Upper Alameda Creek Watershed – Northern Section
OverviewThe 660-square-mile Alameda Creek Watershed is the largest watershed in the Bay Area, draining roughly the southern two-thirds of the East Bay. 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. There are two major tributaries to Alameda Creek, with many smaller creeks feeding in to them: Arroyo de la Laguna in the north and the south fork of Alameda Creek. The watershed is crossed by two major water delivery systems for the Bay Area, the Hetch Hetchy Aquaduct and the State Water Project, and includes three man-made reservoirs: Lake Del Valle, San Antonio Reservoir and Calaveras Reservoir. Flows in the upper reaches of the Alameda Creek watershed are controlled by water releases from the Calaveras Reservoir, which is managed by the City and County of San Francisco. The Calaveras Reservoir captures natural runoff and stores imported water from the Hetch Hetchy reservoir. The local runoff in the Upper Alameda Creek Watershed is managed by Zone 7 Water Agency, while supplies for public and wildlife use come from the State Water Project. The Alameda Creek Watershed can be broken into two sections, lower and upper. The information in this watershed page focuses on the 198 square mile northern section of the Upper Alameda Creek Watershed. This section is split between Contra Costa and Alameda Counties, drains areas of San Ramon, Pleasanton, Dublin, Livermore and Sunol. The following subwatersheds are included in this northern section of the Upper Alameda Creek Watershed:
- Arroyo de La Laguna
- Alamo Canal
- Arroyo Mocho Canal
- Arroyo Las Positas
- Chain of Lakes
Flora and FaunaThe northern section of the Upper Alameda Creek Watershed is home to a multitude of native plant and animal species. Characterized by a wide range of vegetation communities – grasslands, sage / scrub lands, oak woodlands, and riparian forest – the undeveloped areas of this section of the watershed contain a variety of native plants, including some special status species like the fragrant fritillary, maple-leaved checkerbloom and most-beautiful jewelflower. Small pockets of unique vegetation types such as alkali wetlands, fresh water marshes and alkali meadows are scattered throughout the area as well, concentrated in the Arroyo Las Positas Subwatershed.These vegetation communities also provide habitat for many native birds, amphibians, reptiles, bats and other mammals. The waterways and waterbodies within the northern section of Upper Alameda Creek Watershed provide especially important habitat, as the edges of ponds and the riparian areas along creeks are home to special status species such as the California red-legged frog, California tiger salamander, western pond turtle, and tri-colored blackbirds. Historically, the creeks in the northern section of the Upper Alameda Creek Watershed hosted over a dozen native fish species. Although anadramous species are no longer able to access the upper reaches of the watershed due to downstream barriers, other native fish – like riffle sculpin, hardhead and rainbow trout – still utilize these creeks.
Geology and HydrologyThe northern section of the Upper Alameda Creek Watershed is comprised of steep hills and deep canyons in the rural areas which give way to the Livermore, Amador and San Ramon Valleys. This topography was largely created by the Calaveras fault, which runs from Danville to the area south of the Calaveras Reservoir. Many of these steep slopes are comprised of soil types that are prone to erosion, which can lead to increased runoff and sediment within streams in large storm events or if the land is not managed properly. (Learn more about the different soil types found in the watershed here.)As with many other watersheds throughout the Bay Area, hydrology in the northern section of the Upper Alameda Creek Watershed shows high seasonal variation and periods of drought, with groundwater levels and stream flows high during the rainy winter months and significantly lower during hotter months in the summer and fall. Flows in many creeks are not even visible during these summer months, retreating below ground and resurfacing upon reaching larger streams. The well-draining soils in the valleys drain rain and creek water and recharge large groundwater basins that lie beneath the Livermore Valley. Additional recharge is planned to occur as the use of the gravel mining pits within the Chain of Lakes subwatershed is shifted to stormwater detention, and surface water storage and conveyance.
Major IssuesThe largest issue in this portion of the Upper Alameda Creek Watershed is the rapid growth of the urban and suburban areas of Dublin, Pleasanton and Livermore. Developed areas often contain large amounts of impervious surfaces, which reduce groundwater recharge and may increase contaminants and litter in surface water (such as creeks). Creeks flowing through urban areas are often channelized to control flows and alter stream location. Channelization, which often includes straightening a creek’s natural path, can reduce the amount of native riparian habitat along creek banks and create an environment that is inhospitable for native plants and animals.As with the rest of the Alameda Creek Watershed, dams create barriers for upstream fish migration to the northern section of the Upper Alameda Creek Watershed. This portion of the watershed is not currently accessible to steelhead, although this species was historically present and have been observed downstream from barriers.
The following information pertains to the northern section of the Upper Alameda Creek Watershed, which includes the following subwatersheds: Arroyo de La Laguna; Alamo Canal; Arroyo Mocho Canal; Arroyo Las Positas; and Chain of Lakes. To download a printable PDF map, click on the subwatershed name.Preliminary Lake Use Evaluation for the Chain of Lakes that discusses the uses and future plans for the Chain of Lakes in great detail.
The following information pertains to the northern section of the Upper Alameda Creek Watershed.
Parks and Recreation
Streambank Restoration and RevegetationZone 7 Water Agency works in conjunction with other agencies and organizations including the Alameda County Flood Control and Water Conservation District, Alameda County Public Works, San Francisco Public Utilities Commission, the Alameda County Conservation Partnership, Living Arroyos, and cities within the Tri-Valley area to improve stability and native habitat along stream banks throughout the northern section of the Upper Alameda Creek Watershed. These projects range in scale and include a wide variety of structural, vegetative, and management activities. Some involve moving full-sized trees and boulders to better manage high water flows in major creeks like the Arroyo de la Laguna, while others involve work to improve slope stability along urban canals by planting native grasses. A number of projects have focused on planting native trees along the banks of streams throughout the watershed, which will help keep streams at the correct temperature and provide habitat and food for native animals.
Native Habitat RestorationA variety of organizations and agencies engage regularly in large and small scale habitat restoration efforts throughout the northern section of the Upper Alameda Creek Watershed. Such efforts include creating wetland areasthroughout the watershed (which were historically drained and removed causing a large-scale loss of this habitat in past centuries), allowing for needed water to flow into the unique habitat found in the Springtown Preserve alkali sink, and enhancing upland habitat that is home to special status species. Local agencies throughout this portion of the watershed are engaged in the East Alameda County Conservation Strategy, a large-scale planning effort which will help develop a long-term plan for habitat protection and encourage the implementation of conservation stewardship projects by landowners throughout the area to help offset impacts from local land use, transportation or other infrastructure projects.
South Decoto Green Streets ProjectNumerous agencies throughout Alameda County offer programs and educational materials targeted at reducing contaminants from urban centers, removing litter from creeks within this portion of the Upper Alameda Creek watershed, and preventing trash from entering streams and creeks. The Alameda Countywide Clean Water Program provides free information about ways the public can reduce contamination inputs to local creeks, public education campaigns about proper waste disposal, and shares volunteer clean up days for interested residents of Alameda County. A number of agencies operating in this portion of the watershed support the Adopt a Creek Spot Program, which allows participants to help improve water quality and aquatic habitat in neighborhood creeks through organized litter clean-up events. Alameda County also adopted an ordinance to limit the distribution of single-use plastic bags in groceries stores in 2013 and expanded the ordinance to retail and dining establishments in 2017. Plastic bags are one of the most common litter items found in our waterways and are a threat to the health of animals who use these creeks. Another effort to keep the creek clean are the construction of Green Streets, which capture, retain, and treat stormwater runoff from impervious services, such as roadways, parking lots, sidewalks, and rooftops.
Fisheries RestorationAs with many other watersheds in Alameda County, the Alameda Creek Watershed historically had healthy populations of anadramous fish – specifically, steelhead trout. Instream habitat quality throughout major portions of Alameda Creek has been limited by reduced instream habitat complexity and migration barriers. The northern watershed has been extensively altered by urban development and channel modifications. Nearly a dozen agencies and organizations work closely as the Alameda Creek Fisheries Restoration Workgroup to collaboratively address the local implications of the steelhead trout being placed on the federal Endangered Species List and pursue steelhead restoration. Numerous local agencies are also working directly with the National Marine Fisheries Service through a cooperative agreement on their preparation of a Recovery Plan to address steelhead recovery throughout the Bay Area, including a specific vision for steelhead restoration in the Alameda Creek Watershed. As part of Zone 7 Water Agency’s efforts to restore steelhead populations, fish ladders have been installed along both the Arroyo las Positas and Arroyo Mocho.
Resources in the Watershed
- Alameda Countywide Clean Water Program
- Alameda County Resource Conservation District
- Alameda Creek Alliance
- Alameda Creek Watershed Forum
- Oakland Museum of California’s Guide to Bay Area Creeks
- East Bay Regional Park District
- Living Arroyos
- San Francisco Public Utilities District
- Livermore Area Recreation and Parks District
- Tri Valley Creeks Adopt a Creek Spot
- City of Pleasanton
- City of Dublin
- City of San Ramon
- City of Livermore
- Zone 7 Water Agency
- Friends of Springtown