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The 9.4-square-mile Estudillo Canal Watershed begins on the ridge between Lake Chabot and Fairmont Hospital in San Leandro and drains west through a network of canals and underground culverts in residential and commercial areas of the city on its way to Estudillo Canal. The canal flows toward the San Francisco Bay and connects via a tide gate to Heron Bay tidal marsh. It continues past Tony Lema Golf Course to the bay near San Leandro Marina.
Flora and Fauna
Draining almost entirely through engineered channels and underground culverts through urban San Leandro, the Estudillo Canal Watershed has little in the way of riparian corridors that would support plants and animals. Closer to San Francisco bay, Estudillo Canal connects via a tide gate to Heron Bay tidal marsh and tidal flats, where plants adapted to salty water are abundant. A tidal marsh in San Francisco Bay typically supports, from higher elevation to lower, gum plant, salt grass, pickleweed, and cord grass, which provide habitat for young fish, rails, songbirds, shorebirds, waterfowl, and the endangered salt marsh harvest mouse.
Geology and Hydrology
The ridgeline above Fairmont Hospital in San Leandro drains across volcanic rocks from the Jurassic era. A spring once existed at the current hospital site along the Hayward fault, but an earthquake in 1868 stopped the flow of water. There are still many small seeps in the neighborhood surrounding the hospital, however. In the low-lying flatlands, the watershed is bounded by the large alluvial fans of San Leandro Creek to the north and San Lorenzo Creek to the south.
Major Issues: Drained almost entirely by engineered channels or underground culverts, the Estudillo Canal Watershed lacks adequate sediment, vegetation, and sunlight to sustain a creek ecosystem. Heron Bay Marsh, at the downstream end of Estudillo Canal, supports native pickleweed and cord grass (scientific name Spartina), though the cord grass in this area has been identified by the San Francisco Estuary Invasive Spartina Project as 50-100 percent invasive. In many parts of San Francisco Bay, invasive cord grass from the Atlantic coast threatens tidal marsh habitat for important species such as the California clapper rail. Treatment for invasive cord grass includes controlled and monitored application of the herbicides imazapyr and glyphosate. For more information on the impacts of invasive cord grass and the herbicides used to control it, click here.
Major Creeks & Waterbodies
Located in San Leandro, the Estudillo Canal Watershed includes Estudillo Canal, its contributing engineered channels and culverts, and Heron Bay Marsh.
Estudillo Canal is a 4.8-mile engineered channel that begins just west of I-580 near Halcyon Drive, where it receives drainage from the ridge above the Fairmont Hospital and the surrounding area. A .15-mile section of open, natural creek runs through a tree-lined valley just below the ridge. The creek flows under a bend in Fairmont Boulevard and then resurfaces for another .15 miles before being diverted underground and eventually draining to Estudillo Canal. The canal flows south past East 14th Street and the Bayfair Mall. There, it turns west and flows to San Francisco Bay, capturing storm drain flow from multiple underground culverts and engineered channels along its way.
Heron Bay Marsh
Heron Bay Marsh, also known as San Leandro Shoreline Marsh, is a tidal marsh located between Tony Lema Golf Course and the Heron Bay housing development along Santa Ynez Road and San Lorenzo Creek. To construct the housing development in 2001, the developer was required to restore the adjacent marsh, which had been cut off from San Francisco Bay by an outboard levee. A tide gate connects Estudillo Canal to the inland portion of the marsh, and now a culvert connects the marsh to the bay.
Multi-use trails and two small parks provide recreational opportunities in the watershed, which is located entirely within the city of San Leandro.
San Leandro Shoreline Trail
The San Leandro Shoreline Trail is a segment of the San Francisco Bay Trail, an ongoing project to create a shoreline trail around the entire bay. This section of the trail extends from the San Lorenzo Creek levee along an outboard levee to Marina Park in the San Leandro Marina Watershed. The trail is accessible from several points within the Heron Bay residential development: from the end of Riverside Court, a pullout off of Baypoint Avenue, and at the end of Bayfront Drive. The multi-use trail is paved and wide, extending along Heron Bay Marsh. An unmarked network of small trails provides access to areas within the marsh.
Parks and Recreation
Stenzel Park is located on the edge of Estudillo Canal at Wicks Boulevard and Elvina Drive. It has baseball fields, basketball courts, a playground, barbecue pits, and picnic tables. Trees line the outer edge of the park along the outfield and Estudillo Canal.
Located at the corner of Juniper and Sagewood streets along an engineered tributary to Estudillo Canal, the 5-acre Bonair Park includes picnic areas, play structures, and horseshoe pits.
Heron Bay Marsh Restoration
Heron Bay Marsh, also known as San Leandro Shoreline Marsh, is bounded by San Lorenzo Creek, Heron Bay housing development, Tony Lema Golf Course, and an outboard levee along San Francisco Bay. In 2001, as a condition of approval for the Heron Bay residential development, 406 acres of the marsh were restored. The marsh had been cut off from San Francisco Bay by levees, and portions had been filled. The levees were breached in two places, fill was removed, and channels were graded to allow tidal flow to reach the farthest corners of the marsh. Today, the lush marsh supports pickleweed and other common marsh plants.
The organizations below provide resources, education programs, and volunteer opportunities in the watershed.