- Get Involved
The San Leandro Creek Watershed covers 49.4 square miles, extending east into the hills above Oakland and San Leandro and north to include the town of Moraga in Contra Costa County. The information on this watershed page focuses on the area of the watershed located within the Alameda County Flood Control & Water Conservation District’s jurisdiction. The watershed is unusual among East Bay watersheds today in that its 78.3 miles of creeks remain open and primarily in their natural state. Two large dams, at Upper San Leandro Reservoir and Lake Chabot, provide drinking water storage and regulate the flow of water in San Leandro Creek. Ten tributary creeks flow through parklands and managed watersheds before joining Upper San Leandro Reservoir, Lake Chabot, or San Leandro Creek.
Several creeks with headwaters in the eastern reaches of the East Bay hills drain to Upper San Leandro Reservoir in Alameda County, including Indian Creek, King Canyon Creek, Moraga Creek, Kaiser Creek, Rimer Creek, and Buckhorn Creek. Redwood Creek drains the west side of San Leandro Reservoir; Miller Creek joins San Leandro Creek on the east side just below the reservoir spillway. San Leandro Creek connects the reservoir to Lake Chabot, which is also fed by Grass Valley Creek. Below Lake Chabot, San Leandro Creek continues above ground to San Leandro Boulevard, where it becomes channeled through downtown San Leandro to San Leandro Bay within the greater San Francisco Bay.
Flora and Fauna
The San Leandro Creek Watershed is home to a great forest of coast redwoods, chaparral, and grasslands. The East Bay Regional Park District (EBRPD) provides extensive wild plant checklists of plants found in each of the five regional parks that make up a large portion of this watershed. Notable wildlife includes rare species such as the golden eagle; the Alameda striped racer; the California newt; and, in the tidal marshes near the mouth of San Leandro Creek, the salt marsh harvest mouse. Redwood Creek is particularly noteworthy because it is the primary spawning and rearing habitat for the population of rainbow trout that was originally used to describe the species in 1885. The trout migrate downstream to Upper San Leandro Reservoir and return to the upper sections of Redwood Creek to reproduce in late winter and early spring. San Leandro Creek also supports other native fish, including prickly sculpin, Sacramento sucker, and three-spined stickleback. Prior to construction of the Lake Chabot dam, coho salmon, chinook salmon, and steelhead trout could also be found in the creek.
Geology and Hydrology
At the eastern reaches of the watershed, creeks draining to Upper San Leandro Reservoir flow through sedimentary rock formed during the Pliocene and early Miocene epochs. Creeks along the west side of the reservoir run in steep-sided linear valleys through Cretaceous sandstones. The northern headwaters of San Leandro Creek include a 10-million-year old volcano in Sibley Volcanic Regional Preserve. As San Leandro Creek flows southeast through the hills, it alternately traverses Jurassic era volcanic rock and sedimentary rock from the Oligocene epoch. The creek makes a sharp northwest turn at the Hayward Fault and flows toward the bay across a large alluvial plain that now hosts the city of San Leandro. Before entering San Leandro Bay, San Leandro Creek crosses a mile-wide swath of former tidal marsh, most of which has been covered with artificial fill.
The San Leandro Creek Watershed has been assessed for water quality and the possibility of reintroducing steelhead trout to the creek. According to a technical report prepared for the Alameda Countywide Clean Water Program, higher contaminant concentrations are found where urban development is more extensive. This is typical of watersheds in the Bay Area and suggests contamination from human activity rather than natural sources. A watershed survey report prepared for the Regional Water Quality Control Board found that in water and sediment tested near the mouth of San Leandro Creek, concentrations of chemical contaminants exceeded the board’s guideline values, toxicity levels were detrimental to invertebrate reproduction, and sediment was highly toxic to amphipods (marine crustaceans). At the mouth of San Leandro Creek itself, amphipod survival was zero percent.
Major Creeks & Water Bodies
San Leandro Creek
The Arroyo de San Leandro, or San Leandro Creek, was likely named by the Spanish for a sixth-century archbishop of Seville named Saint Leander. The approximately 22-mile-long creek is remarkably natural and uncovered for most of its length. The headwaters begin in managed parkland at the southern edge of Sibley Volcanic Regional Preserve just beyond its border with Huckleberry Botanic Regional Preserve. The creek travels within similarly undeveloped areas through the Oakland and San Leandro hills to Upper San Leandro Reservoir then to Lake Chabot. Indian Creek joins San Leandro Creek just above the reservoir, and Miller Creek joins it just below the spillway. The Hayward Fault runs just below Lake Chabot, and it is at this juncture that the creek, still uncovered, makes an abrupt northwest turn and heads toward downtown San Leandro. At San Leandro Boulevard, the creek is diverted through an engineered channel to an outflow in San Leandro Bay within the greater San Francisco Bay.
Upper San Leandro Reservoir
Upper San Leandro Reservoir was built by the East Bay Municipal Utility District (EBMUD) in 1926 to replace Lake Chabot as the primary water storage facility for the city of San Leandro. It still serves that function today. Contained within several steep-walled canyons, the reservoir covers a surface area of 794 acres. Its drainage basin covers 18,680 acres, of which EBMUD owns 8,117. The East Bay Regional Park District (EBRPD) owns much of the remaining land. Nearly 90 percent of the basin is managed watershed or parkland. Several creeks, in addition to San Leandro Creek, flow into the reservoir from well into Contra Costa County, including Moraga Creek, Redwood Creek, Buckhorn Creek, and Kaiser Creek.
Miller Creek joins San Leandro Creek below the spillway from Upper San Leandro Reservoir. The creek extends well to the east into open space owned and managed by EBMUD for water supply purposes. Access to the area is by permit only and requires adhering to a strict set of rules.
Redwood Creek meets Upper San Leandro Reservoir on its west side near Redwood Road. The creek parallels Redwood Road to its intersection with Pinehurst Road, and from there the creek travels through a long valley into Redwood Regional Park, where its riparian corridor is one of the park’s central features. Among fishery experts, Redwood Creek is famous as the primary spawning and rearing habitat for the population of rainbow trout that was originally used to describe the species in 1885. Rainbow trout have been introduced to freshwater streams all over the world, and hybrid strains have been created to produce hardier trout that can be successfully transplanted from hatcheries to the wild. The pure, wild strain found in Redwood Creek is becoming rare.
Grass Valley Creek skirts the west side of Upper San Leandro Reservoir, draining a long valley in the Oakland Hills between Redwood Road and Skyline Boulevard. It flows east of the quiet neighborhood of Grass Valley and is crossed by a stone bridge at Grass Valley Road. Downstream of the bridge is a picturesque waterfall that flows in winter and spring. The creek continues through Anthony Chabot Regional Park and into Lake Chabot.
Surrounded by Anthony Chabot Regional Park, Lake Chabot covers 340 acres and is managed by EBMUD for emergency water supplies. The EBRPD manages the undeveloped lands surrounding the lake for recreation. Lake Chabot is named for Anthony Chabot, who designed what was then called the San Leandro Reservoir as the main water supply for San Leandro and parts of Oakland. Construction began in 1874 and lasted until 1892. The brunt of the work fell to Chinese laborers who moved over 600,000 cubic yards of soil with shovels to create the reservoir’s dam. The historical walk near the dam pays tribute to these workers. Lake Chabot is fed by Grass Valley Creek and San Leandro Creek, which also drains the lake through a spillway on the west side as it heads northwest to Arrowhead Marsh where it empties into San Leandro Bay.
San Leandro Creek enters San Leandro Bay through an engineered channel at Arrowhead Marsh in Martin Luther King Jr. Regional Shoreline near Oakland International Airport. Arrowhead Marsh is a young tidal marsh–one of the few left in the East Bay. It was likely created during the construction of the Lake Chabot Dam when a severe storm sent 21,000 cubic yards of the dam’s clay core downstream to the mouth of San Leandro Creek. Since the creation of the regional shoreline, surrounding marshlands have been restored, expanding the available habitat and making the area an important stopping place for migratory waterfowl.
The East Bay Regional Park District (EBRPD) manages four parks within the San Leandro Creek Watershed. In the hills of Oakland and San Leandro, Redwood Regional Park, Roberts Regional Recreation Area, and Anthony Chabot Regional Park provide varied recreational experiences and open space preservation. Downstream at the mouth of San Leandro Creek, Martin Luther King Jr. Regional Shoreline provides shoreline access along the bay and preservation of tidal marsh habitat. Within the regional parks, there are trailheads for two important Bay Area trail systems. Two city parks provide creek access in more developed areas of San Leandro.
Most of the drainage basin east of Upper San Leandro Reservoir is owned and managed by the East Bay Municipal Utility District (EBMUD). The area can be explored through a series of trails accessible only with an EBMUD trail permit, issued to ensure observance of rules that preserve water quality.
The 31-mile East Bay Skyline National Recreation Trail extends through the western side of the San Leandro Creek Watershed. The trail is also part of the Bay Area Ridge Trail system.
At the Tidewater Boating Center near the mouth of San Leandro Creek, boaters will find a launch site for the San Francisco Bay Water Trail system. These launch and landing sites, or “trailheads,” provide human-powered boats and beachable sail craft access to San Francisco Bay for multiple-day and single-day trips. This innovative trail system is designed for people with a variety of boating skills. The launch site at the Tidewater Boating Center provides access to isolated San Leandro Bay and is ideal for less experienced kayakers.
Parks and Recreation
The East Bay Regional Park District’s (EBRPD) 1,830-acre Redwood Regional Park is located on Redwood Road and Skyline Boulevard in the Oakland Hills. Although it was the primary site of extensive clear-cutting during the gold rush era, second and third generation coast redwoods thrive there today. Redwood Creek flows through the forest ecosystem, providing habitat for a unique web of living organisms that includes California newts and the original genetic strain of rainbow trout. Redwood Regional Park hosts an extensive trail system, with opportunities for both avid hikers and casual visitors who want a short walk through the redwoods. Picnic sites and playgrounds can be found near the entrance at the south end of the park.
Also managed by the EBRPD, the 82-acre Roberts Regional Recreation Area borders the west side of Redwood Regional Park along the ridge that drains to Redwood Creek. It includes swimming and archery facilities, picnic sites, sports fields, and a variety of trails. Like Redwood Regional Park, Roberts’ ecosystems include coast redwoods, chaparral, and grasslands.
Anthony Chabot Regional Park, also part of the EBRPD, covers 3,314 acres, extending from Redwood Regional Park along the entire length of Grass Valley Creek to Lake Chabot and its shoreline. It includes a campground; a marksmanship range; an equestrian center; and 70 miles of hiking, bicycling, and riding trails. The park is mostly chaparral, grasslands, and eucalyptus groves, with a healthy riparian corridor along Grass Valley Creek.
Owned and operated by the city of San Leandro, the 10-acre Chabot Park is tucked into the hills just below the Lake Chabot dam at Estudillo Avenue and Sylvan Circle. The San Leandro Creek corridor, thick with greenery, bends along the edge of park. The park offers picnic areas, playgrounds, a volleyball court, and a sports field.
Constructed in 1996, Root Park is located at the corner of Hays and E. 14th streets in downtown San Leandro. The park provides a relaxing green space with direct access to San Leandro Creek via a viewing platform and walkway. This city owned and managed park is often used by local science classes for nature study.
The 741-acre Martin Luther King Jr. Regional Shoreline lies at the mouth of San Leandro Creek adjacent to Oakland International Airport. The park is leased from the Port of Oakland by the EBRPD to preserve what remains of a former extensive tidal marsh and provide public access to the shoreline. The park contains the Tidewater Boating Center and Arrowhead Marsh, which is believed to have been created by sediment carried downstream when Lake Chabot’s dam burst during construction. The marsh is a stopover on the Pacific Flyway and part of the Western Hemisphere Shorebird Reserve Network, which is a conglomerate of dedicated organizations spanning 13 countries and 31 million acres.
Historically, the lower end of San Leandro Creek slowly wound its way through acres of tidal marsh before entering the bay. Martin Luther King, Jr. Regional Shoreline includes the last remaining tidal marshes in San Leandro Bay; the others have been filled in for development. In 1998, at the “handle” of Arrowhead Marsh, fill was removed, artificial levees were breached, and tidal channels were constructed to restore tidal action. Plant and animal colonization began shortly thereafter and continues today.
In Redwood Regional Park, the EBRPD is working on balancing recreational use and protection of Redwood Creek through a series of trail and signage projects geared toward reducing stream bed erosion and keeping park users on the trails. In more urbanized areas of the watershed, the Friends of San Leandro Creek hosts creek cleanup days five times a year. The group is studying the feasibility of restoring steelhead trout to the creek, since the creek is relatively healthy and flows within its natural channel, and juveniles have been found over the years above and below both dams.
The Friends of San Leandro Creek (FSLC) is a nonprofit organization that brings citizens together to protect and enhance San Leandro Creek. It provides outreach and education tools, hosts creek cleanup days, organizes a volunteer creek monitoring program, and works with the city of San Leandro on infrastructure projects that enhance the creek experience. The Regional Parks Foundation assists the EBRPD by funding restoration projects in the regional parks.