As a national emergency looms at the Oroville dam and tens of thousands of people are evacuated, environmental groups can take small comfort in the fact that they saw this disaster coming 12 years ago. A report from The Mercury News details that three environmental groups, Friends of the River, the Sierra Club and the South Yuba Citizens League, warned state and federal regulators of the potential risk in 2005 to no avail.
At the time, the Oroville dam was up for relicensing. The dam, constructed in 1968, did not meet modern safety standards according to the environmental groups and they pushed for an upgrade. They filed a motion with the Federal Energy Regulatory Commission (FERC) to require the earthen emergency spillway to be reinforced with concrete.
The environmental groups warned that heavy rains and flooding could erode this emergency spillway and cause massive flooding. Such an event could destroy entire communities downstream of the dam.
The FERC ultimately rejected the groups' motion. The California state Department of Water Resources and the water agencies that maintained the dam—and were likely to shoulder the burden of paying for any repairs or improvements—argued that any upgrades to the emergency spillway were unnecessary. FERC officials stated that the emergency spillway was designed to handle 350,000 cubic feet of water per second, more than enough to ensure the dam's integrity. "The guidelines specify that during a rare flood event, it is acceptable for the emergency spillway to sustain significant damage," the FERC said at the time.
Over the past weekend, the concerns of those environmental groups were shown to be justified. As severe rains and flooding caused the water level at the dam to rise, and with the primary spillway damaged a few days prior, water began flowing down the emergency spillway for the first time in its history.
Even with less than 15,000 cubic feet of water per second flowing through the spillway—less than 5 percent of what FERC officials believed the spillway could handle—erosion threatened to cause extreme flooding. The danger, according to experts, is that the concrete lip at the top of the spillway could fail, causing 30 feet of water to rush uncontrolled down the spillway toward the communities below.
Source: The Mercury News