MWD Prepares to Chemically Treat Big Bear Lake

Written by Katherine Davis-Young of the Big Bear Grizzly.

The Big Bear Lake Municipal Water District board of directors approved a $772,800 project May 7 to begin treating Big Bear Lake with alum.

The project is intended to improve the health of the lake and to meet total maximum daily load standards for pollutants in a body of water as defined by the US Environmental Protection Agency. The ongoing drought has caused lake levels to drop, and as a result, the chemical balance of the water has changed. The alum will counteract rising levels of phosphorus in the lake water.

Some of the phosphorus is naturally occurring and some comes from runoff from the surrounding community. High levels of phosphorus can contribute to increased chlorophyll or algae. Alum has been used in lakes since the 1970s as a phosphorus treatment.

“(Alum) is used in every drinking water plant,” MWD General Manager Mike Stephenson said. “It’s basically Maalox.”

MWD will spend $400,000 on the project and San Bernardino County and the city of Big Bear Lake will contribute $350,000. Washington-based lake treatment company Aquatechnex will treat the deepest portion of Big Bear Lake, a 420-acre area at the lake’s west end, with about 600,000 gallons of alum.

This is not the first time Big Bear Lake has been treated with alum. In 2004, during another serious drought, the lake dipped as low as 17 feet down from full. MWD treated the lake with 700,000 gallons of alum. The alum did its job, but 2005 brought heavy rain. Stephenson said that caused pollution and runoff to make its way back into the lake. That experience made this proposal a complicated decision for the board. They want to see the lake fill up but they also want to spend their money wisely.

Board member Bob Ludecke said in an April workshop discussing the project, “We’re basically going to spend three quarters of a million dollars then pray that it’s a bust.”

Board president Maryann Lewis said the project would likely be a success. “Unless we have a monster weather event, we’re going to see years of benefit,” she said.

When the board approved the project, Stephenson also reassured the board that the treatment is necessary. “We need to get alum in the water before we start seeing elevated chlorophyll numbers. We need to act quickly,” he said.

Aquatechnex will begin treating the lake in mid May. Stephenson said onlookers can expect to see cloudy water when the treatment is taking place, but when it’s done the lake should look a little clearer.

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