The low summer flows of the Russian River have exposed the massive rock-and-concrete jetty built at the river's mouth at Jenner in the 1930s in an attempt to keep the river open for barge traffic.
"It is definitely more exposed than it has been in the last 10 or 12 years," said Don McEnhill, executive director of Russian Riverkeeper, a Healdsburg conservation program. "It has become the topic of conversation; a lot of people are saying, &‘wow, I had no idea it was even there.'"
The jetty is 1,600 feet long, 10 feet high and 40 feet across at its base and within the boundaries of Sonoma Coast State Beach.
The jetty near Goat Rock is usually buried under a sand bar. Typically, only the jumble of rocks at its northern-most end are visible.
Now, the historic jetty, its affect on the Russian River and whether it should be removed will be part of a $450,000 study being undertaken by the Sonoma County Water Agency.
The analysis was ordered by the federal government to improve conditions to protect chinook salmon, which are on the threatened species list.
Before heading out to sea, juvenile chinook will spend a year in the fresh-water estuary that forms at Jenner when a sand bar builds up across the mouth of the river.
The issue is the effect of the jetty on how the mouth closes, and how often, to form that estuary.
"We will try to get a better understanding of how the beach interacts with the waves and how the outlet channel interacts with the waves and the beach," said Chris Delaney, a water agency engineer.
The closing of the river mouth is critical for the chinook, which need that time to acclimate to a mixture of river and sea water before going to the ocean to feed for two years.