Explore Watersheds

Interactive Map: Alameda County Watersheds

There are many different watersheds throughout Alameda County that overlap within cities and subregions. In order to make these watersheds easy to find and understand, The Alameda County Flood Control and Water Conservation District created full-featured, interactive maps of every watershed in the county.

Each shaded area on the map denotes a different watershed. Hover over any shaded region to see its name and click on that name to see logistics such as where the watershed flows and how many miles it covers. Click on “Learn More” to read more in-depth information about each watershed, such as information about geology, hydrology, creeks, trails, and parks; to view a more detailed map; or to read about current restoration efforts and volunteer opportunities. A PDF of each water shed is available to download in each of these informational sections.

We recommend using Chrome, Safari, Firefox, or Microsoft Edge to use the interactive map. Older browsers (especially Internet Explorer) may fail to load map features.

Alameda County Watersheds on Google Earth

If you are interested in downloading these interactive watershed map files via Google Earth (KMZ files), you must have Google Earth Pro downloaded to your computer or electronic device. Using Google Earth Pro, you can download either of the following watershed maps:

District Act 205

The Alameda County Flood Control & Water Conservation District was created in 1949 when the state legislature passed Act 205 of the California Uncodified Water Code. Act 205 defines the District’s role in providing for the control and conservation of flood and storm waters.Under Act 205, the District is authorized to protect all waterways, watersheds, harbors, and public highways, in addition to lives and property, from damage or destruction caused by flood and storm waters throughout the District.

The District is also authorized to prevent water waste and diminished water supply, or exportation of water from the District. It may use conserved water—obtained from drainage, storm, flood, or other means—for beneficial purposes.

Act 205 authorizes the District to sell bonds and to levy and collect taxes and assessments needed to fund its mandate in the District.

Act 205 of the California Uncodified Water Code
Act 205 of the California Uncodified Water Code

Pertinent Ordinances, Regulations, and Guidelines

Pertinent Regulations

The California Regional Quality Control Board was founded to preserve, enhance, and restore the quality of California’s drinking water and water resources. To read more about the Federal Clean Water Act (CWA), visit the California Regional Quality Control Board website. The most recent Municipal Regional Stormwater NPDES Permit for the entire San Francisco Bay Region can be found on the CA Regional Water Quality Control website (most recently renewed in 2015).


Below are several guidelines from the Alameda County Public Works Agency regarding construction within the county.

Building on or Near Creeks

if a creek or waterway runs through your property, you are responsible for complying with all applicable regulations. Construction, erosion repair, and planting on your property may all require a planning process and permit.Local requirements vary in each county and sometimes within each city. Please contact your city (or Alameda County Public Works agency, for properties in Unincorporated Alameda County) before beginning any project that may affect the waterway. Visit the Alameda County Community Development Agency’s Planning Department website to learn more. For more information, view or download the Guide to Watershed Project Permitting for the State of California. This and other helpful information can be found on the California Association of Resource Conversation Districts (CARCD) website.The following is a brief description of regulatory agencies you may need to consult for your project. California Department of Fish and Wildlife (CDFW) If your project may potentially impact any State-listed endangered or threatened species, in pursuant with the California Endangered Species Act, you must consult with the CDFW. State regulations require that you notify the CDFW if any proposed activity will:
  • Substantially divert or obstruct the natural flow of any river, stream, or lake
  • Substantially change or use any material from the bed, channel, or bank of any river, stream, or lake
  • Deposit or dispose of debris, waste, or other material containing crumbled, flaked, or ground pavement where it may pass into any river, stream, or lake

California State Water Resources Control Board
Water diversions from creeks are only legal if you have an official Riparian Right, an Appropriative Water Right Permit, or a Small Domestic Registration. To find more information about water rights and permits, please visit the California Water Board website.

Regional Water Quality Control Board
The Federal Clean Water Act (CWA) Section 401 Water Quality Certification is required for any activity that may result in a discharge into any waters in the United States, including flood control channelization, channel clearing, and placement of fill.

U.S. Fish and Wildlife Service
You must obtain an Incidental Take Permit for any building projects that might result in hunting, harming, harassing, pursuing, shooting, wounding, killing, capturing, or collecting a listed species.

Army Corps of Engineers
The U.S. Army Corps of Engineers has permitting authority over activities affecting waters of the United States. Waters of the United States include surface waters such as navigable waters and their tributaries, all interstate waters and their tributaries, natural lakes, all wetlands adjacent to other waters, and all impoundments of these waters. Please visit the US Army Corps of Engineers, San Francisco District website for permitting and other useful information.

Annual Reports & Publications

2022-23 Annual Report
2019-20 Annual Report
2017-18 Annual Report
2017-18 Annual Report
2016 Annual Report Microsite
2016 Hydrology & Hydraulics Manual
2014-15 Report to the Community
2012-13 Report to the Community
2011-12 Report to the Community
2010 Report to the Community
2008-09 Report to the Community
2007 Report to the Community
2006 Report to the Community
2005 Report to the Community
2004 Report to the Community
2002-03 Report to the Community
2001 Report to the Community
2000 Report to the Community

Other Publications

Photo Gallery

The Alameda County Flood Control & Water Conservation District is pleased to offer the images in this photo gallery to the public for educational, nonprofit, and/or personal fair use. Unless otherwise noted, users may download or print the image files from this photo gallery without permission from the Alameda County Flood and Water Conservation District or the Alameda County Public Works Agency, provided the fair use conditions are met.

Please note that these images and photos cannot be used for commercial purposes.


Culvert: A drainage pipeline located underground.

Floodplain: The area near a creek that is naturally subject to flooding.

100-Year Flood: A significant flood that has a 1-in-100 chance of occurring in any given year (also called a 1 percent flood).

Infrastructure: A system of built structures and facilities that serve a central purpose, such as flood control.

Line: Another term for a creek or flood channel. For example, Mission Creek is called “Line L” by District staff.

Pump Station: A facility that lifts stormwater after it is collected in channels, creeks, and pipes to an elevation high enough to allow the water to flow by gravity into San Francisco Bay.

Tide Gate: A concrete culvert with a flap on one end that can be controlled to allow tidewater in or out of a channel.

Watershed: The region drained by a creek, river, or man-made drainage system, such as a culvert or channel.

Wetland: Land, characterized by particular soils and vegetation, that is often or always underwater and may serve as a natural habitat.

Zone: Administrative area designated by the local Flood Control District for flood control system design and maintenance.

Frequently Asked Questions

A floodplain is a land area near a river or creek that floods periodically.

The Federal Emergency Management Agency (FEMA) carries out emergency management programs that help communities nationwide prepare for disasters such as hurricanes and floods and helps respond to their aftermath.

In order to reduce potential flood damage, FEMA studies hydrologic and hydraulic information to identify areas that are likely to flood. FEMA determines flood risk and creates a floodplain map for every region.

Areas with a 1 percent chance or more of flooding in any one year are in a 100-year floodplain (in other words, the area is expected to flood at least once in a 100-year period). These 100-year floodplains are mapped as Special Flood Hazard Areas.

Flood Insurance Rate Maps (FIRMs) identify Special Flood Hazard Areas and are used to identify flood insurance requirements for an area. Although a 1-in-100 chance of flooding each year may seem remote, the likelihood of flooding increases over the life of a typical 30-year mortgage. Lenders require flood insurance for homes located in a Special Flood Hazard Area.

The National Flood Insurance Program, administered by FEMA, provides affordable flood insurance to protect against both private and public structures. This insurance is available to communities that meet FEMA’s requirements to reduce flood risk. The Alameda County Flood Control and Water Conservation District, in corporation with the county and its cities, complies with these requirements.

Rain flowing downhill collects in flood control channels and natural creeks, which traverse low-lying communities to the San Francisco Bay. Once rainwater reaches low-lying shoreline and residential areas, the Flood Control District’s 22 pump stations help “lift” the water so that it is discharged into the Bay. The work of pump stations is especially important in periods of high tide, when Bay water levels are higher than the level of flood control channels.
Most of the District pump stations were built by individual cities and then turned over to the District for operation and maintenance. Due to each city’s variations in specifications and design, each pump station varies in design and size. Keeping pump stations in good working order requires time, expertise, and carefully planned preventive maintenance.

All District pump stations are monitored using Supervisory Control and Data Acquisition (SCADA). SCADA systems save time and money by alerting District staff to malfunctions quickly and efficiently. District staff also use SCADA to review long-term equipment use and efficiency data to improve overall station performance. Trend data can be used for improved engineering when replacing or rehabilitating District pump stations.

The District’s Maintenance and Operations field crews regularly inspect and clear obstructions from more than 330 miles of creeks within the District’s jurisdiction. Each year, thousands of cubic yards of debris, from shopping carts to mattresses, furniture, and other trash, are removed from waterways. Cleaning out the creeks is time-consuming and expensive.

Some vegetation that poses a fire hazard and/or obstructs stormwater flow must also be removed. Typically, removal is done by hand, through natural biological means (such as by goat grazing), or by the application of herbicides.
The public can help lower the cost of removing trash and its resulting damage to natural waterways by remembering the motto “Only rain in the drain.” The less litter we have in our communities the healthier and safer our waterways will be.

For more information on the importance of keeping natural waterways clean, visit our Pollution Prevention page or the following websites:

Any technology that employs plants and other natural materials and processes is referred to as bioengineering. The Flood Control District uses bioengineering to reinforce and stabilize creek banks so that waterways remain open and silt deposits are minimized downstream.
Using native plants and natural materials such as tree stumps and rock can lower construction costs. Maintenance costs, however, are usually higher because living materials require trimming and other care.
Some specific bioengineering techniques that the District uses are:

  • Live crib wall – Logs placed in an interlocking pattern and planted with cuttings.
  • Rootwads – Logs, with their root ball still attached, installed into a creek bank.
  • Tree revetment – Trees anchored along a bank for reinforcement.
  • Soil lifts – Layers of coconut fiber wrapped in soil and anchored on the creek bank.

Overall, natural materials are the favored choice. They blend into creekside environments and are likely to thrive once work is completed because they are already acclimated to local soil conditions.

Other Outside Resources

The Alameda County Flood Control District works with many organizations and experts throughout the Bay Area to ensure that we are doing the most efficient and environmentally conscious work that we can in order to keep our waterways clear and to reduce the risk of flooding in Alameda County. Below are some of the organizations we connect with regularly and who provide other helpful resources.

The Association of Bay Area Governments (ABAG) has several wonderful maps. Curious to see where the Bay Trail goes? Would you like to see the Water Trail map? Or even Map of the Month? ABAG has these resources and more.

  • San Francisco Bay Regional Coastal Hazards Adaptation Resiliency Group (CHARG)
    CHARG is an organization of flood control managers and scientists responsible for advancing the technical, scientific, and engineering analysis needed to implement adaptation projects and build resilience to sea level rise and climate change.

  • East Bay Regional Park District
    The Alameda County Flood Control District licenses many of its creek-side and lake-side properties to the EBRPD to manage as recreational facilities for the public’s enjoyment. Click on any park listed to find information about location, hours, programs, and more.

  • Federal Emergency Management Agency (FEMA)
    Find flood maps and information about flood preparedness and aftermath.

  • Alameda Creek Alliance
    The Alameda Creek Alliance is a volunteer-based community watershed group working to restore native steelhead trout to Alameda Creek.

  • Friends of San Leandro Creek
    A community group of dedicated citizens, students, and businesses interested in San Leandro Creek’s ecology, protection, and enhancement.

  • Friends of San Lorenzo Creek
    A nonprofit organization dedicated to the health and preservation of the San Lorenzo Creek system and watershed.
  • Friends of Sausal Creek
    The Friends of Sausal Creek are volunteers working to maintain and improve the Sausal Creek watershed in Oakland. Their website features news, events, creek history, maps of hiking trails, and volunteer opportunities.

  • Piedmont Avenue Neighborhood Improvement League (PANIL) – Glen Echo Creek
    Glen Echo Creek surfaces from underground in two Oakland parks: Glen Echo Park and Oak Glen Park. PANIL is working with the District to plan and repair bank erosion, while volunteers work to retain the creek’s natural environment.

  • Tule Ponds at Tyson Lagoon Wetland Center
    Scenic wetlands and ponds provide flood protection and pollution control for stormwater flowing to the bay. The ponds serve as a habitat for migratory birds, as well as an area for wildlife and wetland study through the Wetland Center, managed by the Math/Science Nucleus. School field trips are welcomed year-round.

  • The Watershed Project – East Bay, Alameda County
    The Watershed Project provides innovative programs in three areas: workshops for educators and the general public; support for creek protection groups; and a marsh and grassland restoration project that incorporates community support and education.

  • Zone 7 Water Agency
    Zone 7 manages the water supply, treats drinking water, and sells treated water to local retail water agencies that serve the public in the Livermore-Amador Valley. Zone 7 also manages flood control for Eastern Alameda County.

  • The South Bay Salt Pond Restoration Project
    The South Bay Salt Pond Restoration Project is the largest tidal wetland restoration project on the West Coast, including the Eden Landing Ecological Reserve in Hayward and Union City.