California Floods Its Fields to Maintain Its Cities From Flooding

To see how close California is to getting drowned by its recent winter storms, just look to the small crowd of spectators and Television newscasters gathered yesterday on the northwest side of the state capital hoping to watch state water managers to open the gates of the Sacramento Weir. The weir, some thing between a dam and a levee, lets dangerously high water spill over its best into a extended, narrow, floodplain filled with rice paddies, grain fields, and other row crops.

Californians pay focus to the weir for 3 factors. One: Individuals here are obsessed with water. Two: The point hasn’t been opened in a decade. Three: Opening the one hundred-year old piece of infrastructure is a spectacle, requiring a particular person wielding a long, hooked pole to manually unlatch every single of its 48 wooden floodgates. The crowd slept via that spectacle state workers opened the weir in the dark, early this morning. They can nonetheless catch the sight of water thundering more than the weir and into the Yolo Bypass, flooding the plain to safeguard the city of Sacramento.

From 1850 on, Sacramento has flooded many occasions. This was why, in 1916, the city built the Sacramento Weir to protect itself. In the following decades, the state added five more upstream weirs, and several extra spillways. In addition to the Sacramento Weir, all of these are automatic failsafes: If the river reaches a particular height, it spills over a weir into the adjoining bypass.

But due to the fact the Sacramento Weir’s gates have to be manually opened, they need to be manually closed, too. And that can not be carried out till the water recedes under the weir gate levels. “Once you open them, you’re producing a choice that you’re going to stick with,” says Michael Anderson, state climatologist for the California Division of Water Sources. And when that choice takes place, Yolo Bypass becomes an inland sea. Birds flock in, and fish swim beneath.

The state does not make that choice lightly. Just before it deploys its hook-wielder to unlatch the gates, it has to meet specific protocols set by the Army Corps of Engineers. 1st, about three and a half miles downstream from the weir—less than a mile upstream from downtown Sacramento—a gauge reports the river’s depth. To proceed, it have to read that the river has risen past 30 feet.

On prime of that, a quorum of meteorologists and water managers must report that the river will preserve increasing. This forecast is not so simple. It entails calculating outflows from the Sacramento River’s key tributaries—some dammed, some with key reservoirs, some that run wild.

“Let’s start with the American River, which has Folsom Lake,” says Michael Anderson, state climatologist with the California Division of Water Sources. “In the final 24 hours, Folsom gained over 60,000 acre feet.” (An acre foot of water would cover an acre in one particular foot of water.) This water, which, for the duration of the height of the storm came in at more than 140,000 cubic feet per second, pushed the dam past its winter storage limit—meaning it need to drain some of that water to make space for a lot more, in case there’s another huge storm coming (which there is).

The lake’s managers cannot drain it without first getting the go-ahead from the Division of Water Resources, which gets reports from the managers of every other river and reservoir, like Lakes Shasta and Oroville—two monster basins now preparing to shunt off this winter’s storm water. Every single reservoir’s managers measure water levels, inflow, precipitation, and snow melt prices prior to calculating who gets to flush their excess down the shared drainpipe: the Sacramento River.

A few factors confound these equations. 1st, the reservoirs do not want to give up as well considerably water—this is, after all, California. Also, a bunch of dam-less rivers and creeks flow into the Sacramento. “Each of these can kick out in between 30 and 50 cubic feet per second,” says Anderson. So the state has hydrologists who measure all the rain falling and snow melting into these. Once all the data is in, the Division of Water Sources confers with the National Climate Service’s California Nevada River Forecast Center to figure out if the water level at Sacramento’s I Street gauge is nonetheless rising.

All of these checks and balances are in place simply because California’s tendency to flood is nearly as notorious as its habit of running dry. “Turns out, we have the most variable climate in nation for water,” says Marty Ralph, study meteorologist and director of the Scripps Institution’s Center for Western Weather and Water Extremes. “Year to year, we vary by 40 or even 50 percent from typical.” Most eastern states only fluctuate by 10 percent either way.

California does not get a lot of credit for how effectively it manages water. Even throughout the worst of the drought—still technically taking place, by the way—the state still delivered water to almost all its residents. Some disasters can not be avoided. But, in the midst of a historic barrage of storms, the bureaucrats and engineers are maintaining the the state’s largest river program from flooding the capital.

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