Almost every watershed in Contra Costa County has been identified with a number. We call these Drainage Areas.
Drainage Areas are formed to collect fees from developers to pay for planned drainage infrastructure including detention basins, pipes, channels, and related costs. An unformed drainage area is a watershed that has been identified, but does not have development fees.
County Map of Formed Drainage Areas
County Wide Drainage Area Index - Formed and Unformed Drainage Areas
You can use http://www.ccmap.us/
to view the drainage area boundaries in the Interactive Map
. Enter an street address or a Assessor's Parcel Number (APN) at the bottom to start the interactive map. Then, zoom in or out as needed. Click "Layers" at the top left and then click the box by "Drainage Boundaries" on the right. You will have to turn off your popup blocker or add the ccmap
site to your allowed popup list.