Stevens Watershed

Stevens Creek drains a watershed of approximately 29 square miles.  The headwaters originate in the Santa Cruz Mountains within the City of Palo Alto and Santa Clara County.  Much of the headwater area is protected open space managed by the County and the Mid Peninsula Open Space District.  In the upper watershed the mainstem flows southeast through for about five miles along the San Andreas Fault, and another three miles northeast to the Stevens Creek Reservoir. From the Reservoir, the Creek flows northward for a total of 12.5 miles through the foothills in the Cities of Cupertino, and Los Altos, and across the alluvial plain through the cities of Sunnyvale, and Mountain View, finally draining into the Lower South San Francisco Bay. Below the reservoir, the watershed is largely developed as residential neighborhoods with commercial areas clustered along major surface streets such as El Camino Real.

Tributaries above the Reservoir include Montebello and Swiss Creeks.  One tributary, Heney Creek, joins the mainstem 3.7 miles below the Reservoir.  Additionally, a diversion channel from Permanente Creek (constructed in 1959) can divert winter storm flows (up to 1,500 cfs) into Stevens Creek approximately 6.3 miles below the reservoir (SCBWMI 2001).

The Stevens Creek Reservoir was constructed in 1935 to provide storage capacity of winter runoff that could be used to recharge the Santa Clara Groundwater Basin during the summer months (SCBWMI, 2001). The Reservoir is managed by the SCVWD and has a current capacity of 3,465 acre-feet of water (SCBWMI 2001).  As currently managed by the SCVWD, flows of 4 –5 cfs are released during summer months which result in maintaining a wet channel for approximately 5.7 miles downstream of the Reservoir (to Fremont Avenue).  Downstream of this point a dryback zone typically exists for about 3.25 miles (about 1/3 mile downstream of Central Avenue).

Watershed Facts

  • Drainage area:  29.2 square miles
  • Number of creeks:  12
  • Miles of creek:  54.2
  • Miles of Engineered Channel:  1.1
  • Miles of Underground Culvert or Stormdrain:  30.0
  • Local jurisdictions:  Santa Clara County, Palo Alto, Cupertino, Los Altos, Sunnyvale, Mountain View
  • Percent area by land use:
    • Residential 24.5%
    • Industrial/Commercial 9.0%
    • Forest 49.2%
    • Rangeland 12.5%
    • Other 4.8%
  • Percent Impervious Area:  28.6%
  • Beneficial Uses:  COLD, WARM, WILD, MIGR, REC-1, REC-2, FRSH, GWR, MUN

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