The Watershed
A Watershed Shaped by Nature and Community
Lying in the rugged Coast Range some twelve miles north of San Francisco, the 28-square-mile Corte Madera Creek watershed drains southeasterly into the shallow waters of San Francisco Bay.
The valley’s communities of Fairfax, Sleepy Hollow, San Anselmo, Ross, Kentfield, Greenbrae, Larkspur and Corte Madera—the older ones dating back 120 years—together have a population of 61,000, most densely distributed on the valley floor. Development thins out as the elevation increases towards largely publicly owned ridge-land.
The watershed is bounded on the west by a steep, forested ridge running northwest from the East Peak of Mt. Tamalpais (elevation 2,571 ft) to Pine Mountain and then north-northeast to White’s Hill (elevation 1,430 ft).
Major Creeks
San Anselmo and Fairfax creeks rise in the northeastern corner of the watershed and drain steep upland areas onto relatively narrow valley flats; these creeks combine as San Anselmo Creek in the town of Fairfax. San Anselmo Creek then flows southeast through Ross Valley, bounded by a sandstone ridge running southeast.
Sleepy Hollow Creek joins San Anselmo Creek in San Anselmo downstream of Saunders Avenue. Ross Creek is a major tributary descending from the northern flank of Mount Tamalpais to join San Anselmo Creek in Ross. The channel is called Corte Madera Creek from the Ross Creek confluence to San Francisco Bay Estuary. For a mile of its length, it is confined to a concrete-lined channel, which empties into a tidal salt marsh at Kentfield, and then into San Francisco Bay at the Larkspur Ferry Terminal, east of Highway 101.
Other Features
Including San Anselmo, Fairfax, Sleepy Hollow, and Ross creeks mentioned above, Corte Madera Creek has approximately 29 named tributaries, with an aggregate length of approximately 44 miles. In addition to these streams, Phoenix Lake, which covers 28 acres, is located above Ross, and is an impoundment of Ross Creek.
Several intermittent tributaries rise on the grassland and grass-oak woodland-covered hills along the northern and eastern edges of the basin, dominated by Loma Alta. Larkspur Creek and Tamalpais Creek are the only major tributaries to Corte Madera Creek that enter downstream of the concrete channel.
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