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A wet winter may seem like exactly what California needs after four years of crippling drought, but the El Nino weather pattern forecasters are calling too-big-to-fail may be too much for the state's infrastructure. Southern California got a taste of severe thunderstorms and flash floods late last week, and its weather like that that has officials concerned about dams and levees throughout the state, many of which are in dire need of repair. NPR's Kirk Siegler went out to survey some of California's flood control system.
KIRK SIEGLER, BYLINE: On this balmy and bone-dry fall afternoon, it's hard to imagine a torrent of floodwater overwhelming this lazy stretch of the Sacramento River lined with willow and cottonwood trees. But then again, that's not my job. It's Michael Mierzwa's.
MICHAEL MIERZWA: Our flood's management system is old, and it's in need of repair.
SIEGLER: He's the state of California's chief flood planner. To illustrate, we're standing underneath what looks like an ordinary highway underpass not far from the riverbank. It's actually called the Sacramento Weir.
MIERZWA: A weir is - think of it like a freeway off-ramp.
SIEGLER: It has dozens of narrow gates. When the river hits a flood stage, they're designed to open up and divert the deluge to an adjacent floodplain where there are no homes or farms.
MIERZWA: In doing so, it will drastically reduce the water levels in the river to protect the city of Sacramento, our state capital.
SIEGLER: There's just one problem. This weir was built in 1916.
MIERZWA: It was really based off of 1907 and 1909 data.
SIEGLER: Not only is it outdated - we now know a lot more about California's often extreme climate - but it's also rusty orange and brown. Some of the gates are missing. Others have been replaced temporarily with pieces of wood. Whether it would hold up in a big flood is an open question.
MIERZWA: Hundred years ago, they thought it would last a hundred years, and here it is still standing and working today. But we have different needs of it today.
SIEGLER: This right here is a emblematic of a much bigger problem in the Sacramento Delta's dam and levee system, one of the oldest and largest in the country. About half of it is in need of either repair or replacement. That's the bad news. The good news is that, due in large part to the drought, there's a flurry of work going on to make California's water infrastructure more resilient. One of the best places to see this in action is a short drive up a windy road into the foothills.
At the Folsom Dam, jackhammers are chipping through boulders beneath the reservoir. This is a billion-dollar federal project, building a massive new 2,400-foot-long spillway. It will allow the dam's operators to release more water downstream into that aging levee system several days before a big storm is predicted so it's not overwhelmed all at once. For a good look, I'm hiking out onto a bluff with the project manager, Mark Curney of the Bureau of Reclamation, the West's federal water agency. There are signs warning of rattlesnakes everywhere.
MARK CURNEY: Yeah, they're a little docile from what I hear, so they probably won't strike you as fast as some other rattlesnakes.
SIEGLER: Good to know.
CURNEY: If you look towards the control structure, you see about three cranes. So all this...
SIEGLER: Curney points to the spillway and to where crews are burrowing down deeper into the dam to build new outtake valves. Now together, this may buy some time for people down in Sacramento to evacuate during a big storm.
CURNEY: It's almost like having an extra valve to where you can actually say, OK, I want to turn my water on three days sooner, and I want to lower my reservoir by X amount of feet to where I can have just that much in extra storage to capture any storm that's coming in.
SIEGLER: Even though this project is on the fast track, it will not be completed in time for the predicted El Nino this winter. But most water managers I talked to didn't seem too worried. They say the state is used to extremes. It's a fact of life here. Drought and flood planning - they go hand-in-hand.
JAY LUND: California every year experiences the worst drought than the eastern part of the United States has ever seen since the end of the last Ice Age.
SIEGLER: Jay Lund is an engineer who heads the Center for Watershed Sciences at UC Davis. He says some of the short-term fixes being put in place right now to prepare for El Nino should hold until some of the bigger things like the Folsom Dam project come online.
LUND: We're not going to get surprised by a big flood immediately. It will take, probably, a series of storms to wet up the watershed and to start filling reservoirs.
SIEGLER: After all, most of the reservoirs like Folsom right now are historically low thanks to four years of drought. Kirk Siegler, NPR News, Sacramento. Transcript provided by NPR, Copyright NPR.