What is a Watershed?

A watershed is an area of land that channels water such as rivers, creeks, rainfall, and stormwater to outflow points (or outfalls). Watersheds extend from a high elevation point, such as a ridgeline, down to a low point where the water flows into a creek, river, bay, ocean, or other waterbody. Wherever you live, you are in a watershed. In Palo Alto, the outflow points for the City’s watersheds are the Baylands and South San Francisco Bay. The City’s watersheds include those drained by San Francisquito, Matadero, Barron, and Adobe Creeks. View the Palo Alto watershed map(PDF, 7MB) to learn more.

What is Stormwater?

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Stormwater is rainwater that picks up pollutants from surfaces as it flows through our urban landscapes. It then flows from the curb and gutter through the storm drain system to local creeks and finally to the San Francisco Bay. The storm drain system includes the inlets and underground pipes that help regulate flooding during rain events. It is part of the broader watershed, which is the area of land that channels water into creeks and the Bay. 

Because stormwater is not treated, everyone must help keep pollutants from entering our storm drain system. Only rain should flow into storm drains. Report accidental spills, illegal dumping, and improperly stored materials to the City. Please contact us when:

  • you observe anyone pouring or dumping material into the storm drain, or if you see dumped wastes and materials in or near the storm drain or on the street;
  • there are unusual odors in or near the storm drain, indicating a potential hazardous spill;
  • you observe a sanitary sewer overflowing into the street or storm drain; or
  • the storm drain system has larger than normal flows during dry-weather periods.

Find out more about how you can keep stormwater clean on our Stormwater Pollution Prevention pages for Residents and for Businesses.

County-Wide Resources

The Watershed Watch Campaign is a public education initiative of the Santa Clara Valley Urban Runoff Pollution Prevention Program (SCVURPPP), an association of fifteen government agencies in Santa Clara Valley. The Campaign is dedicated to raising awareness about protecting watersheds and preventing stormwater pollution. This website provides free resources and easy everyday ways to prevent pollution in your neighborhood, our local creeks, and the Bay.