Deadly Dennett Dam, intended to create a serene Lake Modesto, will finally be removed

An eyesore and hazard along the Tuolumne River in Modesto soon will be gone.

Work started this week on the removal of the remnants of Dennett Dam, a roughly $1.6 million project that is a partnership between the city and the Tuolumne River Trust.

The tiny dam — which is near the Ninth Street Bridge — impedes fish and people who canoe and kayak along the river. It also has been the site of three drownings since 2006. Trust Executive Director Patrick Koepele said the water flowing over the dam can create a whirlpool that pulls swimmers down into a hole created by the falling water.

The project will return that section of the river to its natural state and provide salmon and steelhead with unimpeded access to 37 miles of upstream habitat. Canoeists and kayakers also will have an easier and more enjoyable time.

“This is a like a win, win, win,” Koepele said.

The trust has been working on removing the dam since 2010. It raised the money for the project through state grants and one private grant and hired the engineering firm FlowWest to do the planning, engineering and environmental work and acquire the state and federal permits.

Koepele said the trust partnered with Modesto because of the city’s experience overseeing big public works projects. “The city has been great to work with,” he said.

The city hired Innovative Construction Solutions as the general contractor at a cost of roughly $1 million. (The $1.6 million project’s other costs include reimbursing the trust for what it has spent.) ICS workers are doing the prep work before they can start removing the dam, which should start later this month and take several weeks.

ICS will temporarily divert the river around the dam through a channel near the river. ICS also will remove the depression in the riverbed created by the water flowing over the dam and remove all traces that this had been the site of a major construction project. The entire project should wrap up in October.

“It’s great to be part of removing a dam and restoring the river to its natural condition,” said Claire Walker, the ICS project manager. “And we are very happy to be part of that.”

Dennett Dam was built in 1933 to create Lake Modesto, a 97-acre water and recreation resort. But the dam washed out twice. The state condemned it in 1947, but never removed it.

Neither did the city or any state or federal agency with authority over the river. Modesto earmarked $300,000 for its removal about a dozen years ago. But budget cuts, combined with higher than projected demolition costs, forced the city to delay the project.

This story was originally published August 1, 2018 at 4:40 PM.