Sonoma County Water Agency Opens the Russian River Estuary

At about 9:00 this morning the Sonoma County Water Agency opened a channel in the sandbar at the mouth of the Russian River Estuary to avoid flooding waterfront properties in the lower Russian River.

Backhoe Closeup 6:27:16

Note the worker in the red PFD. He was part of a surveying crew.

The work was accomplished using this big excavator, called a track hoe, because of the tracks it rides on and the big boom and bucket similar to what is found on a backhoe. (I guess it’s not coincidental that “track hoe” rhymes with “backhoe.”)

A survey crew was on hand to help manage the depth of the channel. The elusive goal is to let just a little of the water out, down to 7 feet as measured at the visitors center in Jenner. By keeping the lagoon almost full they make conditions ideal for young salmonids to feed and grow. The warm lagoon waters are full of little creatures, mostly invertebrates, that the salmonoid fry like to eat.

Last time the water agency excavated a channel in the mouth, the water running out scoured an ever-deeper channel and the level of the river receded down to just above the level at low tide, about two feet or so. The fast-emptying lagoon washed the fish fry out into the ocean before they were ready for the presumably greater challenges of life in the ocean.

Moment of Truth 6:27:16

About two hours before the 0.5′ low tide they opened the channel and water began running gently out of the lagoon making the lagoon an estuary once more. Within 30 minutes harbor seals were using the new channel to transit between estuary and ocean.

Seals Swim Upstream

About a dozen or so of interested onlookers watched from the turnout above the mouth. Several spectators—equipped with expensive camera gear trained on a small group of seals sunning on the beach about 50 meters north of the excavation—watched after the welfare of these pinnipeds. Others observers were from the Water Agency providing oversight to be sure everything would proceed according to plan.

Here’s a video of the first moments of the opening of the mouth.

Here is another video showing the harbor seals swimming through it taken about a half hour later.