Replies

1.0 2017/02/14 02:56:01 39.542N 121.510W -0.0 5 km ( 3 mi) NW of Oroville East, CA

0.8 2017/02/14 02:39:52 39.547N 121.487W 1.6 4 km ( 3 mi) NNW of Oroville East, CA

More Trouble: Late night emergency repairs going on near the top of the main spillway. A flow of water has collapsed a section of the hillside next to the upper main spillway. The source of this vigorous flow of water is not clear. However it is doing hydraulic erosion on the side of the main spillway near the top of the dam. It is very likely that this hydraulic erosion may be occurring under the main spillway slabs. If so, this could compromise the support of the concrete slabs. We certainly do not want another failure like the middle of the main spillway. This could cause a huge hydraulic back erosion at the top of the main spillway. Emergency repairs are underway using a pumping crane to insert grout and/or concrete to try to fix this. The vigorous flow & the hydraulic erosion indicate that this fix would be challenging. This may only be a stop-gap attempt rather than do nothing. I feel for these workers.