Faulty comparison on Delta water exports, flows to S.F. Bay

Despite this winter’s storms, the Sacramento-San Joaquin Delta is still reeling from decades of unsustainable water diversions and shortsighted management responses to the drought. Multiple indicators point to a crisis: California’s coastal salmon fishery will be closed for more than half the normal season; surveys for imperiled species report the lowest counts on record; and the frequency of harmful algal blooms in the Delta is increasing.

The scientific evidence is overwhelming that these ominous developments stem, in large part, from human diversion and storage of vast amounts of water before it can reach the bay. Yet, despite the fact that we are still in a drought, most agricultural districts served by the federal Central Valley Project will receive 100 percent of the water they claim and the State Water Project will deliver more than 2.5 million acre-feet to its customers.

These points were obscured in The Sacramento Bee’s article “More water reaches sea than is shipped south” (Page 1A, April 17), which framed water allocation decisions as a struggle between agriculture and endangered fish. The article’s alarmist headline notwithstanding, there is nothing surprising or inappropriate about the volume of water flowing to the bay exceeding exports from the Delta. Inflows to the bay should be compared to the volume flowing in the Central Valley watershed, not the amount exported from the Delta.

What is alarming is that, in a typical year, California diverts more than half of the winter-spring flow in Central Valley rivers; that proportion increases in drier years. During the fall and winter, nearly 60 percent of Central Valley runoff never reached the bay, and 80 percent of the San Joaquin River’s flow never made it to the Delta. Protections for endangered species increased flows by an amount equal to 4 percent of storm runoff. In contrast, 12 percent of the runoff flowing to the bay served to prevent Delta water from becoming too salty for human use.

Far from acting to save the estuary, government agencies have bent over backward to send more water to irrigators. For example, the State Water Resources Control Board waived numerous water-quality standards in the past three years to facilitate diversions for agriculture.

Unless government agencies start protecting our water quality and fisheries soon, we will witness the extinction of several species that have survived in this ecosystem for millennia; toxic water quality will become common; and the last major fisheries will close. In order to stop this nightmare, Californians must reject the self-serving narrative that environmental stewardship conflicts with food production or the economy at large.

Jon Rosenfield is the conservation biologist and lead scientist for The Bay Institute. Contact him at