City Council
September 26, 2023
Colin Close
Senior Water Resources Planner
Feasibility Analysis & Portfolios for the
Water Supply Alternatives Plan
2 Purpose for Today
Staff will present
Final evaluation of supply options
Draft portfolios (mixes of water
supply options to achieve goals)
Seeking Council input on
Study Results
Draft Portfolios
3 Water Supply Alternatives Plan
Purpose
Enhance Santa Rosa’s water supply
resiliency and reliability to mitigate
impacts of shortages due to severe
droughts and emergencies.
Approach
Assess the feasibility of new water
supply options and develop a plan
for increasing resiliency.
4 Key Questions
• How much new water supply is optimal
to mitigate the risk of shortages?
• Which supply options should be studied?
• What criteria should be used to assess
each supply option?
• Which mix(es) of options will best help
us meet our supply resiliency goal?
• What is the most reasonable and
adaptive path forward?
Study
Portfolios
Plan
5 Project Initiation
• April 28, 2022 – City Council / Board of Public Utilities Liaison Subcommittee, by motion, approved staff recommendation to • Solicit proposals for assistance,
• Have the BPU award the contract,
• Have staff and consultant complete the study and prepare a plan, • Have the BPU review the plan, and
• Have staff implement over time and report progress to the BPU. • May 19, 2022 – BPU, by motion, approved staff request to issue a Request for Proposals (RFP) to solicit proposals from qualified consultants to assist.
• July 14, 2022 – Review panel selected Woodard & Curran. • August 10, 2022 – Contract was executed, and work began.
6 Project Overview
ENGAGE STAKEHOLDERS
Get input from a wide range of stakeholders on
project objectives, supply study, portfolios, & plan.
SET OBJECTIVES
Set water supply goals, identify potential supply
options, establish criteria and study methods.
STUDY SUPPLY OPTIONS
Study feasibility of potential water supply options.
Develop and assess portfolios of feasible options.
DEVELOP A PLAN
Develop long-term plan for achieving supply goals.
7 Water Team
Director Burke
Deputy Directors & Staff
Engineering Services
Environmental Services
Local Operations
Regional Operations
Water Resources
7 8
Stakeholder Group
Held 4 three-hour working sessions to
gather input on:
• Goals, supply options, study methodology
• Study results and draft portfolios
• Early draft of plan
Participants included leaders of
organizations in these areas:
• Business & economic interests
• Community & service organizations
• Regional recycled water users
• Environmental & climate interests
• Resources agencies
1. Calpine
2. Community Action Partnership
3. Los Cien Sonoma County
4. NAACP Santa Rosa
5. North Bay Black Chamber of Commerce
6. North Coast Builders Exchange
7. Recycled Water User – Ag
8. Recycled Water User – Urban
9. RED Housing Fund
10. Regional Climate Protection Authority
11. Russian River Watershed Association
12. Russian River Water Protection Committee
13. Santa Rosa Metro Chamber of Commerce
14. Santa Rosa Plain Groundwater Sustainability Agency
15. Santa Rosa Subregional TAC
16. Sonoma Clean Power
17. Sonoma County Alliance
18. Sonoma RCD
19. Sonoma Water
9 • Held 4 two-hour community meetings (Zoom)
• Oct 26, Jan 25, Jun 26, Aug 28
• Provided background, scope, timeline, & updates
• Solicited community input:
Goal & targets, potential supply options, criteria
for assessing options
Study results & portfolios (mixes of supplies)
• Live Spanish interpretation
• Webpage with recordings, slides, meeting schedule
• srcity.org/OurWaterFuture
Our Water Future Community Meetings
10 Board of Public Utilities
• Sep. 15, 2022 - BPU received a staff briefing on
the project scope, timeline, budget, and team.
• Jan. 19, 2023 - BPU held a study session to
receive information and provide input to staff on
the water supply goal and targets, list of water
supply options for consideration, and criteria and
methodology for the feasibility analysis.
• Aug. 17, 2023 - BPU held a study session to
receive information and provide input to staff on
the supply feasibility analysis and draft portfolios.
11 Additional Outreach
• Oct. 2022 – Sep. 2023, staff solicited additional
public input through pubic presentations at
• General Plan open house events
• Subregional Technical Advisory Committee
• Sonoma County Alliance – Water Committee and
General Membership
• Santa Rosa Metro Chamber – Advocacy Committee
• Santa Rosa Plain Groundwater Sustainability
Agency – Advisory Committee
12 Work Completed to Date
Understand the foundational work to build the plan
Katie Cole, Woodard & Curran
13 Project Timeline
We are here!
Soliciting input on
study & portfolios.
Under review by
Water Team &
Stakeholder Group
14 Project Work
Update
Water Team
• 5 working sessions (Oct, Dec, May, Jul, Aug).
• Input on study parameters, study results, portfolios, and early draft of plan.
Community
• 4 community webinars (Oct, Jan, Jun, Aug).
• Input on study parameters, study results, portfolios, and early draft of plan.
Stakeholder Group
• 4 working sessions (Nov, Dec, May, July).
• Input on study parameters, study results, portfolios, and early draft of plan.
Board of Public Utilities
• Contract award, updates, and two study sessions.
Woodard & Curran
• Stakeholder engagement.
• Preparation of deliverables.
15 Feasibility Analysis
Review analysis of water supply options
Katie Cole, Woodard & Curran
16 Water Supply Resiliency Goals
Diversify and increase city supplies
to reduce dependence on Sonoma
Water, particularly during Sonoma
Water supply shortages or
disruption in delivery
Mitigate Droughts
• Produce 30% of city’s water demand
with city supplies
• About 7,500 acre-feet/year in 2045
Mitigate Disasters/Catastrophic Events
• Produce half of normal domestic/indoor
demand with city supplies
• About 9 million gallons per day in 2045
Mitigating Peak Day Demand
• Produce 30% of summer average peak
day demand with city supplies
• About 9 million gallons per day in 2045
17 Study Methodology
1. Pre-screen all supply options to identify any infeasible or duplicative efforts.
2. Screen remaining supply options.
• Use 2 key criteria: high-level assessment of cost effectiveness and scalability. • Document reasoning for why supply options advance for further consideration (or not) • Yield manageable “short list” of options for detailed analysis.
3. Use defined metrics for each criterion for scoring. Assign weight to each criterion to inform scoring process.
18 18 Supply Options for Assessment
Groundwater
GW-1 Additional groundwater extraction wells
GW-2 Conversion of emergency wells to production
GW-3 Aquifer Storage and Recovery (ASR) wells
GW-4 Regional groundwater extraction wells
GW-5 Regional Aquifer Storage and Recovery wells
Purified Recycled Water
PR-1 Produce at LTP for direct potable reuse (DPR)
PR-2 Produce at a satellite location (DPR)
PR-3a Produce at LTP and inject into groundwater
via ASR wells for indirect potable reuse (IPR)
PR-3b Produce at LTP and add to Lake Ralphine
before use (IPR)
PR-3c Produce at LTP and add to Lake Sonoma (or
alternate) before use (IPR)
PR-4 Regional purified recycled water (DPR)
Nonpotable Recycled
RW-1 Expand Nonpotable Recycled Water Service (City)
Desalination
DE-1 Brackish desalination (likely Regional)
DE-2 Ocean desalination (Santa Rosa or Regional)
Surface/Stormwater
SW-1 Capture excess winter flows from Santa Rosa
Creek/Laguna de Santa Rosa, store in aquifer for
later withdrawal
SW-2 Store excess winter flows from Santa Rosa
Creek/Laguna de Santa Rosa, store in enlarged
Lake Ralphine, construct water treatment plant to
withdraw from Lake Ralphine
SW-3 Regional Stormwater
Efficiency Programs
E-1 Aggressive incentives for toilets & turf replacement 18 19
Rationale for Supply Options
• 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, Community, and Stakeholder Group. 19 20
Five Options Removed During Pre-screening Process
Category Supply Option Reason for Removal
Groundwater
GW-4: Regional groundwater wells Regional efforts planned or underway with significant City involvement.
GW-5 Regional Aquifer Storage and Recovery Regional efforts planned or underway with significant City involvement.
Purified
Recycled
Water
PR-3b: Produce at Laguna Treatment Plant and
add to Lake Ralphine before use (indirect use)
Lake Ralphine would not be able to function
effectively for storage.
Surface/
stormwater
SW-2 Store excess winter flows from Santa
Rosa Creek/Laguna de Santa Rosa in enlarged
Lake Ralphine; Construct water treatment
plant to withdraw from Lake Ralphine
Lake Ralphine would not be able to function
effectively for storage.
SW-3 Regional Stormwater Regional efforts planned or underway with significant City involvement.
21 Six Options Removed During Screening Process
Category Supply Option Reason for Removal
Purified
Recycled
Water
PR-1: DPR AWPF at LTP Not cost-effective based on current and projected water supply needs.
PR3a: IPR AWPF at LTP
via Delta Pond Not cost-effective based current and projected water supply needs.
PR-3c: IPR AWPF at LTP
via Lake Sonoma
Not cost-effective based on current and projected water supply needs.
Doesn’t reduce Santa Rosa’s reliance on Sonoma Water.
Non-potable
Recycled
Water
RW-1: Expand existing
recycled water system
Not cost-effective based on current needs. Doesn’t increase potable water supplies to mitigate water shortages or supply interruptions.
Desalination
DE-1: Regional brackish
desalination
Not cost-effective based on current needs. Doesn’t reduce reliance on Sonoma Water system. Relies on water transfers between agencies (no new supply in City limits). Faces significant permitting obstacles and regulatory challenges.
DE-2: Ocean
desalination
Not cost-effective based on current needs. Faces significant permitting obstacles and regulatory challenges.
22 Rationale for Screening
• Retains options that rank higher on cost-effectiveness and scalability. • Keeps options that further diversify portfolio (stormwater, satellite purified water).
• Includes City and Regional projects.
• Includes aggressive efficiency incentives to reduce demand over time. • Integrates input from Water Team, Community, and Stakeholder Group. 22 2323
A Further Note on Stormwater & Desalination
• Two of 3 stormwater options did not advance to detailed analysis • Options would require the construction of a treatment plant • Available stormwater should be confirmed before committing costs to a treatment facility
• Neither desalination option advanced to detailed analysis • Significant permitting and environmental challenges
• Turndown capacity is not ideal for Santa Rosa’s use case • Regional brackish facility does not reduce reliance on Sonoma Water • Ocean desalination requires extensive infrastructure (pipeline to Santa Rosa) 2424
Triggers for Reconsidering Desalination
• Technology that reduces baseline operating costs (improved turndown capacity)
• Less expensive energy prices which reduces operating costs • Project configuration that yields direct water to Santa Rosa • Technology that improves water recovery
2525
7 Options Underwent Further Analysis
• GW-1: Add Extraction Wells
• GW-2: Convert Emergency Wells to Production Wells
• GW-3: Add Aquifer Storage & Recovery Wells
• PR-2: Satellite Direct Potable Reuse
• PR-4: Regional Direct Potable Reuse at Laguna Treatment Plant • SW-1: Stormwater Storage in Aquifer
• E-1: Efficiency Programs
2626
Criteria and Weights Used for Evaluation
Criterion How assessed Weight Score
Multiplier
Cost effectiveness Capital and O&M costs High 5
Scalability Can capacity be tailored to need?
Can actual production be tailored to need? High 5
Resiliency How well does the option perform if future conditions differ from projected? High 3
Equity Does option avoid disproportionate impact on
vulnerable communities? High 3
Environmental
performance Does option minimize adverse effects? High 3 Legal, permitting, and
regulatory
Does the option face major implementation
challenges? Consider level of mitigation required. Med 1 City control and
interagency coordination Would the City be able to tailor to meet City priorities? Med 1 Multi-benefit Does the project provide multiple benefits? Med 1 26 2727
Results of Qualitative Scoring (Higher Score is Better) Criterion
Groundwater Purified Recycled Water Stormwater
E-1:
Efficiency
ProgramsGW-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 2 2 2 0 0 0 1
Scalability 2 0 1 2 2 1 1
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
28 Draft Portfolios
Review draft portfolios & analysis
Katie Cole, Woodard & Curran
29 Rationale for Portfolio Development
• Uses variety of themes to capture different outcomes: least cost, fastest implementation, most water, most flexibility.
• Uses options scoring well in multiple portfolios (efficiency & converting emergency wells).
• Includes options that further diversify portfolio (stormwater, satellite purified water).
• Reflects various implementation logic for portfolio components. • Integrates input from Water Team, Community, and Stakeholder Group. 29 30
Portfolios
Option Description
Portfolio 1
Most
Economical
Portfolio 2
Fastest
Portfolio 3
Most Water
Portfolio 4
Most Adaptive
GW-1 Add Extraction Wells (Up to 12)
GW-2 Convert Emergency Wells to
Production Wells
GW-3 Aquifer Storage & Recovery Wells Consider
PR-2 Satellite Direct Potable Reuse Consider
PR-4 Regional Direct Potable Reuse at
Laguna Treatment Plant Consider
SW-1 Stormwater Storage in Aquifer Consider Consider
E-1 Efficiency Programs
31 Portfolio 1: Cost and Yield Performance
32 Phase 3
Portfolio 1: Implementation Concept
E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct Operate
Design
33 Portfolios
Option Description
Portfolio 1
Most
Economical
Portfolio 2
Fastest
Portfolio 3
Most Water
Portfolio 4
Most Adaptive
GW-1 Add Extraction Wells (Up to 12)
GW-2 Convert Emergency Wells to
Production Wells
GW-3 Aquifer Storage & Recovery Wells Consider
PR-2 Satellite Direct Potable Reuse Consider
PR-4 Regional Direct Potable Reuse at
Laguna Treatment Plant Consider
SW-1 Stormwater Storage in Aquifer Consider Consider
E-1 Efficiency Programs
34 Portfolio 2: Cost and Yield Performance
35 Phase 3
Portfolio 2: Implementation Concept
E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct Operate
Design
GW-1: New
Extraction Wells Siting studies
CEQA Design
Construct
Operate
Reg
process
36 Portfolios
Option Description
Portfolio 1
Most
Economical
Portfolio 2
Fastest
Portfolio 3
Most Water
Portfolio 4
Most Adaptive
GW-1 Add Extraction Wells (Up to 12)
GW-2 Convert Emergency Wells to
Production Wells
GW-3 Aquifer Storage & Recovery Wells Consider
PR-2 Satellite Direct Potable Reuse Consider
PR-4 Regional Direct Potable Reuse at
Laguna Treatment Plant Consider
SW-1 Stormwater Storage in Aquifer Consider Consider
E-1 Efficiency Programs
37 Portfolio 3: Cost and Yield Performance
38 Phase 3
Portfolio 3: Implementation Concept
E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
GW-1: New
Extraction Wells
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct
Siting studies
CEQA Design
Construct
Operate
Design
Operate
Reg
process
PR-2: Direct Potable
Reuse
SW-1: Stormwater
Capture in Aquifer
Planning studies
CEQA
Reg
process
Design
Construct
Operate
Planning studies &
modeling
Design Construct OperatePause while E-1, GW-2, GW-1 advance v
39 Portfolios
Option Description
Portfolio 1
Most
Economical
Portfolio 2
Fastest
Portfolio 3
Most Water
Portfolio 4
Most Adaptive
GW-1 Add Extraction Wells (Up to 12)
GW-2 Convert Emergency Wells to
Production Wells
GW-3 Aquifer Storage & Recovery Wells Consider
PR-2 Satellite Direct Potable Reuse Consider
PR-4 Regional Direct Potable Reuse at
Laguna Treatment Plant Consider
SW-1 Stormwater Storage in Aquifer Consider Consider
E-1 Efficiency Programs
40 Portfolio 4: Cost and Yield Performance (Baseline
Scenario)
41 Phase 3
Portfolio 4: Implementation Concept (Baseline Scenario) E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
GW-1+: New Wells
(Extraction/ASR)
PR-2+: Direct Potable
Reuse
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct
Siting studies
CEQA Design
Construct
OperateDesign
Operate
Pause while E-1, GW-2 advance
Pause while GW-1+ advances
GW-1+ is sized to meet remaining need for water after
E-1 and GW-2 have advanced
Reg
process
PR-2+ moves forward
based on remaining
need for waterPlanning
studies
Design
Construct
Pause while E-1, GW-2, GW-1+ advance
SW-1: Stormwater
Capture in Aquifer OperatePlanning studies
and modeling
Pause for
regs
42 Phase 3
Portfolio 4: Implementation Concept (Alternative Scenario) E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
GW-1+: New Wells
(Extraction/ASR)
PR-2+: Direct Potable
Reuse
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct
Siting studies
CEQA Design
Construct
OperateDesign
Operate
Pause while E-1, GW-2 advance
Pause while GW-1+ advances
GW-1+ is sized to meet remaining need for water after
E-1 and GW-2 have advanced
Reg
process
PR-2+ and SW-1 do
not move past initial
planning stage
because GW-1+
provides remaining
water needed
Planning
studies
Pause while E-1, GW-2, GW-1+ advance
SW-1: Stormwater
Capture in Aquifer Planning studies
and modeling
Pause for
regs
43 Portfolio 4: Cost and Yield Performance
(Alternative Scenario)
44 Phase 3
Portfolio 4: Implementation Concept (Alternative Scenario, Variant 1) What if SW-1 can provide water to GW-1+?
E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
GW-1+: New Wells
(Extraction/ASR)
PR-2+: Direct Potable
Reuse
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct
Siting studies
CEQA Design
Construct
OperateDesign
Operate
Pause while E-1, GW-2 advance
Pause while GW-1+ advances
GW-1+ is sized to meet remaining need for water after
E-1 and GW-2 have advanced
Reg
process
PR-2+ does not
move past initial
planning because
GW-1+ provides
remaining water
needed
Planning
studies
Design
Construct
Pause while E-1, GW-2, GW-1+ advance
SW-1: Stormwater
Capture in Aquifer OperatePlanning studies
and modeling
Pause for
regs
45 Phase 3
Portfolio 4: Implementation Concept (Alternative Scenario, Variant 2) What if GW-1+ is not able to provide the needed water?
E-1: Water Efficiency
GW-2: Reclassify
Existing Wells
GW-1+: New Wells
(Extraction/ASR)
PR-2+: Direct Potable
Reuse
Decision point
Time
Phase 1 Phase 2
Tech study
CEQA Reg
process
Construct
Siting studies
CEQA Design
Construct
OperateDesign
Operate
Pause while E-1, GW-2 advance
Pause while GW-1+ advances
GW-1+ is sized to meet remaining need for water after
E-1 and GW-2 have advanced
Reg
process
PR-2+ is sized to meet
the City’s remaining
need for water Planning
studies
Pause while E-1, GW-2, GW-1+ advance
SW-1: Stormwater
Capture in Aquifer Planning studies
and modeling
Pause for
regs
SW-1 does not move past initial planning
because there is not sufficient water to
achieve cost-effectiveness
46 Portfolio 1 Portfolio 2 Portfolio 3 Portfolio 4
Baseline
Portfolio 4
Alternative
TAFY $M
Comparison of Portfolio Cost and Yield Performances
47 Summary of BPU Discussion
• Supportive of study and portfolio approach.
• Several Board Members requested more information about why desalination options did not advance past the screening step, and what changes in future would trigger reassessing the viability of desalination for City water supply.
• Study report now includes additional information and an appendix discussing desalination.
• Provides more information about its suitability for the City and triggers that may cause the City to reconsider it in the future.
• Portfolio 4 will be updated in the Plan, to identify when and why the City may reconsider desalination as a potential supply source in the future. • Memo appended to the Study Technical Memorandum and the Plan. 48 Next Steps
Review of next steps
Colin Close, Santa Rosa Water
49 Project Timeline and Milestones
WORKING
SESSIONS OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT Water Team WT WT WT WT WT
Stakeholder
Group SG SG SG SG
BPU BPU BPU BPU
Council CC CC
Community Com Com Com Com
KEY
DELIVERABLES
1. Supply goals
2. Supply options
3. Criteria & methods
1. Feasibility study report
2. Synopsis of portfolios
1. Working draft Plan
2. Admin draft Plan
3. Final Plan
50 Discussion/Direction
Seeking Council questions on information
presented.
Seeking Council input on study and
portfolios:
• Is the Council supportive of the evaluation?
• Is the Council supportive of the portfolio
approach, which provides an adaptive
pathway for decision making and
implementation?
51 QUESTIONS and COMMENTS