Guadalupe Creek is a 10.5 miles (16.9 km) northward-flowing stream originating just east of the peak of Mount Umunhum in Santa Clara County, California, United States. It courses along the northwestern border of Almaden Quicksilver County Park in the Cañada de los Capitancillos before joining Los Alamitos Creek after the latter exits Lake Almaden. This confluence forms the Guadalupe River mainstem, which in turn flows through San Jose and empties into south San Francisco Bay at Alviso Slough.

Guadalupe Creek Los Capitancillos Creek[1]
View overlooking man-made Cherry Springs Lake, near Cherry Springs, the origin of Guadalupe Creek's Cherry Springs Creek tributary
Location
Country	United States
State	California
Region	Santa Clara County
City	Blossom Valley, San Jose, California
Physical characteristics
Source	Mount Umunhum
• location	Santa Clara County, California
• coordinates	37°09′31″N 121°53′59″W[1]
• elevation	3,161 ft (963 m)[2]
Mouth	Guadalupe River
• coordinates	37°14′48″N 121°52′16″W[1]
• elevation	197 ft (60 m)[1]
Basin features
Tributaries
• left	Rincon Creek (Santa Clara County, California), Cherry Springs Creek, Pheasant Creek, Shannon Creek
• right	Los Capitancillos Creek

History

The "Valley of the Little Captains" or Rancho Cañada de los Capitancillos is named for the cañada, or valley, through which Guadalupe Creek courses.[3] The river was once used for recreation prior to the removal of the Guadalupe Dam.^{[citation needed]}

Watershed and course

The Guadalupe Creek subwatershed drains 14.8 square miles (38 km²).[4] Heading downstream east from the peak of Mount Umunhum, Guadalupe Creek is joined on the left by Rincon Creek,[5] then on the right by Los Capitancillos Creek[6] before reaching Guadalupe Reservoir. Guadalupe Dam,[7] built in 1935, formed the reservoir. The main purpose of the reservoir is to capture runoff from winter storms to recharge in the Alamitos percolation pond system during the summer.[8]

Below Guadalupe Dam, Guadalupe Creek follows Hicks Road, and just below the intersection of Reynolds Road is joined on the left first by perennial Cherry Springs (aka Reynolds) Creek, which originates at Cherry Springs.[4][9] Cherry Springs Creek has a small perennial tributary, Hicks Creek,[10] which originates on the northern side of El Sombroso Peak[11] and flows into Reynolds Creek from the west.[12] The next Guadalupe River tributary is Pheasant Creek,[13] which runs below Hicks Road between Pheasant and Wagner Roads to join Guadalupe Creek from the left. At the intersection of Shannon Road and Hicks Road, Guadalupe Creek is joined from the left next by Shannon Creek.

Masson Dam, built in 1964, is a small diversion dam about 1.3 miles (2.1 km) upstream of Almaden Expressway. The dam conveys water into the Los Capitancillos percolation ponds continually, unless Guadalupe Reservoir spills, in which case diversion operations terminate until the rainy season ends. In 1999, Masson Dam, which had been a complete barrier to fish passage, was removed and then re-built, along with a fish ladder which was completed in 2000.[8] Completed in 1962 and reconstructed in 1964, the Los Capitancillos percolation ponds occupy about 63 acres, from Almaden Expressway (east) to Camden Avenue (west).

Guadalupe Creek crosses Almaden Expressway just before joining Los Alamitos Creek at Lake Almaden, the beginning of the Guadalupe River. Lake Almaden was historically a meadow but was formed by a gravel removing quarry operation. Guadalupe Creek has been entirely earthen since a short 500 foot section of concrete channel was removed near its confluence with Pheasant Creek.

Ecology

Steelhead (Oncorhynchus mykiss) spawned historically in Guadalupe Creek and its Pheasant Creek and Hicks (Cherry Springs) Creek tributaries through the 1950s[14] but construction of Masson Dam formed an impassable barrier. It is not clear whether steelhead use the fish ladder constructed in 2000. Resident rainbow trout persist in the upper Guadalupe Creek above the dam.[14] The creek below Guadalupe Dam supports the western pond turtle (Actinemys marmorata), foothill yellow-legged frog (Rana boylii), yellow warbler, double crested cormorant, and rainbow trout.

Rare flora include Mount Hamilton thistle (Cirsium fontinale var. campylon ), Santa Clara Valley dudleya (Dudleya setchellii)(Endangered), Santa Clara red ribbons (Clarkia concinna automixa), fragrant fritillary (Fritillaria liliacea) and the Mount Hamilton jewelflower (Streptanthus callistus).[8]

Mercury contamination

Guadalupe Creek is impaired (303(d) listed) by mercury contamination. Historically, workers disposed of roasted mercury mining wastes, called calcines, and other waste in or near Guadalupe Creek and Los Alamitos Creek so that waste materials would be transported downstream by winter flows. Guadalupe Reservoir covers a former mercury ore processing area. Calcines and other mining wastes are still present along the banks of Guadalupe Creek above Camden Avenue, along the banks of upper Guadalupe Creek near the former Guadalupe Mine outside of the Almaden Quicksilver County Park. A partly vegetated mining waste pile is present at Hicks Flat on the opposite side of Guadalupe Creek from the main mine.[4]

A half-mile stretch of Guadalupe Creek between Almaden Expressway and Masson Dam was restored in 2001 as mitigation for the downtown San Jose flood control project. Restoration included removal of mercury-contaminated sediments and recreation of a meandering stream course with native vegetation.[4]

The California Office of Environmental Health Hazard Assessment (OEHHA) has developed a safe eating advisory for Guadelupe Creek, stating that no one should eat any fish caught here.[15]

See also

• List of watercourses in the San Francisco Bay Area

References

External links

• U.S. Geological Survey Geographic Names Information System: Guadalupe Creek - Geographic Names Information System