Officials say a reservoir in Santa Clara County is on the cusp of spilling over for the first time since 2006. But KNTV reported Wednesday (http://bit.ly/2ljg9TP) that unlike Oroville Dam, the Anderson Reservoir is not at risk of failure or causing major flooding. County officials are warning nearby residents to watch out for flooding. At 99.3 percent full, authorities are trying to drain the reservoir before storms arrive.
California’s water regulators just can’t give up their control of our lawn watering and shower times, despite a federal analysis showing that most of the state is no longer in drought. Even as Gov. Jerry Brown declared a state of emergency for 50 counties last month due to flooding, erosion and mud flows, and the snowpack in the Sierra Nevada is nearly twice average levels, the State Water Resources Control Board voted unanimously last week to extend water conservation rules until at least May.
What is most surprising about the near-collapse of a spillway at Oroville Dam is that events like that have not happened more often. Located 75 miles north of Sacramento, Oroville is the nation’s tallest dam and holds back the state’s second-largest reservoir. Both its main spillway and an auxiliary one have experienced major erosion because of massive emergency releases of reservoir water during this winter’s heavy storms. On Sunday, engineers worried that the top 20 or 30 feet of the emergency spillway could give way, causing devastating flooding on the Feather River.
With the water level at California’s Lake Oroville dropping, authorities lifted a mandatory evacuation order, allowing tens of thousands of residents to return to homes near the reservoir’s dam. But Butte County Sheriff Kory Honea on Tuesday cautioned residents and business owners to “maintain situational awareness” with a series of storms forecast for later in the week. “People who have special needs or require extended time to evacuate should consider remaining evacuated,” the sheriff said. Heavy rains last week caused the lake level to rise until the water began to pour down the emergency spillway on Sunday.
Lake Oroville and its dam in Northern California are critical components in California’s complex water-delivery system. Damage to spillways that are used to drop water levels in the lake and relieve pressure on the dam prompted evacuation orders covering nearly 200,000 people. Here’s a look at Lake Oroville and its place in California’s water system: How important is Lake Oroville? Lake Oroville is the starting point for California’s State Water Project, which provides drinking water to 23 million of the state’s 39 million people and irrigates 750,000 acres of farms.
The Oroville Dam in Northern California may seem far removed from San Diego. But there are millions of reasons, most in gallon form, for locals to be keeping an eye on the ongoing battle to keep its emergency spillway from collapsing. The dam, as the L.A. Times puts it, is the “linchpin” of the statewide water system that brings water from the Sierra Nevada mountains to Southern California. Its fate affects our water supply. And that’s not all.
A powerful new storm is expected to arrive in Southern California on Friday, and it could provide a walloping, with possible flash flooding, mudslides and rock slides. “The Friday storm in particular could in fact become the strongest of the season in the Los Angeles region,” said UCLA climate scientist Daniel Swain.
Even as rain began to fall in Northern California on Wednesday, state officials said the storms forecast over the next few days will not be enough to test the integrity of the Oroville Dam or its two damaged spillways. Bill Croyle, acting director of the state Department of Water Resources, called the storms “fairly small” and said the public “won’t see a blip in the reservoir” levels, now dropping about eight inches an hour.
A comprehensive condition assessment of nine dams owned by the city of San Diego has been underway for the past year, according to the Public Utilities Department said. Asked about the condition of San Diego dams after Sunday’s mass evacuation in Oroville in Northern California, department officials told City News Service that they hired independent experts in dam design, construction and safety to perform detailed inspections of the dams in February of last year.
In 1905, an engineer gave California a lake. He didn’t do it on purpose; the cuts he made in a canal a few miles into Mexico burst open, releasing the full force of a flooding Colorado River into the Imperial Valley. For two years it filled a pit known as the Salton Sink, in southeastern California, until the government managed to close the breach.
