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San Francisco Bay Water Salinity (26,000)
Pacific Ocean Salinity (34,000)
Brackish Water Source: Mallard Slough
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Drinking Water Standard (1,000)
Mallard Slough
Site Salinity
Starting Assumptions for Analysis
Facility
• Produce up to 20 MGD of desalinated water at Mallard
Slough (up to 25 MGD from Mallard Slough)
Operations
• Year-round operations at full capacity (with no April
diversions); SFPUC taking up to 9 MGD and Zone 7 taking
up to 5 MGD every year
• Storage available at Los Vaqueros via exchange with CCWD
• Optimize use of existing facilities:
− Direct connections to EBMUD, CCWD
− Wheeled through EBMUD system to Zone 7, SFPUC, SCVWD
CCWD
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Regional Setting
7
ECC Site
Zone 7
Intertie
Los Vaqueros
Reservoir
Hayward
Intertie
Questions Agencies Need to Answer Before
Deciding to Proceed to Next Step
• What are the potential Delta water quality
and water supply impacts?
• What are the potential impacts to fisheries?
• Are there opportunities to optimize the project
by using storage in Los Vaqueros?
• What are the Greenhouse Gas emissions
and what can we do to mitigate them?
• Does EBMUD have the capacity to deliver
water to partner agencies?
• What are the full costs to each agency?
Greenhouse Gas
Analysis
Storage
Optimization
Delta Modeling
Hydraulic
Computer
Modeling
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DELTA MODELING STUDY(Storage Optimization)
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Delta Modeling: Water Quality & Supply
• Findings:
- Modeled ambient water quality changes
are <0.25% in existing and future conditions
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Brine Blending with Central Contra Costa Sanitary
District (CCCSD) Effluent
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000O
ct-
86
Ja
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7
Apr-
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Oct-
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Apr-
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Oct-
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9
Apr-
89
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Oct-
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0
Apr-
90
Ju
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Oct-
90
Ja
n-9
1
Apr-
91
Ju
l-91
Sali
nit
y (
mg
/L)
Ambient Water CCCSD Effluent Combined
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Brine Blending with Central Contra Costa Sanitary
District (CCCSD) Effluent
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000O
ct-
86
Ja
n-8
7
Apr-
87
Ju
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Oct-
87
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8
Apr-
88
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Oct-
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9
Apr-
89
Ju
l-89
Oct-
89
Ja
n-9
0
Apr-
90
Ju
l-90
Oct-
90
Ja
n-9
1
Apr-
91
Ju
l-91
Sali
nit
y (
mg
/L)
Ambient Water CCCSD Effluent Combined
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Delta Modeling: Fisheries
- Sensitive Fish Species are present in
the MSPS vicinity.
- Applied a DWR regional-scale
computer model to predict larvae
entrainment
Findings:
- Entrainment at BARDP was less than
0.5% of total particles released
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Storage Optimization
Findings:
• Storage increases reliability and dry year
supplies
• With Storage, the project delivers 84%
of drought year partner demands
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GREENHOUSE GAS STUDY
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Delivery Alternatives Analyzed
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225 85 1,250-1,800 100 600-1,500 kWh/AF
2,260 - 3,700 kWh/AF(1,660 – 2,210 kWh/AF without EBMUD conveyance)
Energy Use of the Desal Facilities
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0
1000
2000
3000
4000
5000
6000
7000
Average Annual Total Energy Use Per Household
Average Refrigerator (80
Watts)
Household Desalinated Water Supply (100% of
Supply)
Household Desalinated Water
Supply (8% of Supply - Zone 7)
6600
701
1314
105
An
nu
al
En
erg
y U
se
(k
Wh
/Ye
ar)
Comparison of Energy Consumption
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GHG Reduction Goal Examples
Carbon-Free: offset all GHG emissions (9,240 MT CO2e/yr)
No Net Increase: offset the difference between GHG
emissions with and without the BARDP (5,810 MT CO2e/yr)
Estimated Costs for GHG reduction: $10 to $50/AF
CCWD 5% EBMUD 11%
SCVWD 12%
SFPUC 46%
Zone 7 26%
Partner
Projected Annual
Indirect Emissions
(MT CO2e/year)
30-Yr Average
CCWD 470
EBMUD 1,060
SCVWD 1,070
SFPUC 4,280
Zone 7 2,360
Total
Indirect
Emissions9,240
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HYDRAULIC MODELING STUDY(Wheeling Cost Estimate)
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EBMUD System - Key Wheeling Facilities
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Hydraulic Modeling Results (MGD)
EBMUD can deliver (normal years, 2040 conditions):
- 10 mgd to Zone 7: 95% of the time (peak day is exceeded 20 days in a year)
- 20 mgd to SFPUC/SCVWD: 90% of the time
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20 MGD Desalination Facility at MSPS - (2013 $/AF)
PRELIMINARY SFPUC Zone 7 SCVWD EBMUD CCWD
Mallard Slough Pump Station $125 $125 $125 $125 $125
Desalination Facility $900 $900 $900 $900 $900
Wheeling (EBMUD) $420 $360 $420 -- --
Hayward Intertie Costs $60 -- $60 -- --
GHG Reduction $50 $50 $50 $50 $50
Total ($/AF) $1,555 $1,435 $1,555 $1,075 $1,075
Note: Does not include cost of fisheries mitigation (??), or storage in LV ($100/AF)
Cost Estimates – $/Acre-Foot
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Questions?
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