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Water Update

Water was the dominate theme this week in California. After three very dry years, the winter of 2023 is starting to look wet. Everyone is grateful for that despite the great inconveniences and costs that accompany sloppy corrals, tired cows and milkers, and occasionally flooded roads, driveways and power outages.

The most frustrating news of the week was reading about massive flows of water running through the Delta and hearing that Delta pumps that are used to fill the two main aqueducts, the California Aqueduct and the Delta Mendota Canal, were being throttled back because of fish regulations.

Explainer: Cubic Feet Per Second (cfs) is the measurement of water volume moving through a pipe or waterway. Water flowing at 1 cfs for 24 hours (one day) will move 2 acre feet of water. So, a flow of 10 cfs for a day translates into 20 acre-feet of water moved for that day. By the way, one acre-foot of water is 326,000 gallons.

As this article by the SJV Sun explains, over 100,000 cfs of water was moving through the Delta this week and 95% of it was flowing to the ocean. The reason more wasn’t being captured and put into the aqueduct system is the frustrating part. It’s complicated, but essentially it is environmental rules to protect Delta smelt that are controlling the process. There are a lot of questions about whether those rules are appropriate, but the bottom line is the people in charge are preventing the pumping, and the frustration and cost to the water supply is real. You wonder if the Governor couldn’t fix all this under an Emergency Executive Order.

The potential impacts to fish by the major water projects California depends on for our water supply is why the San Joaquin Valley Water Blueprint is promoting a new environmentally friendly diversion approach. This proposal separates the diversion from the fish by essentially putting the intakes for the pumps under the bottom of the water column with a French drain style manifold of pipes that would extract the water slowly through the bottom of the water column such that the fish do not even notice the water being extracted. You can read more about this here.

Meanwhile, the Sierra lakes that supply local water to the Central Valley are filling up.

Lake Isabella on the Kern River is fully operational after a 15-year safety enhancement project that limited its holding capacity. The full storage capacity is 568,000 acre-feet, and as of today, there is 92,000 acre feet in the lake, but it’s climbing daily.

Lake Success on the Tule River is an 84,000-acre-foot lake. The spillway is currently under construction to enlarge the lake, so for this year the capacity will be less than 84,000 acre-feet. That means flood releases are occurring already, which is sending water down the Tule River. The Lower Tule River Irrigation District and neighboring districts will receive this water and hopefully be able to recharge a lot of it.

Lake Kaweah has a capacity of 186,000 acre-feet. There is about 82,000 acre-feet in the lake, and to preserve flood control space, 3,000 cfs is being released. This water too will hopefully be recharged.

Pine Flat is on the Kings River and holds 1 million acre-feet of water. It started the rainy season relatively empty and has lots of storage space. There is 422,000 acre-feet of water in Pine Flat today. That is up over 100,000 acre-feet in the last 5 days. But so far there are not flood releases from Pine Flat.

Millerton Lake is on the San Joaquin River. It has a capacity of 520,000 acre-feet. It started the season with quite a bit of water in it and it is a small reservoir compared to the large water producing area upstream of it. It currently has 431,000 acre-feet in the lake. The Friant Kern Canal (FKC) which can take nearly 4,000 cfs is shut down until February 1 because of the capacity correction construction. Even when the FKC is reopened, because of the subsidence in the canal near Porterville, the capacity of the canal South of that point is restricted to about 1,300 cfs. Currently, to preserve flood control space in the lake, 6,000 cfs is being released to the San Joaquin River. Unfortunately, much of that water will flow to the Delta and not be captured for recharge. Although ironically, because of the increased San Joaquin River flows to the Delta, there is less of a fish related restriction on pumping than otherwise would be the case if there was no San Joaquin River water showing up there.

North of Millerton, the lakes are all in pretty good shape. Lake Shasta and Folsom Lake are very important to the federal Central Valley Project. Both are off to great starts for the water year. Lake Oroville on the Feather River is the major supply for the State Water Project. It is also in good shape. The snowpack is off to a terrific start throughout the state with over 100% of the April 1 average already on the ground in two of the three regions (see below).

So, a lot to be thankful for. Also, a lot to be working on. We need to manage this year’s abundant water prudently and we need to work diligently to put in place the infrastructure and policies that will enable us to store water in these abundant years for the dry years we know are coming.

Geoff Vanden Heuvel

Director of Regulatory and Economic Affairs

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