Now we know how much water needs to flow

This week, the California Water Resources Control Board released a draft report identifying increased water flows needed to protect fisheries and water quality in the Sacramento-San Joaquin Delta Estuary.

According to Mike Taugher of the Bay Area News Group, “The key finding is that of all the snowmelt and rain that falls into the Delta’s watershed, which covers 40 percent of California, about 75 percent of it should be allowed to flow through the Delta into San Francisco Bay.”

“Today, only about 50 percent of the flow passes through the Delta on average as nearly all of California taps into its rivers and the Delta itself.”

A press release from the California Sportfishing Protection Alliance (CSPA) notes that the report was mandated by the California legislature as part of the comprehensive water bill, enacted on 12 November 2001, which directed the water board to “develop new flow criteria for the Delta ecosystem necessary to protect public trust resources” within nine months of enactment. Extensive hearings were conducted during March 2010 and the report will be finalized at the Board’s August meeting.

“For the first time, the Board has come forth with explicit estimates on flows needed to protect the estuary and the results are not surprising,” said Bill Jennings, Executive Director of CSPA, “The increased flow recommendations are consistent with the vast majority of testimony by scientists, biologists and hydrologists during the recent hearing and with the recommendations of resource agencies and scientists during previous evidentiary hearings over the last 30 years.”

In addition to making recommendations about increased net outflows for the Sacramento and San Joaquin Rivers, the report also recommends fall pulse flows for migrating fish and increased fall outflow in above normal years. The report emphasizes that the flow recommendations are based on the “best scientific information,” that ecosystem variability in the Delta is crucial and “fundamentally inconsistent with continuing to move large volumes of water through the Delta for export” and that the recommendations are designed to restore estuarine populations as required by law and not simply, as in the biological opinions, to prevent extinction of listed species.

CSPA notes that these Delta flow recommendations will inform both the Bay Delta Conservation Plan (BDCP) process underway and proceedings of the Delta Stewardship Council. The culmination of those efforts will result in a comprehensive “Delta Plan” that will be forwarded to the State Water Board for subsequent evidentiary hearings that will balance competing water needs, approve potential structural modifications of delivery systems and revise water rights to implement the plan.

Over the years, the State Water Board has conducted a number of hearings on measures necessary to protect the estuary. For example, following a long evidentiary hearing in 1988, the State Board issued a draft water quality control plan that called for substantial reductions in Delta exports. However, then Governor George Deukmejian, at the behest of state and federal water project operators, directed the State Board to withdraw the draft order.

Again, in 1992 the State Water Board conducted an extensive evidentiary proceeding and issued a draft water rights order that required increases in flow to protect the estuary (D-1630). And again, the Governor, this time Pete Wilson, directed the Board to withdraw the draft order.

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