Environmental

After 17 years, California DWR uses Kern River Intertie to redirect flood water

After 17 years, California DWR uses Kern River Intertie to redirect flood water
(An aerial overview of the recently completed Lake Oroville main spillway during Phase 2 of the recovery efforts. Work continues on the concrete cap below the Lake Oroville emergency spillway weir at the Butte County, California site. Photo taken January 24, 2019. Kelly M. Grow / California Department of Water Resources, FOR EDITORIAL USE ONLY)

The California Department of Water Resources (DWR) is using its Kern River Intertie, a unique piece of State Water Project (SWP) infrastructure, for the first time since 2006 to reduce the flood waters going into Tulare Lake in the Central Valley.

At the request of the Kern River Watermaster, the intertie is redirecting flood flows at a rate of 500 cubic feet per second (cfs) from the Kern River to the California Aqueduct to lower flood risk in Tulare Lake and for downstream communities in Tulare County. The Kern River Intertie is located west of Bakersfield near where Highway 119 crosses the aqueduct.

California DWR said there are no immediate flooding or public safety concerns, but timely use of the intertie is critical to help prevent additional floodwater from exacerbating flooding in Tulare Lake as river flows increase.

Water flows entering the California Aqueduct will stay at 500 cfs and may increase to 1,000 cfs later this month. The intertie is capable of handling up to 3,500 cfs of maximum flood inflows, but the expected operations will be 500 to 1,500 cfs.

If the Kern River Intertie flows remain at about 1,000 cfs until the end of June, it is estimated that about 75,000 acre-feet of water will be redirected from the river to the aqueduct.

The SWP provides water to 29 public water agencies that serve 27 million Californians and also uses the water for hydropower generation. The SWP is a system of 32 storage facilities, 21 pumping plants, four pumping-generating plants, eight conventional hydroelectric plants and about 700 miles of canals and pipelines. Among these generating plants is the 762 MW Hyatt Powerplant at the foot of Oroville Dam.

Once the water that is being redirected enters the aqueduct, it is considered SWP water. The flood water is not additional water for the system but rather is part of the 100% allocation that DWR announced in April. The Kern River flood water will offset water that would have otherwise been exported from the Delta or drawn down from San Luis Reservoir.

The intertie’s operations will be monitored, adjusted and terminated by DWR in coordination with and at the request of the Kern River Watermaster.

This year marks the 10th time the intertie has been used since it was built in 1977, DWR said. Of all the uses, the 755,514 acre-feet of water in 1983 was the largest amount of water entering the California Aqueduct from the intertie.