San Tomas Aquino Creek

San Tomas Aquinas Creek Arroyo de San Tomás Aquinas, San Tomas Aquino Creek
San Tomas Aquino Creek in Santa Clara running alongside Levi's Stadium
Location
Country	United States
State	California
Region	Santa Clara County
Cities	Saratoga, Monte Sereno, Los Gatos, Campbell, Santa Clara, San Jose
Physical characteristics
Source	El Sereno Summit in the Santa Cruz Mountains[1]
• location	Saratoga, California
• coordinates	37°13′04″N 122°01′32″W / 37.21778°N 122.02556°W / 37.21778; -122.02556[2]
• elevation	2,400 ft (730 m)
Mouth	Guadalupe Slough in South San Francisco Bay
• location	Sunnyvale, California
• coordinates	37°23′20″N 121°58′07″W / 37.38889°N 121.96861°W / 37.38889; -121.96861[2]
• elevation	13 ft (4.0 m)[2]
Basin features
Tributaries
• left	Wildcat Creek, Saratoga Creek
• right	Mistletoe Creek, Smith Creek

San Tomas Aquinas Creek, known locally as San Tomas Aquino Creek, is a 16.5-mile-long (26.6 km) stream^[2] that heads on El Sereno mountain in El Sereno Open Space Preserve in Saratoga, California in Santa Clara County, California, United States. It flows north through the cities of Saratoga, Monte Sereno, Los Gatos, Campbell, Santa Clara and San Jose before its confluence with the Guadalupe Slough in south San Francisco Bay.

In the 1850s the creek appeared on several land grant maps as San Tomas Aquinas Creek and Arroyo de San Tomás Aquinas, named after Saint Thomas Aquinas.^[3][4] Historically, San Tomas Aquino Creek formed the eastern boundary of the 1841 Rancho Quito and the western boundary of the 1840 Rancho Rinconada de Los Gatos land grants.^[5]

The San Tomas Aquino Creek watershed drains about 45 square miles.^[6] It begins in the foothills of the Santa Cruz Mountains within the city of Saratoga and flows north through Campbell.

The middle portion of the creek runs under or alongside San Tomas Expressway. From Bucknall Road in Campbell, it runs along the west side of the expressway until Williams Road in West San Jose. From there, it runs under the median of the expressway until shortly north of Cabrillo Avenue in Santa Clara. Some portions are partially exposed, but much is completely underground. North of Cabrillo Avenue, it flows north until it meets the Guadalupe Slough.

The Guadalupe Slough carries the flows of San Thomas Aquino, Calabazas, and Saratoga Creeks out into south San Francisco Bay, passing just to the east of the Sunnyvale Water Pollution Control Ponds.

The San Tomas Aquino/Saratoga Creek Trail for bicycles and pedestrians follows the creek from Monroe Street in Santa Clara to the San Francisco Bay.^[7]

The major tributaries of San Tomas Aquino Creek include (heading downstream) Mistletoe, Wildcat (and its Vasona sub-tributary), Smith and Saratoga Creeks.^[8]

Smith Creek is a headwaters tributary of San Tomas Aquino Creek,^[9] but is largely dry except during the winter months. It begins in the foothills of the Santa Cruz Mountains within the city of Monte Sereno, then flows northerly through portions of Los Gatos and Campbell until its confluence with San Tomas Aquino Creek.^[10][11]

Saratoga Creek is the largest tributary and joins San Tomas Aquino Creek south of Highway 101, near Monroe Street. Due to its relatively large size, the Saratoga Creek subwatershed is often viewed as a distinct watershed even though it does not directly discharge to the Lower South San Francisco Bay. In fact, San Tomas Aquino Creek historically used to be a tributary of Saratoga Creek and thence to the Guadalupe River, but when the latter was redirected from Guadalupe Slough to Alviso Slough to facilitate navigation, San Tomas Aquino Creek was extended directly to Guadalupe Slough at Sunnyvale Baylands Park in Sunnyvale and Saratoga Creek became tributary to San Tomas Aquino Creek.^[12][13]

Vasona Creek is a short creek that runs through West Valley College and joins Wildcat Creek just before the latter reaches San Tomas Aquino Creek.^[14] With $570,000 in grants from the Santa Clara Valley Water District, the one mile section of Vasona Creek running through the college campus has undergone restoration since 2011, repairing deep channel incision and restoring riparian vegetation.^[15]

In 1898 John Otterbein Snyder collected steelhead trout (then Salmo irideus Gibbons) specimens in Campbell Creek (now Saratoga Creek, a tributary of San Tomas Aquino Creek).^[16] A 1985 California Department of Fish and Game (CDFG) survey of Saratoga Creek noted "a major steelhead and king salmon spawning area" on San Tomas Aquino Creek located approximately 200 yards downstream of the Saratoga and San Tomas Aquino creeks confluence. Stream resident coastal rainbow trout (Oncorhynchus mykiss irideus) persist in the Saratoga Creek watershed but anadromous steelhead cannot run up from the Bay because of a barrier at the confluence of San Tomas Aquino Creek and Saratoga Creek that prevents their passage upstream.^[9] Recent genetic analysis has shown that the San Tomas Aquino watershed trout are of native origin and not hatchery stock.^[17]

Leidy (2007) identified the native fishes in San Tomas Aquino Creek as Hitch (Lavinia exilicauda), California roach (Lavinia symmetricus), Sacramento sucker (Catostomus occidentalis occidentalis), Three-spined stickleback (Gasterosteus aculeatus), rainbow trout (Oncohrynchus mykiss irideus) and possibly Chinook salmon (Oncorhynchus tshawytscha). Although the latter had been considered now absent from the watershed, in mid-October, 1996, Roger Castillo, the founder of the Salmon and Steelhead Restoration Group, recovered a giant Chinook salmon from San Tomas Aquino Creek beneath Highway 237 (see photo). Non-native fishes include Common carp (Cyprinus carpio), Goldfish (Carassius auratus auratus), Golden shiner (Notemigonus crysoleucas), and Western mosquitofish (Gambusia affinis).^[18]

• List of watercourses in the San Francisco Bay Area

• Guadalupe Slough Watershed maps page at Guide to San Francisco Bay Area Creeks
• Santa Clara County Creeks Coalition
• Santa Clara Basin Watershed Management Initiative (SCBWMI)
• Salmon and Steelhead Restoration Group