Worth A Dam (martinezbeavers.org) has been saving beavers and their Martinez, Calif., habitat for more than eight years. Fiscally sponsored by Inquiring Systems Inc., Worth a Dam was formed by a group of citizens when the beavers of Alhambra Creek were threatened with extermination because their dams caused a flooding hazard merchants didn’t want. The creek runs through downtown Martinez, a city of 37,000 and county seat of Contra Costa County.

Beavers live in lodges they build in the pools they create by damming streams. In Martinez, five residents and two City Council members brought in a consultant who installed a Castor Master, a flow device that subverts the beavers’ damming instinct.

The device consists of flexible tubing that moves the water from upstream to downstream, disguising the source of the leak so the beavers’ instinct to repair their dam isn’t triggered by hearing or sensing water flowing. Moving the water keeps the dam low and reduces the threat of floods. When a hard rain comes, the dam washes out and the beavers return later to rebuild it. Alhambra Creek has had multiple generations of beavers since the project began.

Worth A Dam volunteers and consultants manage habitat replacement, teach kids in classrooms about beaver ecosystems, field requests from other communities about beaver management and host the annual daylong downtown Martinez Beaver Festival. Visitors to this year’s Aug. 1 fest can stay till evening and watch the beavers engage in their engineering feats. Can’t make it? Watch the beavers.

Fiscal sponsor Inquiring Systems Inc. in Sonoma, Calif., has been helping nonprofits and local governments in the Bay Area and internationally manage ecology projects ethically and sustainably since 1978.