The Guadalupe River Watershed drains approximately 171 square miles. The headwaters drain from the eastern Santa Cruz Mountains near the summit of Loma Prieta in heavily forested unincorporated county land with pockets of low-density residential developments. The Guadalupe River actually begins on the Valley floor at the confluence of Alamitos Creek and Guadalupe Creek, just downstream of Coleman Road in San Jose. From here it flows north, approximately 14 miles until it discharges to the Lower South San Francisco Bay via Alviso Slough. On its journey, it traverses through the town of Los Gatos, and the Cities of San Jose, Campbell, and Santa Clara, and is joined by three other tributaries: Ross, Canoas, and Los Gatos Creek. The largest of these, Los Gatos Creek joins the mainstem about 3 ½ miles downstream of its origination, and passes from unincorporated county land, through the towns of Monte Sereno, Los Gatos, and the Cities of Campbell and San Jose.
The Guadalupe River Watershed covers an area of approximately 171 square miles. The headwaters lie in the eastern Santa Cruz Mountains near the summit of Loma Prieta. The Guadalupe River actually begins on the Valley floor at the confluence of Alamitos Creek and Guadalupe Creek, just downstream of Coleman Road in San Jose. From here it flows north, approximately 14 miles until it flows into the Lower South San Francisco Bay via Alviso Slough. On its journey, the Guadalupe River traverses through the town of Los Gatos, and the Cities of San Jose, Campbell, and Santa Clara, and is joined by three other tributaries: Ross, Canoas, and Los Gatos Creeks. The upper watershed is characterized by heavily forested areas with pockets of scattered residential areas. Residential density gradually increases to high density on the valley floor. Commercial development is focused along major surface streets. Industrial developments are located closer to the Bay, primarily downstream of the El Camino Real crossing. Six major reservoirs exist in the watershed: Calero Reservoir on Calero Creek, Guadalupe Reservoir on Guadalupe Creek, Almaden Reservoir on Alamitos Creek, Vasona Reservoir, Lexington Reservoir, and Lake Elsman on Los Gatos Creek. Guadalupe River watershed supports both warm and cold water native fish. Although much of the river is dominated by nonnative fish species, nine native fish species have been collected and/or observed during the last 20 years, including: Pacific lamprey, rainbow/steelhead trout, Chinook salmon, hitch, California roach, Sacramento sucker, threespine stickleback, riffle sculpin, and prickly sculpin. The Guadalupe River supports a reproducing steelhead trout population, as well as a small run of Chinook salmon.
Watershed Facts
- Watershed area: 171.3 square miles
- Number of tributary creeks: 50
- Miles of natural creek bed: 207.3
- Miles of Engineered Channel: 45.5
- Local towns and cities: Santa Clara County, Los Gatos, San Jose, Santa Clara, Monte Sereno, Campbell
- Percent area by land use:
- Residential 29.6%
- Industrial/Commercial 13.6%
- Forest 34.7%
- Rangeland 15.5%
- Other 6.6%
- Miles of Underground Culvert or Stormdrain: 265.3
- Percent Impervious Area: 37.1%
- Beneficial Uses: Cold Freshwater Habitat (COLD), Warm Freshwater Habitat (WARM), Wildlife Habitat (WILD), Fish Spawning (SPWN), Water Contact Recreation (REC-1), Noncontact Water Recreation (REC-2), Freshwater Replenishment (FRSH), Groundwater Recharge (GWR), Municipal Supply (MUN)
- Water Quality Impairments:
- Guadalupe River: Urban Pesticide Toxicity (Diazinon), Mercury, Trash
- Guadalupe Creek: Mercury
- Alamitos Creek: Mercury
- Los Gatos Creek: Urban Pesticide Toxicity (Diazinon)
- Lake Almaden: Mercury
- Almaden, Calero, and Guadalupe Reservoirs: Mercury