At least one Northern California tribal community is in the direct path of the near-disaster currently unfolding at the Oroville Dam as officials frantically work to shore up damaged spillways and prevent a projected 30-foot wall of water boiling through the Feather River Canyon, which encloses the U.S.’s tallest dam. Members of the Estom Yumeka Maidu and the Mechoopda Indian tribes are directly in the water’s path and are among the nearly 200,000 evacuees.
The 770-foot-high Oroville Dam provides water to 23 million state residents and thousands of farms in the San Joaquin Valley, the Los Angeles basin and other areas of California. Nearly drained during the state’s historic drought, the reservoir behind the dam has been filled by record snowfall and rain this winter past its 3.53 million acre-feet capacity. When the regular spillway, damaged by soil shifts under its concrete channel, developed a 30-foot-deep crater, the emergency spillway, a low earthen embankment topped with a lip of concrete, was put into action. However, water gushing over this spillway is also working its way under the concrete and washing away the soil beneath. Officials fear the spillway may completely fail, sending millions of gallons of water down to inundate the city of Oroville and other lower-lying areas in the Sacramento Valley.
So far the dam itself is not in danger of breach. However, on Sunday February 12, Butte County Sheriff Kory Honea called for the evacuation of nearly 200,000 people in flood zones in Butte, Yolo and Yuba counties.
Just eight miles southwest of the Oroville Dam, many of the Estom Yumeka Maidu Tribe of the Enterprise Rancheria’s 800 members, and members of the Mechoopda Indian Tribe who live in the area have had to evacuate their homes, said Anacita Agustinez, Navajo, tribal policy adviser for the California Division of Water Resources. The Mechoopda are another band of Maidu from nearby Chico. The Maidu people’s traditional lands range from Mount Lassen and Honey Lake to the north, westward to the Sacramento River, south to the American River and east to the crest of the Sierra Nevada Mountains. The Feather River area is in the heart of Mountain Maidu country.
Reports in the San Jose Mercury News and the Sacramento Bee offer clues as to the underlying reason behind the near-disaster: As early as 2002, the Yuba County Water Agency, one of the Oroville Dam’s stakeholders, discovered the spillway’s flaws.
“The discharge area below the emergency spillway is not armored, and extensive erosion would take place if the emergency spillway were used,” a memorandum stated. “The spillway road and possibly high voltage transmission towers would be impacted.”
And in 2003, three environmental groups, the Friends of the River, the South Yuba Citizens League and the Sierra Club, called for proper lining of the auxiliary spillway during the federal government’s dam relicensing process. Those repairs were never made.
CDWR quickly mobilized resources from other agencies including the Army Corps of Engineers, state and federal wildlife agencies, local police and sheriff agencies and the state’s dam safety division to deal with the emergency. Trucks and helicopters moved large rocks and gravel to fill the erosion compromising the emergency spillway. CDWR representatives report that, as of 7 a.m. Pacific Standard Time on February 14, lake levels have decreased to 889.22 feet; the Oroville Dam spillway is releasing 99,690 cubic feet per minute, and 43,113 cubic feet are flowing into the reservoir from the watershed.
Although the immediate danger seems to be over, the evacuation is still in effect. Officials are also watching the skies for more water: The National Weather Service is predicting another winter storm to hit beginning on Wednesday February 15 with “warm and wet” conditions.