It's That Dam Season in Sonoma

The Sonoma County Water Agency today began inflating its rubber dam on the Russian River near Forestville.  

One week from now, beginning on June 24, the county's Veterans Memorial Beach Park will start construction of their dam, a wood brace and plank model across the Russian River in Healdsburg. It's usually up by July 1.

These are two signs of summer, and of a record low-water year. At Memorial Beach the Russian River is flowing at just 69 cubic feet per second; downstream at Hacienda Bridge, near the site of the Water Agency's inflatable dam, it's still below 100 CFS. 

Normal water flow this time of year is between 200 and 300 CFS.

At Memorial Beach, the six-foot dam will create a deeper pool for bathing and swimming, and back up approximately a mile and a half to two miles upstream. It usually stays in place until the week after Labor Day. 

The Water Agency's rubber dam will be inflated slowly to maintain flows downstream, and may take around two weeks to be fully inflated. The rubber dam is inflated in the spring when demand for potable water increases. 

The rubber dam is a critical component of the Russian River water supply system that provides naturally filtered drinking water to more than 600,000 residents in portions of Sonoma and Marin counties.  

When fully inflated, the rubber dam creates a small pool of water from which the Water Agency 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 the Water Agency’s customers.  

The rubber dam remains inflated through summer and into the fall.  It typically is deflated in the fall when natural flows exceed 1,000 cubic-feet-per-second.

Permanent fish ladders provide fish passage around the rubber dam when it is inflated.

Boaters must portage around the rubber dam downstream of Wohler Bridge.  Public notices will be posted around the rubber dam warning the public not to recreate on or near the dam.  

California Department of Fish and Wildlife regulations prohibit fishing within 250 feet of the upstream and downstream sides of the rubber dam. 

For more information about the rubber dam and how the Water Agency delivers naturally filtered Russian River water to its customers, please visit www.sonomacountywater.org/water-system.