This has been studied a great deal. Here is what we found.
Between 2018 and 2025, the county, , consultants and residents wrote at least nine serious documents about this one neighborhood of a few hundred acres. Together they run to well over a thousand pages, scattered across several websites, with no single list we could find. Most people whose homes flood have probably never seen any of them.
So here is the list: what each one is, what it found, roughly how long it is, and a link to open or download it. None of it is our work, and nobody has to start from nothing: the ideas already exist, in writing, with costs attached. The timeline lays the same material out by date, with what has been funded and what is scheduled, and pictures from the studies pulls the photographs and figures out of them.
Engineering study
Marin City Stormwater Plan 2025
Marin County Flood Control and Water Conservation District · October 2025 · 135 pages
The current umbrella plan, and the best single starting point. It gathers the drainage study, the watershed guide and the People's Plan into one document and sets out what the county intends to build, in priority order.
What it found
Four projects, ranked: the pond pump station, a Phillips Drive outfall, upsizing the Drake pipe and its inlets, and a longer-term partial bypass to a new bay outfall. It also states the vertical datum for all its work as NAVD88 feet, records the pond invert as silted from about 0.7 ft to around 3 ft, and reports that modeled Low Impact Development showed “little flood control benefit” while still recommending it for water quality.
Permaculture and Social Equity Team with a Marin City resident cohort and Shore Up Marin, for the Resilient by Design Bay Area Challenge · 2018 · 69 pages
The only document here written by the people whose homes flood. It is also the most readable, and the one to start with if you read only one.
What it found
Six priority projects, determined by residents: an intergenerational garden and resiliency hub at the Manzanita Rec Center, erosion work in the gullies above Golden Gate Village, dredging the detention basin and making it a park, a storm-drain retrofit at the First Missionary Baptist Church, bioswales along Donahue, and catchment in Golden Gate Village's open space at Drake and Donahue. It also makes an argument nothing else here answers: that pipe resizing at the bottom of the watershed “would only be temporarily effective until headwaters erosion mitigation work is performed”.
Marin City Urban Wetland Revitalization Project — fact sheet
Earth Economics, with Shore Up Marin City and Audubon California · 2021 · 4 pages
Four pages on the wetland plan for the pond, by the people proposing it: the clearest short statement of what the restoration would be (1.6 acres of wetland habitat around the edge of the basin and a park beside it, with a walking path, viewing piers and exercise stations) and what its proponents think it is for. Read it beside the county's pump station plan for the same three acres.
What it found
That the basin “was historically a tidal wetland” and that the project is “led by residents of Marin City”, with Shore Up Marin City partnering with Audubon California. Earth Economics values the benefits at $137,837 a year (recreation $92,335, exercise and health $23,986, flood reduction $3,126), plus a one-time aesthetic value of about $990,000, and about $4.4 million over 35 years, or $4.40 for each dollar of a $1 million investment. Funded by the National Fish and Wildlife Foundation's National Coastal Resilience Fund, the California Ocean Protection Council and the State Coastal Conservancy, with the economic analysis supported by the Doris Duke Charitable Foundation. It presents the wetland as complementing the county's flood work (“increasing the size of outfall structures and installing tide gates”) rather than replacing it.
Supplied by the project team, who want it kept reachable. The address it was published at has not been located, so the publisher link goes to Earth Economics' site and the copy to read is the one saved here. Its usage figures (25,550 visits a year, 200 volunteer hours, 500 school children) are, in the sheet's own words, “educated guesses”.
Wood Rodgers, for Marin County Flood Control Zone No. 3 · January 22, 2018 · 317 pages
The engineering study everything since is built on. It measures the existing system, maps the floodplain, and then costs four whole-system alternatives plus six individual improvements against both rainfall and tide frequency.
What it found
Existing conditions flood 16.4 acres in a 10-year storm and 43.7 acres in a 100-year. Alternative 1 was the most effective, cutting those to 6.4 and 30.1 acres for about $7.6 million plus $1.9 million of 20-year operating cost; Alternative 3 achieved almost the same for about $5.4 million. Its six individual elements are the striking part: a culvert inlet flap gate, desilting the basin and lowering the culvert inlet, a floodwall or levee, a detention basin pump station, an additional Highway 101 culvert, and a Caltrans detention basin.
Marin City Second Culvert Project — Draft Initial Study / Mitigated Negative Declaration
Caltrans District 4 · 2025 · 193 pages
The environmental document for the project. Read chapter 1 for how the drainage works today (the clearest published description of the existing system anywhere in this list) and section 2 for the hydraulic modeling.
What it found
The existing box culvert under US 101 at post mile 3.60 is 6 ft by 4 ft, with a manual slide headgate on the pond side closed by hand when storms are expected to meet high tides. The new culvert is a bypass, not a second outlet for the pond: it reroutes the 60-inch Phillips Drive drainage away from the existing culvert through a new 6 ft by 4 ft box at post mile 3.65, discharging through a duckbill check valve that shuts against the tide on its own. Modeled peak pond level falls from 7.6 to 7.0 ft NAVD88 in a 10-year storm, and flooded area at Donahue Street and US 101 from 18.7 to 17.0 acres.
The file link is the final version; the draft read for this page carries the same project description.
Marin City Flood Risk Management Study, Section 205 (CAP)
US Army Corps of Engineers, San Francisco District · Ongoing, agreement signed June 2025
Not a report yet — a project sheet for a federal feasibility study that is still running. Read it for the schedule and the money, both more specific than anything else on this list.
What it found
$15 million at a federal cost share of 100 percent, with the Marin City Community Services District as non-federal sponsor. The Corps describes the watershed as “a bowl turned on its side”, gives the population as “approximately 3,000 people”, citing the 2020 Census, records that storms in 2017 and 2021 left people unable to enter or leave, and states that “it is believed that flood waters contain contaminants threatening public health and local ecosystems”. Milestones run from a public meeting in April 2026 to construction ending September 2032.
Marin City Pond Pump Station Flood Reduction Project — environmental documents
Marin County Flood Control District, via CEQAnet · 2025
The environmental review for the permanent pump station and floodwall at the pond. CEQAnet, the state's public clearinghouse where California environmental documents are posted for review, is worth knowing how to search.
What it found
A platform pump station at the northeast corner of the pond with a floodwall along its edge, using the existing pipe under US 101 to push water to the bay when the tide holds the gravity system shut. Designed so more pumps can be added later.
Read from the CEQAnet listing and the county's project pages, not from the document itself.
Not a document but an index — the District's own file drawer for Flood Control Zone 3, the zone Marin City sits in. Board agendas, minutes and technical reports. If something in this list has moved, look for it here.
Marin City eyes incorporation to become independent city
Mark Prado, Marin Independent Journal · July 31, 2012
Not a study, and not about the flooding. The most recent time this project has found the question of becoming a town asked in public: in July 2012 the Marin IJ reported that the Community Services District board would meet that week to decide whether to form a committee to study whether Marin City could be a city. Read it for what was said about the money and the process by the district's director, a community activist, and the head of the commission whose approval would be needed.
What it found
The district's director, Johnathan Logan: “No one has ever put the legwork into it to see if it is feasible. But it is still very early in the process.” The board was to decide whether to form a committee to study feasibility. A city would be Marin's twelfth, with its own council and mayor, and would have to set up police and fire protection; the plan would go to voters before being finalized, Logan said. On money: sales tax from the Gateway Shopping Center and possible redevelopment revenue, and, in the article's words, “the most recent study, done in late 2004, showed Marin City generated a combined $7.6 million in property and sales taxes annually, some of which could be used to run a city” (a line read from beneath the newspaper's banner in the saved copy). Logan said that study “needs to” (the next words are hidden under the banner) and that this was “some of the work the committee would do”. Marin LAFCO's head, Peter Banning, called incorporation “the most complex type of local reorganization that can be undertaken in California.” Population given as 3,500.
Supplied by the project team as a printout of the web page made on September 14, 2026, saved here unchanged. The newspaper's subscription banner covers several lines at the foot of the first three printed pages, including the sentence with the $7.6 million figure and Logan's remark about the 2004 study. Those lines were read from the text beneath the banner; a few words of that remark stay hidden behind the banner's own text. Whether the committee was formed, and what it found, the article does not say and this project has not found.
‘It Comes to Race’: Marin City Residents Demand Flood Protections
Ezra David Romero, KQED · 2024
Not a study. The clearest published account of what the flooding is actually like and why residents connect it to how Marin City has been treated — the context every document above leaves out.
What it found
Carries Kristina Hill of UC Berkeley describing Marin City as “a bathtub with only one drain”, and Terrie Harris-Green, executive director of Marin City Climate Resilience and Health Justice, on what residents have been asking for and not getting.
Having the studies in one place shows which ideas survive all of them. Five of these six were already named and costed in the 2018 drainage study, and five now have an agency project behind them. This is our own reading of the documents above, not any agency's.
01
A second culvert under Highway 101
Proposed as element LL5 in the 2018 drainage study, carried into the 2025 stormwater plan, and now a Caltrans project with an environmental document and money attached.
Where it stands: Environmental document published. Construction reported for 2027.
02
A pump at the pond
Element LL4 in 2018. First in the 2025 plan's priority order. A portable pump was installed on Donahue Street in 2024 as an interim measure.
Where it stands: Permanent station designed, environmental review done, FEMA grant matched by Zone 3.
03
A floodwall at the pond
Element LL3 in 2018. A temporary floodwall already runs along the east side of the pond, per Caltrans' description of existing conditions.
Where it stands: Permanent version part of the pump station project; $750,000 reported allocated.
04
Getting the silt out
Element LL2 in 2018, “desilt basin and lowering of Highway 101 culvert inlet”. Named by residents in the People's Plan the same year. Documented by the county in 2025 as roughly two feet of accumulation.
Where it stands: $3 million of the federal allocation reported as going to pond sediment removal.
05
A gate that shuts by itself
Element LL1 in 2018, a culvert inlet flap gate. The existing gate is still a manual slide headgate, closed by hand when a storm is forecast to meet a high tide.
Where it stands: The new Caltrans culvert gets a duckbill check valve. The existing one, as described in 2025, is still manual.
06
Fixing the hillside, not just the pipe
The People's Plan, 2018: pipe resizing at the toe of the watershed “would only be temporarily effective until headwaters erosion mitigation work is performed”. Its second priority project was erosion work in the gullies above Golden Gate Village.
Where it stands: The one recurring idea with no agency project behind it. Everything funded is at the bottom of the bowl.
Five of the six have agency projects behind them. The sixth does not. Every funded project on this list sits at the bottom of the bowl: the culvert, the pump, the wall, the silt. The sixth is the People's Plan's 2018 argument that fixing pipes at the toe of a only works until the hillside above refills them. That is not an argument against the pumps and , which are needed and are happening. It is just an observation: the studies agree on something nobody has funded.
If you want to do something with these
You can write to the agency, and your comment goes on the record
Two of the documents above are environmental reviews under the California Environmental Quality Act, which matters more than it sounds. An agency circulating a draft environmental document has to consider every comment it receives during the comment period before it decides, and those comments become part of the project's public record.
A comment does not have to be technical. “My house floods, here is a photograph with a date on it, and the document does not mention this street” is a substantive comment. So is pointing at a document above and asking why its recommendation was not carried forward. A measured depth from a photograph is stronger still: evidence, not recollection.
CEQAnet is the state clearinghouse where the pump-station document is posted and its comment period announced. The Flood Control Zone 3 advisory board (Zone 3 is the county flood-control zone Marin City sits in) meets in public; its agendas are in the District's file drawer.