The water from Oroville dam
comes down like a battering ram.
They skipped maintenance, when
it was drought. That was then.
Repairs? Always bill Uncle Sam!
On May 31, 1889 The South Fork dam failed and unleashed 20,000,000 tons of water that devastated Johnstown, PA. The flood killed 2,209 people, and is remembered as one of the worst dam disasters to have ever befallen innocent and unaware people.
The dam was small by today’s standard, releasing only 16,220 acre-feet of water. Compare this to the water behind Lake Oroville Dam, 3,500,000 acre-feet, and another 370,000 acre feet of rain expected in the next few days.
Right now the dam is releasing 80 to 100,000 cubic feet of water a second, or about 2 acre-feet per second, about 6 times the capacity of the power station, which is rated at 835 MW. This means the release is about 5.5 GW of power rushing down and eroding the new spillway channel carved out by up to 7.5 million horse-power of destructive force. Normally this energy is absorbed as heat in a functional spillway, but if unleashed, much of its power is erosion force. The new channel of water, mixed with debris choked the normal water outlet from the power station and its diversion pool, so the power has been turned off since the emergency began.
For now, the main dam seems to be undamaged, but if more rains come, and there are 2 more major storms lined up coming from Japan and Taiwan with torrential rains, so this scare is far from over. Meanwhile, residents downstream are told to have their bags packed, and listen to emergency radio every hour, if the spillway gives way much further, this is going to be big.
The repair bill for damage done so far is probably a quarter billion dollars, not counting the cost of the evacuation. Proper maintenance would probably have cost less than 20 million dollars. This is about par for California politicians.
The original spillway is now totally diverted by erosion.
The spillway while it was still functioning as planned
Len Bilén's blog, a blog about faith, politics and the environment. 