No, humans cannot make it rain, stop the rain, or produce real rainbows in the sky. But we can do things that protect ourselves from the rain and get it to work for our agriculture and overall economy. And it’s clearer than ever that Californians have simply failed to do those things as the Oroville Dam crisis continues to force massive evacuations and raises fears of a potential disaster.
The area around a huge dam at California’s second-largest reservoir is in a state of emergency, with some 180,000 residents ordered to evacuate the area Sunday out of fears that part of Oroville Dam could fail. A glimmer of hope arrived late Sunday night, when officials said water had finally stopped pouring over the dam’s emergency spillway. The secondary spillway was in use because the main spillway had developed a huge hole, stressed by the need to release water accumulated from California’s wet winter — and brought to a new crisis point by last week’s heavy rains.
At Northern California’s Lake Oroville, water levels receded Monday, stopping the overflow of water from the dam’s emergency spillway. This reduced the risk of immediate uncontrolled flooding — but longer-term concerns remain. William Brangham speaks with Jeffrey Mount of the Public Policy Institute of California about the massive evacuation that took place and the outlook for the dam’s future.
Few people realize how outdated our systems for water information are. Because of data limitations, real-time, transparent decisions about drought management, flood response and groundwater protection have eluded the state for the past century. Without basic numbers on where, when and how much water is available and being used, we can’t improve how we manage our most precious water and natural resources.
Sacramento County advised residents in the Tyler Island area south of Walnut Grove to evacuate Monday due to a compromised levee. About 20 homes are in the area, said Sacramento County Water Resources spokesman Matt Robinson. Tyler Island is protected by a ring levee. The county expected imminent failure of the North Fork Mokelumne River levee, the National Weather Service warned early in the afternoon. Robinson said there was some disintegration on the land side of the levee but no water has gotten through. Workers are piling rocks at the weakened point to shore it up, he said.
It wasn’t so long ago that residents here had to drag their houseboats into a dusty field from the barren banks of Lake Oroville, which had almost no water left to keep them afloat. Now after weeks of rain, that dusty field is swelling with water and nearly 200,000 people had to evacuate the area when the state’s second-largest reservoir developed a hole in its auxiliary spillway and threatened to catastrophically flood nearby towns.
Federal officials Monday ordered California to convene a five-member independent board of dam experts to review the condition of Oroville’s auxiliary spillway and the damaged regular concrete spillway, and to make recommendations about how to improve safety during the emergency and over the long-term. In a letter to the state Department of Water Resources, the Federal Energy Regulatory Commission also required the state to hire “a fully independent third party” to perform a “forensic analysis” to determine the cause of the main spillway failure and whether it could occur again.
With more storms expected to slam Northern California later this week, officials worked frantically Monday to drain water from brimming Lake Oroville in hopes of heading off a potentially catastrophic flood. The operators at America’s tallest dam found themselves in a precarious position Monday, with both of the spillways used to release water compromised and the reservoir still filled almost to capacity after a winter of record rain and snow. Meanwhile, tens of thousands of evacuated residents downstream of the dam still have no clear word when they can return home.
Any dam engineer would be terrified of this nightmare scenario — the possible collapse of a retaining wall in California’s second largest reservoir. That’s the prospect officials faced when they ordered more than 100,000 people evacuated downstream of the nation’s tallest dam Sunday. It occurred insidiously: a pocket of erosion that crept ever closer to a low concrete wall that was supposed to be the last, best defense against disaster.
Eleven years ago, as three environmental groups were urging the state and federal government to require that concrete be used to armor the emergency spillway at Oroville Dam — an earthen spillway whose near collapse caused the evacuation of 200,000 people this week — state water officials said that was unnecessary. “The spillway is a safe and solid structure founded on solid bedrock that will not erode,” the state Department of Water Resources concluded in a May 26, 2006, filing to federal officials.
The Water News Network is San Diego County’s source for water news and information.
