Imagine you are a raindrop. One day, you fall from the sky and hit the ground high up on a mountain ridge (ouch!). Where do you go next?
From a high point of elevation, gravity pulls you downhill. At first, you are only a part of a tiny trickle of water. Eventually, that trickle builds into a small creek, which, along with several other creeks, feeds into a pond. The entire area of land that drains water down into that pond is called a watershed.
Watersheds include water both above and below ground. They can be as small as a puddle or as large as several countries, and they are distinguished by the common outlet they feed into. This outlet can be any body of water from a stream to a lake to a bay to an ocean. Larger watersheds are often made up of smaller watersheds that converge within the larger watershed area.
Every square inch of land on Earth is a part of a watershed, whether in city streets or on remote mountaintops. In the Bay Area, all of our watersheds drain into the Pacific Ocean directly or via the San Francisco Bay. Generally, these watersheds center around large creeks and rivers, such as the Guadalupe River in the South Bay or the San Gregorio Creek on the Coastside.
Watershed management is an important part of Midpen’s mission to protect and restore the natural environment. The restoration and protection of watersheds create a ripple effect of benefits for the fish, insects, amphibians and other wildlife that live in and around the water. In addition to supporting ecosystems, watershed management can help enhance water quality for human and wildlife usage.
On the San Mateo County Coast, the San Gregorio Creek watershed is of particular importance because of its designation as a critical habitat for the endangered coho salmon and steelhead trout. These fish are anadromous, meaning they migrate from the ocean into freshwater streams to reproduce. However, due to structural barriers and reduced water flow and quality, there are limited streams remaining on the California central coast where these fish can still migrate. Midpen preserves protect approximately one-third of the entire San Gregorio Creek watershed, helping to support these endangered populations through creek and habitat restoration projects.
On the eastern side of the Santa Cruz Mountains, San Francisquito Creek and Stevens Creek also sustain steelhead trout migration from the San Francisco Bay through urban areas.