Thứ Ba, Tháng Năm 30, 2023
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The rarely used pressure relief valve diverts the Kern River floodwaters to the California Aqueduct

The Kern River is rising due to so much water flowing out of the thick snow in the Sierra Nevada that state water officials decided to open a rarely used relief valve, diverting floodwater into the California Aqueduct to drinking water in Southern California.

The opening of this flow-reducing valve, known as the Kern River Intertie, is intended to prevent floodwaters from overflowing Lake Tulare, has reappeared in recent weeks, supplemented by strong winter storms and now heavy spring currents. In the early 20th century, the lake was systematically drained and channeled, allowing farmers to turn this arid region of the San Joaquin Valley into a center of industrial agriculture.

Now, the reappearance of the ghost lake has swallowed thousands of acres of farmland and encroached on low-lying towns like Corcoran.

It marks the first time since 2006, the junction connecting Kern to the west Bakersfield aqueduct has been activated. The gates of the 320-foot canal will open on Saturday to begin taking in floodwater.

Karla Nemeth, director of the state’s Water Resources Department, stressed that the move was not a response to an “immediate public safety issue” facing residents. The overall goal, she said, is “to do what we can to limit the amount of water that goes into the lake bed.”

“The less water that rises to the Corcoran dike, the better,” she said.

Locator of the Kern-California River Aqueduct Intersection.

(Paul Duginski/Los Angeles Times)

The Intertie functions like a gated alley connecting two much larger streets. On one side is the stretch of the Kern River known as the Buena Vista Canal, and on the other is the California Aqueduct, the simple name for an intricate system of tunnels and pipes that transport water from Northern California and the Sierra to the arid central region. of the state. and southern lands.

To open the connection, the operator lowers the water level of the aqueduct below the level of the associated basin. When the gates separating the two sides are opened, gravity will guide the water of the Kern River into the aqueduct. The flow is expected to start at 500 cubic feet per second and will increase to 1,000 cubic feet per second later this month.

In two months, about 75,000 acres of Kern River water will flow into the aqueduct, enough to supply about 225,000 households for a year, state officials say.

The U.S. Army Corps of Engineers built the aqueduct connection in 1977 to reduce flood risk to communities around the Lake Tulare Basin by diverting flow as the Kern River rages and rises. Dam managers have released unusually high flows from Lake Isabella in the southern Sierra, where Kern was built, to make way for a historic snow melt. That, in turn, prompted Kern and the water managers to say they determined that without intervention, flows would follow the river and empty into Lake Tulare.

“That’s why the intertie was designed, licensed and built, just for flood control like this,” said Mark Mulkay, Kern water manager, who asked the state to activate the facility. like this.

Governor Gavin Newsom signed an executive order This week facilitated water transfers as part of an emergency flood response effort. Local irrigation districts have diverted as much water as they can to supply crops and fill groundwater replenishment facilities.

“Everything is complete. All of our irrigation needs are being met,” Mulkay said. “We’ve given everyone water, and we think we’ve done a pretty good job of making sure that all the reservoirs are full. So, in effect, this is more than manageable water here in Kern County without flood damage.”

The only place left to safely send water is through the aqueduct to Southern California cities, where the Urban Water District will mix the water with other runoff from Northern California, treat it, and deliver it. water to the faucets.

Snow cover in the southern Sierra is 400% higher than average for this time of year, meaning unusually high rainfall could continue for months. But Nemeth said the peak of snowmelt in the Kern basin will occur “within the next week or two.”

In addition to dealing with the massive snow and ice, local water officials have struggled to develop plans to combat the frequent over-exploitation of groundwater, which has left some residents with dry wells and land subsided several feet in areas of the Lake Tulare Basin.

The state management agency has declared the local groundwater management plan inadequate in the six regions of the San Joaquin Valleyincludes the Kern and Tulare Lake sub-basins.

With more water entering the Kern River than the area can handle, Nemeth said, this situation demonstrates the area’s unrealized aquifer regeneration potential. Local agencies need the right infrastructure in place to allow them to save more money the next time California has a wet year, she said.

“As we look to the future, we want to use the link less and less often so that local communities and groundwater sustainability agencies can capture those flood flows,” Nemeth said. and replenish their groundwater basins. “It’s the future.”

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