Appendix B - Screening Tool Baseline Scenario
Choose an option to model, and a scenario to model it against. Those are the only two inputs on this sheet! Option : DE-1 Regional Desalination (MMWD)
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 6.12 as entered in Options definition Fixed OMR ($M/yr) 0.91 as entered in Options definition Fixed capital + OMR ($M/yr) 7.03 sum of amoritized capital plus fixed OMR Scenario: 2 Replay it again Sam, historic hydrology with base year 1920 Hydrology type: Historic
Base year: 1920 Base year of historic replay
Synthetic hydrology ID: n/a
Synthetic hydrology index: n/a
Sonoma reductions by year type: Wet 0%
Normal 0%
Dry 30%
SUMMARY OF RESULTS
Years with any rationing 15 out of 50 years
Years with rationing over state levels 0
Max rationing 10% based on nominal demand
Max AFY supplemental supply 6,962 AF/yr
Avg Sonoma Water 18,509 AF/yr
Avg Sonoma Water Cost 22.2 $M/yr
Average AFY supplemental 4,441 based on scenario usage year-by-year, shown below Max supplemental AFY 6,962
Average marginal OMR $M/yr 1.78 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 8.82 combining with fixed costs shown above Average $/AF supplemental $1,985
Avg total cost including supplement + Sonoma 31.0 $M/yr Average OMR $/yr 2.69 sum of fixed and marginal OMR
Year Year type
Sonoma
Water %
redu for
year type Demand
Supply
from
existing
wells
Min supp
AF
Max supp
AF
Baseline
demand
for SW
Sonoma
Water
max avail
(AF)
State-
imposed
rationing
for year
type
Eff demand
AF
Sonoma
Water
Sonoma
Water
cost $M
Supply
deficit AF
Supp supply
Marginal cost
$/AF
Supp supply
used for
demand (AF)
AF Residual
shortage
(surplus)
Needed
rationing
based on
supply
Actual
rationing
level Rationing Supp. Supply
2045 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2046 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2047 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2048 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2049 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2050 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2051 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2052 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2053 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2054 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2055 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2056 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2057 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2058 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2059 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2060 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2061 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2062 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2063 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2064 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2065 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2066 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2067 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2068 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2069 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2070 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2071 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2072 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2073 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2074 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2075 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2076 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2077 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2078 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2079 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2080 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2081 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2082 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2083 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2084 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2085 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2086 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2087 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2088 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2089 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $401 6,962 0 0% 10% 2,500 6,962 2090 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2091 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2092 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2093 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 2094 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $401 3,360 0 0% 0% 0 3,360 0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
RW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-4
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3c
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3a
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-3
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2045 2050 2055 2060 2065 2070 2075 2080 2085 2090
Supply (TAF)
Year
DE-1
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand
Appendix B - Screening Tool Baseline Scenario
Choose an option to model, and a scenario to model it against. Those are the only two inputs on this sheet! Option : DE-2 Ocean Desalination
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 13.33 as entered in Options definition Fixed OMR ($M/yr) 1.60 as entered in Options definition Fixed capital + OMR ($M/yr) 14.93 sum of amoritized capital plus fixed OMR Scenario: 2 Replay it again Sam, historic hydrology with base year 1920 Hydrology type: Historic
Base year: 1920 Base year of historic replay
Synthetic hydrology ID: n/a
Synthetic hydrology index: n/a
Sonoma reductions by year type: Wet 0%
Normal 0%
Dry 30%
SUMMARY OF RESULTS
Years with any rationing 15 out of 50 years
Years with rationing over state levels 0
Max rationing 10% based on nominal demand
Max AFY supplemental supply 6,962 AF/yr
Avg Sonoma Water 18,509 AF/yr
Avg Sonoma Water Cost 22.2 $M/yr
Average AFY supplemental 4,441 based on scenario usage year-by-year, shown below Max supplemental AFY 6,962
Average marginal OMR $M/yr 5.17 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 20.11 combining with fixed costs shown above Average $/AF supplemental $4,528
Avg total cost including supplement + Sonoma 42.3 $M/yr Average OMR $/yr 6.78 sum of fixed and marginal OMR
Year Year type
Sonoma
Water %
redu for
year type Demand
Supply
from
existing
wells
Min supp
AF
Max supp
AF
Baseline
demand
for SW
Sonoma
Water
max avail
(AF)
State-
imposed
rationing
for year
type
Eff demand
AF
Sonoma
Water
Sonoma
Water
cost $M
Supply
deficit AF
Supp supply
Marginal cost
$/AF
Supp supply
used for
demand (AF)
AF Residual
shortage
(surplus)
Needed
rationing
based on
supply
Actual
rationing
level Rationing Supp. Supply
2045 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2046 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2047 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2048 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2049 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2050 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2051 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2052 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2053 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2054 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2055 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2056 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2057 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2058 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2059 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2060 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2061 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2062 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2063 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2064 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2065 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2066 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2067 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2068 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2069 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2070 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2071 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2072 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2073 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2074 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2075 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2076 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2077 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2078 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2079 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2080 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2081 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2082 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2083 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2084 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2085 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2086 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2087 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2088 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2089 Dry 30% 25,000 1,300 3,360 10,080 20,340 14,238 10% 22,500 14,238 17.1 6,962 $1,165 6,962 0 0% 10% 2,500 6,962 2090 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2091 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2092 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2093 Normal 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 2094 Wet 0% 25,000 1,300 3,360 10,080 20,340 20,340 0% 25,000 20,340 24.4 3,360 $1,165 3,360 0 0% 0% 0 3,360 0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
RW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-4
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3c
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3a
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-3
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2045 2050 2055 2060 2065 2070 2075 2080 2085 2090
Supply (TAF)
Year
DE-2
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand
Appendix B - Screening Tool Baseline Scenario
Choose an option to model, and a scenario to model it against. Those are the only two inputs on this sheet! Option : SW-1 Stormwater stored in aquifer
Storage (AF): 5,000 as entered in Options definition
Storage threshold ($/AF): 500 supplemental supply is only used for discretionary storage puts when price is less than this value Capital cost ($M/yr) 7.84 as entered in Options definition Fixed OMR ($M/yr) 0.54 as entered in Options definition Fixed capital + OMR ($M/yr) 8.39 sum of amoritized capital plus fixed OMR Scenario: 2 Replay it again Sam, historic hydrology with base year 1920 Hydrology type: Historic
Base year: 1920 Base year of historic replay
Synthetic hydrology ID: n/a
Synthetic hydrology index: n/a
Sonoma reductions by year type: Wet 0%
Normal 0%
Dry 30%
SUMMARY OF RESULTS
Years with any rationing 15 out of 50 years
Years with rationing over state levels 0
Max rationing 10% based on nominal demand
Max AFY supplemental supply 6,008 AF/yr
Avg Sonoma Water 20,650 AF/yr
Avg Sonoma Water Cost 24.8 $M/yr
Average AFY supplemental 2,618 based on scenario usage year-by-year, shown below Max supplemental AFY 6,008
Average marginal OMR $M/yr 0.79 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 9.18 combining with fixed costs shown above Average $/AF supplemental $3,507
Avg total cost including supplement + Sonoma 34.0 $M/yr Average OMR $/yr 1.34 sum of fixed and marginal OMR
Year Year type
Sonoma
Water %
redu for
year type Demand
Supply
from
existing
wells
Min supp
AF
Max supp
AF
Baseline
demand
for SW
Sonoma
Water
max avail
(AF)
State-
imposed
rationing
for year
type
Eff demand
AF
Sonoma
Water
Sonoma
Water
cost $M
Supply
deficit AF
Supp supply
Marginal cost
$/AF
Supp supply
used for
demand (AF)
AF Residual
shortage
(surplus)
Needed
rationing
based on
supply
Actual
rationing
level Rationing Supp. Supply
2045 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2046 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 6,008 2047 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 2,008 2048 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,208 2049 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2050 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,599 2051 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2052 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,677 2053 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,142 2054 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2055 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,586 2056 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2057 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2058 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2059 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2060 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 3,328 2061 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,472 2062 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2063 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,652 2064 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2065 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,688 2066 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,144 2067 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,035 2068 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,013 2069 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2070 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,560 2071 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,118 2072 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2073 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,581 2074 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2075 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,674 2076 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,141 2077 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,035 2078 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,013 2079 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,009 2080 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2081 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,559 2082 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,118 2083 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,030 2084 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,012 2085 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,009 2086 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,008 2087 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,008 2088 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,008 2089 Dry 30% 25,000 1,300 1,008 10,080 22,692 15,884 10% 22,500 15,884 19.1 5,316 $303 5,316 0 0% 10% 2,500 5,316 2090 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,559 2091 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,118 2092 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,030 2093 Normal 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,012 2094 Wet 0% 25,000 1,300 1,008 10,080 22,692 22,692 0% 25,000 22,692 27.2 1,008 $303 1,008 0 0% 0% 0 1,009 0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
SW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
RW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-4
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3c
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3a
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-3
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2045 2050 2055 2060 2065 2070 2075 2080 2085 2090
Supply (TAF)
Year
SW-1
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand
Appendix B - Screening Tool Baseline Scenario
Choose an option to model, and a scenario to model it against. Those are the only two inputs on this sheet! Option : E-1 Efficiency programs
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 5.96 as entered in Options definition Fixed OMR ($M/yr) 0.00 as entered in Options definition Fixed capital + OMR ($M/yr) 5.96 sum of amoritized capital plus fixed OMR Scenario: 2 Replay it again Sam, historic hydrology with base year 1920 Hydrology type: Historic
Base year: 1920 Base year of historic replay
Synthetic hydrology ID: n/a
Synthetic hydrology index: n/a
Sonoma reductions by year type: Wet 0%
Normal 0%
Dry 30%
SUMMARY OF RESULTS
Years with any rationing 15 out of 50 years
Years with rationing over state levels 15
Max rationing 26% based on nominal demand
Max AFY supplemental supply 2,145 AF/yr
Avg Sonoma Water 19,615 AF/yr
Avg Sonoma Water Cost 23.5 $M/yr
Average AFY supplemental 2,145 based on scenario usage year-by-year, shown below Max supplemental AFY 2,145
Average marginal OMR $M/yr 0.00 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 5.96 combining with fixed costs shown above Average $/AF supplemental $2,778
Avg total cost including supplement + Sonoma 29.5 $M/yr Average OMR $/yr 0.00 sum of fixed and marginal OMR
Year Year type
Sonoma
Water %
redu for
year type Demand
Supply
from
existing
wells
Min supp
AF
Max supp
AF
Baseline
demand
for SW
Sonoma
Water
max avail
(AF)
State-
imposed
rationing
for year
type
Eff demand
AF
Sonoma
Water
Sonoma
Water
cost $M
Supply
deficit AF
Supp supply
Marginal cost
$/AF
Supp supply
used for
demand (AF)
AF Residual
shortage
(surplus)
Needed
rationing
based on
supply
Actual
rationing
level Rationing Supp. Supply
2045 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2046 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2047 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2048 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2049 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2050 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2051 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2052 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2053 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2054 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2055 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2056 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2057 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2058 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2059 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2060 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2061 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2062 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2063 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2064 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2065 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2066 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2067 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2068 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2069 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2070 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2071 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2072 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2073 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2074 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2075 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2076 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2077 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2078 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2079 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2080 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2081 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2082 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2083 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2084 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2085 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2086 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2087 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2088 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2089 Dry 30% 25,000 1,300 2,145 2,145 21,555 15,088 10% 22,500 15,088 18.1 6,112 $0 2,145 3,966 26% 26% 6,466 2,145 2090 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2091 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2092 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2093 Normal 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 2094 Wet 0% 25,000 1,300 2,145 2,145 21,555 21,555 0% 25,000 21,555 25.9 2,145 $0 2,145 0 0% 0% 0 2,145 0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
E-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
SW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
DE-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
RW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-4
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3c
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-3a
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
PR-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-3
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-2
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2046 2051 2056 2061 2066 2071 2076 2081 2086
Supply (TAF)
Year
GW-1
sum of fixed and marginal OMR
0 5
10 15
20 25
30 0
5 10
15 20
25 30
2045 2050 2055 2060 2065 2070 2075 2080 2085 2090
Supply (TAF)
Year
E-1
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand
City of Santa Rosa (project #0012267.00) Woodard & Curran, Inc.
Feasibility Analysis August 2023
APPENDIX C: MEMORANDUM ON DESALINATION SUPPLY OPTIONS IN THE
WATER SUPPLY FEASIBILITY ANALYSIS
95 Third Street | 2nd Floor
San Francisco CA 94103
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MEMORANDUM
DATE: August 31, 2023
RE: Desalination Supply Options in the Water Supply Feasibility Analysis
This memorandum provides additional context for desalination as a potential water supply for the feasibility analysis conducted for the City of Santa Rosa’s Water Supply Alternatives Plan (WSAP).
Strengths and Weaknesses of Desalination as a Water Supply Source Desalination is the process of removing salts from seawater or brackish water. Generally, salty water is piped from its location to the desalination facility, which requires a significant amount of power to run the treatment components. While there are a number of technologies used for treatment, reverse osmosis is the most common. O nce the salts are removed, the water undergoes further adjustments so that it can be introduced into the existing system via storage tanks and pipelines. Depending on the proxim ity of the desalination facility to the end users, the pipeline could be significant and require one or more pump stations to convey the water to a point where it can be introduced into the distribution system. Another pipeline is required to dispose of the brine that is created during the treatment process. Figure 1 shows the general process of an ocean desalination facility.
FIGURE 1: EXAMPLE DIAGRAM OF OCEAN DESALINATION FACILITY
Source: Perez-Zuniga, et.al. September 2020. Fault detection and isolation system based on structural analysis of an industrial seawater reverse osmosis desalination plant.
City of Santa Rosa 2 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 As with any supply type, desalination has a variety of strengths and weaknesses.
Strengths
• Immune to drought and variations in hydrologic conditions that are a concern for surface water (e.g., lakes and streams) , stormwater, and groundwater supply options , thus providing a continuous supply of water.
• Local source for coastal communities located in Mediterranean climates that experience more frequent boom-bust water cycles and for communities with large local sources of brackish water, such as salty groundwater.
• Benefits from advancements in treatment technology, energy efficiency, and availability of renewable energy sources.
• Scalable to meet water needs given that its source (in the case of ocean desalination) is nearly unlimited.
• Desalination facilities perform optimally when running at full capacity, benefiting from economies of scale and lowering the cost of desalinated water.
Weaknesses
• Extensive permitting requirements that can take a decade or more to resolve, particularly for ocean desalination facilities. For example, both the Carlsbad facility and the new recently approved Monterey facility took over 10 years to permit and secure approvals from the California Coastal Commission 1. Recently, the Coastal Commission denied a permit to a proposed facility in Huntington Beach, a project that has been in development for over 20 years2. While there have been some positive signs relative to permitting, including the Governor’s stated interest in desalination and the streamlined permitting process proposed by the State Water Resources Control Board, there remains significant uncertainty given the multiple permitting agencies involved 3. • Financial capital required to build desalination facilities can be in the hundreds of millions of dollars. The recently completed Claude “Bud” Lewis Carlsbad Desalination Plant in Carlsbad, California cost nearly $1 billion, well above initial estimates of $300 million4.
• Carries high annual operating costs due to the energy required in salt removal and treatment.
1 Becker, Rachel. CalMatters. 17 November 2022. Another California desalination plant approved – the most contentious one yet.
2 James, Ian. Los Angeles Times. 12 May 2022. California Coastal Commission rejects plan for Poseidon desalination plant.
3 State Water Resources Control Board. Ocean Plan Requirements for Seawater Desalination Facilities. 4 Dawid, Irvin. Planetizen. 2 November 2016. What Happened to all those Desalination Plants Proposed for California?
City of Santa Rosa 3 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 • Expensive membrane replacement (every three to five years) is critical to maintaining the health of desalination facilities, further contributing to large operation & maintenance costs. In addition, membranes can be “fouled” by algal blooms due to warming oceans, requiring more frequent maintenance, repair, and replacement costs. • Environmental concerns associated with the high greenhouse gas emissions footprint due to substantial energy required for treatment, particularly if the facility is supplied with fossil fuels.
• Environmental concerns associated with waste disposal. Desalination processes generate waste referred to as “brine ,” which can contain highly concentrated salts, heavy metals, cleaning chemical residues, and treatment reaction by -products.
Oftentimes, this waste stream is heated, which can cause concerns for the local environment when its discharged. Current reverse osmosis technology can recover only 50% of water entering treatment for ocean desalination facilities and 85% for brackish water facilities. This means that for an ocean desalination project, every 10 gallons of water treated would result in 5 gallons of brine requiring disposal. If future regulations require waste treatment before disposal, project costs would increase significantly. • Vulnerable to certain climate change related impacts, including rising sea levels and warming ocean temperatures (for ocean desalination projects). By their location alone, ocean desalination projects need to account for rising sea levels, which can be addressed during the design phase of a project. Warming ocean temperatures can create algal blooms, which can hasten the fouling of treatment components. One such example is the Carlsbad desalination facility, which experienced shut -downs and ultimately needed to move intakes and make process changes due to an algal bloom1. • Poor turndown capacity which keeps baseline costs high. Desalination facilities must maintain production levels at a minimum of 30% of capacity or risk the facility’s long - term health and performance. Thus, even in periods when no water from the facility may be needed, the plant must continue producing water and incurring the associated operating costs.
Review of Desalination Options Considered for Santa Rosa As discussed above, an ideal user for desalinated water is one that lives near the source water body and has a consistent demand that can be met with the supply. Santa Rosa has neither of these qualities: it is not proxima te to the ocean nor to another significant source of brackish water and its most significant need for water is during drought or catastrophic events, neither of which occur every year. Despite these challenges and others listed above , the feasibility analysis does consider two desalination supply options: a regional brackish water desalination facility (DE-1) and an ocean desalination facility (DE -2). The two options are further described in the following paragraphs.
1 Rivard, Ry. Voice of San Diego. 29 August 2017. Desal plant is producing less water than promised.
City of Santa Rosa 4 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 DE-1: Regional Brackish Water Desalination
Option DE-1 was conceived as a way to potentially reduce the major operating and capital costs associated with desalination. The defining aspect of the option is treatment of brackish water instead of ocean water, since that would have the potential to greatly lower costs.
However, because Santa Rosa is not located near a large brackish water source, DE -1 cannot move forward without significant involvement from major partners. Santa Rosa would not own or operate the facility so these partners would need to be a driving force in the implementation of any regional brackish water facility. Marin Water, a viable partner for such a project, has been evaluating desalination since the early 1980’s. In its recently released Strategic Water Supply Assessment, Marin Water discusses a Petaluma Brackish Regional Desalination project which it notes as being a late addition to the document and using a number of assumptions to develop its concept and costs1.
Option DE-1 would be implemented as follows:
• MMWD would construct a brackish water desalination plant, using funds provided by Santa Rosa to oversize the plant beyond MMWD’s own needs. In essence, Santa Rosa would have a certain percent stake in the project.
• Santa Rosa would pay MMWD for its share of capital and operating costs. Those costs would include operations even in wet and normal years, which are substantial because current desalination plants need to be run at about 30% of capacity to maintain their readiness.
• Rather than physically transporting the water from the treatment plant to Santa Rosa, Santa Rosa would trade water, such that water which MMWD would otherwise have taken from the Sonoma Water system would instead be taken by Santa Rosa.
Several aspects of the project impact its current viability:
1. Technical questions. The supply of brackish water has not been established, and may be insufficient even for MMWD’s needs, let alone for MMWD plus Santa Rosa. The cost and other technical aspects are not well developed.
2. MMWD may not build the project or may not wish to partner with Santa Rosa . This highlights a unique aspect of this option among the 18 options studied as part of water supply feasibility analysis: while many of the 18 options could potentially be enhanced with regional partnerships, DE-1 stands alone as the only option that simply could not move forward without a regional partner driving the project.
3. The technical and legal bases of the necessary water trade have not been established.
The proposed trade would occur in dry years and thus be limited to the amount of water that MMWD would be allowed to purchase from Sonoma Water in a dry year. In
1Marin Water. May 2023. Strategic Water Supply Assessment. https://www.marinwater.org/sites/default/files/2023-06/MMWD_SWSA_Final%20Draft%20Report.pdf
City of Santa Rosa 5 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 the most recent drought, Sonoma Water reduced MMWD’s supply to about 85% of its minimum take-or-pay amount, or about 4.5 TAF1. This falls short of Santa Rosa’s need for water. Further, MMWD’s contractual right to trade any water it would otherwise purchase from Sonoma Water has not been established.
4. The project would rely entirely on Sonoma Water infrastructure for its operations. This is at odds with the WSAP goal of improving Santa Rosa’s resilience to delivery interruptions from Sonoma Water.
Over time, many of the aspects listed above may resolve , although the fundamental mismatch between the option and the WSAP goal of increased self -sufficiency would remain. The next desalination option, DE-2, was conceived to overcome that concern.
DE-2: Ocean Desalination
Option DE-2 includes the construction and operation of an ocean desalination facility, located roughly 17 miles west of Santa Rosa in Bodega Bay. In contrast to DE -1, this option would be owned and operated by Santa Rosa and serve water directly to City cu stomers, thereby addressing the WSAP goal of providing increased self-sufficiency to the City.
DE-2 has the benefit of a largely unlimited, drought-proof water supply source and, as a result, any facility could be sized to meet whatever need exists. However, there is a minimum practical project size from both a cost and water yield perspective : certain economies of scale would favor a slightly larger project over a slightly smaller project and the City would want to ensure that such a facility would be able to provide a large portion of the water needed. As noted in the water supply feasibility analy sis, Santa Rosa does not require a large amount of water in every year type ; water is only needed during drought and any catastrophic interruptions of Russian River supply. Even though water wouldn’t be needed in an average year, the City would be required to run the desalination facility at 30% capacity to keep the components from souring, a concept referred to as turn-down capacity.
Running such a desalination facility 24/7 incurs very high operational and energy costs, one of the driving factors for DE -2’s high unit cost of water. Also impacting the capital costs of this option is the massive amount of infrastructure required to build this facility and convey the treated water back to Santa Rosa . The pipeline conveying the water to Santa Rosa is over 17 miles, requiring significant initial investment to build and more long -term O&M costs, particularly when that pipeline would require replacement. This pipeline also has the po tential to cross sensitive habitat, which would likely require substantial mitigation and permitting costs.
Given its location, pipeline design must also account for significant topography challenges and fault zones.
1 Marin Water Board meeting packet May 18, 2021 item 7: Due to the dry conditions and reservoir levels Sonoma Water will reduce allocations to their retail customers, including MMWD beginning in July. From July through September MMWD will be restricted to 4-MGD and a slight increase in October to 4.6-MGD. Staff expects that reduced allocation may continue if rainfall is below average in the fall. [In the event, heavy rain in October 2021 ended the restrictions.]
City of Santa Rosa 6 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 Given its already high cost, DE-2 was not analyzed in detail so the currently estimated costs are considered to be best -case with current technology. If detailed studies are done, several technical areas would be analyzed which could result in increased estimated costs. Such technical areas include plant siting, establishing how brine would be disposed, routing the pipeline or tunnel, and providing line power to the plant. Any one of these facets of facility design could drive costs upward from the estimate s included in the water supply feasibility analysis.
Despite the challenges outlined in this memo , future conditions may prompt reconsideration of desalination by Santa Rosa. Those potential future conditions are discussed in the last section of this memo.
Scoring Desalination as a Supply
If the two desalination options had advanced past the screening phase of the analysis, they would have been scored as shown in Table 1 for DE-1 (Regional Brackish) and Table 2 for DE- 2 (Ocean) . Because of the challenges discussed above, neither option scores well in environmental performance and legal, permitting, and regulatory. DE-2 scores favorably in city control and interagency coordination since the option is a city -controlled project. For cost effectiveness, DE-1 scores more favorably with a unit cost of water less than half that of DE -2.
In the future, there may be circumstances that would alter the individual criterion scores, resulting in a better overall score for desalination in Santa Rosa. Triggers that should cause the City to reconsider desalination as a supply are discussed in the next section. Table 3 is a reproduction of the summary scoring table presented in the water supply feasibility analysis with the addition of the two desalination scores. DE -2 (Ocean) has the least total weighted score of the options (18); DE-1 (Regional Brackish) has the least total unweighted score (5) but the same total weighted score as PR -2 (Satellite DPR). While these two overall scores are the same, potable reuse as a supply option is better suited to Santa Rosa than desalination as highlighted in the “Purified Water vs Desalination” side bar above.
City of Santa Rosa 7 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 TABLE 1: DETAILED SCORING FOR OPTION DE-1 (REGIONAL BRACKISH) Criterion Description Score
Cost
effectiveness
Based on conceptual level cost estimates, a brackish
water desalination facility would provide a minimum of
3,360 AFY with an average cost of water of at least
$2,000/AF.
1 Scalability
A brackish water desalination facility could be
constructed in modular phases to best fit City water
needs. Additionally, the facility could be scaled down
30% in low demand periods. However, the facility’s
scalability would potentially be limited not only by the yield of the project itself, but by the terms imposed by potentially multiple project partners. potentially be
limited not only by the yield of the project itself, but by the terms imposed by potentially multiple project
partners.
1 Resiliency
Low resiliency. While the ability to desalinate brackish water into potable supply would improve resiliency in
times of drought or future hydrologic uncertainty, under this supply option, Santa Rosa would be receiving a
partnering agency’s Sonoma Water allocation rather than desalinated water.
0 Equity
The additional desalinated water supply would have no
impact on vulnerable communities. Because this option
relies on a water transfer, ratepayers would be
responsible for contributing to the construction of the desalination facility while ultimately receiving water from Sonoma Water.
1 Environmental
performance
The construction and operation of a brackish water
desalination facility would have a high potential for
environmental impacts due to its high energy demands
and brine production.
0 Legal,
permitting, and
regulatory
High permitting/regulatory effort would be required to
construct a brackish water desalination facility. 0
City control and
interagency
coordination
Coordination with a regional partner for the paper
exchange would be required in addition to continuing
coordination with Sonoma Water if its aqueduct were
used for distribution.
0 Multi-benefit No other benefits provided. 0
City of Santa Rosa 8 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 TABLE 2: DETAILED SCORING FOR OPTION DE-2 (OCEAN)
Criterion Description Score
Cost
effectiveness
Under the baseline scenario cost estimate, a seawater
desalination facility would provide a minimum of 3,360
AFY with an average cost of water of approximately
$4,500/AF. This compares to $1,300/AF for the existing
Sonoma Water supply.
0 Scalability
While the ocean offers an infinitely scalable water supply, a seawater desalination facility would need to be
constructed at full capacity rather than in phases
because it would require the construction of a properly sized pipeline to convey desalinated water to the City.
Additionally, the facility would need to run at 30%
capacity even when not needed to meet City water
supply.
1 Resiliency
Moderate resiliency. The ability to desalinate seawater into potable supply would improve resiliency, even in
times of drought or future hydrologic uncertainty.
However, this supply option is highly sensitive to rising energy costs, decreasing overall cost-effectiveness.
The desalination process is also subject to disruption
from ocean conditions such as red tides, which are
expected to worsen in future years due to climate
change.
1 Equity
The additional desalinated water supply would have no
impact on the City’s vulnerable communities. However,
the City would need to consider potential equity issues if desalinated water were to be delivered to only a portion of its residents.
1 Environmental
performance
The construction and operation of a seawater
desalination facility would have a high potential for
environmental impacts due to its high energy demands
and brine production.
0 Legal,
permitting, and
regulatory
High permitting/regulatory effort would be required to
construct a seawater desalination facility. 0
City control and
interagency
coordination
No significant interagency coordination would be
required. 2
Multi-benefit No other benefits provided. 0
City of Santa Rosa 9 Woodard & Curran, Inc.
Desalination Options Water Supply Feasibility Analysis August 31, 2023 TABLE 3: SUMMARY OF SUPPLY OPTION SCORES WITH DESALINATION OPTIONS Criterion
Groundwater Purified Recycled Water Desalination Stormwater E-1:
Efficiency
Programs
GW-1:
Add
Extraction
Wells
GW-2:
Convert
Emergency
Wells
GW-3:
City ASR
Wells
PR-2:
Satellite
DPR
PR-4:
Regional
DPR
DE-1:
Brackish
Desal
DE-2:
Ocean
Desal
SW-1:
Stormwater
Storage in
Aquifer
Cost
effectiveness *
[$/AF]
2 [$840/AF]
2 [$540/AF]
2 [$1,100/AF]
0 [$3,900/AF]
0 [$3,200/AF]
1 [$2,000/AF]
0 [$4,500/AF]
0 [$3,500/AF]
1 [$2,800/AF]
Scalability
[Yield in AFY]
2 [5,880 -
10,080 AFY]
0 [1,436 - 2,462
AFY]
1 [2,993 - 5,130
AFY]
2 [3,019 - 10,065
AFY]
2 [3,019 - 10,065
AFY]
1 [3,360 - 10,080
AFY]
1 [3,360 - 10,080
AFY]
1 [1,008 - 10,080
AFY]
1 [2,145 AFY]
Resiliency 1 1 2 2 2 0 1 1 1
Equity 1 1 1 1 1 1 1 1 2
Environmental
performance 1 2 1 0 1 0 0 1 2
Legal,
permitting, and
regulatory
1 2 0 0 0 0 0 1 2
City control &
interagency
coordination
2 2 1 2 0 0 2 2 2
Multi-benefit 0 0 1 0 0 0 0 2 1
Total
Unweighted 10 10 9 7 6 3 5 9 12
Total
Weighted 32 26 29 21 22 13 13 19 30
* Costs shown reflect a realistic baseline usage scenario and include both capital and operating costs.
City of Santa Rosa 10 Woodard & Curran, Inc.
Desalination Options in the Water Supply Feasibility Analysis August 31, 2023 Triggers for Reconsidering Desalination in the Future
While the water supply feasibility analysis does not show the desalination options advancing past the screening phase, the City may, at some point in the future, determine that work to further desalination as a supply for Santa Rosa is warranted. Triggers that might cause the City to reconsider desalination include:
• Technology that reduces baseline operating costs. As discussed in this memo, desalination has poor turndown capacity; current technology requires that plants be operated at a minimum of 30% capacity. This results in significant annual operating costs to keep the plant “healthy” while waiting for times when its water is really needed (i.e., during droughts and catastrophic supply interruptions). Advancements in turndown capacity would reduce baseline operating costs and decrease the unit cost of water, particularly for DE-2.
• Less expensive energy prices which reduces operating costs. Because desalination plants require significant amounts of energy, their operating costs are heavily influenced by the cost of energy. The assumption used for costing desalination options in the water supply feasibility analysis was $0.20/kWh. Should there be a sustained drop in price, operating costs would decrease, perhaps making the unit cost of water of ocean desalination more comparable with other supply options. • Project configuration that yields direct water to Santa Rosa. DE-1 is configured as a regional brackish water desalination project that results in a water transfer, wherein Santa Rosa would accept additional Sonoma Water. While this configuration would reduce regional reliance on the Russian River system, it would not reduce the City’s reliance on Sonoma Water. The City could reconsider regional desalination if such a project were to provide desalinated water directly to Santa Rosa, thus reducing the City’s reliance on water from the Russian River system. • Technology that improves water recovery. With current technology, ocean desalination facilities have roughly 50% recovery; brackish facilities have up to 85% recovery. In either case, there is still a significant brine management and disposal challenge. This is one area where the industry is already seeing the impact of technological advances. In a recent City of Santa Monica pilot project, new technology increased recovery from 80% to 90%1. Santa Rosa should monitor advancements in this area as this new technology becomes more widely applied.
Prior to committing implementation funding to additional water supply projects, City s taff should revisit these triggers to determine if any developments or changes in these areas warrant a closer look at a desalination project for Santa Rosa. The Water Supply Alternatives Plan integrates the suggested revisit points in the discussion of Portfolio 4.
1 Sawicki, Emily. Santa Monica Daily Press. 21 January 2022. New water projects set to expand local supply.