The U.S. Army Corps of Engineers is moving forward with a flood control project along Corte Madera Creek in Ross and Kentfield.
A draft environmental impact report on the project was released Friday. Comments are being accepted on the findings through Nov. 27.
The draft 500-page report identifies potential problems that could be caused by flood control work in the area. The report analyzes potential impacts on water quality, biological resources and aesthetics, among other concerns.
“We’re pretty early in the process here,” said Tom Kendall, chief of planning of the Army Corps’ San Francisco district. “We’re wanting to hear from the public and wanting to hear their perception of how acceptable these impacts are.”
The project calls for potentially removing the fish ladder behind the Ross Post Office; removing the concrete channel and creating a floodplain park at Frederick Allen Park; and installing flood walls adjacent to banks and stabilizing creek slopes.
The fish ladder and concrete channel through Ross were built in the 1960s and ’70s. After years of storm damage, the ladder is considered an impediment to fish migration, and it blocks water flow.
The report presents five alternatives and a cost-benefit analysis including a no-project option.
The preferred option, dubbed alternative J, would create a bypass culvert beneath Sir Francis Drake Boulevard. According to the report, that “would alleviate the need to construct floodwalls in Unit 4.” Unit 4 is a 0.4-mile segment of the creek downstream from Sir Francis Drake Boulevard that continues about 600 feet downstream from the Lagunitas Road Bridge.
“A requirement to get the federal dollars comes with showing that the benefits are in excess of cost,” Kendall said. “The only way we could demonstrate benefits in excess of cost was with alternative J.”
Alternative A, for example, would require the full purchase of 30 parcels and the relocation of residents at each address in order to make way for the flood control improvements. Alternatives B and G called for the purchase of 18 properties. Each of those alternatives showed that the costs outweighed the benefits, according to the report. Alternative J does not require purchasing any residential properties.
Last year, the Ross Town Council adopted a resolution that supports the project, which is sponsored by the county. The decision kept the project on track to meet a 2020 project deadline.
That move also secured a $7.6 million state grant, which was originally earmarked for a plan to use Phoenix Lake as a detention basin. But that project was deemed infeasible, and the grant money became available.
Ross Mayor Beach Kuhl said town officials want to hear what the community has to say about the report and each alternative before the town submits its own comments to the Army Corps.
“I’m certainly in support of getting some flood relief in Ross,” he said. “This is really the start of the process to determine what we want in terms of flood protection.”
The project is a component of the Ross Valley Flood Protection and Watershed Program, which looks at broader flood mitigation measures within the 28-square-mile watershed. An EIR for the entire program is also underway, according to the county.
There will be four community meetings for residents to learn more about the project and give feedback at Ross Town Hall.
The meetings are 6 to 7:30 p.m. Oct. 23 for residents of Ross; 10 to 11:30 a.m. Oct. 24 for Ross commercial businesses; and 6 to 7:30 p.m. Oct. 25 for residents and businesses in Kentfield and unincorporated Marin along the lower part of Corte Madera Creek. A workshop for all Ross Valley residents will be scheduled in November.
The Marin County Board of Supervisors will hold a public hearing on the draft report at 5:30 p.m. Nov. 13 in room 330 at the Civic Center in San Rafael.
The final report is expected to be ready for certification by the Army Corps and county supervisors in September 2019.
Construction would be expected to begin in 2020 and be completed within five years.
More information is available at bit.ly/2CbUNQe.
