DISB stresses diversified water supply portfolio

Friday, 12/08/2017, 6:00 am

As the recent fires across the state have shown, the record rains from earlier this year are long gone, extending the fire season for parts of California into December. Improving water supply reliability is on the minds of Delta Independent Science Board (DISB) members now as the year comes to a close. with Delta reliability estimates the focus.

“Is this just the reliability of water exported from the Delta?...Or is it maybe better viewed in a more integrated sense, what's the reliability of water supply for users of water from the Delta?” former DISB Chair Jay Lund said at the DISB meeting in Sacramento last month. Delta Independent Science Board meeting, Sacramento

Lund pointed out that major water users have been considering water supply portfolios of actions for drought management, and that the Delta Stewardship Council's role is to encourage people to broaden their water source and become less dependent on the Delta as a water supply. “It seems to me that we probably should take a look at reliability from that bigger perspective rather than just the Delta perspective,” Lund said.

In order to educate and engage the public, the DISB is considering a workshop in the future with presentations of water supply reliability estimates to show the public how big the Delta's role is. Panel discussions could be included as well with a draft drawn up from the input and suggestions. At this point, the idea is to organize the subject matter, then investigate it fully.

Drought and regulatory conditions such as drinking water standards may be big hurdles in controlling reliability. Mechanical reliability, earthquake reliability, and economic perspectives are also being considered.

“Is reliability just the probability distribution of water deliveries or of water shortages after conservation and demand reductions or is it the probability distribution of economic losses that the users see because they've had to do alternative things that were more expensive or less convenient to respond to that,” Lund said.

Fellow DISB member John Wiens weighed in, reminding of the reality of political obstacles. “I think of water reliability, and I say, 'okay, you've got to think about what is the reliability of water coming into the Delta, what happens to the water in the Delta, where does it go, and what is the probability distribution of the flows out of the Delta to various directions?'” Wiens said. “How do you deal with the farmers versus fish kinds of aspects of reliability?...That is very much a societal [and] political value judgement that potentially gets into endangered species legislation, and places you don't want to go.” California Delta

While water supply reliability is often considered in terms of agricultural and urban use, it applies to environmental use as well. A report was released last month from the Public Policy Institute of California that looks at Delta inflows since 1980. It breaks down the outflows required to maintain water quality standards for cities that farm in the Delta while also meeting fish regulatory requirements.

“It's a wonderful set of analysis because it looks at every day, essentially since 1980,” Lund said.

The report could help the DISB as they move forward in addressing water supply reliability. The next steps are to revise the prospectus planning with consideration of the November discussions, plan public workshops and a tour in the Delta for 2018, and organize the review to accomplish new goals.