May rainstorm forces water agency to lower Russian River dam

Recent heavy rains that swept through the North Bay forced Sonoma County water officials to lower a rubber dam inflated on the Russian River less than a week ago.

The Sonoma County Water Agency began lowering the dam back down on Thursday.

Officials anticipate that this month's unusual rainstorms will raise river flows to 6,000 cubic feet per second by Sunday night, which could potentially damage the inflatable dam.

The water agency typically lowers the dam when river flows exceed 2,000 cubic feet per second.

The dam had been gradually inflated between May 6 and May 11. Boaters are encouraged to be cautious in the area of the dam while it's being lowered.

Once inflated, the dam normally would remain inflated through summer and into the fall.

When fully inflated, the rubber dam creates a small pool from which Sonoma Water draws water for use in four off-stream infiltration ponds.

The infiltration ponds help recharge groundwater, which is then naturally filtered through sand and gravel and delivered to Sonoma Water's customers.

For more information about the rubber dam and how Sonoma Water delivers naturally filtered Russian River water to its customers, please visit