About this site
Everything known about this flooding, in one place
This site exists to put everything known about the flooding in Marin City in one place: the proposals, the studies, the money, the dates and the ideas. Residents can see all of it without going all over the web to find basic information.
What it is
Either somebody else's work, cited, or our own model, labeled as one
Since 1992, at least nine serious documents have been written about this bowl. Four agencies are working on it, on schedules that mostly do not mention each other, with money committed and dates on the calendar. Almost none of it was anywhere you would think to look, so this site puts all of it in one place. Everything here is either somebody else's work, with the source named, or our own model, clearly labeled as one.
“” is the idea the site is named after: streets, yards and open ground built to soak up rain and hold it back, using soil, plants and storage instead of pipes, so less water reaches the low corner while the gate is shut. What is a sponge? explains the idea and shows six places that built it. It slows the water down; on its own it does not keep the street dry.
This is an independent website, not run by Marin County, Caltrans, the flood district, the Community Services District or the Army Corps, and it does not speak for any of them. Nor is it picking a fight with the county's engineers: where a county study and our model disagree on a number, treat the study as right until somebody goes out and measures. Sources & limits lists where they disagree.
Nothing here is for sale or asks you to vote for or against anything, and there are no ads and no trackers. A photo you measure never leaves your phone, and the bulletin board keeps only what you choose to post. Built and kept up by [TODO: project team to say who, in one line]. If you spot something wrong, please say so on the bulletin board.
In a resident's words
“We're at a place in Marin City where we're saying enough is enough. It comes to race.”
There is history behind that sentence, and it is on the record. The timeline starts with it: the deed covenants written across Marin from 1926 on, the shipyard that opened in 1942 and closed in 1946, and who was allowed to move to higher ground afterwards and who was not.
The limits
What this can tell you, and what it cannot
The full account of the limits, next to the sources, is in Sources & limits.
The model behind this site is simple on purpose: rain falls on the hills, a fixed share reaches the pond and the streets, and it leaves through the one culvert whenever the pond is higher than the bay. That is enough to show why the flooding happens, and nowhere near enough to tell you how deep the water will be outside your own door.
The ground heights are measured by a federal laser survey () in the same reference level the county uses. The culvert, the pond and the street drain match the figures in three published agency documents. The tide in the model is not measured: it is a typical tide, not a forecast for any date, and it never drops as low as a real one can. We say so plainly rather than in a footnote.
What would make the model better is measurement. A depth read off a photograph, paired with the bay level at that minute, is evidence in a way no rendering is, and only someone standing in the neighborhood can collect it. The photo tool is for exactly that.