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Water GM holds hope that tunnel still on track

Twin Tunnel system. Graphic courtesy Department of Water Resources.

On hearing Gov. Gavin Newsom’s support for a one-tunnel — and not a two-tunnel — system for getting Northern California water to Southern California, the head of the SCV Water Agency expressed measured optimism that much-needed improvements to a key portion of the imported water delivery system to the Santa Clarita Valley are still on track.

Newsom in his State of the State speech Tuesday said: “I do not support (two-tunnel) WaterFix as currently configured.

“We can, however, build on the important work that’s already been done,” he said. “I do support a one-tunnel system. The status quo is not an option.”

Matt Stone, general manager of the SCV Water Agency, sat down Wednesday to express his thoughts on plans to improve the way water is conveyed from melting snow in the Sierra Nevadas to the Santa Clarita Valley.

Half of the water supplied to SCV ratepayers comes from Northern California. The other half comes from groundwater.

“We are currently relying on getting water across the (Sacramento-San Joaquin) Delta, which is a whole series of levees, and islands with rivers flowing across it while we’re trying to move water north to south,” Stone said. “This creates conflicts with endangered fish species at a number of times each year.”

“Relying on the Delta as a stand-alone conveyance has risks,” said Stone, who has attended many of the WaterFix meetings pursuing the feasibility of a twin-tunnel system.

“A significant levee failure due to earthquake or other factors could cause sea water to rush inward, fouling the Delta and knocking out a key water source for an extended period of time.  As predicted sea level rise builds in the future, these risks will only increase,” he said.

One tunnel

“One tunnel is far superior than doing nothing,” Stone said. “I think the governor,  while he said he wasn’t in support of two tunnels, he very clearly said two other things — one, that the status quo is not an option.

“And that he does support a single-tunnel alternative,” he said.

“For us, the next steps are to obviously to try to work with the state and our other partners who depend on water from the Delta to figure out what exactly that one-tunnel project look like,” Stone said. “Is it half the capacity? Is it some other percentage of the capacity? And how do we share that capacity so that hopefully we get a similar benefit?”

Climate change

One of the things Newsom pointed out in his State of the State address was the changing state of water in light of a changing climate.

“We need a fresh approach when it comes to meeting California’s massive water challenges,” Newsom said Tuesday. “Our water supply is becoming less reliable because of climate change and our population keeps growing and that means a lot of demand on an unpredictable supply.”

Stone agrees.

“Over time,” Stone said. “Projections are that our climate change is going to cause the sea levels to rise. The Delta is influenced by tidal action. It’s in direct interface with the Pacific Ocean.”

A constant problem for state water officials is addressing salt water intrusion into the Sacramento-San Joaquin Delta.

“We think a tunnel will help in two ways,” Stone said. “Having a diversion point in another location gives us a lot more flexibility in how we take water. That allows us to better manage our water system and minimize ecological impacts.

“Over time, with sea levels rising, we think a tunnel will become even more important for resilience and reliability of our ability to deliver water — for future generations, that is going to become very important,” he said.

“As one of the interested agencies that will be benefiting and paying for the project, my understanding is the two-tunnel concept was a combination of factors, a couple of which were the idea of multiple river intake points for the amount of water that would move through two tunnels, which would spread the impacts out and provide a bit more operating flexibility.”

Two tunnel merits

A two-tunnel system was not without its merits, Stone said.

“Having two tunnels means you can have one down for maintenance,” Stone said. “You can be a little more selective in operating them.”

A half-century ago, water officials discussed from the1960s to the early 1980s, building a peripheral canal in a plan to divert water around the Delta.

As Stone pointed out Wednesday: “The original Peripheral Canal proposal was a concrete canal sized with a capacity to move 22,000 cubic feet per second of water.”

During the “CalFed” planning process for the Delta in the late 1990s to early 2000s, a so-called Isolated Facility — a smaller canal alternative — was sized to move water at a maximum rate of 10,000 cubic feet per second.

That option promised about 45 percent of the original Peripheral Canal concept.

Peripheral canal

State water officials describe WaterFix as: “a long-overdue infrastructure upgrade that will improve the reliability and sustainability of California’s aging water system, improve river flows and benefit the fragile Sacramento-San Joaquin Delta ecosystem.”

The current two-tunnel WaterFix plan — which the governor said he does not support — was sized, Stone said, “to move water at a maximum rate of 9,000 cubic feet per second.”

Details of a single-tunnel concept would still need to be developed, Stone said, but “some have mentioned 6,000 cubic feet per second as the possible single tunnel capacity — promising about 27 percent of the original view of water moved north to south.

“Should we experience an earthquake or other cause of levee failures that draw seawater further into the interior Delta, the availability of an alternative way to move water will be very critical to maintain access to our imported water supply,” Stone said.

[email protected]


On Twitter @jamesarthurholt

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