David Keller, president of the Petaluma River Council and a longtime environmental activist, is pushing the city to conduct a more in-depth analysis of a flood control project in North Petaluma that he says will increase the risk of flooding to downtown while reducing it upstream.
The city is expected to begin work on Denman Reach portion of the Petaluma River, roughly at Stony Point and Denman Road, next year after receiving a $1 million grant this month. The area is prone to flooding, so the project will build a flood terrace, a sort of pocket that will increase the river’s capacity to hold storm water.
But Keller believes that the flood control project is an attempt to “green light” development by reducing the area designated as floodplain. (Currently the area around Denman Reach is a natural water storage area preserved from development by local ordinances.)
He quotes a 2005 U.S. Army Corps of Engineers study that shows that additional runoff in the river will increase the frequency and depth of flooding in other areas of the river, such as First and B streets and Payran, the latter badly damaged by flooding in previous years.
“I think the city’s calculation is grossly understated,” Keller says. “They don’t talk about the duration of the flood, flows and erosion capabilities…If we want to increase the risk of flooding to one area at an expense of another, fine, but these are public policy decisions that have to be decided by an elected body in view of the public.”
Pamela Tuft, Special Project Manager at the city’s Water and Conservation Resources Department says the flood control project has been vetted by experts has “absolutely no impacts on downstream flooding.”
“With this project, we can reduce the flood elevation in that area (Denman Reach). including to the homes that do get flooded in that neighborhood by .7 of a foot, so I think it’s a significant improvement by just doing terracing,” Tuft says.” We studied it thoroughly and feel that we can go ahead with the improvements.”
Check out Keller’s letter on the right.