Oroville Dam emergency Spillway expected to Be used as soon as Saturday
- Author: Salvatore Jensen Feb 12, 2017,
Feb 12, 2017, 8:15
Although inflows decreased Friday and into Saturday morning to 89,000 cubic feet per second, water officials have also decreased outflows to 55,100 cfs, according to KCRA chief meteorologist Mark Finan. It's the first time water has ever been released from this area of the Oroville Dam in the facility's 48 years of existence.
But, slower releases could cause the rushing water to top the emergency structure and flow into the emergency spillway. The dam's 3,000-foot main spillway was being used for the controlled release of water, but on Tuesday this past week, the concrete spillway split open and is continuing to erode.
Crews had cleared the path Friday, so debris wouldn't flow into the Feather River. At 770 feet high, the structure, built between 1962 and 1968, is the tallest dam in the United States, besting the famed Hoover Dam by more than 40 feet.
Stay with KCRA for updates.
The U.S. Bureau of Reclamation offered $1.1 billion to raise the height of Shasta Dam by 18.5 feet to increase water storage by 14 percent, but the Obama administration killed the project in 2014 by filing a 349-page report claiming any expansion would threated salmon under the Endangered Species Act.
"The integrity of the dam is not jeopardized in any way because the problem is with the spillway and not the dam", department spokesman Eric See said. Its reservoir provides fresh water to much of Central California's farmlands and homes, and businesses in Southern California.
Officials are hoping that with a spell of dry weather, and a few more days of water releases, the lake will recede to 890 feet, or 11 feet below the lip of the emergency spillway.
The erosion to the Oroville Dam spillway was originally estimated to be a 200-foot-long strip, and about 30-foot depth but Friday the length of the erosion had grown by at least 50 percent due to more concrete crumbling.
The emergency outlet is created to kick in automatically if the reservoir reaches the 901 feet elevation. That led to the shutdown of the spillway while engineers assess its condition. The water flowing out of the hole quickly turned brown with mud as it consumed trees and soil before rejoining the main channel below in a massive confluence wave that sent up clouds of mist in the tree-lined canyon.
"The loss of hatchery-produced salmon from Feather River Hatchery would be a major blow to salmon fishermen in California", McManus said, the Sacramento Bee reported. The same erosion also threatens the towers that hold the power lines that take electricity from the power plant to the electrical grid; such a connection is needed for the power plant to operate.