Water officials will begin inflating a rubber dam on the Russian River on Monday to boost supplies for Sonoma and Marin counties.
The Sonoma County Water Agency inflates the dam in the spring or early summer every year to create a small pool used to recharge groundwater.
The process to inflate the dam can take from four to 14 days, depending on river levels, according to the water agency.
The dam is downstream of Wohler Bridge near Forestville. When it is inflated, boaters will have to carry their boats around it.
Fish will be able to get past the dam via a fish ladder, fitted with underwater cameras that Sonoma Water uses to count the migration of adult salmon and steelhead.
People aren’t allowed to play on or near the dam and fishing is prohibited within 250 feet of it on both the upstream and downstream sides.