BAWSCA to press SFPUC for design-drought review
Bay Area Water Supply and Conservation Agency, California · Meeting date: October 14, 2026 · Published: October 15, 2026
BAWSCA’s Board Policy Committee voiced support for asking the SFPUC to revisit the drought scenario it has used since 1992 to test system reliability. The review could cost $1 million-$3 million and take at least a year, but BAWSCA stressed that it could support either a more or less severe planning drought.
Key points
- BAWSCA’s CEO/General Manager said he is likely to send the SFPUC a request within the next month for a robust, independent and documented review of the design drought.
- The SFPUC’s current design drought was selected after the 1987-92 drought and tests conditions in which dry weather continues for two additional years.
- BAWSCA estimated that a review could take a minimum of one year and cost $1 million-$3 million, while drawing on a small SFPUC water-modelling team.
- The outcome could affect long-term capital planning, although alternative water-supply investments are not in the current CIP until 2034.
Full report
BAWSCA is set to ask the San Francisco Public Utilities Commission to reassess the design drought that has guided reliability planning for the regional water system for roughly three decades, with its Board Policy Committee backing a request for a technically independent review rather than presuming a particular result.
The SFPUC selected its existing design drought in 1992, following the 1987-92 drought. The scenario asks what would happen if dry conditions persisted for another two years, and is used to test the system against a drought worse than any experienced to date. BAWSCA’s CEO/General Manager said the scenario reflects the system’s heavy dependence on the Tuolumne River, the priority water rights held by two irrigation districts, and SFPUC technical judgement.
BAWSCA’s formal position in 2022 was that changing the design drought did not appear warranted at the time, while saying it would not oppose an SFPUC review if the process were robust, independent, documented by expert analysis and included BAWSCA participation. The proposed letter would move beyond that stance by actively requesting a review.
The CEO/General Manager cited the age of the underlying scenario, climate change, changing demand and growth patterns, and evolving environmental release requirements associated with the Bay-Delta Plan and the Don Pedro Federal Energy Regulatory Commission process as reasons to revisit the assumption. He also cautioned that an objective assessment could validate the existing drought, find that a less severe scenario is appropriate, or point to a more severe one.
Committee members generally supported sending the request without imposing an immediate deadline. One director said the letter would clarify BAWSCA’s intentions while allowing time for unresolved issues to develop. Another said the analysis was prudent given that the plan dates from 1992. The chair suggested sending the request to the current SFPUC general manager and also to the incoming general manager once selected.
BAWSCA staff estimated that an SFPUC-led review could cost between $1 million and $3 million, take at least a year, and place demands on an SFPUC modelling team described as comprising perhaps two or three staff with other duties. The timing may also be affected by the State Water Resources Control Board’s pending Bay-Delta Plan decisions. SFPUC may prefer to wait until the board acts on Phase 1 amendments before beginning an analysis that may need to be repeated afterward, staff said.
The review has potentially significant implications for future supply investments, but BAWSCA noted that the existing 10-year capital improvement plan contains no alternative water-supply investments until 2034. The CEO/General Manager said the request could be accommodated through a minor work-plan adjustment with no budget change this fiscal year; BAWSCA would add a work-plan item and assign resources if the SFPUC takes up the work.
The CEO/General Manager said he had heard no opposition from the committee and expected to send the letter in the next month, then report back to the BAWSCA board in November.
This summary was generated by AI based on the source document and may contain errors.
Source: Board Policy Committee, Bay Area Water Supply and Conservation Agency