Bay-Delta Conservation Plan: Comparison of Estimated Yields - Sept. 26, 2013
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This document summarizes a presentation made to the Imported Water Committee on September 26, 2013 regarding options for addressing water supply reliability and ecosystem restoration in the Sacramento-San Joaquin River Delta. Four alternatives were analyzed: the BDCP proposed action with a 9,000 cfs north Delta conveyance; a 6,000 cfs alternative; a 3,000 cfs alternative; and relying solely on existing south Delta diversions. The 9,000 cfs and 6,000 cfs options were found to provide greater water exports than the other options. However, uncertainties remained around the operating scenarios that would be used when project operations begin. A decision tree process was proposed to help determine appropriate outflow criteria as more data is collected through studies and adaptive
Bay-Delta Conservation Plan: Comparison of Estimated Yields - Sept. 26, 2013
- 1. Imported Water Committee September 26, 2013 Presented by: Dana Friehauf, Principal Water Resource Specialist Larry Purcell, Water Resources Manager
- 2. Achieve co-equal goals of restoring ecosystem and securing water supply reliability within stable regulatory framework 2 Ecosystem Restoration Water Supply Reliability Comprehensive conservation strategy for Sacramento- San Joaquin River Delta Results in 50 year ESA permits to operate CVP/SWP 22 Conservation Measures (CMs) CM 1: water conveyance facilities and operations CM 2-22: restore, protect and conserve ecosystem
- 3. ◦ Include storage, local supplies as part of BDCP NRDC portfolio option ◦ 3,000cfs north Delta conveyance ◦ Include storage, local supplies as part of BDCP Existing conveyance (no project alternative) ◦ Sole reliance on south delta diversion and pumping ◦ Levee and habitat improvements as currently identified 3 High level analysis of four Delta fix options BDCP proposed action ◦ 9,000cfs north Delta conveyance Delta Vision Foundation (DVF) ◦ 6,000cfs north Delta conveyance
- 4. Two Step Approach 1. Using BDCP documents conduct “apples to apples” comparison of key in-delta features of each alternative ◦ August 11 Workshop, Board directed staff to conduct “apples to apples” comparisons between alternatives 2. Qualitatively assess benefits and risks of adding local supplies and storage to each alterative ◦ Insufficient information in NRDC and DVF proposals to quantitatively evaluate out-of–delta components ◦ Where possible, conduct quantitative analysis 4
- 5. SWP/CVP operating rules and objectives have a major influence on export yields ◦ Required to balance conflicting uses and protect species ◦ Guide daily Delta operations 5 SWP Banks Delta Pumping Plant Operating rules and objectives (scenarios) affect amount of diversions ◦ Existing south Delta diversions ◦ Proposed new north Delta diversion Important that scenarios for each conveyance option be consistent ◦ Allow for “apples-to-apples” comparison for yields
- 6. NEW NORTH DELTA CONVEYANCE DIVERSION STRUCTURE SOUTH DELTA PUMPS Seawater EBMUD DIVERSION SFPUC SUPPLY Balancing the Delta System
- 8. BDCP EIR/EIS Alternatives developed to evaluate potential environmental impacts Different operating scenarios applied to conveyance options Cannot conduct “apples to apples” comparison BDCP Planning Documents Analysis of “take alternatives” includes practicability analysis Applied high-outflow scenario to all conveyance alternatives Allows for comparison among alternatives 8
- 9. 9 Delta Flows Delta outflow is the net amount of water flowing out of the Delta toward the San Francisco Bay
- 10. 10 Correlation between Delta Outflow Criteria and resulting Supply Export Yield High-Outflow Criteria Decrease in Export Yield High-Outflow Criteria = Decrease in Export Yield
- 11. 11 Correlation between Delta Outflow Criteria and resulting Supply Export Yield Low -Outflow Criteria Increase in Export Yield Low-Outflow Criteria = Increase in Export Yield
- 12. 12 2.4 2.9 2.6 3.0 3.4 3.9 2.3 2.7 1.8 1.2 0.0 1.0 2.0 3.0 4.0 5.0 6.0 Proposed Action High-Outflow Scenario 9,000 cfs Proposed Action Low-Outflow Scenario 9,000 cfs 6,000 cfs Alt (High-Outflow) 3,000 cfs Alt (High Outflow) Existing Conveyance High-Ouflow Scenario Existing Conveyance Low-Ouflow Scenario South Delta North Delta Alternative or Scenario Early Long-Term (2025) AverageAnnualExports(MAF) 4.7 4.2 4.4 5.6 Source: BDCP Chapter 9, Table 9-3 12 51% 28% 72% 41% 59% 48% 52% 49%
- 13. 13 0 0.5 1 1.5 2 2.5 3 3.5 4 Proposed Action 9,000 cfs 6,000 cfs Alternative 3,000 cfs Alternative MAF Source: BDCP Appendix 9.A, Table 9.A-9 13
- 14. 9,000cfs and 6,000cfs delta conveyance options provides greater SWP yield than 3,000cfs and no action ◦ Additional south of Delta storage adds yield to all alternatives 14 SWP California Aqueduct The greater the amount of north Delta diversions the greater the improvement in SWP water quality ◦ Lower salinity and organics Greater reliance on south Delta diversions creates more risk ◦ Impacts to fish species and uncertainty over export yields ◦ Reliability during levee failure, other catastrophic events
- 15. An analytical tool to decide between options ◦ Project possible outcomes when uncertainty exists Two main uncertainties identified in BDCP: ◦ Is the USFWS reasonable and prudent alternative for fall outflow criteria necessary to achieve delta smelt biological objectives? ◦ Are the initial spring outflow criteria necessary to achieve the longfin smelt biological objectives?
- 16. Current scientific uncertainty on spring and fall outflows ◦ Can be reduced by new studies before operations Habitat restoration will alter Delta flow patterns and habitat quality There is good understanding of the biological goals for covered fish species Using a decision tree increases the chances of meeting the biological goals
- 17. Conduct scientific studies on outflow criteria during years before dual-conveyance operations commence Permitting agencies will identify spring and fall outflow criteria ◦ Sets initial outflow amount to meet biological goals ◦ Decision Tree process ends Adaptive management is the primary process for making all future adjustments ◦ Decision Tree functions as an early part of the overall adaptive management process 17
- 18. Combines different spring and fall outflows Permit would cover all four outcomes One would be selected for initial operations 18 Spring Outflows per D-1641 (Low Outflow) Enhanced Outflow (High Outflow) Fall Outflows per D-1641 (Low Outflow) H1 5.6 MAFY H2 4.7-5.6 MAFY Outflows per USFWS 2008 Smelt BiOp for Fall X2 (High Outflow) H3 4.7-5.6 MAFY H4 4.7 MAFY
- 19. Restoring wildlife habitat and recovering endangered species relies on complex but known biological principles Specific success criteria must be met ◦ Can require additional studies that affect future operations ◦ Water Authority NCCP/HCP wetlands mitigation ◦ Carryover Storage Project Section 404 permit Decision Tree process and adaptive management not unusual in large NCCP/HCPs ◦ Direct link between achieving biological objectives and export yield ◦ Habitat restoration objectives (other conservation measures) also subject to change as new information developed 19
- 20. BDCP is voluntary process to comply with state and federal Endangered Species Acts ◦ Based on best available science ◦ Negotiated; both parties have to benefit and accept some risk ◦ Wildlife Agencies get habitat and species conservation assurances ◦ Permittees get long-term financial and yield assurances Not clear if BDCP contains adequate “assurances” and “no surprises” to justify the cost/yield uncertainty ◦ Concern that permitting agencies will impose further restrictions on exports if biological objectives are not met ◦ Currently being negotiated between permitting agencies, DWR and other stakeholders ◦ Public review documents need to provide additional clarity 20
- 21. SWP/CVP operating rules and objectives have a major influence on export yields Important that the comparison of dual conveyance options is “apples to apples” From in-Delta only perspective, 9,000cfs Delta option provides: ◦ Most SWP yield ◦ Better export water quality ◦ Greatest reliability in a seismic event 21 Ecosystem Restoration Water Supply Reliability Uncertainties remain regarding operating scenario to be utilized when project operations begins
- 22. Meeting Imported Water Committee/Board Activity 7/25/2013 Provide input on scope of proposed Water Authority analysis of BDCP alternatives; provide input on policy questions to be addressed √ 8/8/2013 Special Meeting Overview of Bay-Delta and proposals for Delta fix, including description of alternatives √ 8/22/2013 Review of technical analysis – demand assumptions; alternative project yield assumptions; projected costs √ 9/12/2013 Special Meeting BDCP economic study on cost-benefit of BDCP preferred alternative √ 9/26/2013 Review of technical analysis (cont.), including yield review 10/24/2013 Information: Review of technical analysis (cont.), including baselines; preliminary review of conveyance facilities; other potential impacts to BDCP 11/14/2013 Special Meeting Continuing review 1/9/2014 Special Meeting Information: Review of public draft EIR/EIS – identify issues 1/23/2014 Information: Comparison of alternatives with Board’s adopted Bay-Delta policy principles; answers to policy questions 2/13/2014 Special Meeting Information: review draft EIR/EIS comment letter 2/27/2014 Action: approve EIR/EIS comment letter 22