Attachment 1 - Study Technical Memorandum — Santa Rosa City Council, September 26, 2023 (part 1 of 2)

City of Santa Rosa (project #0012267.00) i Woodard & Curran, Inc.

Feasibility Analysis August 2023

TECHNICAL MEMORANDUM
TO: Colin Close
PREPARED BY: Jennifer Kidson, Martha de Maria y Campos
REVIEWED BY: Xavier Irias, Christy Kennedy, Katie Cole
DATE: August 31, 2023
RE: Santa Rosa Water Supply Alternatives Plan Feasibility Analysis Findings, Task 7

TABLE OF CONTENTS
Executive Summary ....................................................................................................................................................................... ES-1

1. Purpose and Background ......................................................................................................................................................... 1

2. Study Parameters and Methods ............................................................................................................................................ 1

2.1 Collaborative Development of Study Parameters .................................................................................................. 1

2.2 Water Supply Goal .............................................................................................................................................................. 3

2.3 Water Supply Options ........................................................................................................................................................ 3

2.4 Evaluation Criteria and Metrics ...................................................................................................................................... 5

2.5 Screening Analysis ............................................................................................................................................................... 7

2.5.1 Screening Tool .............................................................................................................................................................. 8

2.5.2 Capital Cost Estimate Methodology ................................................................................................................. 10

2.5.3 Feasibility Scoring Methodology........................................................................................................................ 11

3. Findings ........................................................................................................................................................................................ 13

3.1 Water Supply Option Descriptions ............................................................................................................................ 13

3.1.1 Groundwater Supply Options .............................................................................................................................. 14

3.1.2 Purified Recycled Water Supply Options ........................................................................................................ 27

3.1.3 Non-Potable Recycled Water Option ............................................................................................................... 49

3.1.4 Desalinated Water Supply Options ................................................................................................................... 50

3.1.5 Stormwater Capture Options ............................................................................................................................... 57

3.1.6 Efficiency Programs ................................................................................................................................................. 62

3.2 Screening Analysis Results ............................................................................................................................................ 63

3.3 Feasibility Analysis Results ............................................................................................................................................ 66

3.3.1 Groundwater Options ............................................................................................................................................. 68 Attachment 1

City of Santa Rosa (project #0012267.00) ii Woodard & Curran, Inc.

Feasibility Analysis August 2023

3.3.2 Purified Recycled Water Options ....................................................................................................................... 72

3.3.3 Stormwater Capture ................................................................................................................................................ 74

3.3.4 Efficiency Programs ................................................................................................................................................. 75

3.3.5 Cost Sensitivity Analysis ......................................................................................................................................... 76

4. Conclusions ................................................................................................................................................................................ 77

5. References ................................................................................................................................................................................... 79

LIST OF FIGURES
Figure ES-1-1: Cost-Effectiveness vs Max Yield (with Weighted Score) .................................................................. ES-6 Figure 2-1: Screening and Feasibility Analysis Process ......................................................................................................... 8 Figure 3-1: Existing City Wells ...................................................................................................................................................... 15 Figure 3-2: Supply Option GW-1 ................................................................................................................................................. 19 Figure 3-3: Supply Option GW-3 ................................................................................................................................................. 24 Figure 3-4: Regional System Facilities ....................................................................................................................................... 29 Figure 3-5: Average Recycled Water Use (2019-2022) ....................................................................................................... 30 Figure 3-6: Forms of Potable Reuse in California ................................................................................................................. 31 Figure 3-7: Supply Option PR-1 ................................................................................................................................................... 34 Figure 3-8: Supply Option PR-2 ................................................................................................................................................... 37 Figure 3-9: Supply Option PR-3a ................................................................................................................................................ 40 Figure 3-10: Supply Option PR-3c .............................................................................................................................................. 44 Figure 3-11: Supply Option PR-4 ................................................................................................................................................ 47 Figure 3-12: Supply Option DE-1 ................................................................................................................................................ 53 Figure 3-13: Supply Option DE-2 ................................................................................................................................................ 55 Figure 3-14: Supply Option SW-1 ............................................................................................................................................... 58 Figure 3-15: Cost-Effectiveness vs Max Yield (with Weighted Score) .......................................................................... 68 Figure 3-16: Supply Option Cost Performance with Varying Hydrology ($/AF) ....................................................... 76 Figure 3-17: Supply Option Cost Performance with Varying Sonoma Water Cutbacks ($M/yr) ....................... 77

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Feasibility Analysis August 2023

LIST OF TABLES
Table ES-1: Water Supply Options.......................................................................................................................................... ES-2 Table ES-2: Screening Analysis Results Summary ............................................................................................................ ES-3 Table ES-3: Summary of Supply Option Scores................................................................................................................. ES-5 Table 2-1: Stakeholder and Community Outreach Meeting Summary........................................................................... 2 Table 2-2: Water Supply Options ................................................................................................................................................... 4 Table 2-3: Evaluation Criteria, Metrics, and Weights.............................................................................................................. 6 Table 2-4: Baseline Screening Analysis Parameters and Assumptions ........................................................................... 9 Table 2-5: Evaluation Criteria Scoring Rubric ......................................................................................................................... 12 Table 3-1: Summary of Water Supply Options ...................................................................................................................... 13 Table 3-2: Preliminary Capital Cost, Supply Option GW-1 ............................................................................................... 17 Table 3-3: Preliminary Annual O&M Cost, Supply Option GW-1 ................................................................................... 18 Table 3-4: Preliminary Capital Cost, Supply Option GW-2 ............................................................................................... 21 Table 3-5: Preliminary Annual O&M Cost, Supply Option GW-2 ................................................................................... 21 Table 3-6: Preliminary Capital Cost, Supply Option GW-3 ............................................................................................... 25 Table 3-7: Preliminary Annual O&M Cost, Supply Option GW-3 ................................................................................... 26 Table 3-8: Preliminary AWPF Flow Summaries ...................................................................................................................... 33 Table 3-9: Preliminary Capital Cost, Supply Option PR-1 .................................................................................................. 35 Table 3-10: Preliminary Annual O&M Cost, Supply Option PR-1 .................................................................................. 36 Table 3-11: Preliminary Capital Cost, Supply Option PR-2 ............................................................................................... 38 Table 3-12: Preliminary Annual O&M Cost, Supply Option PR-2 .................................................................................. 39 Table 3-13: Preliminary Capital Cost, Supply Option PR-3a ............................................................................................. 41 Table 3-14: Preliminary Annual O&M Cost, Supply Option PR-3a ................................................................................ 42 Table 3-15: Preliminary Capital Cost, Supply Option PR-3c ............................................................................................. 45 Table 3-16: Preliminary Annual O&M Cost, Supply Option PR-3c ................................................................................ 46 Table 3-17: Preliminary Capital Cost, Supply Option PR-4 ............................................................................................... 48 Table 3-18: Preliminary Annual O&M Cost, Supply Option PR-4 .................................................................................. 49 Table 3-19: Preliminary Capital Cost, Supply Option DE-1 ............................................................................................... 51 Table 3-20: Preliminary Annual O&M Cost, Supply Option DE-1 .................................................................................. 52 Table 3-21: Preliminary Capital Cost, Supply Option DE-2 ............................................................................................... 56 Table 3-22: Preliminary Annual O&M Cost, Supply Option DE-2 .................................................................................. 57 Table 3-23: Preliminary Capital Cost, Supply Option SW-1 .............................................................................................. 59 Table 3-24: Preliminary Annual O&M Cost, Supply Option SW-1 ................................................................................. 60 Table 3-25: Screening Analysis Results Summary ................................................................................................................ 64 Table 3-26: Summary of Supply Option Scores .................................................................................................................... 67 Table 3-27: Detailed Scoring for Option GW-1 ..................................................................................................................... 69 Table 3-28: Detailed Scoring for Option GW-2 ..................................................................................................................... 70 Table 3-29: Detailed Scoring for Option GW-3 ..................................................................................................................... 71 Table 3-30: Detailed Scoring for Option PR-2 ....................................................................................................................... 72 Table 3-31: Detailed Scoring for Option PR-4 ....................................................................................................................... 73 Table 3-32: Detailed Scoring for Option SW-1 ...................................................................................................................... 74 Table 3-33: Detailed Scoring for Option E-1 .......................................................................................................................... 75 Table 3-34: Distribution of Water Year Types in Hydrologic Scenarios ....................................................................... 76

City of Santa Rosa (project #0012267.00) iv Woodard & Curran, Inc.

Feasibility Analysis August 2023

ACRONYMS AND ABBREVIATIONS
AACEI Association for the Advancement of Cost Engineering International AF acre-foot
AFY acre-feet per year
AOP advanced oxidation process
ASR Aquifer Storage and Recovery
AWPF Advanced Water Purification Facility
BAF biological activated filtration
BPU Board of Public Utilities
City City of Santa Rosa
CII Commercial, industrial, institutional
DPR direct potable reuse
FAT full advanced treatment
gpf gallons per flush
gpm gallons per minute
GSP Groundwater Sustainability Plan
GWR groundwater recharge
IPR Indirect Potable Reuse
LTP Laguna Treatment Plant
MF microfiltration
MGD million gallons per day
O&M Operations and Maintenance
Regional System Santa Rosa Regional Water Reuse System
RO reverse osmosis
RWA raw water augmentation
SFR Single family residential
SWA surface water augmentation
TM Technical Memorandum
TWA treated water augmentation
UF Ultra filtration
UWMP Urban Water Management Plan
WSAP Water Supply Alternatives Plan

APPENDICES
Appendix A: Cost Details
Appendix B: Screening Tool Detail (Baseline Scenario)
Appendix C: Memorandum on Desalination Supply Options in the Water Supply Feasibility Analysis

City of Santa Rosa (project #0012267.00) ES-1 Woodard & Curran, Inc.

Feasibility Analysis August 2023

EXECUTIVE SUMMARY
Purpose and Background
The City of Santa Rosa (City) is in the process of preparing a Water Supply Alternatives Plan (WSAP).

Ultimately, the WSAP will provide a menu of water supply options and portfolios for the City to consider when planning future strategic investments and projects. The planning process for the WSAP includes engaging a broad base of stakeholders in establishing water supply goals, identifying potential conceptual-level water supply options, establishing evaluation criteria for these options, and conducting a feasibility analysis of the supply options. Participants include the Water Team (Deputy Directors and k ey staff), an external Stakeholder Group (leaders from a range of community organizations, resource agencies, environmental groups, and social service providers), the community at large through webinars and public meetings, and the Board of Public Utilities (BPU). This Technical Memorandum (TM) summarizes the results of the feasibility analysis.

Study Methods
The WSAP effort began by establishing water supply goals, supply options, and evaluation criteria, collectively referred to as the “study parameters.” City staff and other stakeholders participated directly in this process during late 2022 based on their input, and the study parameters were finalized in early 2023.

In brief, the study parameters include:
• Water Supply Goal: Diversify and increase city potable water supplies to reduce dependence on Sonoma Water, particularly during Russian River supply shortages during droughts or due to emergency disruption in delivery. Targets established in conjunction with the stakeholders were:
o Minimize impact of shortages due to droughts – be able to provide 30 percent of annual water demand with City supplies to mitigate droughts (about 7,500 acre-feet per year (AFY) capacity in 2045)
o Minimize impacts of disruption in Sonoma Water service – be able to provide 50 percent of normal indoor demand with City supplies for catastrophic events (about 9 million gallons per day (MGD) in 2045)
o Minimize impacts of peak demand – be able to provide 30 percent of peak month , average day demand from City supplies from late spring through early fall (about 9 MGD in 2045)
• Water Supply Options: Table ES-1, below, summarizes the 18 water supply options that were considered.
• The following evaluation criteria were selected and assigned relative weights:
o Cost-effectiveness and scalability (high weight). These two criteria were also used as screening criteria to determine which water supply options merited full feasibility analysis. This screening step was implemented as part of the study parameters in order to focus the feasibility analysis on the most promising water supply options. o Resiliency, equity, and environmental performance (high weight). o Legal, permitting, and regulatory; City control and interagency coordination; and multi- benefit (medium weight).

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Feasibility Analysis August 2023
Table ES-1: Water Supply Options
Supply Type Supply Option Name
Groundwater
GW-1: Construct Additional Groundwater Extraction Wells GW-2: Convert Emergency Wells to Production Wells
GW-3: Construct Aquifer Storage and Recovery (ASR) Wells GW-4: Construct Regional Groundwater Extraction Wells
GW-5: Construct Regional ASR Wells
Purified Recycled
Water
PR-1: Direct Potable Reuse (DPR) with Advanced Water Purification Facility (AWPF) at Laguna Treatment Plant (LTP)
PR-2: Satellite DPR with AWPF
PR-3a: Indirect Potable Reuse (IPR) with AWPF LTP into Groundwater Basin PR-3b: IPR with AWPF LTP into Lake Ralphine
PR-3c: IPR with AWPF at LTP into Lake Sonoma
PR-4: Regional DPR with AWPF at LTP
Recycled Water RW-1: Expand City’s Non-Potable Recycled Water System Desalination DE-1: Regional Brackish Desalination
DE-2: Ocean Desalination
Stormwater
SW-1: Stormwater Treatment and Storage in Aquifer
SW-2: Stormwater Storage in Lake Ralphine with Treatment SW-3: Regional Stormwater
Efficiency Programs E-1: Efficiency Programs
Acronyms:

AWPF – Advanced Water Purification Facility
ASR – Aquifer Storage and Recovery
DPR – Direct Potable Reuse
IPR – Indirect Potable Reuse
LTP – Laguna Treatment Plant
Screening Analysis
Following identification of the study parameters, a pre-screening analysis was conducted to narrow the list of 18 water supply options for screening. Five options were set aside, and 13 options were advanced to the screening step. Each of the water supply options was developed at a conceptual level to estimate potential water supply yield and costs. Cost estimates in this document are considered Class 5 per Association for the Advancement of Cost Engineering International (AACEI) guidelines, i.e., conceptual.

Actual project costs would be expected to fall within +50 percent to -15 percent of the cost estimate.

Based on the yield and costs, cost-effectiveness of each water supply option was evaluated under two general scenarios:
• Maximum production: This scenario assumed that each water supply option would be operated to maximize water supply and meet as much of the water supply goal as possible, regardless of whether shortages would be present requiring additional supply. • “Baseline” scenario: This scenario assumed that each water supply option would be operated in a way that minimized operational costs. This is a more realistic scenario than the “maximum production” scenario.

The results of the screening analysis are summarized in Table ES-2 below.

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Table ES-2: Screening Analysis Results Summary
Option
Maximum Yield Baseline Usage Carried forward
for full Feasibility
Analysis?
Acre-
Feet/Year
$/Acre-
Foot
Avg Acre-
Feet/Year
$/Acre-
Foot*
GW-1: Construct Additional Groundwater Extraction Wells 10,080 $700 6,734 $840 Yes GW-2: Convert Emergency Wells to Production Wells 2,462 $500 1,744 $540 Yes GW-3: Construct Aquifer Storage and Recovery (ASR) Wells 5,130 $900 3,634 $1,100 Yes PR-1: Direct Potable Reuse (DPR) with Advanced Water Purification Facility (AWPF) at Laguna Treatment Plant (LTP) 10,065 $2,000 4,131 $3,600 No PR-2: Satellite DPR with AWPF 10,065 $2,100 4,131 $3,900 Yes PR-3a: IPR with AWPF at LTP into Groundwater Basin 10,065 $2,500 4,131 $4,800 No PR-3c: IPR with AWPF at LTP into Lake Sonoma 10,065 $3,700 4,131 $6,400 No PR-4: Regional DPR with AWPF at LTP 10,065 $1,800 4,131 $3,200 Yes RW-1: Expand City’s Non-Potable Recycled Water System 3,000 $2,900 900 $9,800 No DE-1: Regional Brackish Desalination 10,080 $1,100 4,441 $2,000 No DE-2: Ocean Desalination 10,080 $2,600 4,441 $4,500 No
SW-1: Stormwater Storage in Aquifer 10,080 $1,400 2,618 $3,500 Yes E-1: Efficiency Programs 2,145 $2,800 2,145 $2,800 Yes
Notes:

The following options are not shown in the table as they were eliminated from further consideration prior to completing the detailed cost/yield analysis:

GW-4, GW-5, PR-3b, SW-2 and SW-3. All of the water supply options considered in this study are described in more detail in Section 3.1.

* Costs include capital and operating costs consistent with a realistic baseline usage scenario.

Acronyms:

AWPF - Advanced Water Purification Facility
ASR – Aquifer Storage and Recovery
DPR – Direct Potable Reuse
IPR – Indirect Potable Reuse
LTP – Laguna Treatment Plant

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Feasibility Analysis August 2023
Feasibility Analysis
The water supply options that passed the screening analysis were then scored based on the evaluation criteria established with input from stakeholders, the BPU, the community, and City staff. A numeric score was assigned for each criterion using a 3-point scale from 0 to 2, with 2 being the most favorable. A score of zero implies that an option is not responsive to a criterion or performs relatively poorly compared to the other options, while a score of 2 implies that the option performs very well.

The raw scores were then weighted consistent with the relative importance of each criterion described earlier, e.g., cost and scalability were assigned very high weight, permitting ease medium weight, etc. The specific weights are as follows:
• Cost-effectiveness and scalability: 5x multiplier
• Resiliency, equity, and environmental performance: 3x multiplier • Legal, permitting, and regulatory; City control and interagency coordination; and multi -benefit: 1x multiplier
Table ES-3, below, table summarizes the results of the feasibility scoring:

City of Santa Rosa (project #0012267.00) ES-5 Woodard & Curran, Inc.

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Table ES-3: Summary of Supply Option Scores
Criterion
Groundwater Purified Recycled Water 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
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]
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 [1,008 - 10,080
AFY]
1 [2,145 AFY]
Resiliency 1 1 2 2 2 1 1
Equity 1 1 1 1 1 1 2
Environmental
performance 1 2 1 0 1 1 2
Legal, permitting,
and regulatory 1 2 0 0 0 1 2
City control and
interagency
coordination
2 2 1 2 0 2 2
Multi-benefit 0 0 1 0 0 2 1
Total Unweighted 10 10 9 7 6 9 12
Total Weighted 32 26 29 21 22 19 30
* Costs include capital and operating costs consistent with a realistic baseline usage scenario.

City of Santa Rosa (project #0012267.00) ES-6 Woodard & Curran, Inc.

Feasibility Analysis August 2023
As shown in Figure ES-1-1, most supply options did not score substantially differently from one another.

Figure ES-1-1: Cost-Effectiveness vs Max Yield (with Weighted Score)

Notes: Water Supply options:
• E-1: Efficiency Programs
• GW-1: Construct Additional Groundwater Extraction Wells • GW-2: Convert Emergency Wells to Production Wells
• GW-3: Construct Aquifer Storage and Recovery (ASR) Wells • PR-2: Satellite Direct Potable Reuse (DPR) with Advanced Water Purification Facility (AWPF) • PR-4: Regional DPR with AWPF at Laguna Treatment Plant • SW-1: Stormwater Storage in Aquifer
The feasibility analysis also assessed supply option performance under a range of future conditions beyond the baseline scenario. Performance of the options was examined under varying future hydrologic conditions, and varying Sonoma Water dry-year allocations were evaluated. In general, as future conditions become less favorable, a supplemental water supply is used more and becomes more cost - effective.

Conclusions
This Feasibility Analysis reveals several key considerations for the City as it conducts future water supply planning:

City of Santa Rosa (project #0012267.00) ES-7 Woodard & Curran, Inc.

Feasibility Analysis August 2023
• Future conditions: Depending on the City’s assumptions about future hydrology, Sonoma Water cutbacks, cost of Sonoma Water supplies, and customer demand/conservation, the City may reach different conclusions about the potential best fit water supplies. For example, if the City assumes a less conservative scenario (e.g., business as usual), the amount of new water needed may be relatively modest, in which case the City would be well served by bridging that gap with a small number of new wells, which could be added one by one as the need arises. On the other hand, if the City assumes a more conservative scenario in which existing water supplies decrease, a broader range of options could be considered, including options such as potable reuse that would be run continuously once implemented. Options that could be implemented in phases (e.g., rehabilitating one well at a time, rather than 3 at once) may help provide resiliency while minimizing capital outlay.
• Operational assumptions: Similar to future conditions, the City would need to consider its operational philosophy for a new supply source. If the City elects to operate a new supply on a 24/7 basis, this would reduce the cost per AF of water but could also increase total operational costs.
• Sensitivity: This analysis considered the impact of changing hydrology and reduced Sonoma Water dry-year allocations. The supply options generally become more cost-effective under more pessimistic scenarios (drier hydrology and higher Sonoma Water cutbacks) because more water is produced via the new options. However, the analysis indicates that the relative rankings of the supply options do not vary substantially with changes to the baseline condition.

The next step of the WSAP project will be to propose portfolio options (mixes of water supply options to achieve the goals) based on the findings in this TM. This will involve developing portfolio alternatives and analyzing them to further assess the water supply options that passed the screening analysis. The portfolio analysis may consider downscaled versions of some supply options and will consider potential groupings of supply options that would allow the City to optimize different areas such as resiliency, supply volume, cost, and consistency with the multiple goals.

City of Santa Rosa (project #0012267.00) 1 Woodard & Curran, Inc.

Feasibility Analysis August 2023

1. PURPOSE AND BACKGROUND
On August 10, 2022, the City of Santa Rosa (City) contracted with Woodard & Curran to prepare the City’s Water Supply Alternatives Plan (WSAP). Ultimately, the WSAP will provide a menu of water supply options and portfolios for the City to consider when planning future strategic investments and projects for increasing water supply resiliency and reliability.

The planning process for the WSAP includes establishing water supply goals, identifying potential conceptual-level water supply options, establishing evaluation criteria for these options, and conducting a feasibility analysis of the supply options. This Technical Memorandum (TM) summarizes the results of the feasibility analysis and supporting work.

To increase the City’s water supply resiliency and reliability during a drought year or interruption of the Russian River supply, supplemental water is needed. Water conservation and recycled water alone or combined would not generate sufﬁcient water to meet normal water needs through 2045 during a reasonable, worst-case drought event. This TM explores a number of supply options including expansion of existing groundwater supplies, groundwater banking/exchange projects, construction of new purified recycled water projects, construction of a new ocean desalination plant, participation in the development of a regional desalination plant, and stormwater capture along with additional efficiency programs. These options include both local and collaborative regional efforts that would require the City to partner with one or more local water agencies. Each supplemental supply component would provide different amounts of water. When combined with one another in various portfolios (mixes of water supplies) and various levels of water conservation and existing water supplies, new water supplies would help to meet projected normal water needs throughout the planning period.

2. STUDY PARAMETERS AND METHODS
The WSAP effort began by establishing water supply goals, supply options, and evaluation criteria, collectively referred to as the “study parameters.” The following subsections describe the development of the study parameters and list the final parameters which acted as the foundation for the feasibility study.

2.1 Collaborative Development of Study Parameters
The study parameters were established through a collaborative process with four groups of participants:
the City, stakeholders, the community, and BPU.

Table 2-1 summarizes the series of meetings held with four distinct groups to gather input on the study parameters. The first group, referred to as the Water Team, was composed of City staff from multiple divisions (e.g., water resources planning, wastewater treatment and water recycling, stormwater and environmental compliance, water efficiency, and water and sewer operations). The second group, referred to as the Stakeholder Group, included leaders of local interest organizations (e.g., environmental groups, community associations, social justice organizations, local business groups, agricultural interests , and resource agencies). The third group is referred to as “the community”. Community meetings were open to all and held virtually. Community meetings were advertised via social media, email, bill inserts, and postings on the City website. Lastly, the study parameters were reviewed by the City’s BPU, which provides oversight of and direction for the management and operation of the City’s water and wastewater facilities.

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The project team incorporated feedback from the Water Team, Stakeholder Group, the community, and the BPU into the study parameters, resulting in the final water supply goal, water supply options, and evaluation criteria and methodology. These study parameters guided the feasibility analysis.

Table 2-1: Stakeholder and Community Outreach Meeting Summary Meeting Date Topics
Water Team
Meeting #1
October
17, 2022
Project overview; introduction of study parameters (water supply goals, water supply options, evaluation criteria, and methodology); input on study parameters.

Community
Meeting #1
October
26, 2022
Overview of Santa Rosa water supplies; project background and overview; introduction of water supply goals, supply options, and evaluation criteria; polling questions, input on study parameters, and question and answer time.

Stakeholder Group
Meeting #1
November
16, 2022
Overview of Santa Rosa water supplies; project background and overview; high-level group discussion of study parameters, and input on study parameters.

Stakeholder Group
Meeting #2
December
14, 2022
Project update; group discussion of proposed study parameters, and input on the refined study parameters.

Water Team
Meeting #2
December
15, 2022
Proposed study parameters; input on final refinements of study parameters, and input on the refined study parameters.

Board of Public
Utilities study
session
January
19, 2023
BPU direction on proposed study parameters.

Community
Meeting #2
January
25, 2023
Project update; review of proposed study parameters; question and answer time.

Water Team
Meeting #3
May 17,
2023
Project update on options development and refinement, screening analysis; input on draft study results and portfolio approach.

Stakeholder Group
Meeting #3
May 24,
2023
Project update on options development and screening analysis; input on draft study results and portfolio approach.

Water Team
Meeting #4
July 6,
2023
Project update and input on feasibility analysis and draft portfolios.

Stakeholder Group
Meeting #4
July 18,
2023
Project update and input on feasibility analysis and draft portfolios.

Water Team
Meeting #5
August
14, 2023
Project update and input on early draft of plan.

Board of Public
Utilities study
session
August
17, 2023
BPU direction on feasibility analysis and draft portfolios.

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2.2 Water Supply Goal
The City’s water supply goal for the WSAP effort is as follows:

Diversify and increase city potable water supplies to reduce dependence on Sonoma Water, particularly during Sonoma Water supply shortages or disruption in delivery:
• Mitigating Droughts: Meet 30 percent of city’s water demand with city supplies to mitigate impacts of Russian River supply shortages (e.g., due to prolonged and/or severe drought).

This goal assumes strict limits on, or banning of, landscape irrigation in severe droughts. • Mitigating Natural Disasters and Catastrophic Events: Provide half of normal domestic/indoor demand for potable water with city supplies during Russian River supply disruption. Critical facilities would be prioritized for health and safety. Landscape irrigation would be prohibited.
• Mitigating Peak Day Demand: Meet 30 percent of peak month average day demand for potable water with city supplies.

Based on current City demand projections, the volume of water required to meet these goals in 2045 would be:
• 7,500 acre-feet per year (AFY) (30 percent of the City’s annual water demand) • 9 million gallons per day (MGD) (which equates to half of normal indoor demand, or 30 percent of peak month average day demand)
This TM assumes that potential water supply options would need to provide 7,500 AFY and 9 MGD of supply for the City, either individually or collectively. The water supply(ies) would generally be used in response to droughts or disruptive events, since in normal years the City’s supplies are adequate.

During the goal development process, the following rationale was cited for selecting the goal:
• Provides guidance to support decision making regarding magnitude of resiliency portfolio. • Increases city potable water supply resiliency and reduces demand on Sonoma Water supplies. • Mitigates shortages in Sonoma Water supply and interruptions in service. • Increases ability to meet a portion of peak day demand using local supply. • Could be achieved over time with a mix of supplies.
• Allows for adjustments to volume target if demands are lower/higher than anticipated (percentage-based goals).
• Integrates input from the Water Team, Stakeholder Group, and the community.

2.3 Water Supply Options
Based on review of existing information and discussions with the City’s Water Team, Stakeholder Group, community, and BPU, a list of water supply options was established, as summarized in Table 2-2.

Potential water supply options and facilities were identiﬁed based on the City’s exist ing facilities and planning efforts already underway. Sources of information included, but were not limited to, the following:
• City of Santa Rosa 2020 Urban Water Management Plan (UWMP) • City of Santa Rosa 2020 Water Master Plan Update
• City of Santa Rosa 2018 Regional Water Reuse System Master Plan

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• City of Santa Rosa Subregional Water Resources Recovery Facilities Master Plan • Groundwater Sustainability Plan (GSP) Santa Rosa Plain Groundwater Subbasin • City of Santa Rosa Groundwater Master Plan
• Recycled water agreements
• Desalination white papers
• Peer agency work from Sonoma Water, North Marin, and Marin Municipal on water supplies, as well as UWMPs
• Well test boring results
• City of Santa Rosa Water Use Efficiency water savings workbook • Recycled water pond storage capacities
• GIS Info: City parcels; stormwater, recycled water, wastewater, and water distribution facilities; well locations
The City’s rationale for the selected suite of water supply options is listed below. The list of options achieves the following:
• Retains a broad diversity of options.
• Includes City and Regional projects.
• Includes aggressive efficiency incentives to reduce demand over time. • Integrates input from Water Team, Stakeholder Group, and the Community.

Table 2-2: Water Supply Options
Supply Type Supply Option Name
Groundwater
GW-1: Construct Additional Groundwater Extraction Wells GW-2: Convert Emergency Wells to Production Wells
GW-3: Construct Aquifer Storage and Recovery (ASR) Wells GW-4: Construct Regional ASR Wells
GW-5: Construct Regional Groundwater Extraction Wells
Purified Recycled
Water
PR-1: Direct Potable Reuse (DPR) with Advanced Water Purification Facility (AWPF) at Laguna Treatment Plant (LTP)
PR-2: Satellite DPR with AWPF
PR-3a: Indirect Potable Reuse (IPR) with AWPF LTP into Groundwater Basin PR-3b: IPR with AWPF LTP into Lake Ralphine
PR-3c: IPR with AWPF at LTP into Lake Sonoma
PR-4: Regional DPR with AWPF at LTP
Recycled Water RW-1: Expand City’s Non-Potable Recycled Water System Desalination DE-1: Regional Brackish Desalination
DE-2: Ocean Desalination
Stormwater
SW-1: Stormwater Treatment and Storage in Aquifer
SW-2: Stormwater Storage in Lake Ralphine with Treatment SW-3: Regional Stormwater
Efficiency Programs E-1: Efficiency Programs
The water supply options then went through a screening analysis to focus the list of options to undergo detailed feasibility analysis. This process is described in Section 2.5. All of the supply options are described in further detail in Section 3.1.

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2.4 Evaluation Criteria and Metrics
To assess the feasibility of each water supply option, a list of evaluation criteria and associated metrics and weights were established. After beginning the WSAP process with a list of approximately 16 individual criteria, the list was consolidated and refined with stakeholder input to a focused list of evaluation criteria to be used in the feasibility analysis. The criteria and their descriptions are provided in Table 2-3.

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Table 2-3: Evaluation Criteria, Metrics, and Weights
Criterion Description Proposed Metric Weight
Cost
effectiveness
Quantitative calculation of life-cycle costs,
based on future scenarios per the project
goals (e.g., five-year drought occurring on
average every 10 years).

Life cycle cost effectiveness
for key scenarios ($/acre-foot)
(quantitative)
High
Scalability
Qualitative assessment of ability to
provide sufficient supply to satisfy goals,
i.e., achieve desired level of service for
each scenario; secondarily, ability to scale
further to address future uncertainty.

Volume of water provided
(AFY/MGD) (quantitative)
Ability to meet goals, and
secondarily to increase
production later, without
undue effort/cost increase
(qualitative)
High
Resiliency
Qualitative assessment of performance in
the face of future uncertainty; for
example, future regulations, energy costs,
hydrology. The best options will suffer
only modest degradation of performance
if future conditions are worse than
anticipated while inferior options will
show marked degradation if planning
assumptions aren’t met.

Performance in the face of
uncertainty (qualitative) High
Equity
Qualitative assessment of any
disproportionate impacts on vulnerable
communities.

Level of disproportionate
impact on vulnerable
communities (qualitative)
High
Environmental
performance
Qualitative assessment of potential
environmental impacts not already
included in permitting/regulatory
compliance (e.g., level of GHG emissions).

Magnitude of potential impact
(qualitative) High
Legal,
permitting,
and regulatory
Qualitative assessment of
complexity/effort to address legal issues
(e.g., water rights), obtain necessary
permits, and comply with regulations
Level of complexity and effort
to address (qualitative) Medium
City control
and
interagency
coordination
Qualitative assessment of level of City
control and coordination with potential
partner agencies, if any (e.g., agreements
needed for regional projects).

Level of City control and
coordination with potential
partner agencies, if any
(qualitative)
Medium
Multi-benefit Qualitative assessment of benefits
provided in addition to water supply.

Benefits provided in addition
to water supply (qualitative) Medium

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The selected criteria achieve the following:
• Captures key considerations that differentiate projects. • Consolidates criteria where appropriate. (For example, individual criteria for construction and operations costs were consolidated into the overall cost-effectiveness metric.) • Removes criteria that would pose a fatal flaw if not met. (For example, water quality was removed from the list of criteria because a supply option that would not provide adequate water quality would not merit further analysis.)
• Removes criteria that did not need to stand alone. (For example, a criterion for “ability to integrate with existing distribution systems” was removed since facilities required to integrate into the existing system would be captured as part of a supply option and its costs.) • Integrates input from Water Team, Stakeholder Group, the community, and BPU.

Additionally, each criterion was assigned a metric and weight so the feasibility analysis could reflect City priorities about the relative importance of each criterion. Weights and metrics are summarized in Table 2-3. The evaluation metrics and weights achieve the following:
• Emphasizes key considerations such as cost, resiliency, and equity via weighting. • Enables comparisons based on qualitative factors such as permitting/regulatory considerations. • Provides enough detail for meaningful comparison, given level of available information. • Integrates input from Water Team, Stakeholder Group, BPU, and the community.

Based on Water Team, BPU, and Stakeholders Group input, all criteria included on the final list were weighted as “high” or “medium” because criteria of lower importance had been removed from the criteria list. The final list of evaluation criteria represents a focused list of key considerations.

As part of the detailed feasibility analysis, a detailed rubric was developed to allow water supply options to be scored against the qualitative criteria (described further in Section 2.5.3).

2.5 Screening Analysis
Prior to detailed analysis, all supply options were subjected to a high-level pre-screening to identify and remove options deemed infeasible or substantially similar to existing and anticipated reginal efforts or other supply options considered in the analysis to remove options deemed infeasible or substantially similar to existing or anticipated regional efforts. After pre-screening, a screening step was implemented to yield a focused and manageable “short list” of water supply options to undergo detailed analysis. Some options were removed from consideration prior to screening based on obvious flaws. The workflow is shown in Figure 2-1. Each water supply option listed in Table 2-2 was evaluated against two key criteria:
cost-effectiveness and scalability (yield). The screening analysis involved a high-level assessment of these two criteria in order to determine which supply options are most promising for the City and document the reasoning by which certain supply options should advance for further detailed analysis, or not. The screening process allowed the City to identify any non-starter options early on and focus the remaining analysis. The results of the screening analysis are described further in Section 3.2.

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Figure 2-1: Screening and Feasibility Analysis Process

2.5.1 Screening Tool
The screening analysis was accomplished with the aid of a spreadsheet model. The model was used to determine the conceptual performance of each supply option. Specifically, the model evaluated the volume of water that would be supplied under various hydrologic, regulatory, and operational scenarios, and determined the associated unit cost for each supply option based on its projected usage. The screening tool included a number of default assumptions and options, referred to as the baseline scenario, as summarized in Table 2-4. Each of these variables can be manipulated in the model to evaluate changing conditions (e.g., higher energy prices).

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Table 2-4: Baseline Screening Analysis Parameters and Assumptions Parameter Default Value Source Notes
2045 demand 25,000 AFY Provided by City
Sonoma Water
nominal allotment 29,100 AFY
Provided by City. In dry years, allotment is subject to reduction based on a percent of baseline demand,
which is significantly lower than nominal allotment.

Current groundwater
firm capacity 1,300 AFY Provided by City
Discount rate 2.5%
Federal water resources planning discount rate for FY
2023. This rate is used to compute the present-day
equivalent cost of future cash flows.

Price of energy $200/megawatt
hour
Prevailing price in California (note that time of use
surcharges were not considered in this high-level
analysis)
First year of simulation 2045
Water supply goal. Assumes water supply is available
in 2045, at which point the model begins its 50-year
simulation.

Planning horizon 50 years Typical water infrastructure planning horizon Sonoma Water
reduction in dry years 30%
Provided by City. The dry-year Sonoma Water supply is
assumed to be 70% of baseline purchases, which in
turn are baseline demands less non-Sonoma supplies
including existing groundwater plus the water supply
option being modeled.

Demand reduction in
dry years 10% Provided by City
Hydrology Historical replay
(beginning in 1920)
United States Geological Survey Russian River
Historical Data
A final key model parameter was the assumed hydrologic scenario. The model uses hydrologic scenarios to determine the distribution of normal, dry, and wet years modeled, which in turn determine the volume of supplemental supply required over the planning horizon. The model included the following hydrological scenarios: historical hydrology with selectable starting year (total range from 1911 to 2013); a synthetic hydrology which assumes a greater proportion of dry years; and a synthetic hydrology which assumes a greater proportion of wet years. The synthetic hydrologies employ a blend of inter-year randomness and first-order autoregression to capture the tendency of dry years to appear in runs, and thus cause droughts. The goal of using synthetic hydrologies is not to predict future climate, but rather to evaluate the performance of various water supply options under a variety of potential futures.

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Model inputs included the following for each water supply option (except for options that were screened out at the conceptual stage):
• Maximum and minimum supply option yields in normal, wet, and dry years in acre-feet per year (AFY).
• Marginal operation and maintenance cost in normal, wet, and dry years as dollars per acre-foot $/AF). These costs include energy costs as appropriate, and purchase cost of water for the ASR option (GW-3).
• Fixed operations and maintenance costs ($/year).
• Capital costs ($).
• Storage capacity included in the supply option as acre-feet (AF) • Leave-behind percentage (if applicable) (%).

The key model output is cost-effectiveness ($/AF) for a supply option under the chosen scenario. Cost- effectiveness is determined within a given model scenario and is based on actual volume used from the supply source. The cost-effectiveness accounts for the water year type, potential required water allocations (reductions from normal use during water shortages) from Sonoma Water, and demand reduction during dry years (whether imposed by the state, imposed by the City, or done voluntarily) , assumed demand, supply from existing wells, and any storage associated with the water supply option.

The cost tables in Section 3.1 include the cost-effectiveness of each water supply option under the baseline scenario.

In addition, by varying the model parameters such as hydrology and demand reduction percent, the cost- sensitivity of each supply option could be evaluated under a range of conditions.

2.5.2 Capital Cost Estimate Methodology
A key component of the screening analysis included compiling cost estimates for each supply option on the initial list. The high-level cost estimates presented in this TM were developed from bid tabulations, information obtained from previous studies, and experience on other projects. Life cycle costs presented in this TM include planning level construction costs and operations and maintenance (O&M) costs. The Association for the Advancement of Cost Engineering International (AACEI) developed metrics to classify estimating accuracy through project development. The cost estimates presented in this document are considered Class 5 for a planning-level feasibility study estimate. Based on AACEI guidelines, actual project costs are typically within +50 percent to -15 percent of the planning-level cost estimate. However, there could be additional uncertainty not modeled in the initial estimates. Project feasibility and funding should consider the inherent level of uncertainty associated with planning level cost estimates.

Each planning level cost estimate includes an estimating contingency of 50 percent. Implementation costs were estimated at 40 percent for legal and administration, engineering design, engineering services during construction and construction management. The annual O&M cost estimate includes electricity, labor and maintenance costs.

Project costs were calculated in 2023 dollars using the January 2023 Construction Cost Index for San Francisco, 15498.78. Annual Project costs are amortized using a 2.5 percent interest rate over a 50-year period.

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2.5.3 Feasibility Scoring Methodology
Upon completion of the screening analysis, Woodard & Curran completed the feasibility analysis by evaluating and scoring the short-listed water supply options. This step of the analysis built upon the evaluation criteria established during development of the study parameters (Table 2-3). The evaluation process included developing criteria for the projects, adding numerical weights to each criterion, and scoring the projects against each criterion. The numerical system provides a score of zero through 2, with 2 being most favorable. A score of zero implies that an option is not responsive to a criterion or performs relatively poorly compared to the other options, while a score of 2 implies that the option performs very well. Applying a weight allows the ranking to better reflect the priorities of the City and its stakeholders, showing the relative importance of each criterion. The evaluation criteria scoring rubric used for the evaluation of the short-listed supplemental supply options is summarized in Table 2-5.

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Table 2-5: Evaluation Criteria Scoring Rubric
Criterion Proposed Evaluation Metric Quantitative Score Qualitative Score: 0 Qualitative Score: 1 Qualitative Score: 2 Weight Score Multiplier Cost
effectiveness
Quantitative calculation of life-cycle costs,
based on the baseline scenario per the
project goals (e.g., five-year drought
occurring on average every 10 years).
$/AF >$3,000/AF under baseline scenario
Between $2,000/AF and $3,000/AF
under baseline scenario < $2,000/AF under baseline scenario High + Screening Criterion 5 Scalability
Qualitative assessment of ability to provide
sufficient supply to satisfy goals, i.e., achieve
desired level of service for each scenario;
secondarily, ability to scale further to address
future uncertainty.

Yield (AFY)
Low flexibility: No ability, or
minimal ability, to scale down
production when supply is not
needed.

Moderate flexibility: Some ability to
scale production up or down
depending on need for supply but
would require significant effort or
construction of new facility phases.

High flexibility: Production can be
easily scaled up or down depending
on need without significant
investment.

High + Screening Criterion 5
Resiliency
Qualitative assessment of performance in the
face of future uncertainty; for example, future
regulations, energy costs, hydrology. The best
options will suffer only modest degradation
of performance if future conditions are worse
than anticipated while inferior options will
show marked degradation if planning
assumptions aren’t met.

Change in costs due
to energy prices and
hydrology scenarios
can be accounted for
quantitatively. These
would feed into the
qualitative scores.

Substantial change in cost-
effectiveness under changing
energy and hydrology conditions.

Moderate change in cost-effectiveness
under changing energy and hydrology
conditions.

Little or no change in cost-
effectiveness under changing
energy and hydrology conditions.

High 3
Equity
Qualitative assessment of any
disproportionate impacts on vulnerable
communities.

N/A
Would have the potential for a
disproportionate impact (such as
providing different water supply
sources to certain parts of City).

Would have no impact on vulnerable
communities.

Would have a benefit to vulnerable
communities. High 3
Environmental
performance
Qualitative assessment of potential
environmental impacts not already included
in permitting/regulatory compliance (e.g.,
level of GHG emissions).

N/A
Unknown or high potential for
environmental impacts (e.g., large
project footprint, high energy use,
or location in undeveloped area).

Moderate potential for environmental
impacts (e.g., medium or unknown
project footprint, moderate energy use,
unknown project location).

Limited potential for environmental
impacts (e.g., small project footprint,
low energy use, location in existing
developed area).

High 3
Legal,
permitting, and
regulatory
Qualitative assessment of complexity/effort
to address legal issues (e.g., water rights),
obtain necessary permits, and comply with
regulations
N/A
High complexity/effort: Requires
major permitting/ regulatory effort,
with little or no established
precedent to follow.

Moderate complexity/effort: May have
major permitting/ regulatory effort
permits, etc., but there is an
established process to follow.

Low complexity/effort: Permitting/
regulatory steps are known, and
projects of this type are routinely
implemented.

Med 1
City control and
interagency
coordination
Qualitative assessment of level of City control
and coordination with potential partner
agencies, if any (e.g., agreements needed for
regional projects).

N/A
Coordination required with partner
agencies that City does not already
work with.

Coordination required with partner
agencies that City already works with.

No need for coordination with other
parties. Med 1
Multi-benefit Qualitative assessment of benefits provided in addition to water supply. N/A No other benefits provided. One additional benefit would be provided by the project.

Two or more additional benefits
would be provided by the project. Med 1

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3. FINDINGS

3.1 Water Supply Option Descriptions
This section describes each of the evaluated supplemental supply options, listed in Table 3-1. The options remained substantially the same as those listed in Table 2-2, with a numbering system applied and some revisions to the option titles. The preliminary level concepts were developed closely with the Water Team, as well as with input from the Stakeholder Group, BPU, and the community. Preliminary-level cost estimates are also summarized in the following subsections, where applicable. Additionally, the results of the screening tool’s baseline scenario average cost of water are presented in the following subsections. A summary of the results is provided in Section 3-2 Screening Analysis Results (see Table 3-35).

Table 3-1: Summary of Water Supply Options
Supply Type Supply Option Name
Groundwater
GW-1: Construct Additional Groundwater Extraction Wells GW-2: Convert Emergency Wells to Production Wells
GW-3: Construct ASR Wells
GW-4: Construct Regional Groundwater Extraction Wells
GW-5: Construct Regional ASR Wells
Purified Recycled Water
PR-1: DPR Advanced Water Purification Facility (AWPF) at LTP PR-2: Satellite DPR AWPF
PR-3a: IPR AWPF at LTP into Groundwater Basin
PR-3b: IPR AWPF at LTP into Lake Ralphine
PR-3c: IPR AWPF at LTP into Lake Sonoma
PR-4: Regional DPR AWPF at LTP
Recycled Water RW-1: Expand City’s Non-Potable Recycled Water System Desalination
DE-1: Regional Brackish Desalination
DE-2: Ocean Desalination
Stormwater
SW-1: Stormwater Storage in Aquifer
SW-2: Stormwater Storage in Lake Ralphine
SW-3: Regional Stormwater
Efficiency Programs E-1: Efficiency Programs
Baseline No Project Option, Continue to Import from Sonoma Water

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3.1.1 Groundwater Supply Options
The City has a total of six municipal groundwater wells, all within the Santa Rosa Plain Subbasin.1 These wells are shown in Figure 3-1.

Two of the City’s municipal wells (Carley and Peter Springs Wells) are currently operated primarily to serve an adjacent park and school for landscape irrigation but are also available and approved by the California Division of Drinking Water for emergency potable use on standby status. Two of the wells (Farmers Lane Wells No. W4-1 and W4-2) are on active status. One well is operated to provide landscape irrigation water supply only (Farmers Lane Well No. W4-3), and one well is used for emergency potable purposes only (Leete Well). In addition, a new emergency water supply well facility is currently being built at A Place to Play Park, with anticipated completion in calendar year 2023.

For all groundwater supply options developed, it is assumed that groundwater pumping would occur seasonally in the spring and summer months. In dry years, it is assumed that pumping would occur for a greater portion of the year.

1 Note that the City has two other municipal wells that are either out of service or inactive: Freeway Well (W3) is out of service due to groundwater contamination caused by others; Sharon Park Well (W6) is inactive due to severe sanding.

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Figure 3-1: Existing City Wells

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GW-1: Local Groundwater Extraction Wells
Supply option GW-1 proposes to construct additional production wells, wellhead disinfection, and iron and manganese treatment (if necessary) to connect to the City’s existing potable water distribution system. Based on existing well data for the City, an estimated 9 wells would be required to provide 7,500 AFY (i.e., to meet the City’s water supply goal 30 percent of the annual water demand), and 12 wells would be required to meet 30 percent of the peak month average day demand (9 MGD), based on a per- well capacity of ~500 gpm.1
For this conceptual-level analysis, the following potential limiting factors for the GW-1 supply option were identified:
• Identification of appropriate locations for new we lls. For this preliminary analysis, City -owned property was assumed as the location of the new groundwater extraction wells . For this preliminary analysis a 500-foot well depth was assumed. The City has both deep and medium deep wells in the vicinity.
• Well pumping capacity. For this preliminary analysis, well capacity was assumed to be 500 gpm. • Potential well interference . The proposed wells are assumed to be constructed with even spacing to avoid potential well interference.
• Sustainability. The City's wells generally have very stable non-pumping groundwater levels, with artesian conditions reported for Farmers 1, 2 , and Leete wells. However, additional studies would be needed to verify sustainable yields.

The 12 proposed extraction wells are assumed to be located within the City’s Greenway Area, north of Hoen Avenue. Figure 3-2 shows the proposed extraction well location zone and conveyance pipelines connecting to the Sonoma Water Aqueduct for distribution throughout the City’s R6R1 pressure zone. The 12 extraction wells would be constructed to be evenly spaced within the Greenway Area. Approximately 3,000 linear feet (LF) of 20-inch pipe and a 240 horsepower (hp) pump station would be required to convey the extracted groundwater to the Sonoma Water aqueduct for distribution. This conceptual option assumes the 12 wells to be connected to each other and one 20-inch water main connecting from the well zone to the City’s distribution system via Sonoma Water’s aqueduct as shown. Based on discussions with City staff, pumping into the aqueduct would not currently be an option; this configuration would require engaging in negotiations with Sonoma Water in the future.

The proposed infrastructure as part of GW-1 supply option may include:
• Well equipment including well head, pump, well house building for 12 wells • Conveyance pipelines
• Electrical service for each well
• Treatment systems for disinfection, manganese and iron onsite, if needed • Backup generator for power outage

1 For simplicity, this analysis assumes construction of 12 new wells. Other possible approaches could include converting emergency wells to production, in combination with new wells, to meet the 9 MGD goal, if GW-2 is not pursued. The City also has Freeway Well and Sharon Park Well, but they don’t appear feasible at this time due to site and water quality constraints.

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• Backwashing treatment system (assumes disposal to nearby sanitary sewer) The total preliminary capital cost for option GW-1, including all infrastructure listed, is approximately $96 million. A summary of the GW-1 capital cost is shown in Table 3-2. Additional cost detail can be found in Appendix A.

Table 3-2: Preliminary Capital Cost, Supply Option GW-1 Component Description Cost, in 2023
Dollars
New Well Construction
12 extraction wells, ~500 gpm capacity, 500 feet
deep, includes well head, casing, well pump and
equipment, electrical service, disinfection, backup
generator, well housing ($3.5 million per well)
$42,000,000
Groundwater Conveyance
Line 20-inch diameter; 3,000 linear feet linear feet $2,225,000 Groundwater Pump Station 240 horsepower $1,560,000
Potable System Connection $100,000
Estimating Contingency 50% of raw construction costs $22,950,000 Implementation 40% of total construction costs $27,540,000 Total Capital Cost $96,380,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $3,398,000 The O&M cost of the project was estimated on a per AF basis for scalability. The GW -1 option has a fixed annual O&M cost of $500,000 and an annual marginal O&M cost of approximately $264/ AF. Annual O&M costs will vary depending on the production of the extraction wells. The estimated annual O&M costs for the maximum potential yield of 10,080 AFY is approximately $3 million. Table 3-3 summarizes the annual O&M costs for option GW-1. Under the Baseline Scenario, as modeled by the screening tool, actual production would be less, resulting in a somewhat higher cost per AF. Constructing fewer wells would reduce the cost per AF under the Baseline Scenario but would not necessarily meet the 9 MGD goal.

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Table 3-3: Preliminary Annual O&M Cost, Supply Option GW-1 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, chemical addition, water/sewer fees $264/ AF
Fixed Cost
Fixed costs include routine maintenance practices, water quality testing, Santa Rosa Plain Groundwater
Sustainability Agency fees
$501,000
Average cost of water (Baseline Scenario)1 $843/ AF
Annual O&M (10,080 AFY)2 $3,165,000
Cost of water (10,080 AFY)2 $700/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, in which 6,734 AFY are used. That baseline is based on operating wells at least from April through October in all years, i.e., at a minimum of 7/12 of full capacity, and more as needed in dry years. The cited costs include capital and operating costs for the baseline usage scenario.

2. The maximum supply yield of 10,080 AFY assumes 24/7 operation of all supply option infrastructure. While this scenario does not reflect realistic operations because it would produce more water than the City would use, and because it does not reflect downtime for maintenance. The baseline scenario is more informative as to likely unit costs.

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Figure 3-2: Supply Option GW-1

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GW-2: Convert Existing Emergency Wells into Production Wells Supply option GW-2 proposes to rehabilitate the City’s three existing emergency wells into production wells. The three emergency wells for the City include the Leete Well, Carley Well, and Peter Springs Well, as shown in Figure 3-1.1 The Leete Well is currently out of service due to concerns over a possible casing separation, rehabilitation is currently in design. The Carley and Peter Springs wells have the capacity to provide the City with approximately 1 MGD of groundwater capacity on a stand-by-emergency basis.

For this conceptual-level analysis, the following potential limiting factors for the GW-2 supply option were identified:
• Well pumping capacity: Leete, Peter Springs, and Carley standby/emergency supply wells have a pumping capacity of 240, 500 and 700 gpm, respectively. The GW-2 option will provide up to 2,462 AFY of additional supply.
• Technical studies to verify that long-term use of the wells would be sustainable. • Permitting considerations to allow for water supply from the Leete, Peter Springs , and Carley wells.

The proposed infrastructure rehabilitation and upgrades as part of GW-2 supply option may include:
• Rehabilitation of the three emergency wells, using mechanical and chemical methods • Redevelopment of the wells
• Well house improvements for the w ells, including a pump and motor, a pre -packaged disinfection system with eyewash, and a SCADA connection • Site improvements including electrical, plumbing, and mechanical • Instrumentation and control
The total preliminary capital cost for option GW-2, including the improvements listed, is approximately $11.6 million. A summary of the GW-2 capital cost is shown in Table 3-4. Additional cost details can be found in Appendix A.

1 For simplicity, this analysis assumes rehabilitation of the three existing emergency supply wells. Other possible approaches could include rehabilitating existing inactive wells to production status (such as Freeway Well and Sharon Park Well), in combination with rehabilitation of the existing emergency wells, to provide additional supply. However at this time, Freeway Well and Sharon Park Well do not appear feasible due to water quality concerns.

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Table 3-4: Preliminary Capital Cost, Supply Option GW-2 Component Description Cost, $2023
Well Rehabilitation and
Upgrades
Rehabilitation and redevelopment of the three-
emergency stand-by wells, well house
improvements, instrumentation and control
$5,520,000
Estimating Contingency 50% of raw construction costs $2,760,000 Implementation 40% of total construction costs $3,310,000 Total Capital Cost $11,590,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $409,000 The O&M cost of the project was estimated on a per AF basis for scalability. The GW -2 option has a fixed annual O&M cost of $123,000 and an annual marginal O&M cost of approximately $236/ AF. Annual O&M costs will vary depending on the production of the converted wells. The estimated annual O&M costs for the maximum potential yield of 2,462 AFY is approximately $705,000. Table 3-5 summarizes the annual O&M costs for option GW-2. Under the Baseline Scenario, as modeled by the screening tool, actual production would be less than 2,462 AFY, resulting in a greater cost per AF.

Table 3-5: Preliminary Annual O&M Cost, Supply Option GW-2 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, chemical addition, water/sewer fees $236/ AF
Fixed Cost
Fixed costs include routine maintenance practices,
water quality testing, Santa Rosa Plain Groundwater
Sustainability Agency fees
$123,000
Average cost of water (Baseline Scenario)1 $540/ AF
Annual O&M (2,462 AFY)2 $705,000
Cost of water (2,462 AFY)2 $452/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which 1,744 AFY are used. That baseline is based on operating wells at least from April through October in all years, i.e., at a minimum of 7/12 of full capacity, and more in dry years as needed. Costs for the baseline scenario include capital and operating costs.

2. The maximum supply yield of 2,462 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations.

GW-3: Local Aquifer Storage and Recovery (ASR) Wells
An additional groundwater supply option is GW-3, which proposes to inject water directly into the groundwater aquifer for later recovery and use. Water is typically injected during wet periods when there is supply available (e.g., potable water) and extracted during dry periods and/or during peak demands

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when additional supplies are needed. GW-3 could include injecting excess potable supplies when available into the groundwater basin.

ASR offers advantages as a method to increase water supply for drought mitigation. Due to the underground storage nature of ASR projects, this supply is more resilient than other alternative storage methods such as surface recharge or storage, which experience water losses due to evaporation. A phased approach can be followed to develop a pilot ASR project to understand local conditions and ensure there are no “fatal flaws” before a full-scale ASR implementation. The number of wells to meet the demand would vary depending on well capacities, for this conceptual-level analysis, a 500 gpm capacity and 500 feet well depth was assumed.

For this conceptual-level analysis, the following potential limiting factors for the GW-3 supply option were identified:
• Appropriate site selection for ASR wells; right-of-way issues. • Hydrogeologic constraints with aquifer potential for injection, storage, and extraction of water.
o Well capacities range 400-1,000 gpm or greater. Assumed 500 gpm for this level of analysis based on existing City well information.
o Well depths range from 300-1,000 feet. Assumed 500 feet for this level of analysis based on existing City well information. (Note that actual well depth could be deeper depending on hydrogeologic conditions; for reference, Sonoma Water wells range from about 800 to 1,000 feet deep (Sonoma Water, n.d.)). • Source of water for injection
• Chemical properties of source water versus native groundwater and potential reactions due to mixing
• Retention time or storage capacity of aquifer prior to injection • Regulatory constraints and compliance with environmental requirements with injection of water into groundwater
• Pre-treatment of water prior to injection for storage to meet regulatory requirements • Disinfection and potential treatment prior to distribution (high concentrations of iron and manganese were noted in this area)
• Extensive monitoring of water levels and quality and reporting Preliminary review of Airborne Electromagnetic survey data available from the Department of Water Resources (DWR) shows potential target areas along the western boundary of the subbasin that appear promising for ASR (California Department of Water Resources, 2022). Figure 3-3 below shows potential ASR well areas within the City’s boundary. Additional areas would be considered as well, if this option is chosen for further development.

In the Santa Rosa Plain Subbasin, groundwater generally flows westward from recharge areas in the mountains into the west side of the subbasin. The shallow aquifer generally extends from the water table to depths ranging from 150 feet to 200 feet below land surface (Santa Rosa Plain Groundwater Sustainability Agency, 2021). Elevations in the deeper zone aquifers are approximately 10 to 40 feet lower than groundwater elevations in the shallow aquifer system in the Subbasin (Santa Rosa Plain Groundwater Sustainability Agency, 2021). The shallow aquifer is present over the entire extent of the subbasin and generally present under unconfined or semiconfined conditions. Shallow wells in this area (with depths

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ranging from 90 to 167 ft below land surface) do not show enough injection capacity with groundwater levels being close to the land surface.

For the concept-level analysis for this feasibility analysis, the proposed six ASR wells were assumed to be constructed within the intermediate/deep aquifer (although the City could elect to include both shallow and deep ASR wells in order to minimize mounding of groundwater levels in areas with lower storage coefficients). The deep aquifer occurs under confined or semiconfined conditions with groundwater levels generally 20 feet lower in this area compared to the shallow aquifer system. The proposed well area is also home to existing dedicated shallow monitoring wells (three wells SRP0713, SRP0355, and SRP0357) and deep monitoring wells (SRP0347, SRP0359, and SRP0725) established as part of the Santa Rosa Plain GSP.

These existing wells can be used for future monitoring of local conditions in support of future ASR implementation for sustainable management of the basin. Wells in this area are generally completed in the Wilson Grove Formation (formerly known as the Merced Formation). The Wilson Grove Formation is a sand-dominated formation exposed in the western Santa Rosa Plain Subbasin. Further hydrogeologic investigations would be needed to confirm local conditions.

The potential ASR and conveyance infrastructure required for GW-3 would be:
• Well equipment including well head, pump, and well house building for six ASR wells • Conveyance pipelines
• Electrical service for each well
• Treatment systems for disinfection and if needed for manganese and iron • Backup generator for power outage
• Backwashing treatment system (assumes disposal to nearby sanitary sewer) • Dechlorination prior to injection

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Figure 3-3: Supply Option GW-3

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The total preliminary capital cost for option GW-3, including the improvements listed, is approximately $81 million. A summary of the GW-3 capital cost is shown in Table 3-6. Additional cost details can be found in Appendix A.

Table 3-6: Preliminary Capital Cost, Supply Option GW-3 Component Description Cost, $2023
ASR Well Construction
Six ASR (injection/extraction) wells, 500 feet
deep, well head, casing, well pump and
equipment ($5 million/ well)
$30,000,000
Groundwater Conveyance Line 16-inch diameter; 12,000 linear feet $7,120,000 Groundwater Pump Station 210 horsepower $1,365,000
Potable system connection $100,000
Estimating Contingency 50% of raw construction costs $19,300,000 Implementation 40% of total construction costs $23,160,000 Total Capital Cost $81,050,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $2,858,000

The O&M cost of the project was estimated on a per AF basis for scalability. The GW -3 option has a fixed annual O&M cost of $121,000 and an annual marginal O&M cost of approximately $1,813, which includes the cost to purchase water from Sonoma Water for injection. Annual O&M costs will vary depending on the production of the ASR wells. The estimated annual O&M costs for the maximum potential yield of 5,130 AFY is approximately $9.42 million. Table 3-7 summarizes the annual O&M costs for option GW-3.

Under the Baseline Scenario, as modeled by the screening tool, actual production would be less than 5,130 AFY, resulting in a greater cost per AF. Installing fewer ASR wells would reduce the cost per AF under the Baseline Scenario.

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Table 3-7: Preliminary Annual O&M Cost, Supply Option GW-3 Component Description Cost, $2023
Marginal Cost
Marginal costs include power consumption, labor,
chemical addition, water/sewer fees, purchase of
water for injection.
$1,813/ AF
Fixed Cost
Fixed costs include routine maintenance practices,
water quality testing, Santa Rosa Plain Groundwater
Sustainability Agency fees
$121,000
Average cost of water (Baseline Scenario)1 $2,600/ AF
Annual O&M (5,130 AFY)2 $9,420,000
Cost of water (5,130 AFY)2 $2,400/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which on average 3,634 AFY would be used. That baseline is based on operating wells at least from April through October in all years, i.e., at a minimum of 7/12 of full capacity, and more in dry years as needed. Cited costs include operating and capital.

2. The maximum supply yield of 5,130 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations. Cited costs include operating and capital.

GW-4: Regional Groundwater Extraction Wells
Option GW-4 consists of constructing new production wells outside the City limits (in neighboring jurisdictions) where the geology may allow for greater well yields than within the City. Provided that the wells are located in or near another Sonoma Water contractor agency’s jurisdiction, a paper exchange could be completed where the City takes a portion of the partner’s Sonoma Water allocation, and the pumped groundwater is used directly by the partner. The paper exchange option would not reduce regional reliance on the Sonoma Water system overall.

Implementation of option GW-4 would require identification of possible well locations, connections to existing distribution systems, regional coordination and agreements, and possible need for regulatory approvals. Components that would need to be constructed could include:
• Well equipping including well head, pump, well house building and equipment • Conveyance pipelines
• Electrical service for each well
• Treatment systems for manganese and iron onsite, if needed • Backup generator for power outage
• Backwashing treatment system (assumes disposal to nearby sanitary sewer) This option assumes that the potential partner would need to be a Sonoma Water contractor who receives sufficient Sonoma Water contract supplies to make them open to a partial trade with Santa Rosa. Based on historical Sonoma Water deliveries, potential candidates could be Petaluma, North Marin Water District, Rohnert Park, and possibly City of Sonoma or Valley of the Moon Water District. This option also assumes that the City would find a partner for whom well yields of 1,000 gpm or more could be achieved, in order to provide a benefit over existing pumping rates of City wells. Based on an initial review of

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information from Urban Water Management Plans of potential partners and DWR Bulletin 118, the Sonoma Valley Subbasin may provide enough yield to meet this threshold. The City of Sonoma and Valley of the Moon Water District are located within the Sonoma Valley Subbasin. Each of these agencies typically receives around 2,000 AFY or less from Sonoma Water. Based on these figures, it is assumed that 3,000 AFY at most would be available for trading, which would provide a portion of the City’s water supply goal of 7,500 AFY.

Were such a project to be implemented, it is assumed that in wet years with sufficient Sonoma Water allocations, no groundwater pumping would occur. In normal years, pumping would occur in summer months, and in dry years, pumping would occur for a greater portion of the year. According to the Sonoma Valley Basin GSP, groundwater levels in the subbasin are generally stable but have some persistent pumping depressions, and groundwater in storage declined by about 900 AFY during 2012- 2018. Therefore, it is assumed that any increase in groundwater extraction in Sonoma Valley would need to be offset by some form of recharge, and without recharge the project may not be compatible with groundwater management practices. Adding a recharge component to this supply option would likely yield a project similar to the Regional Aquifer Storage and Recovery option described in GW-5. Therefore, this supply option was not carried forward for detailed cost analysis or feasibility scoring.

GW-5: Regional Aquifer Storage and Recovery
Supply option GW-5 proposes developing a regional ASR project in collaboration with one or more agencies in the region and using Sonoma Water supplies and ASR water conjunctively. ASR wells can be constructed in the aquifer most feasible and promising in the region. Potential options would include: 1) the City connecting to ASR wells directly, and 2) the City utilizing participating agencies’ surface water supplies from Sonoma Water while partnering agencies pump from ASR wells by the same amount in lieu of taking Sonoma Water supply.

Implementation of this supply option would require identification of feasible ASR well locations, connections to existing distribution systems, regional coordination and agreements, and possible need for additional water rights.

Overall, a regional ASR project would include similar components as a local ASR project. In addition, the City would be part of future regional ASR projects implemented by Sonoma Water (and possibly by the GSA) by default. For example, Sonoma Water has been in the process of evaluating feasibility of ASR in the Sonoma Valley Subbasin, including a pilot test in 2018 (Santa Rosa Plain Groundwater Sustainability Agency, 2021). Because many project elements and implementation considerations for regional ASR would be similar to the local ASR option above (GW-3), and because the City would effectively be participating in possible future ASR projects implemented by Sonoma Water, this option did not undergo any further separate technical analysis.

3.1.2 Purified Recycled Water Supply Options
The City operates the LTP for the Santa Rosa Regional Water Reuse System (Regional System). Figure 3-4 depicts the location of the wastewater treatment facilities and the Regional System key facilities. LTP is a tertiary level treatment facility that has an overall average daily flow of 15.1 MGD and average dry weather flow of 13.6 MGD in 2020. LTP is permitted for 21.34 MGD average daily dry weather flow and takes wastewater from homes, businesses, and industry located within the Cities of Santa Rosa, Rohnert Park, Sebastopol, and Cotati, and the South Park Sanitation District. Over 500 miles of underground pipes bring

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wastewater to the LTP where water goes through three stages of treatment prior to disinfection, storage, and reuse. The water is treated to the highest non-potable level recognized in State water recycling regulations (Title 22 Tertiary).

The Regional System provides recycled water to the City of Rohnert Park for its urban reuse program for irrigation at many Rohnert Park schools, parks, and businesses, as well as Sonoma State University. In Santa Rosa, recycled water is used within the City’s urban growth boundary for landscape irrigation at City facilities (including the municipal services center, bus transfer station, Finley Park, and A Place to Play sports complex), as well as multi-family residential complexes, institutions, and business parks.

Depending upon the amount of rainfall in any given year, approximately 98 to 100 percent of the Regional System’s recycled water is reused for urban landscapes, rural agricultural irrigation, and the Geysers Recharge Project. The volume of Title 22 tertiary water produced by the City in recent years (2019 through 2022) is summarized in Figure 3-5; it should be noted that 2020-2022were historically dry years.

The purified recycled water options (also known as potable reuse) are limited by the reliable volume of tertiary effluent available given its existing use by current customers. For this level of study, it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs. This requires instantaneous flows as high as 11.4 MGD. That value is less than the average dry-weather flow available in 2020 of 13.6 MGD. However, should this option (or others involving purified water) move forward, an analysis of daily low flows would be needed to verify that the assumed amount of equalization storage was sufficient to allow the plant to run at full rate even during days and hours of low wastewater flows.

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Figure 3-4: Regional System Facilities

Source: Regional Water Reuse System Master Plan (City of Santa Rosa, 2018)

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Figure 3-5: Average Recycled Water Use (2019-2022)

Source: Recycled Water Flows - Volume and User Type by Month 2019-2022 (City of Santa Rosa, 2023) 0 100
200
300
400
500
600
700
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Million Gallons
City RW to Geysers Windsor to Geysers Urban
Landscape
Regional
Landscape
Agriculture Commercial Wholesale
To Rohnert Park

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Potable Reuse Approaches
The spectrum of potable reuse approaches is commonly distinguished by the degree of separation between the treatment and ultimate consumption of purified water. This separation may be physical (e.g., when purified water travels through a groundwater aquifer), temporal (e.g., when water is retained in a tank or a reservoir), or both. IPR projects are characterized by the use of one of two environmental buffers—a groundwater aquifer or a surface water reservoir—that increase the separation between treatment and consumers. DPR projects are defined by the absence of a significant environmental buffer.

The State of California recognizes five forms of IPR and DPR that are depicted in Figure 3-6, all requiring a multitude of pathogen and chemical control requirements.

Figure 3-6: Forms of Potable Reuse in California

3.1.2.1.1 Indirect Potable Reuse
The first form of IPR distinguished by California regulations is groundwater recharge (GWR), which can be achieved by two different approaches: surface spreading and subsurface injection (Title 22, Chapter 3, Articles 5.1 and 5.2, respectively). The second form of IPR is surface water augmentation (SWA) which introduces purified water directly into a surface water reservoir that is used as a source of domestic drinking water supply.

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One of the benefits of pursuing IPR projects in California is the regulatory certainty associated with the existence of final, adopted regulations for both GWR and SWA. This streamlines the permitting process by providing clarity on the requirements for IPR implementation. In the case of GWR, there are also multiple precedents given that permitted California GWR projects have been producing water for nearly 60 years.

Based on this experience, the regulatory community has first-hand knowledge of the challenges with GWR allowing them to adapt the requirements to address these needs.

3.1.2.1.2 Direct Potable Reuse
The State Water Resources Control Board released draft criteria for DPR in March 2021 and revised criteria in August 2021 (State Water Resources Control Board, 2021). The draft criteria include stricter requirements than IPR to compensate for the protections that are lost from bypassing the environment al buffer. The criteria can be broken down into four major categories: 1) pathogen control, 2) chemical control, 3) monitoring and control, and 4) technical, managerial, and financial capacity.

Compared to IPR, DPR projects have stricter requirements for nearly all of these categories. One example of this difference is the level of treatment needed for IPR and DPR. Most categories of IPR require full advanced treatment (FAT), which is the treatment of the entire flow of water through both reverse osmosis (RO) and an advanced oxidation process (AOP). The draft DPR criteria specify higher levels of treatment, namely, pre-treatment with ozone and biological activated carbon (BAC) followed by FAT.

State regulations define two types of DPR—raw water augmentation (RWA) and treated water augmentation (TWA)—that are differentiated depending on whether the reuse project is providing a raw source water upstream of a surface water treatment plant, or a finished water directly into a public water system’s distribution system. RWA also encompasses projects that provide raw source water into an environmental buffer that cannot meet the IPR requirements. Despite the differences between RWA and TWA, the draft DPR criteria contain a single set of requirements to cover both forms. The State’s DPR Expert Panel—who is currently reviewing the public health protectiveness of the draft DPR criteria —has asked the State Board to provide separate criteria for these two forms. If the future regulations do not include separate requirements, then it is possible that projects designed for RWA may also have the flexibility to pursue TWA (and vice versa).

One benefit of DPR is that it does not restrict projects to areas with access to groundwater aquifers or reservoirs. Many agencies in California are considering the RWA form of DPR to continue leveraging investments they have made in existing treatment plant infrastructure. The main challenges in pursuing DPR include the lack of regulatory certainty (though draft criteria are on track to be finalized by the end of 2023) and the lack of permitting precedents.

Table 3-8 summarizes the flow requirements for the proposed DPR and IPR AWPFs assumed for this study.

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Table 3-8: Preliminary AWPF Flow Summaries
Parameter Units
DPR Maximum
Treatment Flow
IPR Maximum
Treatment Flow
Production Capacity MGD 9.0 9.0
System Feed MGD 11.6 11.4
Ozone/Biological Activated Filtration (BAF)
Assumed Recovery % 98 --
Feed MGD 11.60 --
Brine MGD 0.23 --
Effluent MGD 11.37 --
Microfiltration System (MF)
Assumed Recovery % 93 93
Feed MGD 11.37 11.40
Backwash MGD 0.80 0.80
Effluent MGD 10.6 10.6
Reverse Osmosis (RO) System
Assumed Recovery % 85 85
Feed MGD 10.6 10.6
Brine MGD 1.59 1.59
Effluent MGD 9.0 9.0
Ultraviolet-Peroxide Disinfection (Ultraviolet/Advanced Oxidation Process -

UV/AOP)
Assumed Recovery % 100 100
Feed MGD 9.0 9.0
Effluent MGD 9.0 9.0
Free Chlorine Disinfection
Assumed Recovery % 100 --
Feed MGD 9.0 --
Effluent MGD 9.0 --
PR-1: DPR AWPF at LTP
Option PR-1 would convey the City’s tertiary effluent to an AWPF co-located at the City’s existing LTP and return AWPF waste streams to the LTP headworks. The concept 9 MGD AWPF would include treatment processes in compliance with future anticipated regulations for TWA. The purified water would be conveyed to Sonoma Water’s 36-inch Kawana Pipeline for distribution to the City’s potable water system.

PR-1 is limited by the reliable volume of tertiary effluent available. For this level of study, it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs. Figure 3-7 shows the PR-1 concept, including the AWPF and conveyance infrastructure to the proposed potable connection point along Occidental Road.

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Figure 3-7: Supply Option PR-1

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Components that would need to be constructed as part of PR-1 include:
• 24-inch tertiary water pipeline from LTP to AWPF
• 1.8 million gallon equalization basin
• AWPF to meet anticipated DPR regulations, conventional FAT plus ozone/ BAF o Ozone/BAF
o Microfiltration system (MF)
o Reverse Osmosis (RO) system
o UV/AOP
o RO brine disposal system (Evaporator and Crystallizer) o Ancillary facilities
• 20-inch product water pipeline and pump station to potable connection point • Potable connection infrastructure
The total preliminary capital cost for option PR-1, including all infrastructure listed, is approximately $289 million. A summary of the PR-1 capital cost is shown in Table 3-9. Additional cost detail can be found in Appendix A.

Table 3-9: Preliminary Capital Cost, Supply Option PR-1 Component Description Cost, $2023
Equalization 1,820,000 gallon equalization basin prior to feeding AWPF $2,275,000
Tertiary Water Pipeline 24-inch diameter; assumed 500 linear feet $445,000 9 MGD DPR AWPF
Ozone, BAF, Ultra Filtration (UF)/Micro Filtration
(MF), RO, chemical storage and feed systems,
sitework, piping, structures, waste disposal to
headworks
$100,659,000
Brine Disposal Brine evaporator and crystallizer for zero liquid discharge $10,730,000
Purified Water Line 20-inch diameter; 26,330 linear feet $19,528,000 Purified Water Pump Station 625 horsepower $4,063,000
Potable system connection $100,000
Estimating Contingency 50% of raw construction costs $68,900,000 Implementation 40% of total construction costs $82,680,000 Total Capital Cost $289,380,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $10,203,000 The O&M cost of the project was estimated on a per AF basis for scalability. The PR-1 option has a fixed annual O&M cost of $873,000 and an annual marginal O&M cost of approximately $927/ AF. Annual O&M costs will vary depending on the production of the AWPF. It is assumed the AWPF could be turned down to a production capacity of 30 percent during low demand periods. The estimated annual O&M

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costs for the maximum potential yield of 10,065 AFY is approximately $10.2 million. Table 3-10 summarizes the annual O&M costs for option PR-1.

Table 3-10: Preliminary Annual O&M Cost, Supply Option PR-1 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $927/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $873,000
Average cost of water (Baseline Scenario)1 $3,600/AF
Annual O&M (10,065 AFY)2 $10,200,000
Cost of water (10,065 AFY)2 $2,050/ AF
Annual O&M (3,019 AFY)3 $3,671,000
Cost of water (3,019 AFY)3 $4,600/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which on average 4,131 AFY are produced by PR-

1. Costs including operating and capital.

2. The maximum supply yield of 10,065 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations because it would produce more water than the City would use, which causes the unit cost of water to appear artificially low.

3. The minimal yield of 3,019 AFY assumes 30 percent turndown of the AWPF’s maximum yield to provide a range of supply available for the PR options.

PR-2: Satellite DPR AWPF
Option PR-2 would convey the City’s tertiary effluent to a satellite AWPF and return AWPF waste stream s to the nearest sewer. The AWPF would include treatment processes in compliance with future anticipated regulations for TWA. The purified water would be conveyed to Sonoma Water’s 36-inch diameter pipeline for distribution to the City’s potable water system. The satellite AWPF is assumed to be located on City- owned agricultural leased land, Stone Farm. Although siting the AWPF as a satellite facility allows the City to reduce the purified water conveyance facilities, the satellite AWPF requires more ancillary facilities to support operations staff than if the AWPF were sited within the existing LTP.

For this level of study, it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs. The tertiary effluent to feed the AWPF would be conveyed to the satellite AWPF through new conveyance infrastructure assuming the existing Geysers pipeline corridor/ easement. The purified water would be conveyed to Sonoma Water’s aqueduct for distribution to the City as shown in Figure 3-8.

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Figure 3-8: Supply Option PR-2

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Components that would need to be constructed as part of PR-2 include:
• 24-inch tertiary water pipeline from LTP to AWPF
• 400 horsepower tertiary water pump station
• 1.8 million gallon equalization basin
• AWPF to meet anticipated DPR regulations, conventional FAT plus ozone/BA C o Ozone/BAC
o MF/Spell out (UF) System
o RO System
o UV/AOP
o RO brine disposal system (Evaporator and Crystallizer) o Ancillary facilities
o 10-inch AWPF waste disposal to nearest sewer with capacity • 20-inch purified water pipeline
• 250 horsepower pump station to potable connection point • Potable connection infrastructure
The total preliminary capital cost for option PR-2, including all infrastructure listed, is approximately $314 million. A summary of the PR-2 capital cost is shown in Table 3-11. Additional cost detail can be found in Appendix A.

Table 3-11: Preliminary Capital Cost, Supply Option PR-2 Component Description Cost, $2023
Equalization 1,820,000 gallon equalization basin $2,275,000 Tertiary Water Pipeline 24-inch diameter; 30,100 linear feet $26,789,000 9 MGD DPR AWPF
Ozone, BAC, MF, RO, chemical storage and feed
systems, sitework, piping, structures, waste disposal
to nearest sewer
$103,191,000
Brine Disposal Brine evaporator and crystallizer for zero liquid discharge $10,730,000
Purified Water Line 20-inch diameter; 26,330 linear feet $1,520,000 Purified Water Pump Station 250 horsepower $1,625,000
Potable system connection $100,000
Estimating Contingency 50% of raw construction costs $74,780,000 Implementation 40% of total construction costs $89,730,000 Total Capital Cost $314,060,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $11,073,000 The O&M cost of the project was estimated on a per AF basis for scalability. The PR -2 option has a fixed annual O&M cost of $954,000 and an annual marginal O&M cost of approximately $943/ AF. Annual O&M costs will vary depending on the production of the AWPF. It is assumed the AWPF could be turned

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down to a production capacity of 30 percent during low demand periods. The estimated annual O&M costs for the maximum potential yield of 10,065 AFY is approximately $10.4 million. Table 3-12 summarizes the annual O&M costs for option PR-2.

Table 3-12: Preliminary Annual O&M Cost, Supply Option PR-2 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $943/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $954,000
Average cost of water (Baseline Scenario)1 $3,900/ AF
Annual O&M (10,065 AFY)2 $10,443,000
Cost of water (10,065 AFY)2 $2,150/ AF
Annual O&M (3,019 AFY)3 $3,800,000
Cost of water (3,019 AFY)3 $5,000/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which on average 4,131 AFY are produced. Costs include operating and capital.

3. The minimal yield of 3,019 AFY assumes 30 percent turndown of the AWPF’s maximum yield to provide a range of supply available for the PR options.

PR-3a: IPR AWPF at LTP, Ground Water Augmentation (GWA) via Delta Pond Option PR-3a would convey the City’s tertiary effluent to an AWPF at LTP and return AWPF waste stream to the headworks at LTP. The AWPF would include treatment processes in compliance with regulations for GWR. The purified water would be conveyed to the City-owned Delta Pond, after the minimum retention time of 2-months in the groundwater aquifer, the recharged groundwater could then be extracted. The purified water would be injected into and later extracted from the groundwater aquifer via new ASR wells.

The same capital cost assumptions for the GW-3 option were applied for the 12 new ASR wells. For this level of study, it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs .

As shown in Figure 3-9, the 9 MGD AWPF would be co-located at LTP and the purified water would be conveyed to the Delta Pond area through new conveyance infrastructure assuming use of the existing Geysers pipeline corridor/ easement.

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Figure 3-9: Supply Option PR-3a

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Components that would need to be constructed as part of PR-3a include:
• 24-inch tertiary water pipeline from LTP to AWPF
• 1.8 million gallon equalization basin
• AWPF to meet IPR GWA regulations, conventional FAT
o MF System
o RO System
o UV/AOP
o RO brine disposal system (Evaporator and Crystallizer) o Ancillary facilities
o 8-inch AWPF waste disposal to LTP headworks
• 22-inch purified water pipeline
• 490 horsepower pump station to Delta Pond
• ASR wells
The total preliminary capital cost for option PR-3a, is approximately $419 million. A summary of the PR-3a capital cost is shown in Table 3-13. Additional cost detail can be found in Appendix A.

Table 3-13: Preliminary Capital Cost, Supply Option PR-3a Component Description Cost, $2023
Equalization 1,820,000 gallon equalization basin $2,275,000 Tertiary Water Pipeline 24-inch diameter; assumed 500 linear feet $445,000 9 MGD IPR AWPF
UF, RO, chemical storage and feed systems,
sitework, piping, structures, waste disposal to
headworks
$89,390,000
Brine Disposal Brine evaporator and crystallizer for zero liquid discharge $10,760,000
Purified Water Line to Delta Pond 22-inch diameter; 41,220 linear feet $33,628,700 Purified Water Pump Station 490 horsepower $3,185,000
New Well Construction
12 ASR wells (injection/ extraction) wells, 500
gpm capacity, 500 feet deep, well head,
casing, well pump and equipment
($5 million/ well)
$60,000,000
Estimating Contingency 50% of raw construction costs $99,840,000 Implementation 40% of total construction costs $119,810,000 Total Capital Cost $419,330,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $14,785,000

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The O&M cost of the project was estimated on a per AF basis for scalability. The PR -3a option has a fixed annual O&M cost of $1,069,000 and an annual marginal O&M cost of approximately $936/ AF. Annual O&M costs will vary depending on the production of the AWPF. It is assumed the AWPF could be turned down to a production capacity of 30 percent during low demand periods. The estimated annual O&M costs for the maximum potential yield of 10,065 AFY is approximately $12.7 million. Table 3-14 summarizes the annual O&M costs for option PR-3a.

Table 3-14: Preliminary Annual O&M Cost, Supply Option PR-3a Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $936/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $1,069,000
Average cost of water (Baseline Scenario)1 $4,800/AF
Annual O&M (10,065 AFY)2 $12,700,000
Cost of water (10,065 AFY)2 $2,730/AF
Annual O&M (3,019 AFY)3 $4,558,000
Cost of water (3,019 AFY)3 $6,400/AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which on average 4,131 AFY of water would be produced. Costs include capital and operating.

2. The maximum supply yield of 10,065 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations.

3. The minimal yield of 3,019 AFY assumes 30 percent turndown of the AWPF’s maximum yield to provide a range of supply available for the PR options.

PR-3b: IPR AWPF at LTP, SWA via Lake Ralphine
Option PR-3b would convey the City’s tertiary effluent to an AWPF at LTP and return AWPF waste stream to the headworks at LTP. The AWPF would include treatment processes in compliance with regulations for SWA. After preliminary retention calculations it was determined that Lake Ralphine would not provide the minimum required 2-month retention time to quality as IPR per California regulations. Therefore, option PR-3b would qualify as a DPR and would likely yield a project similar to the PR-1 option described above.

Therefore, this supply option was not carried forward for detailed cost analysis or feasibility scoring.

PR-3c: IPR AWPF at LTP, SWA via Lake Sonoma
Option PR-3c would convey the City’s tertiary effluent to an AWPF at LTP and return AWPF waste stream to the headworks at LTP. The AWPF would include treatment processes in compliance with regulations for SWA. The purified water would be conveyed to Lake Sonoma through a new purified water line assuming the existing Geysers pipeline corridor/ easement and extending to Lake Sonoma as shown in Figure 3-10.

For this level of study, it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs

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The AWPF would be located at LTP, and the purified water would be conveyed to Lake Sonoma through new conveyance infrastructure . Water would be withdrawn from Lake Sonoma using Sonoma Water’s existing infrastructure.

Components that would need to be constructed as part of option PR-3c include:
• 24-inch tertiary water pipeline from LTP to AWPF
• 1.8 million gallon equalization basin
• AWPF to meet IPR GWA regulations, conventional FAT
o MF system
o RO system
o UV/AOP
o RO brine disposal system (Evaporator and Crystallizer) o Ancillary facilities
o 8-inch AWPF waste disposal to LTP headworks
• 22-inch purified water pipeline
• 2,600 horsepower pump station to Lake Sonoma

This option incorporates some assumptions that would need to be vetted and refined if the option were implemented. Among them is an assumption that sufficient space exists in Lake Sonoma, and that withdrawing the water from Lake Sonoma could be done with existing infrastructure. Both of these issues would likely add cost and-or reduce yield to the option. However, given the very high cost of the option even without those burdens, the issues were not fully explored in the current study.

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Figure 3-10: Supply Option PR-3c

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The total preliminary capital cost for option PR-3c is approximately $650 million. A summary of the PR-3c capital cost is shown in Table 3-15. Additional cost detail can be found in Appendix A.

Table 3-15: Preliminary Capital Cost, Supply Option PR-3c Component Description Cost, $2023
Equalization 1,820,000 gallon equalization basin $2,275,000 Tertiary Water Pipeline 24-inch diameter; assumed 500 linear feet $445,000 9 MGD IPR AWPF
UF, RO, chemical storage and feed systems,
sitework, piping, structures, waste disposal to
headworks
$89,390,000
Brine Disposal Brine evaporator and crystallizer for zero liquid discharge $10,760,000
Purified Water Line to Lake
Sonoma 22-inch diameter; 181,300 linear feet $147,910,600 Purified Water Pump Station 2,600 horsepower $16,900,000 Estimating Contingency 50% of raw construction costs $133,840,000 Implementation 40% of total construction costs $160,610,000 Total Capital Cost $562,130,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $19,800,000 The O&M cost of the project was estimated on a per AF basis for scalability. The PR -3c option has a fixed annual O&M cost of $1,790,000 and an annual marginal O&M cost of approximately $1,200/ AF. Annual O&M costs will vary depending on the production of the AWPF. It is assumed the AWPF could be turned down to a production capacity of 30 percent during low demand periods. The estimated annual O&M costs for the maximum potential yield of 10,065 AFY is approximately $15.9 million. Table 3-16 summarizes the annual O&M costs for option PR-3c.

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Table 3-16: Preliminary Annual O&M Cost, Supply Option PR-3c Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $1,200/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $1,786,000
Average cost of water (Baseline Scenario)1 $6,430/AF
Annual O&M (10,065 AFY)2 $13,870,000
Cost of water (10,065 AFY)2 $3,350/ AF
Annual O&M (4,131 AFY)3 $6,319,000
Cost of water (4,131 AFY)3 $6,430/AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which on average 4,131 AFY would be produced.

Operating and capital costs are included.

2. The maximum supply yield of 10,065 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations.

3. The minimal yield of 3,019 AFY assumes 30 percent turndown of the AWPF’s maximum yield to provide a range of supply available for the PR options.

PR-4: Regional DPR AWPF at LTP
Similar to Option PR-1, PR-4 would convey the City’s tertiary effluent to an AWPF located at the LTP and return AWPF waste stream to the LTP headworks. The AWPF would include treatment processes in compliance with future anticipated regulations for TWA. The purified water would be conveyed to Sonoma Water’s 48-inch diameter aqueduct for regional distribution, as shown in Figure 3-11.

Under the PR-4 project concept, the purified water could be delivered to another party rather than used directly by the City, and a paper exchange could be completed whereby the City receives water in return.

The paper exchange option would not reduce reliance on the Sonoma Water system overall.

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Figure 3-11: Supply Option PR-4

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Components that would need to be constructed as part of PR-4 include:
• 24-inch tertiary water pipeline from LTP to AWPF
• 1.8 million gallon equalization basin
• AWPF to meet anticipated DPR regulations, conventional FAT plus ozone/ BAC o Ozone/BAC
o MF System
o RO System
o UV/AOP
o RO brine disposal system (Evaporator and Crystallizer) o Ancillary facilities
• 20-inch product water pipeline and pump station to potable connection point • Potable connection infrastructure
The total preliminary capital cost for option PR-4, including all infrastructure listed, is approximately $247 million. A summary of the PR-4 capital cost is shown in Table 3-17. Additional cost detail can be found in Appendix A.

Table 3-17: Preliminary Capital Cost, Supply Option PR-4 Component Description Cost, $2023
Equalization 1,820,000 gallon equalization basin prior to feeding AWPF $2,275,000
Tertiary Water Pipeline 24-inch diameter; assumed 500 linear feet $445,000 9 MGD DPR AWPF
Ozone, BAF, UF, RO, chemical storage and feed
systems, sitework, piping, structures, waste
disposal to headworks
$100,659,000
Brine Disposal Brine evaporator and crystallizer for zero liquid discharge $10,730,000
Purified Water Line 20-inch diameter; 2,200 linear feet $1,631,700 Purified Water Pump Station 270 horsepower $1,755,000
Potable system connection $100,000
Estimating Contingency 50% of raw construction costs $58,800,000 Implementation 40% of total construction costs $70,560,000 Total Capital Cost $246,960,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $8,707,000 The O&M cost of the project was estimated on a per AF basis for scalability. The PR-4 option has a fixed annual O&M cost of $714,000 and an annual marginal O&M cost of approximately $885/ AF. Annual O&M costs will vary depending on the production of the AWPF. It is assumed the AWPF could be turned down to a production capacity of 30 percent during low demand periods. The estimated annual O&M

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costs for the maximum potential yield of 10,065 AFY is approximately $9.6 million. Table 3-18 summarizes the annual O&M costs for option PR-4.

Table 3-18: Preliminary Annual O&M Cost, Supply Option PR-4 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $885/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $714,000
Average cost of water (Baseline Scenario)1 $3,200/AF
Annual O&M (10,065 AFY) $9,625,000
Cost of water (10,065 AFY) $1,850/ AF
Annual O&M (3,019 AFY) $3,387,000
Cost of water (3,019 AFY) $4,000/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which an average of 4,131 AFY would be produced. Operating and capital costs are included.

3. The minimal yield of 3,019 AFY assumes 30 percent turndown of the AWPF’s maximum yield to provide a range of supply available for the PR options.

The costs presented for PR-4 would represent the total cost of the supply option. Were a regional partner to be identified, the costs would be distributed between the City and its partner(s), and the City presumably would not bear the entire project cost.

3.1.3 Non-Potable Recycled Water Option
As discussed in Section 3.1.2, the City is responsible for the operation and management of the Regional System. The Regional System operates the LTP, oversees the Industrial Pretreatment Program, and operates and maintains the recycled water system for more than 225,000 residents and 6,500 businesses for the Cities of Cotati, Rohnert Park, Santa Rosa, and Sebastopol, and the South Park Sanitation Dist rict and portions of unincorporated Sonoma County. As managing partner of the Regional System, the City is responsible for operating the system economically and safely and for planning for future regulatory changes and growth.

RW-1: Recycled Water System Expansion
Option RW-1 would increase the amount of urban reuse within Santa Rosa, Cotati, and Rohnert Park supplied by recycled water. The Santa Rosa Urban Reuse Project Feasibility Study identified the following phases, each with a capacity of 250 MGY (City of Santa Rosa, 2007). The total expansion would yield an additional 3,000 AFY for distribution. The four phases of the expansion are:

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• Phase 1 West: pipelines generally located in northwest Santa Rosa extending from either the west transmission main or the West College Facility. Diurnal storage may be included in Phase 1 West and would be located between elevation 300 and 400 feet in the Fountaingrove area. • Phase 1 South: pipelines generally located in southeast Santa Rosa extending from the south transmission main. Diurnal storage may be included in Phase 1 South and would be located between elevation 300 and 400 feet within the Santa Rosa U rban Growth Boundary or in the southeast of Santa Rosa area.
• Phase 2 South: pipelines extending from the Phase 1 South system into southwest Santa Rosa.

Connections between the south and west system may be made during this phase. Diurnal storage may be included in Phase 2 South and would be located between elevation 300 and 400 feet or at lower elevations in northwest Rohnert Park or west of Cotati. • Phase 2 West: pipelines extending from the Phase 1 West system to interconnect with the south system. Diurnal storage may be included in Phase 2 West and would be located between elevation 300 and 400 feet or at lower elevations near the Geysers pipeline o r east of Rohnert Park.

The total preliminary capital cost for option RW-1, escalated from the Santa Rosa Urban Reuse Project Feasibility Study in 2006 to 2023 dollars is approximately $214 million. The O&M cost of the project was estimated at $1.3M/year by prorating based on the City’s FY2020- 2021 Wastewater Resource Distribution Expenditure. The average cost of water for the Baseline Scenario (see Section 2.5) is approximately $8,800/ AF. Expanding use of recycled water would not provide a new source of potable drinking water for severe water shortages or emergencies (irrigation would be significantly restricted or banned).

3.1.4 Desalinated Water Supply Options
Marin Municipal Water District (Marin Water) is also considering alternatives for supplemental water supplies with the City of Petaluma, garnering potential for regional partnerships between Marin Water, Petaluma, and the City. The City’s service area is too far from saline water sources and the local groundwater supply does not require desalination. Alternative water supplies Marin Water is currently evaluating include a potential temporary or long-term seawater desalination facility (using brackish bay water) or a brackish groundwater desalination facility. This section evaluated a partnership between Marin Water and the City for a regional brackish bay water desalination facility and the concept of the City’s own ocean desalination facility.

DE-1: Regional Brackish Water Desalination
Option DE-1 would allow the City and Marin Water to partner in constructing a desalination facility to augment Marin Water’s local water supply and the City’s Sonoma Water supply via water transfers. A full- scale facility could have an initial capacity of 5 MGD or 10 MGD and be expandable up to 15 MGD. The full-scale facility could be located at the Marin Water Pelican Way Site in San Rafael as shown in Figure 3-12. The screened intake would be offshore with an on-shore pump station near the Marin Water Pelican Way Site. The bay water intake would include passive screens. The intake screens would be connected to an onshore wet well and pump station via an HDPE pipeline on and under the bay floor. The intake pump station would deliver raw water to the treatment facilities located at either or both the maintenance yard and parking lot sites. The 15 MGD long-term full-scale desalination facilities require approximately 6.5 acres of space. Treated water from the desalination facilities would be delivered to the Marin Water distribution system in San Rafael.

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Provided that the desalination facility would be within the jurisdiction of Marin Water, a paper exchange could be completed where the City receives 9 MGD of Marin Water’s Sonoma Water allocation, and the desalinated water is used directly by Marin Water. Since the Sonoma Water aqueduct would be an integral component of operations, the paper exchange option would not reduce reliance on the Sonoma Water system overall, but it would reduce overall reliance on the Russian River.

The City’s total preliminary capital cost for option DE-1 is approximately $181 million. A summary of the DE-1 capital cost is shown in Table 3-19. Additional cost detail can be found in Appendix A.

Table 3-19: Preliminary Capital Cost, Supply Option DE-1 Component Description City Cost,
$2023
Brackish Water Intake Intake Screens, Pipeline and Pumps, Raw Water Pipe to facility $8,178,000
Desalination Plant
Rapid Mix Strainers, UF and Building, Filtrate and
Backwash Supply Tanks, RO Feed Pump Station, 1st
pass RO and Building, Permeate Tank, Chlorine Contact
Tank, Chemical Facilities, Backwash Equalization Basin, Gravity Thickener, Centrifuges, O&M Building,
Sitework/Piping, Electrical, Instrumentation and
Controls
$71,559,000
Brine Disposal Brine Pump Station, Brine Transmission Line $3,444,000 Distribution Distribution Booster Pumps, Treated Water Line $2,899,200 Estimating Contingency 50% of raw construction costs $43,040,000 Implementation 40% of total construction costs $51,650,000 Total Capital Cost $180,770,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $6,374,000 The O&M cost of the project was estimated on a per AF basis for scalability. The DE-1 option has a fixed annual O&M cost of $909,000 and an annual marginal O&M cost of approximately $401/ AF. Annual O&M costs will vary depending on the production of the desalination facility. It is assumed the desal facility could be turned down to a production capacity of 30 percent during low demand periods. The estimated annual O&M costs for the maximum potential yield of 10,080 AFY is approximately $5 million.

Table 3-20 summarizes the City’s portion of the estimated annual O&M costs for option DE -1.

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Table 3-20: Preliminary Annual O&M Cost, Supply Option DE-1 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $401/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $909,000
Average cost of water (Baseline Scenario)1 $2,041/AF
Annual O&M (10,080 AFY)2 $4,954,000
Cost of water (10,080 AFY)2 $1,200/ AF
Annual O&M (3,360 AFY)3 $2,005,000
Cost of water (3,360 AFY)3 $2,500/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which an average of 4,441 AFY would be produced. Capital and operating costs are included.

2. The maximum supply yield of 10,080 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations.

3. The minimal yield of 3,360 AFY assumes 30 percent turndown of the desalination plant’s maximum yield to provide a range of supply available for the DE options.

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Figure 3-12: Supply Option DE-1

Source: Marin Water Desalination Supply Study Draft Technical Memorandum (Marin Municipal Water District, 2021)

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DE-2: Ocean Desalination
Option DE-2 would construct a seawater desalination facility to increase the City’s local water supply. The desalination facility would be sized to produce 9 MGD to meet the City’s peak month demands. The screened intake would be offshore with an onshore pump station near the desalination site. For costing purposes only, a general location for ocean desalination option was estimated. For purposes of this study, the conceptual full-scale facility was assumed to be located offshore along Bodega Bay as shown in Figure 3-13. A full siting study would be required to determine the most feasible and optimal location for the seawater desalination facility if brought forward through the screening process.

Components that would need to be constructed for DE-2 include:
• The 9 MGD desalination facilities:
o Intake Screens, Pipeline and Pumps
o Raw Water Pipe to facility
o Rapid Mix Strainers
o UF System including Filtrate and Backwash Supply Tanks o RO Feed Pump Station
o RO System and permeate tank
o Chlorine Contact Tank
o Chemical Facilities
o Backwash Equalization Basin
o Gravity Thickener
o Centrifuges
o Ancillary facilities
• Brine disposal
o 290 horsepower pump station
o 24-inch Brine Transmission Line
• Potable Water Distribution
o 1,880 horsepower pump station
o 24-inch potable water pipeline

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Figure 3-13: Supply Option DE-2

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The capital cost estimate for option DE-2 is also based on a recent draft cost estimate from the 2021 Marin Water Desalination Supply Study (Marin Municipal Water District, 2021). The total preliminary capital cost for option DE-2 is approximately $378 million. A summary of the DE-2 capital cost is shown in Table 3-21. Additional cost details can be found in Appendix A.

Table 3-21: Preliminary Capital Cost, Supply Option DE-2 Component Description City Cost,
$2023
Seawater Intake
Intake Screens, Pipeline and Pumps
30-inch; 2,000 linear feet Raw Water Pipe to facility
$10,167,000
Desalination Plant
Rapid Mix Strainers, UF and Building, Filtrate and
Backwash Supply Tanks, RO Feed Pump Station, 1st pass
RO and Building, Permeate Tank, Chlorine Contact Tank,
Chemical Facilities, Backwash Equalization Basin, Gravity Thickener, Centrifuges, O&M Building, Sitework/Piping,
Electrical, Instrumentation and Controls
$71,560,000
Brine Disposal
290 horsepower Brine Pump Station
24-inch; 2,000 linear feet Brine Transmission Line
$3,665,000
Distribution
1,880 horsepower Distribution Pump Station
24-inch; 92,600 linear feet Treated Water Line
$94,634,000
Estimating Contingency 50% of raw construction costs $90,020,000 Implementation 40% of total construction costs $108,020,000 Total Capital Cost $378,070,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest $13,330,000 The O&M cost of the project was estimated on a per AF basis for scalability. The DE-2 option has a fixed annual O&M cost of $1,604,000 and an annual marginal O&M cost of approximately $1,165/ AF. Annual O&M costs will vary depending on the production of the desalination facility. It is assumed the desal facility could be turned down to a production capacity of 30 percent during low demand periods. The estimated annual O&M costs for the maximum potential yield of 10,080 AFY is approximately $13.3 million. Table 3-22 summarizes the City’s portion of the estimated annual O&M costs for option DE-2.

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Table 3-22: Preliminary Annual O&M Cost, Supply Option DE-2 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $1,165/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $1,604,000
Average cost of water (Baseline Scenario)1 $4,500/ AF
Annual O&M (10,080 AFY)2 $13,330,000
Cost of water (10,080 AFY)2 $2,700/ AF
Annual O&M (3,360 AFY)3 $5,520,000
Cost of water (3,360 AFY)3 $5,600/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which an average of 4,441 AFY would be produced. Capital and operating costs are included.

2. The maximum supply yield of 10,080 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations.

3. The minimal yield of 3,360 AFY assumes 30 percent turndown of the desalination plant’s maximum yield to provide a range of supply available for the desalination options.

3.1.5 Stormwater Capture Options
SW-1: Capture Excess Winter Flows in Aquifer Storage
Option SW-1 proposes to construct a diversion structure within Santa Rosa Creek to divert excess winter flows to new spreading basins (it may be determined after future investigations that injection wells will be required for groundwater recharge) for storage within the Santa Rosa aquifer to increase the City’s local water supply. The diversion location for this study was assumed to be within Santa Rosa Creek near the existing USGS stream gage 11466320 due to its proximity to Delta Pond for potential storage prior to aquifer recharge via proposed spreading basins in the vicinity (see Figure 3-14). For the 9 MGD supply, 12 new extraction wells would be required. The same assumptions for the GW-1 option were applied for the proposed extraction wells.

A preliminary stream gage analysis was performed to determine the allowable diversion volume from Santa Rosa Creek. The allowable stream diversion period lies within the months of December through March. This level of analysis assumed that all flows above the 90th percentile of stormwater volume within the creek can be diverted unless the diversion amount is greater than 20 percent of the day’s flow (in which case, this analysis capped the diversion volume at 20 percent of that day’s flow). Based on dry year data from 1999 to 2023, the allowable diversion volume between the months of December through March can range from 1,200 to 212,640 AF. For purposes of the current study, it was assumed that adequate volumes are available on average to support the maximum annual usage of 7,500 AFY, accounting for the need to withdraw less than the amount recharged, and that sufficient aquifer storage exists to buffer intra-year and inter-year supply variations.

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Figure 3-14: Supply Option SW-1

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Components that would need to be constructed as part of option SW-1 include:
• Stormwater diversion structure including pumps, pipes • Spreading basins in the Delta Pond vicinity
• 12 new extraction wells and conveyance
• Treatment plant providing conventional treatment (coagulation, flocculation, sedimentation, filtration); this is a conservative assumption and would need further exploration if the alternative were carried forward.

The total preliminary capital cost for option SW-1 is approximately $223million. A summary of the SW-1 capital cost is shown in Table 3-23. Additional cost details can be found in Appendix A.

Table 3-23: Preliminary Capital Cost, Supply Option SW-1 Component Description Cost, $2023
Santa Rosa Creek Diversion Diversion Structure, including pumps, spreading basins $18,144,000
New Well Construction 12 extraction wells, 500 gpm capacity, 500 feet deep, well head, casing, well pump and equipment $42,000,000 Treatment to Stormwater
Prior to Recharge 9 MGD conventional treatment plant $42,000,000 Groundwater Conveyance 20-inch; 3,000 linear feet $2,225,000 Groundwater Pump Station 240 horsepower $1,560,000
Potable Connection $100,000
Estimating Contingency 50% of raw construction costs $52,980,000 Implementation 40% of total construction costs $38,420,000 Total Capital Cost $222,500,000
Annualized Capital Cost Annualized over 50 years, 2.5% interest 4,741,000 The O&M cost of the project was estimated on a per AF basis for scalability. The SW-1 option has a fixed annual O&M cost of $542,000 and an annual marginal O&M cost of approximately $303/ AF. Annual O&M costs will vary depending on the amount of water diverted from Santa Rosa Creek during winter.

The estimated annual O&M costs for the maximum potential yield of 10,080 AFY is approximately $ 3.6 million. Table 3-24 summarizes the estimated annual O&M costs for option SW-1.

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Table 3-24: Preliminary Annual O&M Cost, Supply Option SW-1 Component Description Cost, $2023
Marginal Cost Marginal costs include power consumption, labor, and chemical addition $303/ AF
Fixed Cost Fixed costs include routine maintenance practices, water quality testing $542,000
Average cost of water (Baseline Scenario)1 $3,500/ AF
Annual O&M (10,080 AFY)2 $3,600,000
Cost of water (10,080 AFY)2 $1,135/ AF
Notes:

1. See Section 2.5 for description of baseline scenario, under which on average 2,600 AFY are produced. Costs include capital and operating.

This baseline estimate of usage is uncertain as it would depend on adequate stormwater being captured and banked to support that level of usage. If this alternative were to be further developed, more detailed modeling would need to be performed.

2. The maximum supply yield of 10,080 AFY assumes 24/7 operation of all supply option infrastructure. This scenario may not reflect realistic operations. This is particularly true for this option, since its operation would be subject to a host of unknowns including hydrologic variations on the intra-seasonal and inter-seasonal timescales that would affect supply availability. Some of those variations, e.g., low stormwater availability, could be temporally correlated with Russian River droughts, thus limiting supplemental supply when it is most needed.

SW-2: Capture Excess Winter Flows in Surface Storage (Lake Ralphine or Alternate) This option explored the possibility of capturing excess winter stormwater flows for surface storage. The City does not currently have unused surface storage. Lake Ralphine holds slightly under 500 AF and served as a historical water supply source for the City (through the late 1950’s) and is currently used for recreation. A review of prior City planning work and City water systems and topography did not yield any alternative surface water sites for further exploration.

In order to store surface water in Lake Ralphine, the existing dam would need to be raised, which would displace the existing recreational areas (picnic areas, ball fields, etc.), which are highly valued by the community and City. The size of a potential reservoir would be limited due to surrounding topography and presence of residential neighborhoods surrounding the reservoir. Even an enlarged Lake Ralphine would likely fill naturally during wet periods, limiting its utility for providing additional stormwater storage in wet months. Furthermore, Lake Ralphine is not used for drinking water supply, meaning that a new water treatment plant would need to be constructed in order to use Lake Ralphine for drinking water supply. Given that enlarging Lake Ralphine would not provide a large water storage benefit and would have substantial financial and social costs (requiring a new treatment plant, impacting City recreational facilities), this supply option did not advance to undergo cost estimation.

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SW-3: Regional Stormwater
Supply option SW-3 proposes developing a regional stormwater project in collaboration with one or more agencies in the region. There are several regional stormwater programs underway that could be bolstered with City partnership and/or used to generate new ideas for a regional project. One such example is a project being explored by North Marin Water District which involves diverting stormwater into Stafford Lake. More information about regional efforts is included in the following plans:

Marin Municipal Water District
• Water Resiliency projects: https://www.marinwater.org/WaterSupplyResiliency North Marin Water District
• Local Water Supply Enhancement Study https://nmwd.com/save-water/new-water-supplies/ Petaluma
• Integrated Water Master Plan https://cityofpetaluma.org/iwmp/ Sonoma Water
• Drought Resiliency Project https://www.sonomawater.org/DroughtResiliency • Regional Water Supply Resiliency Study
• Presentation slides, May 1, 2023
https://www.sonomawater.org/media/PDF/About/WAC/2023_05/Item%207%20 - %202023%20Resiliency%20Update.pdf
• Presentation slides, May 2, 2023
https://www.sonomawater.org/media/PDF/About/WAC/2022_05/7.1.%20SonomaWater_R esiliencyStudy%20WAC%20Update_2022_0502.pdf
• Report: Accelerated 2021-2022 Drought Resiliency Analysis, April 27, 2022 https://www.sonomawater.org/media/PDF/About/WAC/2022_05/7.2.%20Sonoma%20Wat er%20Resiliency%20Study%20-%20Drought%20Analysis%20TM%20FINAL%20DRAFT.pdf • Presentation slides, Drought Options Update, Feb 7, 2023 https://www.sonomawater.org/media/PDF/About/WAC/2022_02/12.%20SonomaWater_R esiliencyStudy_WAC_Update_2022_0207_REDUCED.pdf
• Presentation slides, Nov 1, 2021
https://www.sonomawater.org/media/PDF/About/WAC/2021_11/Presentation- %20Sonoma%20Water%20Resiliency%20Study.pdf
• Memo, July 29, 2021
https://www.sonomawater.org/media/PDF/About/WAC/2021_08/9.%20SRP%20Drought% 20Resiliency%20Project%20WACTAC%20memo.pdf
San Francisco Estuary Institute
• Laguna de Santa Rosa restoration master plan

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Implementation of this supply option would require identification of feasible detention storage and recharge locations, regional coordination and agreements, and possible need for additional water rights.

Because many project elements and implementation considerations for regional stormwater would be similar to the local stormwater option above (SW-1 and SW-2), and because the City would effectively be participating in possible future regional stormwater projects implemented by Sonoma Water, this option did not undergo any further separate technical analysis.

3.1.6 Efficiency Programs
E-1: Efficiency Programs
Efficiency measures would not provide a new source of drinking water supply to mitigate the impacts of drought and emergencies, but these programs would reduce demand over time as efficiency measures penetrate the City’s customer base. The efficiency program would include a suite of efficiency measures, which are evaluated as a single program, which would be implemented City-wide. These measures are:
• Commercial, industrial, institutional (CII) turf removals, • Single-family residential (SFR) turf removals,
• Toilet direct installs, and
• Fixture direct installs (kitchen aerators, bathroom aerators, and showerheads).

Along with these aggressive efficiency measures, the City’s existing efficiency programs would continue, such as indoor water use efficiency surveys, landscape water use efficiency surveys, and rebates for high- efficiency washing machines, graywater use, and other practices (City of Santa Rosa, 2021). The water savings that can be achieved by the efficiency measures would be limited by factors such as: the number of inefficient toilets and fixtures remaining that could be replaced, the area of turfgrass present, and the extent to which the retrofits/relandscaping could penetrate the market (i.e., number of customers willing/able to participate). For the purposes of this study, program budget was not considered to be a limitation.

The City provided information regarding the estimated costs and water savings that could be achieved via the efficiency program (City of Santa Rosa, 2022) if 100 percent participation were achieved. Full participation voluntarily is unlikely, though the City Code could be updated to mandate changes which may achieve near full participation. In total, up to 5,700 AFY of water savings could be achieved over about the next 40 years with full participation. Descriptions of each efficiency measure, including key assumptions, are summarized below:
• CII turf removals: CII turf removals would remove approximately 16.3 million square feet of turf over about 41 years. A replacement rate of 400,000 square feet per year is assumed (based on 100 sites participating per year, removing an average of 4,000 square feet each). The rebate offered would be $1.50 per square foot of turf removed. Water savings would be about 31 gallons per square foot per year, and the assumed life expectancy of the water savings is 15 years (although this may be higher since customers rarely relandscape back to turf). This measure would yield a lifetime savings of up to 23,000 AF.
• SFR turf removals: SFR turf removals would remove approximately 42.7 million square feet of turf over about 43 years. A replacement rate of 1 million square feet per year is assumed (1,200 homes participating per year, removing an average of 833 square feet each). The rebate offered

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would be $1.50 per square foot of turf removed. Water savings would be about 11 gallons per square foot per year and the assumed life expectancy of the water savings is 15 years (although this may be higher since customers rarely relandscape back to turf). This measure would yield a lifetime savings of up to 22,000 AF.
• Toilet direct installs: The City would replace existing 1.6 gallons per flush (gpf) or greater toilets customers with 0.8 gpf toilets in Santa Rosa residences. It is assumed that 45,600 toilets could be replaced over 15 years, at a rate of approximately 3,000 toilets per year. The life expectancy of the toilet is assumed to be 15 years. In total, toilet replacements would achieve a lifetime water savings of about 6,219 AF. It is assumed that future toilet replacements by residents would maintain the water savings as plumbing codes continue to require greater water efficiency. • Fixture direct installs: The City would replace/install kitchen faucet aerators, bathroom faucet aerators, and 1.5 gpm showerheads. One set of fixtures would consist of one kitchen sink aerator, two-bathroom sink aerators, and two showerheads. It is assumed that 3,000 sets of fixtures could be installed per year over 15 years (about 45,600 households in total). In total, updated fixtures would achieve a lifetime water savings of about 16,000 AF. It is assumed that future fixture replacements by residents would maintain the water savings as plumbing codes continue to require greater water efficiency.

Efficiency program costs would include costs of turf rebates, toilets, and fixtures, labor costs to install toilets and fixtures, and City staff time to implement the program (including outreach to expand the reach of the program). The total lifetime program cost is approximately $169 million, with a lifetime water savings of up to 67,000 AF. At the completion of the program, water savings per year would be up to 5,700 AF. However, given the large levels of uncertainty, an annual savings of 2,145 AFY was assumed, based on estimates of anticipated voluntary participation provided by the City.

Additional detail on data sources and assumptions can be found in Appendix A.

3.2 Screening Analysis Results
All potential water supply options were screened using two key criteria: high-level assessments of cost- effectiveness and scalability. Supply options that performed well in the screening analysis were moved forward to undergo more detailed feasibility analysis and to be scored against each criterion identified in the Study Parameters (Section 2.4).

Table 3-25 summarizes the results of the screening analysis. A total of seven water supply options have been selected to move forward for more detailed feasibility analysis.

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Table 3-25: Screening Analysis Results Summary
Category Supply Option
Moving
Forward? Reasoning for Screening Out
Groundwater
GW-1: Add local
groundwater extraction wells
Yes N/A
GW-2: Convert emergency
wells to production wells
Yes N/A
GW-3: Add local ASR wells Yes N/A
GW-4: Regional
groundwater extraction wells
No Regional groundwater extraction is unlikely to be
accepted without including a recharge element,
which would result in a project similar to the local
and regional ASR options. Thus, this option is not
carried forward on its own.

GW-5: Regional ASR wells No Because many project elements and implementation considerations for Regional ASR
would be similar to the local ASR option above,
this option would not undergo separate technical
analysis.

Purified
Recycled
Water
PR-1: DPR AWPF at LTP No Not cost-effective based on City’s current needs.

PR-2: Satellite DPR AWPF Yes Note: Although the option may be less cost- effective than others carried forward, the City
desires to further advance a purified recycled
water option in order to provide a broader suite of
options and greater diversity to potential supplies.

PR3a: IPR AWPF at LTP via
Delta Pond

No Not cost-effective based on City’s current needs.

PR-3b: IPR AWPF at LTP via
Lake Ralphine
No Not cost-effective based on City’s current needs.

PR-3c: IPR AWPF at LTP via
Lake Sonoma

No Not cost-effective based on City’s current needs.

PR-4: Regional DPR AWPF at
LTP
Yes Note: A regional purified recycled water project
appears most promising in terms of cost-
effectiveness. Changing technology, supply needs,
and partnerships could make this option worth
future consideration.

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Category Supply Option
Moving
Forward? Reasoning for Screening Out
Non-potable
Recycled
Water
RW-1: Expand City’s existing
non-potable recycled water
system
No Not cost-effective based on City’s current needs
and does not address potable water needs in
supply-limited circumstances like drought and
catastrophic supply interruptions.

Desalination
DE-1: Regional brackish
desalination
No Not cost-effective based on City’s current needs
and does not reduce reliance on Somona Water
(in the event of a catastrophic supply interruption)
because of the water transfer involved in this
supply option. Implementation is contingent upon
the substantial involvement of partners, including
Sonoma Water. More information on desalination
as a supply and triggers for its reconsideration is
included in Appendix C.

DE-2: Ocean desalination No Not cost-effective based on City’s current needs.

The required pipeline from the ocean to Santa
Rosa’s service area contributes significantly to the
cost. More information on desalination as a supply
and triggers for its reconsideration is included in
Appendix C.

Stormwater
SW-1: Capture stormwater
and store in aquifer for later
potable use
Yes N/A
SW-2: Store in enlarged Lake
Ralphine (or alternate) and
construct water treatment
plant for later potable use
No The space needed to expand Lake Ralphine to
increase the cost-effectiveness of this option is
not available and constructing new surface water
storage is not cost-effective at this time.

Additional work should be completed to confirm
the yield available for this option before
committing to the costs of an additional facility
required to treat the stormwater prior to use.

SW-3: Regional stormwater No Because many project elements and implementation considerations for Regional
stormwater would be similar to the local
stormwater options above and are being carried
forward through other technical teams as present,
this option would not undergo separate technical
analysis. This does not prohibit the City from
continuing to participate in existing regional
stormwater efforts nor does preclude future
partnerships on new regional stormwater efforts.

Efficiency
Programs
E-1: Add aggressive
incentives for efficiency
programs to reduce demand
(in addition to existing
programs)
Yes N/A

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3.3 Feasibility Analysis Results
Upon completion of the screening analysis, the feasibility analysis was completed, which included evaluating and scoring the short-listed water supply options. A numerical system was used for rating (scoring) each short-listed option against each criterion and against each other. The numerical system provides a score of 0 through 2, with 2 being most favorable. The score is based on knowledge of the project area, engineering judgment, and experience on past projects. The evaluation criteria scoring rubric used for the evaluation of the short-listed supplemental supply options is summarized in Table 2-5, a summary of the shortlist supply scores is shown in Table 3-26. Detailed scoring descriptions are found in the following subsections.

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Table 3-26: Summary of Supply Option Scores
Criterion
Groundwater Purified Recycled Water 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
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]
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 [1,008 - 10,080
AFY]
1 [2,145 AFY]
Resiliency 1 1 2 2 2 1 1
Equity 1 1 1 1 1 1 2
Environmental
performance 1 2 1 0 1 1 2
Legal, permitting,
and regulatory 1 2 0 0 0 1 2
City control and
interagency
coordination
2 2 1 2 0 2 2
Multi-benefit 0 0 1 0 0 2 1
Total Unweighted 10 10 9 7 6 9 12
Total Weighted 32 26 29 21 22 19 30
* Costs shown reflect a realistic baseline usage scenario and include both capital and operating costs.

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Figure 3-15 shows cost-effectiveness under baseline operations along with maximum yield and incorporates the weighted scores of each supply option in the bubble sizes (as summarized in Table 3-26).

Figure 3-15: Cost-Effectiveness vs Max Yield (with Weighted Score)

3.3.1 Groundwater Options
The detailed scoring and rationale for the groundwater options are provided in Table 3-27, Table 3-28 and Table 3-29 on the following pages below.

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Table 3-27: Detailed Scoring for Option GW-1
Criterion Description Score
Cost effectiveness Under the baseline scenario, actual costs are estimated at $843/AF, making this option one of the least expensive studied, and less expensive than the current Sonoma Water supply which is $1,200/AF. 2 Scalability As evaluated, this option includes construction of 12 wells to meet the City’s supply goals. However, the City need not construct all 12 wells initially, and could potentially build fewer even in the long run if well yield is higher than estimated. Generally, this option could be scaled or phased to best fit City needs.
2 Resiliency Moderate resiliency. Pumping costs would increase with rising power costs. Cost-effectiveness could decrease under certain hydrologic conditions, but groundwater availability may not be severely impacted unless there is a long-term change in hydrology.
1 Equity The additional groundwater supply would have no impact on vulnerable communities. The additional groundwater supply would be available to the City to offset purchased water from Sonoma Water.
1 Environmental
performance
The new extraction wells would be located in the City within the City's Greenway Area. Construction of 12 wells would have moderate potential for environmental impacts.
1 Legal, permitting,
and regulatory
Well construction would likely require some permitting and regulatory compliance but would not require unusual efforts.
1 City control and
interagency
coordination
While coordination with Sonoma Water and the other GSAs in Santa Rosa Plain would be required, the scope and timing of the work would be generally at the City’s discretion.
2 Multi-benefit No other benefits provided. 0

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Table 3-28: Detailed Scoring for Option GW-2
Criterion Description Score
Cost effectiveness Based on conceptual analyses, the rehabilitation of the three existing emergency wells would provide up to 2,462 AFY of additional groundwater supply. The baseline scenario average cost of water is approximately $541/AF, the least expensive of all options studied. 2 Scalability This option lends itself to phasing since well rehabilitation could occur one well at a time. However, the overall scale of the project would fall far short of the City’s 7,500 AFY need.
0 Resiliency Moderate resiliency. Pumping costs would increase with rising power costs. Cost-effectiveness could decrease under certain hydrologic conditions, but groundwater availability may not be severely impacted unless there is a long-term change in hydrology.
1 Equity The additional groundwater supply would have no impact on vulnerable communities. The additional groundwater supply would be available to the City to offset purchased water from Sonoma Water.
1 Environmental
performance
The rehabilitation of the existing wells would have minimal potential for environmental impacts.
2 Legal, permitting,
and regulatory
The City has previously completed similar permitting/ regulatory efforts required for approval to convert from emergency use to active supply (i.e., 2005 Farmer's Lane well).
2 City control and
interagency
coordination
No interagency coordination would be required. 2
Multi-benefit No other benefits provided. 0

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Table 3-29: Detailed Scoring for Option GW-3
Criterion Description Score
Cost effectiveness Based on conceptual level cost estimates, construction of six ASR wells would provide up to 5,130 AFY of additional groundwater supply. The baseline scenario average cost of water is approximately $2,632/AF which includes purchase of water ASR.
2 Scalability The extraction wells included in this option could be constructed in phases to best fit City needs. At buildout, the option could provide most of the City’s supplemental needs.
1 Resiliency Moderate resiliency. Pumping and injection costs would increase with rising power costs. Cost-effectiveness could decrease under certain hydrologic conditions, but the ability to inject water into the aquifer would improve resiliency relative to extraction-only options. 2 Equity The additional groundwater supply would have no impact on vulnerable communities. The additional groundwater supply would be available to the City to offset purchased water from Sonoma Water.
1 Environmental
performance
The new ASR wells would be located in a less developed area within the City limits. Construction of six wells would have moderate potential for environmental impacts.
1 Legal, permitting,
and regulatory
While ASR projects are increasingly common, they pose more significant permitting and regulatory requirements.
0 City control and
interagency
coordination
Coordination would be required with GSAs in Santa Rosa Plain and with Sonoma Water to coordinate with other ASR programs underway. 1 Multi-benefit This option would enable conjunctive management of surface water and groundwater, which allows for greater flexibility in optimizing surface water and groundwater use (which represents an additional benefit beyond strict water supply).
1 City of Santa Rosa (project #0012267.00) 72 Woodard & Curran, Inc.

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3.3.2 Purified Recycled Water Options
The detailed scoring and rationale for the purified recycled water options are listed in Table 3-30 and Table 3-31.

Table 3-30: Detailed Scoring for Option PR-2
Criterion Description Score
Cost effectiveness Under the baseline scenario the average cost of water is approximately $3,854/AF, making it the most expensive option.

Additionally, the option involves a financial upfront commitment for capital so even if future circumstances changed the obligation to pay for the project would continue unabated. 0 Scalability The AWPF included in this option could be constructed in phases to best fit City needs. The AWPF could be scaled down 30% in low demand periods.
2 Resiliency High resiliency. The ability to purify tertiary treated water into potable supply would improve resiliency, even in times of drought or future hydrologic uncertainty.
2 Equity The additional purified water supply would have no impact on the City’s vulnerable communities as it will meet or exceed drinking water standards.
1 Environmental
performance
The satellite DPR AWPF would be located in a less developed area within the City limits. Construction of the AWPF and extensive conveyance facilities may have moderate to high potential for environmental impacts.
0 Legal, permitting,
and regulatory
High permitting/regulatory effort would be required as
discussed in Section 3.1.2.1.2. The main challenges in pursuing DPR include the lack of regulatory certainty and the lack of permitting precedents.
0 City control and
interagency
coordination
No significant interagency coordination would be required. 2 Multi-benefit This option would provide a potable supply benefit but would reduce tertiary water availability for the Geysers and for the non- potable customers.
0 City of Santa Rosa (project #0012267.00) 73 Woodard & Curran, Inc.

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Table 3-31: Detailed Scoring for Option PR-4
Criterion Description Score
Cost effectiveness Under the baseline scenario the average cost of water is approximately $3,166/AF, making it among the most expensive options. Additionally, the option involves a financial upfront commitment for capital so even if future circumstances changed the obligation to pay for the project would continue unabated. 0 Scalability The AWPF included in this option could be constructed in phases to best fit City needs. The AWPF could be scaled down 30% in low demand periods.
2 Resiliency High resiliency. The ability to purify tertiary treated water into potable supply would improve resiliency, even in times of drought or future hydrologic uncertainty.
2 Equity The additional purified water supply would have no impact on the City’s vulnerable communities.
1 Environmental
performance
The DPR AWPF would be located on the City-owned LTP
property. Construction of the AWPF and purified water
conveyance facilities would have low to moderate potential for environmental impacts.
1 Legal, permitting,
and regulatory
High permitting/regulatory effort would be required as
discussed in Section 3.1.2.1.2. The main challenges in pursuing DPR include the lack of regulatory certainty and the lack of permitting precedents.
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 This option would provide a potable supply benefit but would reduce tertiary water availability for the Geysers and for the non- potable customers.
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3.3.3 Stormwater Capture
The detailed scoring and rationale for SW-1 is listed in Table 3-32.

Table 3-32: Detailed Scoring for Option SW-1
Criterion Description Score
Cost Effectiveness The baseline scenario average cost of water is approximately $3,500/AF, making it among the most expensive options.
0 Scalability While the diversion structure, spreading basins (or injection wells) and extraction wells included in this option could be constructed in phases, the treatment plant, if needed, would require significant cost up-front that could not be recovered even if changes in future conditions reduced the need for the project.
1 Resiliency Moderate resiliency. While the ability to store water in the aquifer would improve resiliency, there are significant uncertainties in the project’s performance, specifically its yield in drought years. 1 Equity The additional groundwater supply would have no impact on vulnerable communities. The recharge areas for the project may tend to focus construction impacts on less-developed, less affluent areas, which could reduce flooding in those areas.
1 Environmental
performance
The new diversion structure, spreading basins and extraction wells would be located in a less developed area within the City limits.

Construction of the twelve wells would have moderate potential for environmental impacts.
1 Legal, permitting,
and regulatory
Some permitting/regulatory effort would be required, but stormwater diversion projects are increasingly common and would not require outsize legal, permitting, or regulatory effort to implement. 1 City control and
interagency
coordination
No interagency coordination would be required.
2 Multi-benefit This option would enable conjunctive management of surface water and groundwater, which allows for greater flexibility in optimizing surface water and groundwater use (which represents an additional benefit beyond strict water supply).
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3.3.4 Efficiency Programs
The detailed scoring and rationale for the Efficiency Programs option is provided in Table 3-33.

Table 3-33: Detailed Scoring for Option E-1
Criterion Description Score
Cost effectiveness As summarized above, based on cost estimates provided by the City, efficiency program would provide water savings at a cost of approximately $2,780/AF under the Baseline Scenario. This makes it less expensive than the options involving major costs for water treatment (e.g., PR-2, PR-4, SW-1) but more expensive than the groundwater options.
1 Scalability Water savings could be increased depending on the scale of the program and number of customers that could be reached. Once water savings are achieved, they are considered to be relatively secure because they are built into the landscapes/fixtures, which have typically become more efficient with time due to plumbing codes and price signals. 1 Resiliency Performance of efficiency measures would not degrade with changes in future regulations, energy costs or hydrology. However, the option does not provide “new water” that would help mitigate catastrophic loss of the Sonoma Water supply.
1 Equity Direct installation programs reduce barriers to participation by low- income residents and organizations and agencies managing low-income and subsidized housing that have not been able to participate in rebate programs in the past due to upfront costs.
2 Environmental
performance
The program would have little to no adverse environmental impact and would provide a potential environmental benefit by reducing water consumption.
2 Legal, permitting,
and regulatory
Large-scale construction would not be needed. Physical changes as a result of the project would include toilet and fixture replacements, and relandscaping in existing developed areas. Work would need to be completed by qualified contractors, but additional permitting and regulatory requirements would not be anticipated for this option. 2 City control and
interagency
coordination
No interagency coordination would be required. 2
Multi-benefit In addition to providing water savings, the program would provide a cost savings to customers by helping them to reduce their water use. 1 City of Santa Rosa (project #0012267.00) 76 Woodard & Curran, Inc.

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3.3.5 Cost Sensitivity Analysis
The screening tool allows the supply option costs to be estimated under a variety of scenarios. The baseline scenario was modified to assess supply option performance under multiple hydrologic scenarios (Figure 3-16), and multiple Sonoma Water dry-year reduction levels (Figure 3-17). In that figure, scenarios SW-35 and SW-40 represent dry-year reductions of 35 percent and 40 percent respectively, versus a base scenario of 30 percent.

In general, most supply options would be more cost-effective in a drier hydrologic scenario because more water would be produced to meet normal demand during Sonoma Water water shortages. The wetter hydrologic scenario contains more wet years than the baseline, but also contains more dry years (as summarized in Table 3-34). Therefore, for some options, the wetter scenario is also more cost-effective than the baseline scenario. All supply options become more cost-effective if greater dry-year Sonoma Water reductions are assumed.

Figure 3-16: Supply Option Cost Performance with Varying Hydrology ($/AF)

Table 3-34: Distribution of Water Year Types in Hydrologic Scenarios Hydrologic Scenario
Year Types by Percent
Wet Normal Dry
Wet 37% 29% 34%
Historic 33% 37% 30%
Dry 23% 30% 47%

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Figure 3-17: Supply Option Cost Performance with Varying Sonoma Water Cutbacks ($M/yr)

SW35: Scenario in which dry-year Sonoma Water supply reduction is 35% of baseline usage rather than the Base assumption of 30% reduction.

SW40: Scenario in which dry-year Sonoma Water supply reduction is 40% of baseline usage.

Although this analysis focused on hydrologic scenarios and Sonoma Water cutbacks, reflecting the City’s goals of addressing climate change and Sonoma Water reliance, future work could use other variables to test cost-sensitivity (such as price of power, interest rate, and demand reduction percent).

4. CONCLUSIONS
This Feasibility Analysis reveals several key considerations for the City to account for as the Water Supply Plan moves forward:
• Future conditions: Depending on the City’s assumptions about future hydrology, Sonoma Water supply reductions, cost of Sonoma Water supplies, and customer demand/conservation, the City may reach different conclusions about the potential best fit water supplies. For example, if the City assumes more optimistic future conditions, the amount of new water needed may be relatively modest, in which case the City would be well served by bridging that gap with a small number of new wells, which could be added one by one as the need arises. On the other hand, if the City assumes more pessimistic future conditions in which existing water supplies decrease, a broader range of options could be considered, including options such as potable reuse that would be run continuously once implemented. Options that could be implemented in phases (e.g., rehabilitating one well at a time, rather than 3 at once) may help provide resiliency against that type of uncertainty while minimizing capital outlay. • Operational assumptions: This analysis has incorporated reasonable operational assumptions into the baseline scenario. The cost per AF of water is sensitive to those assumptions. Generally,

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the cost per AF for a supplemental supply will be reduced as that supply is used more. However, many of the options cost more than the existing Sonoma Water supply. • Sensitivity: This analysis considered the impact of changing hydrology and reduced Sonoma Water dry-year allocations under the baseline scenario. The supply options generally become more cost-effective under more pessimistic scenarios (drier hydrology and higher Sonoma Water cutbacks) because more water is produced via the new options. However, the analysis indicates that the relative rankings of the supply options do not vary substantially with changes to the baseline condition.

The next step of the WSAP will involve a portfolio analysis, which will further assess the water supply options that passed the screening analysis. The portfolio analysis will consider downscaled versions of some supply options and will consider potential groupings of supply options that would allow the City to optimize different areas such as resiliency, supply volume, and cost.

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5. REFERENCES
California Department of Water Resources. (2022, August). The California Department of Water Resources' Statewide Airborne Electromagnetic Survey Project, Report for Survey Area 3.

City of Santa Rosa. (2007). Incremental Recycled Water Program. August 2007 Update to the Recycled Water Master Plan.

City of Santa Rosa. (2018, February). Regional Water Reuse System Master Plan.

City of Santa Rosa. (2021, June). 2020 Urban Water Management Plan.

City of Santa Rosa. (2022, December). WUE Water Savings (Spreadsheet).

City of Santa Rosa. (2023, February). Recycled Water Flows - Volume and User Type by Month 2019-2022.

Marin Municipal Water District. (2021, October 18). Draft Technical Memorandum: MMWD Desalination Supply Study.

Santa Rosa Plain Groundwater Sustainability Agency. (2021, December). Groundwater Sustainability Plan:

Santa Rosa Plain Groundwater Subbasin.

Sonoma Water. (n.d.). Santa Rosa Plain Drought Resiliency Project. Retrieved from https://www.sonomawater.org/DroughtResiliency
State of California Code of Regulations Title 22, Division 4. Environmental Health, Chapter 3 Water Recycling Criteria.

State Water Resources Control Board. (2021, August 17). A Proposed Framework of Regulating Direct Potable Reuse in California Addendum, version 8-17-2021.

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APPENDIX A: COST DETAILS

Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option GW-1a: Groundwater Extraction Wells
Size Units Qty Unit Unit Cost Subtotal
Additional Wells
New Well Construction 500 gpm 12 per well $3,500,000 42,000,000 Product Water Distribution
Product Water Line 20 in 3,000 per inch-dia LF $37 2,225,000 Product Water Pump Station 240 HP $6,500 1,560,000
Potable Connection 1 LS $100,000 100,000
Raw Construction Cost 45,890,000
Construction Contingency 50% 22,950,000
Total Construction Cost 68,840,000
Implementation Cost 40% 27,540,000
Total Capital Cost 96,380,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Product Water Pump Station 6,000 118 1,405,080 $0.20 281,016 Extraction Wells 10,080 $54 547,865
Extraction Well Energy Use 10,080 $182 1,834,401
Fixed O&M Construction Cost Unit Cost
Extraction Wells $443,119 443,119
Pump Stations 1,560,000 3.0% 46,800
Pipelines 2,225,000 0.5% 11,125
Total Annual Operations & Maintenance Cost 3,164,326
Annualized Capital Cost 0.03526 3,398,000
Total Annualized Cost 6,562,326
Max Project Yield (AFY) 10,080
MAX $/AF 651
Annual Operations & Maintenance Cost (0 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Product Water Pump Station 0 118 0 $0.20 -
Extraction Wells 0 $54 -
Extraction Well Energy Use 0 $182 -
Fixed O&M Qty Unit Construction Cost Unit Cost
Extraction Wells $443,119 443,119
Pump Stations 1,560,000 3.0% 46,800
Pipelines 2,225,000 0.5% 11,125
Total Annual Operations & Maintenance Cost 501,044
Annualized Capital Cost 0.03526 3,398,000
Total Annualized Cost 3,899,044
Min Project Yield (AFY) 5,880
MIN $/AF 663
Basis of estimate:

Construct additional production wells and wellhead treatment if necessary and tie into the existing distribution system. The no. of wells to meet the demand would be 9 wells for the drought demand of 7,500 AFY and 12 wells for the peak demand of 9 MGD (or 10,000 AFY), based on the well capacity of 500 gpm. The costs were built upon existing City O&M data and well rehab of Leete Well.

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Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option GW-2: Convert existing emergency wells into groundwater extraction wells Size Units Qty Unit Unit Cost Subtotal
Well Rehabilitation
Well Construction 3 per well $1,440,000 4,320,000
Product Water Distribution
Product Water Line in per inch-dia LF $37 -
Product Water Pump Station HP $6,500 -
Potable Connection LS $100,000 -
Iron and Manganese Treatment 2 per well $600,000 1,200,000 Raw Construction Cost 5,520,000
Construction Contingency 50% 2,760,000
Total Construction Cost 8,280,000
Implementation Cost 40% 3,310,000
Total Capital Cost 11,590,000
Annual Operations & Maintenance Cost (2.19 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
0 $0.20 -
Extraction Wells 2,462 $54 133,814
Extraction Well Energy Use 2,462 $182 448,045
Fixed O&M Construction Cost Unit Cost
Wells $110,780 110,780
Pump Stations - 3.0% -
Pipelines - 0.5% -
Treatment 1,200,000 1.0% 12,000
Total Annual Operations & Maintenance Cost 704,639
Annualized Capital Cost 0.03526 409,000
Total Annualized Cost 1,113,639
Max Project Yield (AFY) 2,462
MAX $/AF 452
Annual Operations & Maintenance Cost (0 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Product Water Pump Station 0 118 0 $0.20 -
Extraction Wells 0 $54 -
Extraction Well Energy Use 0 $182 -
Fixed O&M Qty Unit Construction Cost Unit Cost
Extraction Wells $110,780 110,780
Pump Stations - 3.0% -
Pipelines - 0.5% -
Total Annual Operations & Maintenance Cost 110,780
Annualized Capital Cost 0.03526 409,000
Total Annualized Cost 519,780
Min Project Yield (AFY) 1,436
MIN $/AF 362
Basis of estimate:

Assumes 3 existing emergency wells rehabilitated to become prdocution wells for the City. Assumes the costs to rehabilitate the Leete well. Historic yield for the 3 wells is 2,462 AFY.

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Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option GW-3: ASR Wells
Size Units Qty Unit Unit Cost Subtotal
ASR
New Well Construction 6 per well $5,000,000 30,000,000
Product Water Distribution
Product Water Line 16 in 12,000 per inch-dia LF $37 7,120,000 Product Water Pump Station 210 HP $6,500 1,365,000
Potable Connection 1 LS $100,000 100,000
Raw Construction Cost 38,590,000
Construction Contingency 50% 19,300,000
Total Construction Cost 57,890,000
Implementation Cost 40% 23,160,000
Total Capital Cost 81,050,000
Annual Operations & Maintenance Cost (4.6 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Product Water Pump Station 3,180 118 744,660 $0.20 148,932 ASR Well 5,130 $65 334,589
ASR Well Energy Use 5,130 $218 1,120,295
Fixed O&M Qty Unit Construction Cost Unit Cost
Pump Stations 1,365,000 3.0% 40,950
Pipelines 7,120,000 0.5% 35,600
ASR Well $44,312 44,312
Total Annual Operations & Maintenance Cost 1,724,678
Annualized Capital Cost 0.03526 2,858,000
Total Annualized Cost 4,582,678
Max Project Yield (AFY) 5,130
MAX $/AF 893
Annual Operations & Maintenance Cost (0 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Product Water Pump Station 0 118 0 $0.20 -
ASR Well 5,130 $65 334,589
ASR Well Energy Use 5,130 $218 1,120,295
Fixed O&M Qty Unit Construction Cost Unit Cost
Pump Stations 1,365,000 3.0% 40,950
Pipelines 7,120,000 0.5% 35,600
ASR Well $44,312 44,312
Total Annual Operations & Maintenance Cost 1,575,746
Annualized Capital Cost 0.03526 2,858,000
Total Annualized Cost 4,433,746
Min Project Yield (AFY) 2,993
MIN $/AF 1,482
Basis of estimate:

Constructs six ASR wells in Delta Pond area and wellhead treatment if necessary and tie into the existing distribution system. The costs were built upon existing City O&M data and well rehab of Leete Well.

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Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option PR-1: DPR at LTP
Size Units Qty Unit Unit Cost Subtotal
Equalization 1,820,000 per gallon $1.25 2,275,000
Tertiary to AWTF
Tertiary Water Line to AWPF 24 in 500 per inch-dia LF $37 445,000 Tertiary Pump Station HP $6,500 -

AWTF - DPR
Ozone 11.4 MGD $530,000 6,025,000
BAF 11.4 MGD $480,000 5,457,000
MF/UF 10.6 MGD $1,940,000 20,510,000
Interprocess Tank 220,000 per gallon $1.25 275,000
RO 9.0 MGD $2,340,000 21,028,000
Chemicals (Storage and Feed Systems) 9.0 MGD $200,000 1,797,000 Sitework/Piping/Structures 9.0 MGD $5,050,000 45,381,000 Waste Disposal to Headworks at LTP 10 in 500 per inch-dia LF $37 185,400 Brine Disposal
Zero Liquid Discharge 9.0 per MGD $1,194,000 10,730,000 Product Water Distribution
Product Water Line 20 in 26,330 per inch-dia LF $37 19,528,100 Product Water Pump Station 625 HP $6,500 4,062,500
Potable Connection 1 LS $100,000 100,000
Raw Construction Cost 137,800,000
Construction Contingency 50% 68,900,000
Total Construction Cost 206,700,000
Implementation Cost 40% 82,680,000
Total Capital Cost 289,380,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M QTY GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station
Product Water Pump Station 6,241 297 3,669,660 $0.20 733,932 FAT System 7,157,231 $0.20 1,431,446
Ozone/ BAF System 2,004,332 $0.20 400,866
Evaporator 27,178,376 $0.20 5,435,675
Crystallizer 4,982,702 $0.20 996,540
FAT System - Chemicals 1 $326,250 326,250
Ozone/ BAF System - Chemicals 1 $2,250 2,250
Fixed O&M Construction Cost Unit Cost
Treatment 63,750,000 1.0% 637,500
Storage 2,550,000 0.5% 12,750
Pump Stations 4,062,500 3.0% 121,875
Pipelines 20,158,500 0.5% 100,793
Total Annual Operations & Maintenance Cost 10,199,878
Annualized Capital Cost 0.03526 10,203,000
Total Annualized Cost 20,402,878
Max Project Yield (AFY) 10,065
MAX $/AF 2,027
Annual Operations & Maintenance Cost (2.7 mgd production) Annual O&M Variable O&M QTY GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station -
Product Water Pump Station 1,872 297 1,100,880 $0.20 220,176 FAT System 2,147,169 $0.20 429,434
Ozone/ BAF System 601,300 $0.20 120,260
Evaporator 8,153,513 $0.20 1,630,703
Crystallizer 1,494,811 $0.20 298,962
FAT System - Chemicals 1 $97,875 97,875
Ozone/ BAF System - Chemicals 1 $675 675
Fixed O&M Construction Cost Unit Cost
Treatment 63,750,000 1.0% 637,500
Storage 2,550,000 0.5% 12,750
Pump Stations 4,062,500 3.0% 121,875
Pipelines 20,158,500 0.5% 100,793
Total Annual Operations & Maintenance Cost 3,671,002
Annualized Capital Cost 0.03526 10,203,000
Total Annualized Cost 13,874,002
Min Project Yield (AFY) 3,019
MIN $/AF 4,595
Basis of estimate:

Option PR-1 would convey the City’s tertiary effluent to an AWPF located at the LTP and return AWPF waste stream to the LTP headworks. The AWPF would include treatment processes in compliance with future anticipated regulations for treated water augmentation. The purified water would be conveyed to SCWA’s 48-inch diameter aqueduct for distribution to the City’s potable water system. PR-1 is limited by the reliable volume of tertiary effluent available, assuming the City would be reducing flow to the Geysers by prioritizing recycled water to its existing irrigation customers and the AWPF. For this level of study it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs and provide any remaining tertiary water to its existing irrigation customers and then to the Geysers.

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Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option PR-2: Satellite DPR
Size Units Qty Unit Unit Cost Subtotal
Equalization 1,820,000 per gallon $1.25 2,275,000
Tertiary to Satellite AWTF
Tertiary Water Line to DPR 24 in 30,100 per inch-dia LF $37 26,789,000 Tertiary Pump Station 510 HP $6,500 3,315,000

AWTF - DPR
Ozone 11.4 MGD $530,000 6,025,000
BAF 11.4 MGD $480,000 5,457,000
MF/UF 10.6 MGD $1,940,000 20,510,000
Interprocess Tank 220,000 per gallon $1.25 275,000
RO 9.0 MGD $2,340,000 21,028,000
Chemicals (Storage and Feed Systems) 9.0 MGD $200,000 1,797,000 Sitework/Piping/Structures 9.0 MGD $5,050,000 45,381,000 Waste Disposal to Sewer 10 in 7,330 per inch-dia LF $37 2,718,200 Brine Disposal
Zero Liquid Discharge 9.0 per MGD $1,194,000 10,730,000 Product Water Line 20 in 2,050 per inch-dia LF $37 1,520,400 Product Water Pump Station 250 HP $6,500 1,625,000
Potable Connection 1 LS $100,000 100,000
Raw Construction Cost 149,550,000
Construction Contingency 50% 74,780,000
Total Construction Cost 224,330,000
Implementation Cost 40% 89,730,000
Total Capital Cost 314,060,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station 8,056 188 3,005,730 $0.20 601,000 Product Water Pump Station 6,241 120 1,477,080 $0.20 295,000 FAT System 7,157,231 $0.20 1,431,446
Ozone/ BAF System 2,004,332 $0.20 400,866
Evaporator 27,178,376 $0.20 5,435,675
Crystallizer 4,982,702 $0.20 996,540
FAT System - Chemicals 1 $326,250 326,250 Ozone/ BAF System - Chemicals 1 $2,250 2,250 Fixed O&M Construction Cost Unit Cost
Treatment 63,750,000 1.0% 637,500
Storage 2,550,000 0.5% 12,750
Pump Stations 4,940,000 3.0% 148,200
Pipelines 31,027,600 0.5% 155,138
Total Annual Operations & Maintenance Cost 10,442,616
Annualized Capital Cost 0.03526 11,073,000
Total Annualized Cost 21,515,616
Max Project Yield (AFY) 10,065
MAX $/AF 2,138
Annual Operations & Maintenance Cost (2.7 mgd production) Annual O&M Variable O&M GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station 2,417 188 901,710 $0.20 180,000 Product Water Pump Station 1,872 120 443,160 $0.20 89,000 FAT System 2,147,169 $0.20 429,434
Ozone/ BAF System 601,300 $0.20 120,260
Evaporator 8,153,513 $0.20 1,630,703
Crystallizer 1,494,811 $0.20 298,962
FAT System - Chemicals 1 $97,875 97,875 Ozone/ BAF System - Chemicals 1 $675 675 Fixed O&M Construction Cost Unit Cost
Treatment 63,750,000 1.0% 637,500
Storage 2,550,000 0.5% 12,750
Pump Stations 4,940,000 3.0% 148,200
Pipelines 31,027,600 0.5% 155,138
Total Annual Operations & Maintenance Cost 3,800,497
Annualized Capital Cost 0.03526 11,073,000
Total Annualized Cost 14,873,497
Min Project Yield (AFY) 3,019
MIN $/AF 4,926
Basis of estimate:

Option PR-2 would convey the City’s tertiary effluent to a satellite AWPF and return AWPF waste stream to the nearest sewer. The AWPF would include treatment processes in compliance with future anticipated regulations for treated water augmentation. The purified water would be conveyed to SCWA’s 48-inch diameter aqueduct for distribution to the City’s potable water system. The satellite AWPF is assumed to be located on City-owned agricultural leased land, Stone Farm for its proximity to the 48-inch aqueduct. For this level of study it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs and provide any remaining tertiary water to its existing irrigation customers and then to the Geysers.

Page 5 of 12 ends

Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option PR-3a: IPR to Delta Pond (GWA)
Size Units Qty Unit Unit Cost Subtotal
Equalization 1,820,000 per gallon $1.25 2,275,000
Tertiary to AWTF
Tertiary Water Line to IPR 24 in 500 per inch-dia LF $37 445,000 Tertiary Pump Station HP $6,500 -

AWTF - IPR
Ozone MGD $530,000 -
BAF MGD $480,000 -
MF/UF 10.6 MGD $1,940,000 20,568,000
Interprocess Tank 221,000 per gallon $1.25 276,000
RO 9.0 MGD $2,340,000 21,087,000
Chemicals (Storage and Feed Systems) 9.0 MGD $200,000 1,802,000 Sitework/Piping/Structures 9.0 MGD $5,050,000 45,509,000 Waste Disposal to Headworks 8 in 500 per inch-dia LF $37 148,300 Brine Disposal
Zero Liquid Discharge 9.0 per MGD $1,194,000 10,760,000 Product Water Distribution
Product Water Line 22 in 41,220 per inch-dia LF $37 33,628,700 Product Water Pump Station 490 HP $6,500 3,185,000
Potable Connection LS $100,000 -
ASR Wells
New Well Construction 500 gpm 12 per well $5,000,000 60,000,000 Raw Construction Cost 199,680,000
Construction Contingency 50% 99,840,000
Total Construction Cost 299,520,000
Implementation Cost 40% 119,810,000
Total Capital Cost 419,330,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station
Product Water Pump Station 6,241 234 2,892,420 $0.20 578,000 FAT System 7,157,231 $0.20 1,431,446
Ozone/ BAF System $0.20 -
Evaporator 27,178,376 $0.20 5,435,675
Crystallizer 4,982,702 $0.20 996,540
FAT System - Chemicals 1 $326,250 326,250 Ozone/ BAF System - Chemicals $2,250 -
ASR Well 10,065 $65 656,445
ASR Well Energy Use 10,065 $218 2,197,955
Fixed O&M Construction Cost Unit Cost
Treatment 52,415,000 1.0% 524,150
Storage 2,551,000 0.5% 12,755
Pump Stations 3,185,000 3.0% 95,550
Pipelines 34,222,000 0.5% 171,110
ASR Wells $265,872 265,872
Total Annual Operations & Maintenance Cost 12,691,749
Annualized Capital Cost 0.03526 14,785,000
Total Annualized Cost 27,476,749
Max Project Yield (AFY) 10,065
MAX $/AF 2,730
Annual Operations & Maintenance Cost (2.7 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station -
Product Water Pump Station 1,872 234 867,690 $0.20 174,000 FAT System 2,147,169 $0.20 429,434
Ozone/ BAF System $0.20 -
Evaporator 8,153,513 $0.20 1,630,703
Crystallizer 1,494,811 $0.20 298,962
FAT System - Chemicals $97,875 97,875
Ozone/ BAF System - Chemicals $675 -
ASR Well 3,024 $65 197,232
ASR Well Energy Use 3,024 $218 660,384
Fixed O&M Construction Cost Unit Cost
Treatment 52,415,000 1.0% 524,150
Storage 2,551,000 0.5% 12,755
Pump Stations 3,185,000 3.0% 95,550
Pipelines 34,222,000 0.5% 171,110
ASR Wells $265,872 265,872
Total Annual Operations & Maintenance Cost 4,558,026
Annualized Capital Cost 0.03526 14,785,000
Total Annualized Cost 19,343,026
Min Project Yield (AFY) 3,019
MIN $/AF 6,406
Basis of estimate:

Option PR-3a would convey the City’s tertiary effluent to an AWPF at LTP and return AWPF waste stream to the headworks at LTP. The AWPF would include treatment processes in compliance with regulations for groundwater recharge. The purified water would be conveyed to a repurposed Delta Pond or a new nearby pond for infiltration; after the minimum retention time of 2-months in the groundwater aquifer, the recharged groundwater could then be extracted. For the 9 MGD supply, 12 new extraction wells would be required. The same assumptions for the GW-1 option were applied for these extraction wells. For this level of study it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs and provide any remaining tertiary water to its existing irrigation customers and then to the Geysers.

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Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option PR-3c: IPR to Lake Sonoma
Size Units Qty Unit Unit Cost Subtotal
Equalization 1,820,000 per gallon $1.25 2,275,000
Tertiary to AWTF
Tertiary Water Line to IPR 24 in 500 per inch-dia LF $37 445,000 Tertiary Pump Station HP $6,500 -

AWTF - IPR
Ozone MGD $530,000 -
BAF MGD $480,000 -
MF/UF 10.6 MGD $1,940,000 20,568,000
Interprocess Tank 221,000 per gallon $1.25 276,000
RO 9.0 MGD $2,340,000 21,087,000
Chemicals (Storage and Feed Systems) 9.0 MGD $200,000 1,802,000 Sitework/Piping/Structures 9.0 MGD $5,050,000 45,509,000 Waste Disposal to Headworks 8 in 500 per inch-dia LF $37 148,300 Brine Disposal
Zero Liquid Discharge 9.0 per MGD $1,194,000 10,760,000 Purified Water Distribution to Lake Sonoma
Product Water Line 22 in 181,300 per inch-dia LF $37 147,910,600 Product Water Pump Station 2,600 HP $6,500 16,900,000
Potable Connection LS $100,000 -
Raw Construction Cost 267,680,000
Construction Contingency 50% 133,840,000
Total Construction Cost 401,520,000
Implementation Cost 40% 160,610,000
Total Capital Cost 562,130,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station
Product Water Pump Station 6,258 1,233 15,278,040 $0.20 3,056,000 FAT System 7,157,231 $0.20 1,431,446
Ozone/ BAF System $0.20 -
Evaporator 27,178,376 $0.20 5,435,675
Crystallizer 4,982,702 $0.20 996,540
FAT System - Chemicals 1 $326,250 326,250
Ozone/ BAF System - Chemicals $2,250 -
0 1 $837,511 837,511
Fixed O&M Construction Cost Unit Cost
Treatment 52,415,000 1.0% 524,150
Storage 2,551,000 0.5% 12,755
Pump Stations 16,900,000 3.0% 507,000
Pipelines 148,503,900 0.5% 742,520
Total Annual Operations & Maintenance Cost 13,869,847
Annualized Capital Cost 0.03526 19,820,000
Total Annualized Cost 33,689,847
Max Project Yield (AFY) 10,065
MAX $/AF 3,347
Annual Operations & Maintenance Cost (2.7 mgd production) Annual O&M Variable O&M GPM TDH (ft) kwh-yr Unit Cost
Product Water Pump Station 1,877 1,233 4,583,430 $0.20 917,000 FAT System 2,147,169 $0.20 429,434
Ozone/ BAF System $0.20 -
Evaporator 8,153,513 $0.20 1,630,703
Crystallizer 1,494,811 $0.20 298,962
FAT System - Chemicals 1 $97,875 97,875
Ozone/ BAF System - Chemicals $675 -
0 1 $587,422 587,422
Fixed O&M Construction Cost Unit Cost
Treatment 52,415,000 1.0% 524,150
Storage 2,551,000 0.5% 12,755
Pump Stations 16,900,000 3.0% 507,000
Pipelines 148,503,900 0.5% 742,520
Total Annual Operations & Maintenance Cost 5,747,820
Annualized Capital Cost 0.03526 19,820,000
Total Annualized Cost 25,567,820
Min Project Yield (AFY) 3,019
MIN $/AF 8,468
Basis of estimate:

Option PR-3c would convey the City’s tertiary effluent to an AWPF at LTP and return AWPF waste stream to the headworks at LTP. The AWPF would include treatment processes in compliance with regulations for surface water augmentation. The purified water would be conveyed to Lake Sonoma through a new purified water line extending to the Lake assuming the existing Geyser’s pipeline corridor/ easement. After the minimum retention time of 2-months in the surface water body, the water could then be recovered using Sonoma Water's existing infrastructure via the Russian River. For this level of study it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs and provide any remaining tertiary water to its existing irrigation customers and then to the Geysers.

Page 7 of 12 ends

Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option PR-4: DPR at LTP
Size Units Qty Unit Unit Cost Subtotal
Equalization 1,820,000 per gallon $1.25 2,275,000
Tertiary to AWTF
Tertiary Water Line to AWPF 24 in 500 per inch-dia LF $37 445,000 Tertiary Pump Station HP $6,500 -

AWTF - DPR
Ozone 11.4 MGD $530,000 6,025,000
BAF 11.4 MGD $480,000 5,457,000
MF/UF 10.6 MGD $1,940,000 20,510,000
Interprocess Tank 220,000 per gallon $1.25 275,000
RO 9.0 MGD $2,340,000 21,028,000
Chemicals (Storage and Feed Systems) 9.0 MGD $200,000 1,797,000 Sitework/Piping/Structures 9.0 MGD $5,050,000 45,381,000 Waste Disposal to Headworks at LTP 10 in 500 per inch-dia LF $37 185,400 Brine Disposal
Zero Liquid Discharge 9.0 per MGD $1,194,000 10,730,000 Product Water Distribution
Product Water Line 20 in 2,200 per inch-dia LF $37 1,631,700 Product Water Pump Station 270 HP $6,500 1,755,000
Potable Connection 1 LS $100,000 100,000
Raw Construction Cost 117,600,000
Construction Contingency 50% 58,800,000
Total Construction Cost 176,400,000
Implementation Cost 40% 70,560,000
Total Capital Cost 246,960,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M QTY GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station
Product Water Pump Station 6,241 128 1,587,780 $0.20 317,556 FAT System 7,157,231 $0.20 1,431,446
Ozone/ BAF System 2,004,332 $0.20 400,866
Evaporator 27,178,376 $0.20 5,435,675
Crystallizer 4,982,702 $0.20 996,540
FAT System - Chemicals 1 $326,250 326,250
Ozone/ BAF System - Chemicals 1 $2,250 2,250
Fixed O&M Construction Cost Unit Cost
Treatment 63,750,000 1.0% 637,500
Storage 2,550,000 0.5% 12,750
Pump Stations 1,755,000 3.0% 52,650
Pipelines 2,262,100 0.5% 11,311
Total Annual Operations & Maintenance Cost 9,624,795
Annualized Capital Cost 0.03526 8,707,000
Total Annualized Cost 18,331,795
Max Project Yield (AFY) 10,065
MAX $/AF 1,821
Annual Operations & Maintenance Cost (2.7 mgd production) Annual O&M Variable O&M QTY GPM TDH (ft) kwh-yr Unit Cost
Tertiary Pump Station -
Product Water Pump Station 1,872 128 476,370 $0.20 95,274 FAT System 2,147,169 $0.20 429,434
Ozone/ BAF System 601,300 $0.20 120,260
Evaporator 8,153,513 $0.20 1,630,703
Crystallizer 1,494,811 $0.20 298,962
FAT System - Chemicals 1 $97,875 97,875
Ozone/ BAF System - Chemicals 1 $675 675
Fixed O&M Construction Cost Unit Cost
Treatment 63,750,000 1.0% 637,500
Storage 2,550,000 0.5% 12,750
Pump Stations 1,755,000 3.0% 52,650
Pipelines 2,262,100 0.5% 11,311
Total Annual Operations & Maintenance Cost 3,387,393
Annualized Capital Cost 0.03526 8,707,000
Total Annualized Cost 12,094,393
Min Project Yield (AFY) 3,019
MIN $/AF 4,006
Basis of estimate:

Option PR-4 would convey the City’s tertiary effluent to an AWPF located at the LTP and return AWPF waste stream to the LTP headworks. The AWPF would include treatment processes in compliance with future anticipated regulations for treated water augmentation. The purified water would be conveyed to SCWA’s 48-inch diameter aqueduct for regional distribution south of the City. PR-4 is limited by the reliable volume of tertiary effluent available, assuming the City would be reducing flow to the Geysers by prioritizing recycled water to its existing irrigation customers and the AWPF. For this level of study it was assumed the City would size the AWPF to meet its 9 MGD peak month supply needs and provide any remaining tertiary water to its existing irrigation customers and then to the Geysers.

Page 8 of 12 ends

Appendix A - Cost Details
Santa Rosa Water Supply Options June 2023
Option RW-1: Recycled Water Expansion
Basis of estimate:
2023 Cost
Santa Rosa Urban Reuse Project 214,011,000 $
Total Capital Cost 214,011,000 $
Annualized Capital Cost 0.03526
7,546,000 $
Annual O&M Cost 1,270,000 $
Total Annualized Cost 8,816,000 $
Yield (AFY) 3000
$/AF 2939
Complete the nonpotable recycled water expansion project evaluated in the Santa Rosa Urban Reuse Project Feasibility Study.

Page 9 of 12 ends

Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023 June 2023
Option DE-1: Regional Desalination Full Project City Portion Basis of estimate:

Size Units Qty Unit Unit Cost Subtotal Subtotal
Intake
Intake Screens, Pipeline and Pumps 15 MGD 1 LS $13,236,000 13,236,000 7,941,600 Raw Water Pipe 15 MGD 1 LS $394,000 394,000 236,400 Desalination Plant
Rapid Mix 15 MGD 1 LS $2,033,000 2,033,000 1,219,800 Strainers, UF and Building 15 MGD 1 LS $17,668,000 17,668,000 10,600,800 Filtrate and Backwash Supply Tanks 15 MGD 1 LS $217,000 217,000 130,200 RO Feed Pump Station 15 MGD 1 LS $4,025,000 4,025,000 2,415,000 1st pass RO and Building, Permeate Tank 15 MGD 1 LS $32,591,000 32,591,000 19,554,600 Chlorine Contact Tank 15 MGD 1 LS $993,000 993,000 595,800 Chemical Facilities 15 MGD 1 LS $11,134,000 11,134,000 6,680,400 Backwash Equalization Basin 15 MGD 1 LS $430,000 430,000 258,000 Gravity Thickener 15 MGD 1 LS $2,390,000 2,390,000 1,434,000 Centrifuges 15 MGD 1 LS $6,810,000 6,810,000 4,086,000 O&M Building 15 MGD 1 LS $5,301,000 5,301,000 3,180,600 Sitework/Piping 15 MGD 1 LS $18,861,000 18,861,000 11,316,600 Electrical 15 MGD 1 LS $11,208,000 11,208,000 6,724,800 Instrumentation and Controls 15 MGD 1 LS $5,604,000 5,604,000 Brine Disposal
Brine Pump Station 15 MGD 1 LS $3,977,000 3,977,000 2,386,200 Brine Transmission Line 15 MGD 1 LS $1,763,000 1,763,000 1,057,800 Distribution
Distribution Booster Pumps 15 MGD 1 LS $4,504,000 4,504,000 2,702,400 Treated Water Line 15 MGD 1 LS $328,000 328,000 196,800 Raw Construction Cost 143,470,000 82,720,000
Construction Contingency 50% 71,740,000 41,360,000 Total Construction Cost 215,210,000 124,080,000
Implementation Cost 40% 86,080,000 49,630,000
Total Capital Cost 301,290,000 173,710,000
Annual Operations & Maintenance Cost (15 mgd production) Annual O&M Annual O&M Variable O&M gpm TDH AFY kwh-yr Unit Cost
Desalination Facility 16,800 27,384,000 $0.20 5,476,800 3,286,080 Distribution Booster Pumps 10,417 200 4,125,600 $0.20 825,120 495,072 Brine Pump Station 11,111 100 2,200,320 $0.20 440,064 264,038 Fixed O&M Construction Cost Unit Cost
Treatment 78,291,000 1.0% 782,910 469,746 Storage 430,000 0.5% 2,150 1,290 Pump Stations 21,717,000 3.0% 651,510 390,906 Pipelines 15,721,000 0.5% 78,605 47,163 Total Annual Operations & Maintenance Cost 8,257,159 4,954,295 Annualized Capital Cost 0.03526 10,623,000 6,125,000 Total Annualized Cost 18,880,159 11,079,295
Max Project Yield (AFY) 16,800 10,080
MAX $/AF 1,124 1,099
Annual Operations & Maintenance Cost (5 mgd production) Annual O&M Annual O&M Variable O&M gpm TDH AFY kwh-yr Unit Cost
Desalination Facility 5,600 9,128,000 $0.20 1,825,600 1,095,360 Distribution Booster Pumps 3,472 200 1,375,200 $0.20 275,040 165,024 Brine Pump Station 4,028 100 797,580 $0.20 159,516 95,710 Fixed O&M Construction Cost Unit Cost
Treatment 78,291,000 1.0% 782,910 469,746 Storage 430,000 0.5% 2,150 1,290 Pump Stations 21,717,000 3.0% 651,510 390,906 Pipelines 15,721,000 0.5% 78,605 47,163 Total Annual Operations & Maintenance Cost 3,340,775 2,004,465 Annualized Capital Cost 0.03526 10,623,000 6,125,000 Total Annualized Cost 13,963,775 8,129,465
Min Project Yield (AFY) 2,240 3,360
MIN $/AF 6,234 2,419
The cost estimate for this option is based on a recent cost estimate from the 2021 MMWD Desalination Supply Study. This option is for a regional desalination plant to be located the MMWD’s Pelican Way Maintenance Yard facility in San Rafael, CA. The MMWD study was based on 15 MGD. It's assumed that Santa Rosa would "buy in" for up to 9 MGD of that 15 MGD and would pay a prorated share of capital and O&M costs.

Page 10 of 12 ends

Appendix A - Cost Details
Santa Rosa Water Supply Options June 2023
Option DE-2: Ocean Desalination Full Project
Size Units Qty Unit Unit Cost Subtotal
Intake
Intake Screens, Pipeline and Pumps 9 MGD 1 LS $7,942,000 7,942,000 Raw Water Pipe 30 in 2,000 inch-dia LF $37 2,225,000
Desalination Plant
Rapid Mix 9 MGD 1 LS $1,220,000 1,220,000
Strainers, UF and Building 9 MGD 1 LS $10,601,000 10,601,000 Filtrate and Backwash Supply Tanks 9 MGD 1 LS $130,000 130,000 RO Feed Pump Station 9 MGD 1 LS $2,415,000 2,415,000
1st pass RO and Building, Permeate Tank 9 MGD 1 LS $19,555,000 19,555,000 Chlorine Contact Tank 9 MGD 1 LS $596,000 596,000
Chemical Facilities 9 MGD 1 LS $6,680,000 6,680,000
Backwash Equalization Basin 9 MGD 1 LS $258,000 258,000 Gravity Thickener 9 MGD 1 LS $1,434,000 1,434,000
Centrifuges 9 MGD 1 LS $4,086,000 4,086,000
O&M Building 9 MGD 1 LS $3,181,000 3,181,000
Sitework/Piping 9 MGD 1 LS $11,316,000 11,316,000
Electrical 9 MGD 1 LS $6,725,000 6,725,000
Instrumentation and Controls 9 MGD 1 LS $3,363,000 3,363,000 Brine Disposal
Brine Pump Station 290 HP $6,500 1,885,000
Brine Transmission Line 24 in 2,000 inch-dia LF $37 1,780,000 Distribution
Distribution Pump Station 1,880 HP $6,500 12,220,000
Treated Water Line 24 in 92,600 inch-dia LF $37 82,414,000 Raw Construction Cost 180,030,000
Construction Contingency 50% 90,020,000
Total Construction Cost 270,050,000
Implementation Cost 40% 108,020,000
Total Capital Cost 378,070,000
Annual Operations & Maintenance Cost (9mgd production) Annual O&M Variable O&M gpm TDH AFY kwh-yr Unit Cost
Desalination Facility 10,080 45,964,800 $0.20 9,192,960 Distribution Pump Station 6,250 893 11,055,060 $0.20 2,211,012 Brine Pump Station 7,107 122 1,714,410 $0.20 342,882
Fixed O&M Construction Cost Unit Cost
Treatment 46,975,000 1.0% 469,750
Storage 258,000 0.5% 1,290
Pump Stations 22,047,000 3.0% 661,410
Pipelines 94,361,000 0.5% 471,805
Total Annual Operations & Maintenance Cost 13,351,109
Annualized Capital Cost 0.03526 13,330,000
Total Annualized Cost 26,681,109
Max Project Yield (AFY) 10,080
MAX $/AF 2,647
Annual Operations & Maintenance Cost (5mgd production) Annual O&M Variable O&M gpm TDH AFY kwh-yr Unit Cost
Desalination Facility 5,600 25,536,000 $0.20 5,107,200
Distribution Pump Station 3,472 893 6,141,690 $0.20 1,228,338 Brine Pump Station 4,028 122 971,550 $0.20 194,310
Fixed O&M Construction Cost Unit Cost
Treatment 46,975,000 1.0% 469,750
Storage 258,000 0.5% 1,290
Pump Stations 22,047,000 3.0% 661,410
Pipelines 94,361,000 0.5% 471,805
Total Annual Operations & Maintenance Cost 8,134,103
Annualized Capital Cost 0.03526 13,330,000
Total Annualized Cost 21,464,103
Min Project Yield (AFY) 3,360
MIN $/AF 7,941
Basis of estimate:

The cost estimate for this option is based on a recent cost estimate from the 2021 MMWD Desalination Supply Study. This option is for a Santa Rosa owned desalination plant to be located south of Bodega Bay. The MMWD Study was based on 15 mgd, it is assumed Santa Rosa only needs to supply 9mgd, the costs were scaled from the 15 mgd plant down to a 9mgd plant.

Page 11 of 12 ends

Appendix A - Cost Details
Santa Rosa Water Supply Options July 2023
Option SW-1: Divert and store in Aquifer
Size Units Qty Unit Unit Cost Subtotal
Santa Rosa Creek Water Diversion
Diversion Structure, including pumps, spreading basins 10,080 per AF $1,800 18,144,000 Conventional Treatment Plant 9 MGD 1 LS $41,925,000 41,925,000 Extraction Wells
New Well Construction 500 gpm 12 per well $3,500,000 42,000,000 Product Water Distribution
Product Water Line 20 in 3,000 per inch-dia LF $37 2,225,000 Product Water Pump Station 240 HP $6,500 1,560,000
Potable Connection 1 LS $100,000 100,000
Raw Construction Cost 105,950,000
Construction Contingency 50% 52,980,000
Total Construction Cost 158,930,000
Implementation Cost 40% 63,570,000
Total Capital Cost 222,500,000
Annual Operations & Maintenance Cost (9 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Diversion Energy Costs 10,080 $16 163,296
Treatment $418,755 418,755
Product Water Pump Station 6,000 118 465,750 $0.20 93,150 Extraction Wells 10,080 $236 2,382,266
Fixed O&M Construction Cost Unit Cost
Treatment $418,755 418,755
Semi-Annual Basin Clearing $21,200 21,200
Well Inspections $10,000 10,000
Operational Labor Costs $10,000 10,000
Extraction Wells $443,119 443,119
Pump Stations 1,560,000 3.0% 46,800
Pipelines 2,225,000 0.5% 11,125
Total Annual Operations & Maintenance Cost 4,018,467
Annualized Capital Cost 0.03526 7,845,000
Total Annualized Cost 11,863,467
Max Project Yield (AFY) 10,080
MAX $/AF 1,177
Annual Operations & Maintenance Cost (0 mgd production) Annual O&M Variable O&M AFY GPM TDH (ft) kwh-yr Unit Cost
Diversion Energy Costs 0 $16 -
Treatment $0 -
Product Water Pump Station 0 118 0 $0.20 -
Extraction Wells 0 $236 -
Fixed O&M Construction Cost Unit Cost
Treatment $418,755 418,755
Semi-Annual Basin Clearing* $21,200.00 21,200
Well Inspections $10,000.00 10,000
Operational Labor Costs $10,000.00 10,000
Extraction Wells $443,119 443,119
Pump Stations 1,560,000 3.0% 46,800
Pipelines 2,225,000 0.5% 11,125
Total Annual Operations & Maintenance Cost 961,000
Annualized Capital Cost 0.03526 7,845,000
Total Annualized Cost 8,806,000
Min Project Yield (AFY) 1,008
MIN $/AF 8,736
Basis of estimate:

The cost estimate for this option is based on a recent cost estimate from Del Puerto. This option is for a stormwater diversion structure within Santa Rosa Creek to store water in the aquifer. This option assumes spreading basins for percolation into the aquifer and new extraction wells.

Page 12 of 12 ends

City of Santa Rosa (project #0012267.00) Woodard & Curran, Inc.

Feasibility Analysis August 2023

APPENDIX B: SCREENING TOOL DETAIL (BASELINE SCENARIO)

Appendix B - Screening Tool Baseline Scenario
Global modeling parameters and assumptions
apply to all scenarios, all options unless otherwise noted.

Global values
2045 Demand (AF/Y) 25,000 25,000 was given value
Max historic demand 23,993 in 2004, not used in calcs
max active savings 7,584 Table 4-1 UWMP; not used in calcs Sonom Water nominal allotment (AF/Y) 29,100 should be constant Sonoma Water peak historic draft (AF/Y) 20,693 just for info, not used in calcs Current groundwater firm capacity (AF/Y) 1,300
Default Sonoma Water $/AF 1,200
discount rate 2.5%
price of power ($/MWh) $200
first year of simulation 2045
planning horizon (yrs) 50
Sonoma cutback and state-imposed rationing by year type Year type
SCWA
Cutback
State-
imposed
Rationing
Wet 0% 0%
Normal 0% 0%
Dry 30% 10%

Page 1 of 15 ends

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 : DN Do nothing
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 0.00 as entered in Options definition Fixed OMR ($M/yr) 0.00 as entered in Options definition Fixed capital + OMR ($M/yr) 0.00 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 28% based on nominal demand
Max AFY supplemental supply 0 AF/yr
Avg Sonoma Water 21,567 AF/yr
Avg Sonoma Water Cost 25.9 $M/yr
Average AFY supplemental 0 based on scenario usage year-by-year, shown below Max supplemental AFY 0
Average marginal OMR $M/yr 0.00 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 0.00 combining with fixed costs shown above Average $/AF supplemental $0
Avg total cost including supplement + Sonoma 25.9 $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 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2046 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2047 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2048 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2049 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2050 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2051 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2052 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2053 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2054 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2055 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2056 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2057 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2058 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2059 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2060 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2061 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2062 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2063 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2064 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2065 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2066 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2067 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2068 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2069 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2070 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2071 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2072 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2073 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2074 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2075 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2076 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2077 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2078 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2079 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2080 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2081 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2082 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2083 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2084 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2085 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2086 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2087 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2088 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2089 Dry 30% 25,000 1,300 0 0 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 0 4,610 28% 28% 7,110 0 2090 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2091 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2092 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2093 Normal 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2094 Wet 0% 25,000 1,300 0 0 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 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
DN
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 2 of 15 ends

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 : GW-1 Add groundwater extraction wells
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 3.40 as entered in Options definition Fixed OMR ($M/yr) 0.50 as entered in Options definition Fixed capital + OMR ($M/yr) 3.90 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 8,726 AF/yr
Avg Sonoma Water 16,216 AF/yr
Avg Sonoma Water Cost 19.5 $M/yr
Average AFY supplemental 6,734 based on scenario usage year-by-year, shown below Max supplemental AFY 8,726
Average marginal OMR $M/yr 1.78 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 5.68 combining with fixed costs shown above Average $/AF supplemental $843
Avg total cost including supplement + Sonoma 25.1 $M/yr Average OMR $/yr 2.28 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 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2046 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2047 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2048 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2049 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2050 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2051 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2052 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2053 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2054 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2055 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2056 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2057 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2058 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2059 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2060 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2061 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2062 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2063 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2064 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2065 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2066 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2067 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2068 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2069 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2070 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2071 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2072 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2073 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2074 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2075 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2076 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2077 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2078 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2079 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2080 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2081 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2082 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2083 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2084 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2085 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2086 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2087 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2088 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2089 Dry 30% 25,000 1,300 5,880 10,080 17,820 12,474 10% 22,500 12,474 15.0 8,726 $264 8,726 0 5% 10% 2,500 8,726 2090 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2091 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2092 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2093 Normal 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 2094 Wet 0% 25,000 1,300 5,880 10,080 17,820 17,820 0% 25,000 17,820 21.4 5,880 $264 5,880 0 0% 0% 0 5,880 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
GW-1
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 3 of 15 ends

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 : GW-2 Convert emergency wells to production wells Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 0.41 as entered in Options definition Fixed OMR ($M/yr) 0.12 as entered in Options definition Fixed capital + OMR ($M/yr) 0.53 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 23% based on nominal demand
Max AFY supplemental supply 2,462 AF/yr
Avg Sonoma Water 20,260 AF/yr
Avg Sonoma Water Cost 24.3 $M/yr
Average AFY supplemental 1,744 based on scenario usage year-by-year, shown below Max supplemental AFY 2,462
Average marginal OMR $M/yr 0.41 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 0.94 combining with fixed costs shown above Average $/AF supplemental $541
Avg total cost including supplement + Sonoma 25.3 $M/yr Average OMR $/yr 0.53 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 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2046 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2047 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2048 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2049 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2050 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2051 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2052 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2053 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2054 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2055 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2056 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2057 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2058 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2059 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2060 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2061 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2062 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2063 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2064 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2065 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2066 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2067 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2068 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2069 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2070 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2071 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2072 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2073 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2074 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2075 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2076 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2077 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2078 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2079 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2080 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2081 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2082 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2083 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2084 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2085 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2086 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2087 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2088 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2089 Dry 30% 25,000 1,300 1,436 2,462 22,264 15,585 10% 22,500 15,585 18.7 5,615 $236 2,462 3,153 23% 23% 5,653 2,462 2090 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2091 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2092 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2093 Normal 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 2094 Wet 0% 25,000 1,300 1,436 2,462 22,264 22,264 0% 25,000 22,264 26.7 1,436 $236 1,436 0 0% 0% 0 1,436 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
GW-2
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 4 of 15 ends

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 : GW-3 Add ASR wells
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) 2.86 as entered in Options definition Fixed OMR ($M/yr) 0.12 as entered in Options definition Fixed capital + OMR ($M/yr) 2.98 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 16% based on nominal demand
Max AFY supplemental supply 5,130 AF/yr
Avg Sonoma Water 18,844 AF/yr
Avg Sonoma Water Cost 22.6 $M/yr
Average AFY supplemental 3,634 based on scenario usage year-by-year, shown below Max supplemental AFY 5,130
Average marginal OMR $M/yr 6.59 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 9.57 combining with fixed costs shown above Average $/AF supplemental $2,632
Avg total cost including supplement + Sonoma 32.2 $M/yr Average OMR $/yr 6.71 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
Supplemental
Supply
Marginal Cost
$M
Take from
storage (AF)
2045 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2046 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2047 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2048 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2049 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2050 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2051 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2052 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2053 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2054 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2055 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2056 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2057 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2058 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2059 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2060 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2061 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2062 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2063 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2064 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2065 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2066 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2067 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2068 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2069 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2070 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2071 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2072 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2073 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2074 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2075 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2076 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2077 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2078 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2079 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2080 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2081 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2082 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2083 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2084 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2085 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2086 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2087 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2088 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2089 Dry 30% 25,000 1,300 2,993 5,130 20,708 14,495 10% 22,500 14,495 17.4 6,705 $1,813 5,130 1,575 16% 16% 4,075 5,130 9.30 0 2090 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2091 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2092 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2093 Normal 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 2094 Wet 0% 25,000 1,300 2,993 5,130 20,708 20,708 0% 25,000 20,708 24.8 2,993 $1,813 2,993 0 0% 0% 0 2,993 5.42 0 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
GW-3
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 5 of 15 ends

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 : PR-1 DPR at Laguna Treatment Plant
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 10.20 as entered in Options definition Fixed OMR ($M/yr) 0.87 as entered in Options definition Fixed capital + OMR ($M/yr) 11.08 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 6,724 AF/yr
Avg Sonoma Water 18,819 AF/yr
Avg Sonoma Water Cost 22.6 $M/yr
Average AFY supplemental 4,131 based on scenario usage year-by-year, shown below Max supplemental AFY 6,724
Average marginal OMR $M/yr 3.83 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 14.90 combining with fixed costs shown above Average $/AF supplemental $3,608
Avg total cost including supplement + Sonoma 37.5 $M/yr Average OMR $/yr 4.70 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 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2046 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2047 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2048 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2049 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2050 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2051 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2052 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2053 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2054 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2055 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2056 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2057 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2058 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2059 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2060 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2061 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2062 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2063 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2064 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2065 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2066 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2067 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2068 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2069 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2070 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2071 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2072 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2073 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2074 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2075 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2076 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2077 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2078 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2079 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2080 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2081 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2082 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2083 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2084 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2085 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2086 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2087 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2088 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2089 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $927 6,724 0 0% 10% 2,500 6,724 2090 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2091 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2092 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2093 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 2094 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $927 3,019 0 0% 0% 0 3,019 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
PR-1
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 6 of 15 ends

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 : PR-2 Satellite DPR (from RW line)
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 11.07 as entered in Options definition Fixed OMR ($M/yr) 0.95 as entered in Options definition Fixed capital + OMR ($M/yr) 12.03 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 6,724 AF/yr
Avg Sonoma Water 18,819 AF/yr
Avg Sonoma Water Cost 22.6 $M/yr
Average AFY supplemental 4,131 based on scenario usage year-by-year, shown below Max supplemental AFY 6,724
Average marginal OMR $M/yr 3.89 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 15.92 combining with fixed costs shown above Average $/AF supplemental $3,854
Avg total cost including supplement + Sonoma 38.5 $M/yr Average OMR $/yr 4.85 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 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2046 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2047 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2048 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2049 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2050 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2051 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2052 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2053 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2054 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2055 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2056 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2057 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2058 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2059 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2060 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2061 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2062 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2063 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2064 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2065 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2066 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2067 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2068 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2069 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2070 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2071 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2072 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2073 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2074 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2075 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2076 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2077 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2078 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2079 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2080 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2081 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2082 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2083 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2084 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2085 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2086 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2087 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2088 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2089 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $943 6,724 0 0% 10% 2,500 6,724 2090 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2091 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2092 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2093 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 2094 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $943 3,019 0 0% 0% 0 3,019 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
PR-2
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 7 of 15 ends

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 : PR-3a IPR to Delta Pond
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 14.78 as entered in Options definition Fixed OMR ($M/yr) 1.07 as entered in Options definition Fixed capital + OMR ($M/yr) 15.85 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 6,724 AF/yr
Avg Sonoma Water 18,819 AF/yr
Avg Sonoma Water Cost 22.6 $M/yr
Average AFY supplemental 4,131 based on scenario usage year-by-year, shown below Max supplemental AFY 6,724
Average marginal OMR $M/yr 3.87 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 19.72 combining with fixed costs shown above Average $/AF supplemental $4,775
Avg total cost including supplement + Sonoma 42.3 $M/yr Average OMR $/yr 4.94 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 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2046 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2047 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2048 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2049 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2050 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2051 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2052 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2053 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2054 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2055 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2056 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2057 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2058 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2059 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2060 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2061 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2062 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2063 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2064 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2065 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2066 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2067 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2068 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2069 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2070 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2071 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2072 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2073 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2074 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2075 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2076 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2077 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2078 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2079 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2080 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2081 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2082 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2083 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2084 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2085 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2086 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2087 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2088 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2089 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $936 6,724 0 0% 10% 2,500 6,724 2090 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2091 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2092 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2093 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 2094 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $936 3,019 0 0% 0% 0 3,019 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
PR-3a
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 8 of 15 ends

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 : PR-3c IPR to Lake Sonoma
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 19.82 as entered in Options definition Fixed OMR ($M/yr) 1.79 as entered in Options definition Fixed capital + OMR ($M/yr) 21.61 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 6,724 AF/yr
Avg Sonoma Water 18,819 AF/yr
Avg Sonoma Water Cost 22.6 $M/yr
Average AFY supplemental 4,131 based on scenario usage year-by-year, shown below Max supplemental AFY 6,724
Average marginal OMR $M/yr 4.96 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 26.57 combining with fixed costs shown above Average $/AF supplemental $6,431
Avg total cost including supplement + Sonoma 49.1 $M/yr Average OMR $/yr 6.75 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 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2046 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2047 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2048 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2049 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2050 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2051 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2052 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2053 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2054 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2055 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2056 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2057 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2058 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2059 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2060 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2061 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2062 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2063 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2064 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2065 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2066 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2067 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2068 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2069 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2070 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2071 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2072 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2073 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2074 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2075 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2076 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2077 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2078 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2079 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2080 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2081 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2082 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2083 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2084 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2085 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2086 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2087 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2088 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2089 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $1,201 6,724 0 0% 10% 2,500 6,724 2090 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2091 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2092 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2093 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 2094 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $1,201 3,019 0 0% 0% 0 3,019 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
PR-3c
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 9 of 15 ends

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 : PR-4 Regional DPR at LTP
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 8.71 as entered in Options definition Fixed OMR ($M/yr) 0.71 as entered in Options definition Fixed capital + OMR ($M/yr) 9.42 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 6,724 AF/yr
Avg Sonoma Water 18,819 AF/yr
Avg Sonoma Water Cost 22.6 $M/yr
Average AFY supplemental 4,131 based on scenario usage year-by-year, shown below Max supplemental AFY 6,724
Average marginal OMR $M/yr 3.66 based on scenario usage year-by-year, shown below Average total $M/yr for supp. Supply 13.08 combining with fixed costs shown above Average $/AF supplemental $3,166
Avg total cost including supplement + Sonoma 35.7 $M/yr Average OMR $/yr 4.37 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 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2046 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2047 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2048 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2049 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2050 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2051 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2052 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2053 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2054 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2055 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2056 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2057 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2058 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2059 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2060 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2061 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2062 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2063 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2064 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2065 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2066 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2067 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2068 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2069 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2070 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2071 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2072 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2073 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2074 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2075 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2076 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2077 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2078 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2079 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2080 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2081 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2082 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2083 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2084 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2085 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2086 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2087 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2088 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2089 Dry 30% 25,000 1,300 3,019 10,065 20,681 14,476 10% 22,500 14,476 17.4 6,724 $885 6,724 0 0% 10% 2,500 6,724 2090 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2091 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2092 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2093 Normal 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 2094 Wet 0% 25,000 1,300 3,019 10,065 20,681 20,681 0% 25,000 20,681 24.8 3,019 $885 3,019 0 0% 0% 0 3,019 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
PR-4
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 10 of 15 ends

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 : RW-1 Nonpotable Recycled Expansion
Storage (AF): 0 as entered in Options definition
Storage threshold ($/AF): 0 (n/a)
Capital cost ($M/yr) 7.55 as entered in Options definition Fixed OMR ($M/yr) 1.27 as entered in Options definition Fixed capital + OMR ($M/yr) 8.82 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 16% based on nominal demand
Max AFY supplemental supply 3,000 AF/yr
Avg Sonoma Water 21,567 AF/yr
Avg Sonoma Water Cost 25.9 $M/yr
Average AFY supplemental 900 based on scenario usage year-by-year, shown below Max supplemental AFY 3,000
Average marginal OMR $M/yr 0.00 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 $9,795
Avg total cost including supplement + Sonoma 34.7 $M/yr Average OMR $/yr 1.27 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 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2046 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2047 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2048 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2049 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2050 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2051 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2052 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2053 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2054 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2055 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2056 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2057 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2058 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2059 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2060 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2061 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2062 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2063 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2064 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2065 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2066 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2067 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2068 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2069 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2070 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2071 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2072 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2073 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2074 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2075 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2076 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2077 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2078 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2079 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2080 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2081 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2082 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2083 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2084 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2085 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2086 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2087 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2088 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2089 Dry 30% 25,000 1,300 0 3,000 23,700 16,590 10% 22,500 16,590 19.9 4,610 $0 3,000 1,610 16% 16% 4,110 3,000 2090 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2091 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2092 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2093 Normal 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 2094 Wet 0% 25,000 1,300 0 3,000 23,700 23,700 0% 25,000 23,700 28.4 0 $0 0 0 0% 0% 0 0 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
RW-1
Supply from existing wells Supp. Supply Rationing Sonoma Water Demand

Page 11 of 15 ends

Santa Rosa City CouncilSeptember 26, 2023

Santa Rosa City Council
September 26, 2023