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By Tim Hunt

Zone 7 water needs new Delta conveyance

Uploaded: Aug 18, 2022

Sixty years ago, the State Water Project opened and providing potable water to millions of Californians as well as surface water to San Joaquin Valley growers and vineyards in the Livermore Valley.
The foresighted directors of the fledgling Zone7 Water Agency knew the Livermore Valley’s groundwater was being over-drafted and they needed a new source of water. They joined the project that constructed the South Bay Aqueduct and that provides 80% of the agencies’ water in a normal year. Today, the state project provides water for about 23 million Californians, including about 2.7 million in the Bay Area (the valley, the Fremont area and the South Bay).
The project and water are among the public’s top concerns as the state and the western United States continue in a multi-year drought. It’s been so dry in the sprawling Colorado River watershed that both Lake Mead and Lake Powell have huge bathtub rings around their banks. The federal government announced this week cuts to allocations for Nevada and Arizona next year. In California, the state water project is delivering just 5% of requested water.
Many people are correctly concerned and they should grow more so when they consider that the state project has never been finished. The Peripheral Canal, that Gov. Jerry Brown maneuvered through the Legislature only to lose overwhelmingly in a statewide referendum in 1982, has resurfaced in a couple of proposals. Gov. Arnold Schwarzenegger recognized something needed to be done and put together a commission to study it that concluded some sort of conveyance was necessary. The current Delta system creates a north-south flow from Sacramento to the pumps near Tracy while the normal river flows are east to west.
People with excellent memories will recall that the huge pumps in the South Delta were turned off in June 2007 by a federal judge to protect the endangered Delta smelt. That coupled with the commission’s report put a through-Delta project back into the public eye as the Bay Delta Conservation Plan. Late in Gov. Brown’s fourth term a revised project was introduced—twin tunnels under the Delta. The tunnels certainly would have had impact upon the Delta, but significantly less than a surface solution.
When Gov. Gavin Newsom took over, he scraped the two-tunnel project in favor of a single tunnel with a 6,000 cubic-foot-per-second capacity, 2 ½ times smaller than the original two tunnel capacity. The environmental report for this project was released in late July for a 90-day review period. What was true 20 years ago and is still true today is that the current state of the Delta and the water project are unsustainable. The goal has shifted from potentially more stored water to one that is built on dealing with the potential effects of climate change and to build reliability and resiliency into the system.
Valerie Pryor, general manager of Zone 7, said, “This project is smaller than the two previous ones so we lose some service redundancy. Ultimately, we need project that is permittable and buildable. If this is project that gets us there, then it’s the right project.”
Spoken like a pragmatic leader who has been in the water business in California for years.
The permits, from a variety of state and federal agencies, will precede any construction. Pryor pointed out the evolution in the project. It’s now routed on the east side of the Delta with about one-third of the impact on Delta ag land and a planned connection straight to the California Aqueduct that moves water south. The aqueduct serves both the sprawling San Luis Reservoir in the Los Banos area as well as ground water storage in the Southern San Joaquin Valley. Zone 7 has a capacity of 198,000 acre feet in the ground water bank, about a five-year supply of water.
Zone 7 also is exploring three other projects to diversify its water source—a brackish water desalination project in the Pittsburg/Antioch area, 10,000 acre feet of storage in an expanded Los Vaqueros Reservoir between Livermore and Brentwood and 10,000 acre feet in the Sites Reservoir near Colusa, an off-river facility like San Luis, that would divert Sacramento River water during high flows and then release it to supplement releases from Lake Shasta.
Zone 7 does not know the cost of the tunnel or other projects yet, but is committed to continuing to invest in water infrastructure. In the last few years, the agency has added ozone treatment to its drinking water treatment plants. The Delta tunnel, under the current timeline, could be operational in 2040, 33 years after the pumps were shutoff. That’s slow, even by government standards, but water projects and water politics and rights are complicated, to put it mildly.
Pryor said, “It’s important to continue investing and in a number of water supply projects. We ultimately need more than one because of seismic risk and climate change.
The Zone 7 board voted earlier this summer 5-2 to continue in the tunnel process where each of the 27 State Water Project agencies pay a proportional share of the costs.


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