The City of Sonoma, the Sonoma County Water Agency and the Sonoma Ecology Center are collaborating on a series of integrated projects to better manage Valley water, with the most recent work creating a highly visible presence at Montini Open Space Preserve.
The project, in which geologists and hydrologists are currently taking ground samples and drilling test wells in the Fifth Street West meadow at the edge of the preserve, is part of the larger City Watersheds of Sonoma Valley Project. That effort is a multi-benefit project being developed to help address local flooding, promote groundwater recharge and enhance habitat along Fryer Creek. The water agency and its partners recently received a $1.89 million grant from the Department of Water Resources in a statewide competition for its $4.14 million project.
Betty Andrews, who is a principal engineer focusing on environmental hydrology at Environmental Science Associates, Phillip Williams and Associates (ESA PWA),
is working to actively implement the watersheds project in Sonoma through site investigations and research with her team.
The project’s first priority, Andrews explained, is reducing flood hazards by finding the best locations for reduction. In addition to looking at Fryer Creek and areas within the city, researchers are paying specific attention to Nathanson Creek because, if that creek floods, it has the potential to affect the most people in the surrounding city neighborhoods.
The project proposes flood reduction along the main stem of Fryer Creek by capturing runoff and diverting storm water as part of an effort to enhance wetland areas at Montini.
The second objective, she noted, is finding an area of focus with the best potential for groundwater recharge to increase the reliability of the area’s water supply.
Water agency hydrogeologist Marcus Trotta explains one facet of the project at Montini examines the property’s potential for retaining water by contouring the land, building detention basins to slow the flow and capture water, thus allowing water to better percolate into the ground.
“There are opportunities for mixed benefits for this project,” Andrews said.
The project is currently in its first phase, with site investigations and studies taking place so engineers and scientists can collect samples to identify areas most suitable for storm water recharge and water retention.
Other aspects of the project include modification and replacement of a culvert on Fryer Creek at West MacArthur Street because it is currently a “flow trap,” as loose sediment and debris make it difficult for local fish to pass through, and it limits water flow. Another aspect of the project is vegetation management at Fryer Creek, removing excess sediment and invasive weeds, while reshaping the channel banks and replanting native plants.
Hydrologist Jenny Cherney, from Daniel B. Stephens and Associates, a national team of scientists, has been working on site to investigate soil conditions. Cherney and her team are taking samples of the soil at Montini Preserve, using a drill rig, and are installing monitoring wells. This allows the team to check groundwater levels and determine how the soil absorbs water. “We are collecting soil samples to test them for properties that would be most compatible with projects related to recharge,” she said.
As part of an education and outreach effort, the completed project will include signs posted near the new trails at Montini, describing the benefits of storm water retention and groundwater recharge.
Cherney says her team will also be doing soil testing at Sonoma Valley High School and on West MacArthur Street.
Sheri Emerson, stewardship program manager at Sonoma County Agricultural Preservation and Open Space District, which protects the diverse agricultural, natural resource and scenic open space lands in the county, says while the agency is playing a minor role, it greatly supports the project efforts as it will preserve the wetlands and make good use of the land. “Our role in the county is really to protect land for future generations; this kind of project (at Montini) benefits a number of things.”
The Open Space District is working with the City Watersheds partners to make sure the project fits within the deeded requirements of the property when it was originally acquired from the Montini family as public land. “For the project to be totally acceptable for the district,” Emerson said, “it would need to be more of a wetland enhancement rather than a detention basin.”
The water agency and its partners will host a public meeting at the Community Meeting Room, at 177 First St. W. in Sonoma, on Wednesday, Jan. 29, from 6:30 to 8:30 p.m. For more information on the water agency, visit sonomacountywater.org, and for more information on the City Watersheds Project, go to scwa.ca.gov/svflood.