2019 Water Supply Evaluation Update

Transcription

1 2019 Water Supply Evaluation Update Board Meeting Presented by: Wes Mercado

2 Outline 1. Water demand forecasts 2. Reliability Policy 3. Los Vaqueros Expansion water storage 4. Water supply reliability projects 5. Portfolios and their impacts on reliability 6. Preliminary cost summaries 7. Draft findings and next steps Slide 2

3 Basis of working forecast short-term: mean of 5-year retailer demand requests long-term: 5,000 AFY demand reduction relative to prior WSE Update retailers predict buildout by 2040 West Yost forecast Indoor r-gpcd: 50 to [2017 actual] Outdoor r-gpcd: [2017 actual] UWMP CII: 90% to 100% UWMP Landscape: 75% to 100% Losses: current, or 10% max Water Demand Forecasts Slide 3

4 Reliability Policy Focuses on Risk [reliability] = [demand met]/[total demand] x 100% average shows you what to expect it weighs all the outcomes, good and bad tends to make portfolios appear substantially similar thus, not the best metric for decision-making 90%, 99% exceedance show you how bad it might get it s a way to visualize risk current policy: 1. 90% of the time, have 100% reliability 2. 99% of the time, have at least 85% reliability (max 15% shortage) plan for the worst, expect the best (90, 99% exceedance) (average) Slide 4

5 Risk Model Overview does not just rely on one scenario (historical hydrology) simulates thousands of potential future scenarios looks at a range of supply conditions (e.g., critically dry year), not just average yields annual-time scale models various Delta outage scenarios incorporates experience during the recent drought incorporates potential climate change impacts on supplies one of the tools that can be used for decision-making Slide 5

6 Los Vaqueros and Transfer-Bethany Pipeline enhance diversion, storage & conveyance options. (Source: Contra Costa Water District) Slide 6

7 Los Vaqueros Impacts on Reliability as storage: based on modeling, no significant impacts unintuitive result without more supply, the chance of storing surplus water before a Delta outage emergency is low max storage capacity and evaporation loss are additional limiting factors Slide 7

8 Potential Benefits Beyond the Model monthly operations not modeled e.g. delivering in summer, when Kern banks cannot more facilities to divert and convey water CCWD intakes Freeport/Mokelumne Aqueduct system Transfer-Bethany Pipeline other qualitative benefits from improved regional operational flexibility Slide 8

9 Water Supply Reliability Project Descriptions pt. 1 California o restores reliability by safeguarding existing SWP supplies against Delta outages, climate change, and increased environmental restrictions o not new water, but can still quantify reliability benefits ~11,000 AFY average, behaves like a wet-year supply Potable Reuse o local supply using DSRSD and/or Livermore wastewater o raw water augmentation currently modeled, with ability to phase o yield lowered to 4,000 7,000 AFY for a more conservative estimate of wastewater availability (feasibility study estimated 5,500 10,000 AFY) Sites Reservoir o north-of-delta storage and supply, diverting surplus water with delivery via Delta/SBA o operates primarily as a dry-year supply, although could be available every year o assumed net yield of 5,000 10,000 AFY based on about 50% yield (more water may be available) Slide 9

10 Water Supply Reliability Project Descriptions pt. 2 Regional brackish water desalination o brackish water diverted in east Contra Costa using CCWD water rights o 5,600 AFY conveyed via new intertie or Delta/SBA exchange o in risk model, potable reuse used as surrogate Short-term transfers o temporary water transfer agreement before long-term projects come online, conveyed via Delta/SBA (assumed range: 5,000 10,000 AFY) o Yuba Accord and other existing/potential water transfers assumed to be within this category Other transfers o e.g., transfer of additional CA yield most projects only come online after 2030; short-term transfers help in the interim Slide 10

11 Baseline: The CIP-Only Scenario complete planned CIP projects (new wells, reliability intertie, and COL pipeline) but no new water supplies Slide 11

12 One Possible Fully Utilized Scenario Slide 12

13 1. Adding projects (reverse chronological) K Sites K Potable Reuse 4. 5K Interim Transfers Interim Transfer Years 2029 Transfer Delivery (AFY) 5,000 Sites Start Year Average Sites Delivery (AFY) 5,000 5,000 5,000 Augmentation Phase 1 Start Year Phase 1 Delivery (AFY) 4,000 4,000 Augmentation Phase 2 Start Year Phase 2 Delivery (AFY) 7,000 7,000 Start Year Average Supplemental Transfer (AFY) Slide 13

14 1. Adding projects (reverse chronological) K Sites K Potable Reuse 4. 5K Interim Transfers Interim Transfer Years 2029 Transfer Delivery (AFY) 5,000 example: there is a 99% chance we can deliver at least 55% of demand in 2040, but there is a 1% chance we cannot. example: there is a 90% chance we can deliver at least 89% of demand in 2040, but there is a 10% chance we cannot. Sites Start Year Average Sites Delivery (AFY) 5,000 5,000 5,000 Augmentation Phase 1 Start Year Phase 1 Delivery (AFY) 4,000 4,000 Augmentation Phase 2 Start Year Phase 2 Delivery (AFY) 7,000 7,000 Start Year Average Supplemental Transfer (AFY) Slide 14

15 1. Adding projects (reverse chronological) K Sites K Potable Reuse 4. 5K Interim Transfers Interim Transfer Years 2029 Transfer Delivery (AFY) 5,000 example: there is a 1% chance we will have as much as a 45% shortage in 2040, but there is a 99% chance we will not. example: there is a 10% chance we will have as much as a 11% shortage in 2040, but there is a 90% chance we will not. Sites Start Year Average Sites Delivery (AFY) 5,000 5,000 5,000 Augmentation Phase 1 Start Year Phase 1 Delivery (AFY) 4,000 4,000 Augmentation Phase 2 Start Year Phase 2 Delivery (AFY) 7,000 7,000 Start Year Average Supplemental Transfer (AFY) Slide 15

16 1. Adding projects (reverse chronological) interim transfer benefits persist after transfers end K Sites K Potable Reuse 4. 5K Interim Transfers Interim larger transfers than 5,000 Transfer Years 2029 AFY Transfer are needed to meet 99% Delivery (AFY) 5,000 exceedance reliability goals in Sites Start Year the short-term Average Sites Delivery (AFY) 5,000 5,000 5,000 reliability increases as projects are layered Augmentation Phase 1 Start Year need multiple projects to meet reliability goals Phase 1 Delivery (AFY) 4,000 4,000 Augmentation Phase 2 Start Year alone stops the 90% exceedance reliability decline Phase 2 Delivery (AFY) 7,000 7,000 benefit over the status quo increases with time Start Year Average Supplemental Transfer (AFY) Slide 16

17 2. Eliminating single projects 4K PR, 5K Sites, No Potable Reuse No Sites No Interim Transfer Years Transfer Delivery (AFY) 10,000 10,000 10,000 10,000 Sites Start Year Average Sites Delivery (AFY) 5,000 10,000 10,000 Augmentation Phase 1 Start Year Phase 1 Delivery (AFY) 4,000 4,000 4,000 Augmentation Phase 2 Start Year 2035 Phase 2 Delivery (AFY) 7,000 Start Year Average Supplemental Transfer (AFY) 5,000 Slide 17

18 2. Eliminating single projects need to compensate for 4K PR, No 5K Sites, Potable eliminated projects by scaling Reuse No Sites up remaining projects Interim Transfer Years No No scenario (red) not in equilibrium and needs more supply Transfer Delivery (AFY) 10,000 10,000 10,000 10,000 Sites Start Year Average Sites Delivery (AFY) 5,000 10,000 10,000 ~10,000 AFY interim transfers Augmentation needed to meet reliability Phase 1 Start Year goals at 99% exceedance Phase 1 Delivery (AFY) 4,000 4,000 4,000 easier to get 100% reliability Augmentation 90% of the time than to get Phase 2 Start 85% reliability 99% of the time Year 2035 Phase 2 Delivery (AFY) 7,000 Start Year Average Supplemental Transfer (AFY) 5,000 Slide 18

19 3. Constrained to 5,000 AFY interim transfers 5K Transfers+; 7K PR; 5K WF+ 5K Transfers+; 10K Sites 5K Transfers; 10K Sites; 4K PR 5K Transfers; 5K Sites; 7K PR Interim Transfer Years Transfer Delivery (AFY) 5,000 5,000 5,000 5,000 Sites Start Year Average Sites Delivery (AFY) 10,000 10,000 5,000 Augmentation Phase 1 Start Year Phase 1 Delivery (AFY) 4,000 4,000 4,000 Augmentation Phase 2 Start Year Phase 2 Delivery (AFY) 7,000 7,000 Start Year Average Supplemental Transfer (AFY) 5,000 Slide 19

20 3. Constrained to 5,000 AFY interim transfers multiple pathways to achieve long-term reliability goals 5K Transfers+; 7K PR; 5K WF+ 5K Transfers+; 10K Sites 5K Transfers; 10K Sites; 4K PR 5K Transfers; 5K Sites; 7K PR Interim if goals are met by 2035, then Transfer Years little Transfer need for more long-term Delivery (AFY) 5,000 5,000 5,000 5,000 transfers Sites Start Year portfolios with Sites Reservoir Average Sites Delivery (AFY) 10,000 10,000 5,000 have best long-term outlooks Augmentation Phase 1 Start Year will not regain reliability goals at 99% exceedance until 2030 Phase 1 Delivery at the (AFY) earliest, 4,000 in this 4,000 case 4,000 Augmentation potable reuse can augment Phase 2 Start interim Year 2035 reliability starting Phase 2 Delivery almost (AFY) able 7,000 to meet mid-term 7,000 reliability Start goals at 90% Year exceedance Average Supplemental Transfer (AFY) 5,000 Slide 20

21 More Conservation Would Improve Reliability West Yost Demand Study indicates potential for further demand reductions o near-term difference 8,000 AFY o difference at buildout 5,000 AFY Reliability Policy goals could be met with smaller, fewer projects depending on portfolio, shortterm transfers could be delayed by ~5 years, and/or be reduced in duration high uncertainty with demand forecasts; must consider risk of underestimating demand will continue to monitor demand trends note that demands harden with increased conservation Slide 21

22 Preliminary Draft Cost Estimates Will Continue To Be Refined Supply Projects Option Z7 Capital Cost ($M) $/AF CA $220 $740 Potable Reuse $120 - $250 $2,500 - $2,700 Sites Reservoir $220 $700 - $1,000 Regional Desalination $80 $1,800 - $2,200 Short-Term Transfers $0.2 $420 Long-Term Transfers $100 $640 Other Transfers $700 - $1,000 Storage Projects Option Z7 Capital Cost ($M) $/AF Los Vaqueros Expansion $2,050 Slide 22

23 Draft Findings steady annual transfers in interim are needed meeting 99% reliability goal requires large interim transfers up to 10,000 AFY multiple, new water supply reliability projects will be needed a diversified portfolio is best for reliability consider factors such as wet-year, dry-year, steady supply West Yost s demand study shows potential for further demand reductions of additional 5,000 AFY on average at buildout highly uncertain, must weigh against risk of underestimating demand demand forecasts will continue to be refined Risk Model shows Los Vaqueros emergency storage of limited benefit; however, expected benefits from increased operational flexibility, particularly on a monthly time-scale, are not reflected in the model Slide 23

24 Next Steps: Schedule Draft findings & recommendations (December 2018/January 2019) MEETINGS: Retailer Workshop: early-mid December 2018 Water Resources Committee: mid-december 2018 Board Meeting: January 2019 (Sites & LVE) Liaison Committee: January 2019 Draft report/tm (January 2019) Slide 24

25 Thank you for listening.

26 Questions?