The biggest threat to future South County water supplies may not be a lingering drought.

The state — in a bid to increase Delta water quality that will be impacted under the twin tunnels diversion plan pushed by Gov. Jerry Brown — wants to mandate “unimpaired flows” on the Stanislaus, Tuolumne and Merced rivers. Essentially increased water flows from the three rivers is designed to make up for the loss of Sacramento River water that would be diverted north of the Delta and returned to the California Aqueduct south of the Tracy pumps. The loss of the Sacramento River water flowing through the Delta is expected to seriously impact water quality and therefore fish habitat. The specific targeting of the three rivers for more water is the state’s way of addressing critics who contend diverting Sacramento River water into tunnels will severely hurt the Delta’s ecological system.

As it stands now a federal biological opinion is in place requiring unimpaired flows on the Stanislaus River between January and June be set at 30 percent of what precipitation falls in the watershed in a typical year.

The state wants to increase unimpaired flows on the Stanislaus River to between 40 and 50 percent. To do that, the state would have to infringe on the historic superior water rights of both the South San Joaquin Irrigation District and Oakdale Irrigation District. The two districts currently are legally entitled to the first 600,000 acre feet of unimpaired flow into the New Melones Reservoir that they split 50-50. That is based on an agreement reached with the federal government in exchange for the Bureau of Reclamation inundating the original Melones Reservoir built 100 percent on the back of SSJID and OID taxpayers in order to construct New Melones. The 600,000 acre feet ties directly into water rights SSJID property owners secured in 1909 by approving what was then considered a risky $1.4 million bond debt. The SSJID noted a number of Manteca, Ripon, and Escalon area farmers lost their land during the Depression because they couldn’t pay their share of the bond debt. There was no federal or state bailout.

Since the watershed in an average year has a million acre feet of runoff, that means if the state succeeds the only way the unimpaired flows work is if they seize water currently being used for irrigation and to supply drinking water to the cities of Manteca, Lathrop, and Tracy.

At the same time there would be no water from New Melones Reservoir for other basin users, those with Bureau contracts or even for storage.

The Save the Stan — an organization the SSJID and OID formed to inform the public of efforts the two districts are undertaking to protect farming, fish, urban water users, and water recreation against initiatives that they contend threaten the Stanislaus River watershed — note that the “state has not directly acknowledged that increasing unimpaired flows is related to Governor Jerry Brown’s twin tunnels project, for those who are impacted, it’s hard not to think they aren’t linked.”

The two districts argue the more water diverted to the Delta from the Merced, Stanislaus, and Tuolumne watersheds means more Sacramento River water that can be diverted to Southern California before it ever reaches the Delta.

Save the Stan also notes the three rivers are the only ones currently being targeted by the state’s bid to increase unimpaired flows beyond what the federal government has had in place for years.

The districts have been spending $1 million plus annually since 2004 to have biologists study fish and water flows on the Stanislaus River as well as improve habitat for fish.

They note there is no peer-reviewed scientific journal or research showing more water equals more fish. Pulse flows have provided no scientific benefit to improve salmon or rainbow trout/steelhead population. Scientists who actually have worked on the river point out that habitat restoration and predation control are far more effective ways to increase the number of fish. An estimated 95 percent of young salmon and steelhead are eaten before they ever reach the Delta.

The unimpaired flows envisioned for the Stanislaus River would mean less cushion for storage. The two districts cite historical data that shows if unimpaired flows are put in place per the state’s plan, it is estimated New Melones would be “empty” one out of every five years.

The State Water Resources Control Board calls the economic and social impacts that SSJID and OID are warning about “significant but unavoidable.”

The water board, however, hasn’t conducted any meetings in the region to explain its plan.

The SSJID and OID believe the burden of solving the statewide issues connected with the Delta “is falling disproportionately on those who live in the Northern San Joaquim Valley.”

A fact sheet about unimpaired flows can be found on the website www.savethestan.org.



To contact Dennis Wyatt, email dwyatt@mantecabulletin.com