Seasonal dam replacement closes Russian River near Forestville

Closure of the Russian River near Forestville until October, prompted by the replacement of a seasonal dam, throws a kink into recreation on the waterway that offers a respite from summer heat, attracting people from near and far.

The replacement project, however, will not diminish the dam’s role as a key element in delivering water to more than 600,000 North Bay residents, officials said.

Anyone who floats past Riverfront Regional Park west of Windsor will come to a dead end at Wohler Bridge near Forestville, where the portage around the dam site is closed and the gate to the parking lot for a boat ramp and fishing access is locked.

“You’re going to have a roadblock,” said Don McEnhill, the longtime executive director of Russian Riverkeeper, a leading watershed advocacy group.

The upper river down to Healdsburg Veterans Memorial Beach and Riverfront Park is unimpeded, though boaters will experience drought firsthand with the low flows.

The river also is clear for boaters below Steelhead Beach Regional Park near Forestville, the first access point downstream from Wohler Bridge.

But people considering a trip from upper river points such as Cloverdale or Alexander Valley to as far as Jenner near the coast — mostly canoeists known as “through-boaters” — must make arrangements to shuttle themselves and their boats past the closure at Wohler, McEnhill said.

Signs at the Healdsburg and Riverfront parks advise boaters, tubers and paddleboarders of the changed conditions, said Barry Dugan, a spokesman for Sonoma Water, the county agency that is replacing the worn out rubber dam that spans the river at Wohler Bridge.

A 4-by-8 foot warning sign also hangs from the bridge.

“DANGER: Construction ahead,” the sign reads. “No portage downstream. Exit water here.”

The existing seasonal dam was first installed in 1995 and is now “past its useful life expectancy,” Dugan said. He called it a “critical component” of the regional system that provides water to more than 600,000 Sonoma and Marin county residents.

It was scheduled for replacement last summer, but the $2.5 million project was postponed a year due to uncertainty during the COVID shutdown. The main parts are coming from China, he said.

Work can only be done during the river’s low-flow summer period and is scheduled to continue until mid-October.

A cofferdam will be erected a short distance upstream from the 11-foot high seasonal dam and the river will be diverted through the massive concrete fish ladder, temporarily baring the streambed, Dugan said.

The fishing access at Wohler Bridge is always closed to the public during the summer, but the portage affords boaters a way around the dam.

Made of heavy-duty rubber and filled with water through open valves, the dam reaches 175 feet across the river and creates a lagoon backing up to about Riverfront Park.

Water from the lagoon is pumped into four off-stream infiltration ponds that recharge the aquifers around three of Sonoma Water’s six wells that procure water for North Bay cities and communities from Windsor to San Rafael.

The lagoon will be shallower and smaller this year, but still sufficient to maintain the ponds, Dugan said. “We don’t expect (the dam replacement) to impact our ability to deliver water to our customers,” he said.

The dam was filled in April, a month earlier than usual, to meet water demand as temperatures rose and river flows fell, said Jay Jasperse, Sonoma Water chief engineer. The summertime replacement project was anticipated at that time, he said.

Some years the dam has been raised and lowered multiple times, Jasperse said. During the winter, the deflated dam lies on the riverbed.

There was no need for the lagoon until the early 1970s, when the first summer dam was installed to meet the water demands of the county’s growing population, Dugan said.

The closure at Wohler may deter some recreational use of the river, which McEnhill said might be just as well given the low water flow.

“This is not a great year to do a paddle on the river” he said. The river is at its lowest levels since the early 1900s, he said.

Above Healdsburg, most of the riffles from pool to pool are impassible, said McEnhill, a veteran river kayaker.

In eight decades of records, the river’s lowest flow at Healdsburg on June 24 was 59 cubic feet per second during the 2015 drought, Dugan said.

On Thursday the flow was 29 cfs.

Larry Laba, owner of Healdsburg-based Russian River Adventures, said he is sending customers downriver in self-guided inflatable kayaks from Memorial Beach to Wohler, where he has access to the parking lot as a commercial outfitter.

There are narrow passages along the way, but “still plenty of water,” he said. His trips were sold out Saturday and Sunday.

You can reach Staff Writer Guy Kovner at 707-521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.