Officials monitoring shifting sands for flooding and fish
High surf conditions closed the mouth of the Russian River at Jenner for about a week before Sonoma County Water Agency crews dug a channel that biologists hope will balance the interests of the river’s endangered native salmon and steelhead trout along with flood prevention.
On July 17, the Water Agency opened an outlet channel on the beach at Goat Rock State Park appears to be working this week.
“ The goal of the outlet channel is to enhance habitat for federally listed juvenile salmon and minimizing flood risks by keeping freshwater levels in the estuary while allowing river water to flow out of the estuary and prevent ocean water from entering,” said Water Agency spokesperson Ann DuBay.
She said the Water Agency will monitor conditions at the estuary and manage the lagoon’s depth this summer so that high water doesn’t flood low-lying areas in Jenner such as the visitor center on Highway 1.
Ideally the outlet channel would remain in place until mid-October to maintain the estuary lagoon.
The Water Agency is conferring with the National Marine Fisheries Service (NMFS), the state Department of Fish and Wildlife and other agencies to discuss an appropriate outlet channel and lagoon management strategy, said DuBay.
The Water Agency has been trying, with limited success, to maintain a summer lagoon since 2008 when NMFS issued a biological opinion that ordered changes in the agency’s Russian River operations.
Since the biological opinion was issued calling for the Water Agency to maintain a closed summer estuary if and when the Jenner sandbar closes naturally, a maintenance plan has been implemented three times, said Water Agency Environmental Resources Manager Jessica Martini-Lamb.
Each time the managed outlet efforts “ended in self-breaching,” said Martini-Lamb. “So far it hasn’t worked in terms of establishing a lagoon for the whole summer.”
Numerous factors including ocean wave size and direction, currents and beach morphology will have a bearing on the project, said Martini-Lamb.
When the sandbar at Jenner blocks the river from flowing into the ocean, the resulting lagoon can back up as far as Monte Rio, creating beneficial conditions for fish but inundating recreational beach areas in Villa Grande and Monte Rio.
It is normal for the river sandbar to close several times a year due to natural causes such as wave action. Water flooding the visitor center deck is not unusual when the estuary rises. As it backs up from the estuary, the river widens upstream at the Bridgehaven area and the estuary level rises more slowly.