The Butte County Sheriff Saved Many Lives on February 12, 2017
AGENDA 21 RADIO
BY PAUL PRESTON
UPSTREAM FLOWS AND SNOW MELT CRITICAL TO SAVE OROVILLE DAM THIS SEASON
PAUL PRESTON interviews SCOTT CAHILL who discusses the high probability the Oroville Dam will fail even in this current run off season. Scott cites the current reports issued by an independent group who are critical about the way the state of California then adds his own observations regarding the safety of the spillways both emergency and the main spillway along with the main dam itself. Failure of the dam could mean the death of as many as a million people.
In a three hour interview on Agenda 21 Radio SCOTT CAHILL discusses the high probability the Oroville Dam will fail even in this current run off season. Scott cites the current reports issued by an independent group who are critical about the way the state of California has handled the crisis. Scott then adds his own observations regarding the safety of the spillways both emergency and the main spillway along with the main dam itself. Failure of the dam could mean the death of as many as a million people.
Evacuation of the dam by Butte County Sheriff Kory Honea on February 12, 2017 brings high praise from both Cahill and Preston who agree the call to evacuate the dam on February 12, 2017 was a bold and necessary call given the dam was within one hour of failing at the emergency spillway. Nearly 200,000 people were forced to flee and were then caught up in the traffic jams and restrict exits. Little did these people know the dam was within minutes of failure possibly killing thousands. When Sheriff Honea made the call he understood as few did the immediate danger that existed.
Honea’s Call Forced the Department of Water Resources to Immediately Open the Main Spillway to 100,000 cf/s
When water started to spill over the emergency spillway on the morning of February 11, 2017 the flows over the damaged main spillway were between 40,000 and 45,000 cf/s. This rate of flow was suggested in order to maintain the salmon spawning areas in the Feather River so a choice was made to allow the water to rise to 901 feet and ‘sheet’ over the concrete weir of the emergency spillway for the first time in the dam’s 50 year history.
As water sheeted over the emergency spillway vortices on the lake side started to appear and a large crevasse was determined to be growing at a rate of 30 feet per hour in the direction of the weir which could undermine the top structure. Honea made the call to get everyone off the dam and to evacuate the communities down stream along the flood plane of the Feather River. Had Honea not made the decision to evacuate the weir on the emergency spillway would have failed and the dam would have in minutes lost the to 25% of it’s surface water thus inundating the city of Oroville and other communities. As the water would have flooded over the emergency spillway the probability of erosion deepening the level of the soil below the dam would have continued unabated thus creating additional flooding. Inundation maps from 2010 show the inundation would have reached south past Sacramento and west as far as Williams along the I-5 Freeway.
A map intended for planners and first responders plots the likely path of devastation should either of the compromised spillways at Lake Oroville fail while the reservoir is full. The map only represent 13% of the water in the reservoir.
CHRISS STREET joins the conversation and agrees with Scott Cahill’s assessment of the dam, emergency spillway and the main spillway.
SECOND HOUR OF SCOTT CAHILL INTERVIEW, CHRISS STREET JOINS THE INTERVIEW
