The brand new earthen Teton Dam in Eastern Idaho collapsed on June 5, 1976 at 11:57 am. The entire reservoir of about 288,000 acre feet (or about one-twelfth of the Oroville Reservoir’s capacity), roared down upon two towns in the flood plain, demolishing them.
The human death toll was remarkably low, either 11 or 14 according to various sources, but about 13,000 cows were killed.
The Oroville reservoir is now down almost 48 feet below its brim to 853′ elevation. The goal is to lower the water level to 850′, which is what they were holding it at when it suddenly shot up earlier this month to 902′.
Outflow down the damaged main spillway has been cut from 100,000 cubic feet per second down to about 55,000 cfs, while the inflow from the moderate rains a few days ago is up to around 40,000 cfs. So the drop in the lake’s elevation is down to just over 1 inch per hour.
It hasn’t started raining again yet in Oroville, but a fairly big storm is expected from Sunday through Tuesday. The small town of Feather Falls up in the reservoir’s watershed is expecting about 6.5 inches of rain, which would be about 75 or 80 feet of incremental elevation, all other things being equal (which they never are). Fortunately, the week after this onrushing storm is expected have less than one inch of precipitation, with fairly cool temperatures to retard snowmelt.
The official reason for cutting the main spillway’s outflow so far back is to allow the power station to be restarted, which could add 13,000 cfs to outflow.
From the San Francisco Chronicle:
Interestingly, there’s a fourth outlet, the “river valves,” that used to have 5,400 cfs capacity, but were cut to 2,000 after an accident, and apparently haven’t been used in this emergency.
Here’s a curious headline:
5 Oroville Dam workers fired after posting pictures on social media
By Allison Weeks, KRON and Clemence Robineau, KRON
Published: February 18, 2017, 6:27 pm
So, it’s All Hands on Deck … except that managing our social media presence is, of course, the highest priority. We can’t let the 16,000 residents of Oroville, CA, 7 miles downriver, get their information unfiltered.
That would be inappropriate.