California’s long and diverse coastline is the ocean edge of even larger and more diverse watersheds that drain to the ocean through numerous waterways. Roughly 5 million acres, or 5% of the state’s land, drains directly to the Pacific Ocean or into San Francisco Bay. There is an increasing agreement that land and water use within the watershed, essentially watershed management of the planned and unplanned varieties, has a major role in determining water quality along the waterways and along the coastline. Given that the effectiveness of watershed management for protecting ocean water quality is proportional to how well the interventions are matched to underlying conditions, there is a need for broadly accessible tools to identify specific characteristics of the 347 small watersheds that directly drain to the Pacific Ocean or San Francisco Bay.

The Coastal Watershed Mapping Tool allows anyone to locate a watershed of interest by zooming into a statewide map and using watershed boundaries and scanned U.S. Geological Survey quad maps. These maps illustrate key hydrographic components such as streams and watershed boundaries as well as major roads, urbanized areas, and coarse vegetation condition. After an individual watershed is chosen, the linked screens provide information on average rainfall, public and private land ownership, and land use and vegetation cover. The statewide coverages for most of these layers are also available on the FRAP web site. The advantage of the mapping tool is that it allows anyone with access to the internet to retrieve detailed information on factors that play a major role in determining potential non-point source pollution sources, key wildlife habitats, and the impacts of proposed new land uses and resource management practices.