A hillside in Marin City is slowly sliding downhill above a 48-apartment complex.
Shifting soils have toppled sections of a 5-foot-high timber retaining wall behind the Oak Knolls residences at Drake Avenue and Buckalew Street. The complex of two-story apartments above ground floor garages was built in the 1960s. It has since been converted to a privately owned co-operative.
“This came down on Christmas morning,” Curtis Finley, co-op vice president, said Tuesday, pointing to one section. “We had a big storm, a downpour.”
“We didn’t discover until a few seasons ago there was slippage,” he said. “That was another deluge-type situation and that caused movement. The fire department pointed out that the hillside was owned by the CSD.”
“The retaining wall is theirs. We know that,” said Donald Parker, facilities manager for the district. “But how far behind the retaining wall is the CSD property? On the sketch map, it shows it going through the trees. But that’s just a map. That’s what we’re trying to determine.”
The Marin City Community Services District, which covers a square mile of unincorporated Marin County, mostly manages local recreation and cultural programs but also has a role in community development and flood prevention projects.
Donald Parker of the Marin City Community Services District, left, chats with resident Curtis Finley by a partially collapsed retaining wall behind residences on Drake Avenue on Tuesday, April 14, 2026. (Alan Dep/Marin Independent Journal)
The threatened retaining wall has come up at recent Marin City Community Services District meetings. The board instructed Parker to explore what could be done. On April 8, he reported the property lines first need to be surveyed, which could cost upwards of $20,000.
That expense would be lower if it were split between the co-op and the district, Parker said. He and Finley have been assembling property records for that task, he said.
Geotechnical engineers would then analyze the hillside and propose a solution, Finley said during a site visit Tuesday. The slope rises approximately 20 to 30 feet above the back yard of the complex. At the top, it flattens out and there is a drainage ditch.
During the district discussion earlier this month, board members asked about short-term mitigation and longer-term costs. Board chair Terrie Green asked if the hilltop drainage system works. Parker said vegetation is growing there.
Treasurer Henry Mims asked what the overall project costs could be and who would end up paying.
“It will not be anything close to $75,000 to fix that wall,” said Kevin Douglas, board member and a contractor.
Douglas said liquefaction, or the hillside absorbing water and pressure forcing soils apart, caused the slides.
“Do we need the surveys to get estimates?” Mims asked. “So we need to spend this money?”
“Yes,” Parker said. “It’s got to be engineered – the retaining wall and down to the building.”
The board discussed soliciting bids for a surveyor but took no action at the meeting.
“We have to do the surveys, and then the civil engineers – geo and technical – and then we’ll have an idea of the total thing,” Finley said. “But right now we’re at the beginning.”