Oroville Dam Crisis: State, Federal Inspectors Missed Vital Clues
A new report by a team of independent scientists has found that, over a period of decades, state and federal inspectors missed important clues that could have prevented the February collapse of the Oroville Dam spillway in California.
The destruction of the spillway during heavy runoff conditions prompted the evacuation of nearly 200,000 people as a precaution.
Inspectors were too reliant on visual inspections and ignored construction records, blueprints and other documents that could have warned them about the dam’s flood-control spillway well before it fractured, the Sacramento Bee reports.
The investigators said there could be similar problems at other dams in California and elsewhere because of an over-reliance on visual inspections.
Oroville’s spillway failure was likely caused by long-standing problems with cracks in the concrete and a faulty drainage system underneath the concrete chute, which was too thin in places. Visual inspections alone would not allow regulators to pull all the clues together and point to the likelihood of failure.
“Physical inspections, while necessary, are not sufficient to identify risks and manage safety,” the expert team reported.
Despite Wet Winter, Oregon Trending Toward Drought
High temperatures have begun to push Oregon back toward drought conditions, despite winter precipitation that was above normal.
Temperature records have been broken in recent days and much of the state has been under a heat advisory.
As a result, Oregon is abnormally dry and on the cusp of drought conditions, according to the National Drought Mitigation Center.
“When the snowpack melts out too soon or we can’t capture it, that’s when the temperature is really controlling our water situation,” Kathie Dello, deputy director of the Oregon Climate Service at Oregon State University, told the Statesman Journal newspaper.
The heat has contributed to increasing water demand, putting additional stress on resources that are still recovering from several years of drought. One wet winter may not be enough to overcome this.
The heat has played a role in fueling a number of large fires burning in the state. One has torched a portion of the watershed that supplies Portland’s drinking water.
Time for Glen Canyon Dam to Bow Out?
An environmental group has floated a radical proposal: let the Colorado river run through Glen Canyon Dam, draining Lake Powell, to refill Lake Mead, a vitally important water supply for three states and Mexico.
The Glen Canyon Institute’s proposal comes in response to a long-term drought of the Colorado River that has drastically shrunk water supplies in Lake Mead.
The so-called “Lake Mead First” proposal would essentially combine two giant reservoirs into one. Glen Canyon Dam would be left in place, so water could be stored if wetter conditions return to the region at some point in the future.
This would also eliminate seepage losses from Lake Powell and restore some of the grandeur of the landscape that was lost when it was filled, including the canyon’s fabled cliffs and grottoes.
It is not a new idea, but it is getting fresh attention as Lake Mead continues shrinking to a water elevation that could trigger a shortage, requiring drastic cuts in consumption.
“The Colorado River can no longer sustain two huge reservoirs,” Eric Balken, executive director of the nonprofit Glen Canyon Institute, told High Country News. “There isn’t enough water.”
While the proposal might avert or delay that concern, draining Lake Powell into Lake Mead would not result in significant water savings, according to Jack Schmidt. The Utah State University watershed scientist has completed an 80-page analysis on the concept.