Municipal Water District officials are not concerned about an event similar to Oroville happening in Big Bear. Below is an article from Natalie Williams of the Big Bear Grizzly.
Big Bear Dam not at risk
Unlike the damage, flooding and evacuations at the Oroville Dam in Northern California, the dam on Big Bear Lake is in good shape.
“As far as dam safety and issues and concerns of flooding, we’re about half capacity right now, so we have a long ways to go, ” said Mike Stephenson, general manager of the Big Bear Municipal Water District. As of February 1`, the dam was 13 feet, 4 inches from full.
Stephenson said the Big Bear Lake dam is not at risk of experiencing issues similar to the Oroville Dam in Northern California. The problems with Oroville Dam began February 7 after a large hole emerged in a spillway after the region experienced heavy rains. Evacuations for at least 188,000 followed February 12 after there were concerns of the spillway failing, according to The Mercury News.
The Big Bear dam can withstand an 8.3-plus earthquake and 3 feet of water over the top, Stephenson said.
When water is released from the Big Bear dam, it takes nine hours to travel from the Big Bear dam to the Seven Oaks dam. “Seven Oaks is double the capacity of Big Bear and can never be more than half full, so it can take the entire Big Bear Lake and hold it behind it,” Stephenson said. If there were a breach, Seven Oaks would be able to successfully capture the water. There are a few campgrounds near the path of the water, which are unoccupied during the winter months, so Stephenson said there’s really no risk or danger.
“Our capabilities for release are incredible,” Stephenson said. “And if we got into a situation where we saw an impending storm, and we’re a foot or two from full, we certainly would start a release, kind of like what Oroville is doing right now with what’s going on up there.”
To help with the safety, the MWD bolted some rocks to the side of cliffs near the dam and conducted a routing study a few years ago to see if there were erosion or overtopping concerns.
“The routing study, what it does is it kind of models the water going over the top of the dam and what potentially kind of erosion, like what happened in Oroville, could create,” Stephenson said. “And there were no concerns.”
The east side of the dam has experienced some spalling, or erosion, of the concrete, but the MWD said it is damage caused to the original 1-foot archways. In 2005-06 the MWD added a 2-foot thick dam behind that dam, so it is secure, Stephenson said. “Our dam right now is a big blob of concrete, it’s 32 feet, it’s pretty damn strong, there’s no fear of it failing,” he said.
The MWD also has an operations plan from its engineer, Mike Rogers of Montgomery. Watson and Harza, which instructs the district that if there is 12 inches of predicted precipitation and the dam is a foot from full, water needs to be released, Stephenson said.
“We have a pretty robust plan as far as any issue,” Stephenson said. “It’s kind of funny the last conversation I had with reporters was drought, now we’re talking flood and the dam breaks. And that’s how these things come. Right now we’re actually hoping we get some of that rain up north.”
The MWD dam has approval from its engineer and experiences bi-annual inspections from the Division of Safety of Dams for the state of California, Stephenson said. Right now, Stephenson still hopes to receive additional precipitation.
We’re certainly not out of the woods yet as far as drought and low lake level,” Stephenson said.