San Francisquito Creek (Spanish for "Little San Francisco"—the "little" referring to size of the settlement compared to Mission San Francisco de Asís) is a creek whose mainstem flows U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map , accessed January 20, 2025 eastwards to southwest San Francisco Bay in California, United States. Historically it was called the Arroyo de San Francisco by Juan Bautista de Anza in 1776. San Francisquito Creek courses through the towns of Portola Valley and Woodside, as well as the cities of Menlo Park, Palo Alto, and East Palo Alto. The creek and its Los Trancos Creek tributary define the boundary between San Mateo and Santa Clara counties.
History The original inhabitants of the area were the Ohlone people, called by the Spaniards "Costanoans", or Coast-dwellers (from Spanish costeño meaning 'coast dweller'). These local residents lived off the land, gathering nuts, berries and fish from both the ocean and the bay. Because of the abundance of food there was no need for them to practice agriculture. Evidences of their civilization are still being unearthed on the Filoli estate in Woodside, and along San Francisquito Creek.
In 1769, the Spanish exploration party led by Don Gaspar de Portolà camped by the creek for five nights, November 6–11, after their momentous discovery of San Francisco Bay. The Franciscan missionary Juan Crespí, a member of the expedition, noted in his diary that, "The commander decided that we should stop in this valley while the explorers went out again to acquire certain information...They were given four days to be gone". When the scouts returned, the expedition leaders met and decided to turn around and return to Monterey Bay (the original goal), which they had passed but failed to recognize as the place described by earlier maritime explorers.
In 1774 Father Francisco Palou, on Captain Rivera's expedition, erected a cross near the giant creekside redwood they called "El Palo Alto", to mark the site of a proposed mission (later changed to Mission Santa Clara). The colonizing of the Peninsula began after the 1776 expedition of Juan Bautista De Anza left Monterey on the first overland expedition to San Francisco Bay, and passed across the creek on its way to establishing Mission Dolores and the Presidio of San Francisco in 1776. Although de Anza discovered Padre Palou's 1774 wooden cross, the creek's summer flow was deemed too low to support a mission.
Watershed The headwaters of the San Francisquito watershed are in the Santa Cruz Mountains above Menlo Park, around above the Bay. The upper watershed consists of at least 22 named creeks. Including the upper reaches, the total watershed drains an area of .
The creek mainstem originates at the confluence of Bear Creek and Corte Madera Creek just below Searsville Lake in the Jasper Ridge Biological Preserve on lands purchased by Stanford University in 1892. The lake is formed by Searsville Dam, which was built in 1892, one year after the founding of the university itself. The and Searsville Dam consists of a series of interlocking concrete boulders that resemble a massively steep staircase. After leasing the lake for recreational use for 50 years, the Stanford Board of Trustees closed public access to Searsville Lake in 1977. The reservoir has lost over 90% of its original water storage capacity as roughly of sediment has filled it in. Searsville Dam does not provide potable water, flood control, or hydropower. Although removal of the dam would double available spawning habitat on this important steelhead trout stream, Stanford's Jasper Ridge Advisory Committee in 2007 recommended that the dam not be removed and the lake dredged to maintain open water. Stanford University uses water from the lake to irrigate its golf course and other athletic facilities on its campus. Anti-dam proponents point to a growing trend in habitat restoration nationally with over 500 dams removed in recent years.
The first major tributary to San Francisquito Creek is Los Trancos Creek, which joins from the left (heading downstream) just north of I-280.
The creek runs for a length described by different authorities as from , but the mainstem as measured utilizing The National Map from the confluence of Bear Creek and Corte Madera Creek runs to San Francisco Bay. After exiting the foothills near Junipero Serra Boulevard and Alpine Road, runs in an incised channel in a broad alluvial fan, before draining into the Bay south of the Dumbarton Bridge and north of the Palo Alto Flood Basin. Its watershed is about in extent, including areas of San Mateo and Santa Clara counties. In one stretch it forms the boundary between the city of Palo Alto and the cities of East Palo Alto and Menlo Park, and thus between San Mateo and Santa Clara counties, reflecting the fact that it was originally used as the boundary between the lands of the Spanish Missions at San Francisco and Santa Clara. The tree from which Palo Alto takes its name, El Palo Alto, stands on the banks of the creek.
In 1857, the United States Coast Survey (USCS) identified of tidal marsh at the mouth of the creek. There were also two large [] willow groves adjacent to the tidal marsh associated with high groundwater tables and seasonal flooding. In the late 1920s levees were constructed to re-route the creek through a new engineered channel from its former mouth, to a sharp north turn for about half a mile, then to the northeast, before exiting to the Bay. By 2004, filled areas such as the Palo Alto golf course and the Palo Alto Airport have reduced the tidal marsh to .
Ecology Salmonids San Francisquito Creek hosts the most viable remaining anadromous steelhead (Oncorhynchus mykiss irideus) population in southern San Francisco Bay streams. Because the San Francisquito Creek mainstem (and its Los Trancos Creek tributary) forms the boundary of Santa Clara County and San Mateo County, the respective county water districts were unable to agree historically on paying to channelize and concretize the creek, leaving it in a highly natural state. There is a steelhead trout specimen in the California Academy of Sciences that was collected by Edward Z. Hughes in the 1890s. The first President of Stanford University, David Starr Jordan, included a rendering of a "sea-run rainbow trout from San Francisquito Creek" in the Pacific Monthly in 1906. Bear Creek and Los Trancos Creek and their respective tributaries support an observable spawning steelhead population that is threatened by the effects of urbanization. Above the watershed's several dams native resident rainbow trout, a form of landlocked steelhead trout, persist as well. These rainbow trout possess the historical (pre-dam) anadromous steelhead trout genetics and were never introgressed by hatchery-origin fish. However, above dam trout generally suffer from inbreeding depression.
Several lines of evidence support the historical presence of coho salmon (Oncorhynchus kisutch) in San Francisquito Creek. Archaeological remains of unspecified salmonids ("possibly coho") were reported by Gobalet in the creek. Leidy concluded that coho salmon were likely present and cited that the most suitable habitat for coho salmon was in perennial, well shaded reaches of mainstem San Francisquito Creek, and several small, perennial tributaries including Los Trancos, Corte Madera, Bear, and West Union creeks. In addition, three independent oral history sources indicate that coho salmon were abundant in the creek through the first half of the twentieth century. According to local historian Dorothy Regnery's notes from her 1966 interview with Edgar H. Batchelder, who was 2 years old when his father became caretaker of Searsville Dam in 1897, "When the dam was 'wasting', or overflowing in the winter, salmon would swim upstream as far as the base of the dam. Using a pitchfork Mr. Batchelder would spear them to supplement the family's menu." His "favorite place to fish for trout was in the Dennis Martin Creek". A second source described catching "steelhead" and silver (coho) salmon in San Francisquito Creek and the Guadalupe River watershed in the 1930s and 1940s. He said that the Guadalupe River also had runs of chinook salmon (Oncorhynchus tshawytscha) that were very large in wet years." Thirdly, Dennis L. Bark, a senior fellow at the Hoover Institution, recalls playing on San Francisquito Creek around 1947: "Salmon swam up it, and in winter it was a dangerous place." The historical range of coho salmon overlapped geographically with San Francisquito Creek. Coho salmon were historically present in other San Francisco Bay streams south of San Francisco, as evidence by museum specimens from San Mateo Creek and photographic evidence of coho runs in Alameda Creek. The southern limit of coho salmon in coastal California streams was recently confirmed to extend through Santa Cruz County based on both archaeological evidence and historically collected specimens. Recent physical evidence utilizing ancient DNA sequencing of salmonid remains proved that the southern limit of coastal Chinook salmon included the southernmost tributaries of South San Francisco Bay.
Dams impeding salmonid runs
Historically, several dams operated by Stanford presented impassable to nearly impassable barriers to trout, and possibly, salmon spawning runs in the San Francisquito Creek watershed. Several of these dams were constructed to divert stream flows to Stanford's reservoirs, the Lagunita Diversion Dam diverted flows to Lake Lagunita, Searsville Reservoir Dam which diverts minor flows for the Stanford Golf Course, and the Los Trancos Creek Diversion Dam which diverts water to Felt Reservoir. A genetics study of San Francisquito Creek steelhead in 1996 found that the fish are native and not of hatchery stock. In 2006, an Aquatic Habitat Assessment and Limiting Factors Analysis commissioned by the Santa Clara Valley Water District concluded that the key factor limiting smolt production within the study area (San Francisquito Creek mainstem and Los Trancos Creek) and potentially throughout the watershed, is a lack of suitable winter refuge in deep pools and large woody debris. Secondly, outgoing salmonid migration is inhibited by seasonal drying and passage impediments. The Jasper Ridge Road Crossing also presented a significant barrier to fish passage. Stanford has removed two of these barriers, the Lagunitas Diversion Dam was removed in 2018 and the Jasper Ridge Road Crossing, which is now a bridge instead of a weir.
Stanford installed Los Trancos Creek Diversion Dam in 1929, to divert stream flows to its Felt Lake water storage reservoir. The dam, located just below the intersection of Arastradero and Alpine Roads, blocks access of upmigrating steelhead trout to over of pristine upstream spawning grounds. In 2009, Stanford University completed construction of a new fish screen and ladder as the previous fish ladder was an "Alaska Steep Pass" designed for much higher flows. Anadromous steelhead trout now access the upper Los Trancos Creek watershed above Rossotti's Alpine Inn Beer Garden.