The 660-square-mile Alameda Creek Watershed is the largest watershed in the Bay Area. It extends as far south as Mount Hamilton, north to Mount Diablo, east to the Altamont Hills in Livermore, and west to San Francisco Bay. The information in this watershed page focuses on the 6 percent of the watershed located in western Alameda County within the Alameda County Flood Control and Water Conservation District’s (the District) jurisdiction. This 41-square-mile portion includes the Walpert Ridge area of the East Bay hills and the flatlands of Fremont and Union City. The flatlands were created by Alameda Creek itself, each successive flood laying down another layer of sand, silt, and gravel to form a large alluvial fan that slopes gently bayward. Click here to view the entire Alameda Creek watershed.

Alameda Creek Watershed

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Eden Landing Salt Ponds

The Alameda Creek Watershed has been highly modified. In the early 1970s, Alameda Creek was diverted south of its original outflow when it was dredged and channeled for flood control. Lined with levees along both sides, the Alameda Creek Flood Control (ACFC) Channel flows 12 miles from the mouth of Niles Canyon to San Francisco Bay, cutting across the creek’s former alluvial fan where it once deposited sediments that formed rich agricultural soils. Several large dams in eastern Alameda County, including Del Valle, Calaveras, and San Antonio dams, help control water flow in the channel. Small dams within the flood control channel itself prevent erosion or pond the water for groundwater recharge.

Flora and Fauna

Alameda Creek supports about a dozen native fish species including common fish like the threespine stickleback and prickly sculpin and more unusual fish like the Sacramento blackfish and tule perch. Anadramous fish, such as salmon and steelhead trout, were nearly eliminated due to habitat destruction and the construction of dams and water diversions. Significant infrastructure revisions are in progress that will remove barriers and maintain water flow with the goal of restoring steelhead trout populations. Vegetation in the watershed varies, ranging from grassland to oak and bay laurel riparian forests. Along the 12-mile flood control channel, 95 percent of Alameda Creek’s native riparian vegetation has been destroyed. The steelhead restoration effort includes replanting riparian vegetation to provide thermal cover and supplement the food chain for fish and other aquatic organisms. At the baylands, salt grass, pickleweed, and cord grass were former dominant species in the abundant tidal marshes, which were converted to salt ponds in the late 1800s. Many waterfowl species adapted to feed on the plentiful brine shrimp in the salt ponds. Through the South Bay Salt Pond Restoration Project, ponds will be managed alongside restored tidal marsh.

Geology and Hydrology

For thousands of years, the floodwaters of Alameda Creek deposited sediment in a large fan-shaped deposit, or alluvial fan, that spread from Niles Canyon west to San Francisco Bay, north to Union City, and south through the cities of Fremont and Newark. Through the early 1900s, the expanse of silty and sandy soils made for productive farming. Closer to the Niles Canyon outlet, a quarry mined the gravel deposits. Water demands were met by pumping groundwater from deep within the sand and gravel. By the mid-1900s, overdraft of the aquifers led to saltwater intrusion from San Francisco Bay. Today the Alameda County Water District (ACWD) uses surface water and groundwater to meet water demands by employing rubber dams to divert water from the Alameda Creek Watershed and the State Water Project to several hundred acres of ponds within the former gravel quarry. There, it percolates to recharge the underlying groundwater basin and a series of wells allows the ACWD to pump water out again when needed.

Major Issues

The largest issues for Alameda Creek are dams and sedimentation. Dams create barriers for upstream fish migration and control water supply to downstream areas. Migratory fish historically spawned in the upper reaches of Alameda Creek, and steelhead trout are still found in the lower reaches trying to migrate inland. Within the 12 miles of the ACFC Channel, efforts to restore steelhead involve removing or transforming migratory barriers. Historically Alameda Creek deposited silt throughout Union City, Fremont, and Newark. But having been redirected into a flood control channel, the creek is now more confined, and sediment transport has been altered causing sediment accumulation in the lower seven miles. The four miles closest to the bay are influenced by tides and collect estuarine sediment in addition to stream sediment. The District occasionally dredges the channel. Through its involvement in the South Bay Salt Pond Restoration Project, the District and its partners are modifying the mouth of Alameda Creek to promote scouring of upstream sediment and deposition of sediment in areas where it will create tidal marsh habitat and improve flood control.

Major Creeks & Waterbodies

Niles Canyon Rapids

(The following information pertains to the western portion of the Alameda Creek Watershed within the jurisdiction of Alameda County Flood Control and Water Conservation District – from the mouth of Niles Canyon to San Francisco Bay.)

Seven creeks and flood control channels drain to the Alameda Creek Flood Control (ACFC) Channel in western Alameda County; three of these form significant subwatersheds. The north and south forks of Dry Creek drain the hills north of Niles Canyon; Crandall Creek drains the flatlands south of Alameda Creek; The District’s Zone 5, Line J2 drains the flatlands north of Alameda Creek; and Ardenwood Creek, within the Crandall Creek subwatershed, drains the floodplain between Crandall Creek and the managed ponds and wetlands, or “baylands,” of San Francisco Bay.

Alameda Creek

Alameda Creek’s headwaters and tributaries originate at Mt. Hamilton in the south, the Diablo Range to the north, and as far east as the hills of Altamont Pass. Outside the Bay-Delta drainage from the Sierra Nevada, the Alameda Creek Watershed is the largest in the San Francisco Bay area. Alameda Creek enters western Alameda County near the mouth of Niles Canyon. From there, it flows through the 12-mile-long ACFC Channel constructed by the Army Corps of Engineers in the 1970s. The channel passes through Union City and Fremont across the creek’s historic flood plain, then flows north of Coyote Hills Regional Park before reaching San Francisco Bay. With the construction of the flood control channel, Alameda Creek was diverted south of its historic route. Although the historic channel was left intact to form Old Alameda Creek, the western portion of the watershed was bisected into north and south – old and new. For more information on the Old Alameda Creek Watershed, click here.

Dry Creek

Dry Creek is a 9.9-square-mile subwatershed that drains Walpert Ridge in the East Bay hills north of Niles Canyon. The north and south forks of Dry Creek meet near the terminus of Tamarack Drive in Union City. Both forks of Dry Creek run through Garin and Dry Creek Pioneer Regional parks, and through most of the subwatershed Dry Creek remains in its natural condition before its confluence with the ACFC Channel.

Zone 5, Line M

Zone 5, Line M is an engineered channel that collects urban drainage from a series of underground culverts and engineered channels in the neighborhood surrounding the Union City BART Station, between Dry Creek and Niles Canyon.

Crandall Creek

Crandall Creek is a 6.5-square-mile subwatershed that drained the floodwaters across the floodplain south of the historic Alameda Creek channel. Today Crandall Creek drains urban runoff through a series of culverts and engineered channels that flow into the Demonstration Urban Stormwater Treatment (DUST) Marsh, an artificial wetland designed to treat urban runoff, before eventually leading to San Francisco Bay. Historically Crandall Creek made a straight shot across the flatlands and skirted north of Coyote Hills to the extensive tidal marsh that rimmed the south bay. Its former outflow to the bay is now the outflow of the ACFC Channel.

Ardenwood Creek

Ardenwood Creek, within the Crandall Creek subwatershed, historically drained a riparian corridor thick with willows before joining Crandall Creek on the north side of Coyote Hills. Today the drainage flows through underground culverts and engineered channels to the ACFC Channel. One of the area’s largest and most productive historic farms, the Patterson farm, was located along the creek in what is now Fremont, taking advantage of the fertile soils in the alluvial fan of historic Alameda Creek. The Patterson family house and farm are now preserved as part of Ardenwood Regional Preserve. Commercial farming continues today at both Ardenwood and adjacent properties.

Zone 5, Line J2

Zone 5, Line J2 drains a 1.9-square-mile subwatershed in a residential area of Union City near the managed ponds and wetlands of south San Francisco Bay. A series of culverts drain to an engineered channel that joins the ACFC Channel near the historic Patterson Landing. Although there are no remains of the landing today, it was an important transportation hub. Scow-schooners able to navigate the shallow waters took produce from the Patterson’s large farm to San Francisco and brought back manufactured goods.

The Baylands

The shallow waters of south San Francisco Bay provided excellent conditions for the extensive tidal flats and tidal marshes that rimmed the shoreline. These same conditions made the south bay an excellent place for salt farming. Small scale salt production was a traditional activity of the Ohlone Native Americans, the Spanish, and early American settlers. From the mid-1800s through the late 1900s, salt production expanded to include large industrial ponds that transformed the south bay tidal flats and tidal marshes. In 2003, most of the salt ponds were purchased for restoration and are now part of the South Bay Salt Pond Restoration Project managed by the California Coastal Conservancy. Due to natural subsidence and that induced by salt production, many of these ponds will remain behind levees as either restored areas, managed tidal marshes, or managed ponds, all of which provide valuable habitat.

Recreational Opportunities

Tule Ponds

(The following information pertains to the western portion of the Alameda Creek Watershed within the jurisdiction of Alameda County Flood Control and Water Conservation District – from the mouth of Niles Canyon to San Francisco Bay.)

From Niles Canyon to the bay, there are two city parks, four regional parks, and a 12-mile-long regional trail within the Alameda Creek Watershed. The parks provide water-oriented recreation, hiking, bicycling, and nature study and preserve the rich agricultural traditions in the former Alameda Creek floodplain. After flowing through parkland and urban developments, the Alameda Creek Flood Control (ACFC) Channel enters the bay through the Don Edwards San Francisco Bay National Wildlife Refuge.


The Alameda Creek Regional Trail extends 12 miles along the levee of the Alameda Creek Flood Control (ACFC) Channel from the mouth of Niles Canyon in Fremont to San Francisco Bay. The trail connects with Quarry Lakes Regional Recreation Area, Coyote Hills Regional Park, and the Don Edwards San Francisco Bay National Wildlife Refuge. Used most by cyclists, the entire trail along the south side levee is paved, including a loop that circles Coyote Hills.

Parks and Recreation

Quarry Lakes Regional Recreation Area

During the mid-19th century, the gravel deposits of Alameda Creek were mined in the area that is now Quarry Lakes Regional Recreation Area. Among other projects, the gravel was used in the construction of the transcontinental railroad. The leftover pits were later reclaimed by the Alameda County Water District for groundwater recharge. Today the Quarry Lakes cover 350 acres of the 471-acre recreation area, which is managed by the East Bay Regional Parks District (EBRPD). Boating, swimming, and fishing are popular activities. The recreation area is located on Quarry Lakes Boulevard in Fremont.

Niles Community Park

Operated by the city of Fremont, Niles Community Park contains three ponds in former gravel quarry pits adjacent to Quarry Lakes Regional Recreation Area. Located at 472 School Street, the park allows fishing and picnicking. The area in and around Shinn Pond is used as an off-leash dog park.

Arroyo Park

Located on Perry Road in Union City, Arroyo Park is a city property that offers baseball, basketball, and tennis facilities, as well as playgrounds and picnic areas. The park sits adjacent to the creek bed of the historic Alameda Creek and relies on the riparian vegetation along the bank for shade. The creek bed once carried more water than any other creek in Alameda County, evidenced by its width and depth at this location.

Garin and Dry Creek Pioneer Regional Parks

Managed by the EBRPD, Garin and Dry Creek Pioneer Regional parks share a contiguous border, together forming a 4,763-acre area in the hills behind California State University East Bay. The north fork of Dry Creek runs through Garin Regional Park and the south fork runs through Dry Creek Pioneer. Within the two parks, there are 20 miles of unpaved paths and two ponds. Jordan and Newt ponds were created by damming the north fork of Dry Creek. Today anglers fish the ponds for bass, bluegill, sunfish, and stocked catfish. Garin Regional Park sits on the former site of Garin Ranch, owned by Andrew Garin, who maintained large tracts of apple orchards. The ranch was sold to the EBRPD in 1966, but some of the antique apple varieties are still farmed today and celebrated at the annual Garin Apple Festival. A visitor center within Garin Park highlights the rich history of the area. Dry Creek Pioneer Regional Park sits on the former site of Dry Creek Ranch, which was owned by three sisters, Mildred, Edith, and Jeanette Meyers. During the 1950s and 1960s, the philanthropic Meyers sisters hosted fundraising events at the ranch. They eventually donated the 1,200-acre property to EBRPD in 1979 to prevent a freeway from bisecting it. The family cottage and Dry Creek Garden are preserved there today.

Ardenwood Historic Farm

The Ardenwood Historic Farm occupies the site of the Patterson family home and their successful farm from the 1850s. Historic Ardenwood Creek flowed through the farm, draining Alameda Creek floodwaters that, for thousands of years, deposited fertile farming soils in the area. Since 1985, the EBPRD and the city of Fremont have managed the site as a functioning turn-of-the-century farm and restored Victorian mansion. A docent program allows visitors to tour the mansion or participate in seasonal farming activities. The farm also supports the largest overwintering population of monarch butterflies in the Bay Area. A eucalyptus stand, along with EBRPD-maintained milkweed, keeps the monarchs here most years from December through February.

Coyote Hills Regional Park

Standing on San Francisco Bay levees looking east, the Coyote Hills appear as an island rising out of the flat Alameda Creek floodplain. West of the hills are the baylands, a series of managed ponds that are part of the Don Edwards San Francisco Bay National Wildlife Refuge. To the east are freshwater wetlands filled with water from Crandall and Ardenwood engineered creek channels. The EBRPD’s 978-acre Coyote Hills Regional Park was dedicated for public use in 1967. Today it is a popular place for hiking, bicycling, and bird watching. The park boasts a 2,000-year-old Tuibun Ohlone village and shellmound sites. The village contains an Ohlone-style family house, sweat house, and shade shelter that are open for guided tours with reservations. The park can reached via Patterson Ranch Road in Fremont.

Don Edwards San Francisco Bay National Wildlife Refuge

The ACFC Channel feeds into the northern extent of 30,000-acre Don Edwards San Francisco Bay National Wildlife Refuge. The baylands within the refuge consist primarily of tidal marsh, managed ponds, and mud flats. A smaller portion of the refuge includes seasonal wetlands and uplands. The refuge is home to 227 bird species and supports 45,000-75,000 wintering waterfowl each year. The refuge is also one of several entities partnering in the South Bay Salt Pond Restoration Project.

Eden Landing Ecological Reserve

The north levee of the ACFC Channel borders the 5,050-acre Eden Landing State Ecological Reserve. The reserve is undergoing restoration as Phase I of the South Bay Salt Pond Restoration Project. The public access opportunities and restoration effort at Eden Landing are described in depth here.

Restoration Efforts

Alameda Creek Fisheries

Multiple restoration projects are located within the Alameda Creek Watershed that demonstrate both upstream creek restoration and downstream estuarine restoration.

Alameda Creek Restoration

The restoration of ocean-run steelhead trout began in 1999 as a collaborative effort between the Alameda County Flood Control and Water Conservation District and several other agencies. It has been an extensive, ongoing project involving the removal of three dams and the construction of fish passage structures such as fish ladders. Stream flows will be improved for cold water fish, and habitat along the flood channel will be restored. With the completion of these projects, anadromous fish will be able to access up to 20 miles of spawning and rearing habitat in Alameda Creek and its tributaries.

South Bay Salt Pond Restoration Project

The 15,100 acres of industrial salt ponds in south San Francisco Bay will be restored through the South Bay Salt Pond Restoration Project, the largest tidal wetland restoration project east of the Mississippi River. The baylands at the outflow of ACFC Channel are included within this area. Their restoration will create a diverse habitat of tidal marsh and managed ponds for fish, waterfowl, and other wildlife. Phase I of the project restored Eden Landing at the mouth of Old Alameda Creek, just north of the ACFC Channel. As part of Phase II, levees will be modified near the lower reach of Alameda Creek to help create new tideland areas. Bay tides flowing in and out of the lower segment of Alameda Creek will scour sediment that might otherwise require dredging. The restoration of tidal marsh habitat is crucial to the survival of salmonids and marsh-dependent fish. Consequently groups like the Alameda Creek Alliance are working to ensure that the salt pond restoration compliments the restoration of steelhead in Alameda Creek.

South Decoto Green Streets Project

This project covered eight full blocks in the neighborhood between 12th and 15th Streets and F and H Streets. It addressed storm drainage concerns and beautified the area by replacing old, flood-prone infrastructure with raingardens, permeable pavers and planted curb extensions. The project utilized low-impact best management practices to promote infiltration, provide temporary detention, and treat stormwater draining to Alameda Creek and its habitat. It transformed the streetscape with tree-lined, pedestrian-friendly space for community members and protects Alameda Creek from water pollution and high peak flows.

Get Involved

Alameda Creek Cleanup

(The following information pertains to the western portion of the Alameda Creek Watershed within the jurisdiction of Alameda County Flood Control and Water Conservation District – from the mouth of Niles Canyon to San Francisco Bay.)

The Alameda Creek Alliance works to restore native species and habitats and to protect undeveloped areas within the watershed. It hosts an informative and well organized website with an abundance of information about these efforts. The Alameda Creek Watershed Forum coordinates multiple stakeholders to protect and enhance beneficial water-related uses and resources in the watershed. The forum hosts an annual conference and coordinates or sponsors specific projects, such as creek and watershed signage, “adopt a spot” areas, and a sediment forum. The San Francisco Estuary Institute’s Alameda Creek Historical Ecology Study provides in-depth analysis that informs current salt marsh and steelhead restoration efforts in the watershed. The East Bay Regional Park District and the Regional Parks Foundation provide many opportunities for volunteerism and education within the four regional parks in the watershed. The Alameda County Resource Conservation District works with several partners to promote its Hands-On-Conservation program that teaches youth about natural resource conservation through active stewardship.

Resources in the Watershed