The Largest Freshwater Lake West Of The Mississippi — Long A Ghost — Is Back After The Storms

Once upon a time — the early 20th century to be precise — Tulare Lake was the largest freshwater lake west of the Mississippi. And since that time, it hasn’t been a permanent presence. Year after year, the lake has been one of the many "ghost" bodies of water that our colored blue on our maps but are disappointingly dry in person.

But now, Tulare Lake is back. The series of powerful storms that hit the state over the last several weeks, has the lake reemerging in California's Central Valley. And with it comes flood risks that have residents concerns rising along with the water levels.

Just how dire the situation is around Tulare Lake? Los Angeles Times reporter Daniel Miller shared some photos by his colleague Luis Sinco on Twitter earlier this week:

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So, just how big of a lake are we talking about?

An irregular shape

Some estimates put the current surface area at around 10,000 acres, but it’s hard to say for sure, says Kerry Klein, an environmental reporter with NPR member station KVPR in the Central Valley. Klein joined our newsroom's public affairs show "AirTalk" — which airs on 89.3 FM — on Wednesday to talk about what she's learned.

Why is it hard to say? Partly because of the lake’s many levees, or embankments used for flood control. They’re very variable: some have been cut or have overflowed, while others haven’t, resulting in an irregular shape. She says the surface area is certainly in the order of thousands of acres.

“And that's still nothing compared to its fullest, which was around 600 to 800 square miles,” Klein said. “We all hope that it won't reach that. It likely will not reach that this time and it never has since it disappeared.”

History lesson

Tulare Lake circa 1800

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Public domain

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The lake hasn’t existed at that scale since the early 20th century. Before that, its seasonal flows sustained wetlands in the Central Valley, which was generally much less dry than it is now, Klein said. Tulare Lake also supported the thriving fisheries of the region’s native people, who fished for salmon, sturgeon, trout, and even turtles.

But she says when settlers moved west into present day California, in the 19th and 20th centuries, they wanted to use that land for agriculture and cultivation, so they diverted and dammed the water with extensive infrastructure.

“And so the lake was essentially engineered out of existence by the early 20th century,” Klein said.

The only exception? The lake sometimes reappears during massive downpours. And that can create flooding problems for residents.

Check out video of a 1942 reemergence

The problem

Local officials aren't sure what to do with all the excess water from the recent rainfalls, and for the forthcoming snow melt, which will likely be three or more times larger than average. The rivers that feed the lake all drain directly into it, Klein said, and they have no other outlet. Typically, the annual rainfall is diverted to ponding basins and irrigation canals, and eventually to agricultural fields. But this year, much of the land that would be irrigated is actually underwater.

So flood concerns are imminent. Twitter user Cannon Michael, who identifies himself in his profile as a 6th generation farmer in the Central Valley, posted this tweet demonstrating the lengths farmers in the area are going to divert the floodwaters:

Mark Grewal, an agronomist and expert on the area’s farms, said this flood could be more massive than either of the largest floods in recent years, which were in 1969 and 1983. He said the severe pressure and the sheer amount of water has caused the levees to break, which could mean trouble for both plants and people.

Many trees have found themselves underwater, and this is also a concern for homes, businesses, and dairies that have had to evacuate. One historically Black settlement called Allensworth, is an unincorporated community, so it lacks municipal resources and a city government to advocate for it.

Local authorities and residents say they are bracing for the trouble ahead.

Listen to the conversation