Thanks to Controversy (the Journalist’s Best Friend), the subject of salinity in the Sacramento-San Joaquin-San Francisco Bay Delta system has received more attention of late than is usually attached to such arcane topics. But I did not realize how old this issue is.
It was salinity and fish science that caused federal Judge Oliver Wanger to famously tee off on a pair of U.S. Fish and Wildlife Service scientists back in September. The underlying issue is that water removed from the Sacramento and San Joaquin systems that would otherwise have reached the estuary between fresh and salt water changes the system’s salinity. More fresh water flowing to the sea pushes salt water out of the system. Less allows the salt water to flow back in, through Suisun Bay and into the delta. This plays a role in the life history of the endangered delta smelt, which makes salinity a pertinent question in California’s tangled water management these days.
The area of ideal salinity for the smelt shifts back and forth, eastward and westward, depending on the time of year, the amount of rain and the decisions of federal and state water managers. (A fuller explanation with diagrams can be found at the Bay Delta Blog.)
This zone of ideal salinity for young smelt to feed is known as the X2; the Interior Department had decided that in wet years like this one, it should be no farther than 46 miles east of the Golden Gate Bridge. The decision was challenged in the lawsuit by the state and agricultural water interests, which prefer that less go out to the bay.
Pronouncements by two federal scientists on the issue drew Wanger’s ire, which made salinity the hot combat science topic of this past fall in California politics. But I was struck in reading Philip Garone’s environmental history of California’s Central Valley to learn how long this problem has existed.
The first irrigation diversions upstream of the delta date to 1852, and by the 1870s enough water was being taken out of the rivers to make a noticeable change in the delta. As rice farming expanded, the problems increased:
When a record 164,000 acres of rice cultivation coincided with a serious drought in 1920, the salinity problem in the Delta reached crisis proportions. In July of that year, the western Delta city of Antioc, situated near the mouth of the San Joaquin River, together with ninety-seven Delta landowners, brought suit against upstream irrigators in the Sacramento Valley. The plaintiffs requested that the irrigators be enjoined from diverting so much water from the Sacramento River and its tributaries that tidal salinity would advance far enough into the Delta to threaten Antioch’s municipal water supply, which was drawn from the San Joaquin River.
Antioch lost, the court ruling that it had no right to unsalted water if that meant someone upstream had to stop diverting. But efforts to deal with the issue in a long term fashion, Garone writes, eventually led to the creation of the Central Valley Project. Which is what led federal scientists back into court this year talking about salinity.