Contra Costa County Flood Control District / Muir Heritage Land Trust / East Bay Regional Park District
Contra Costa County
Public or private land?
depends on funding
two years after funding received
Property located north of Waterfront Road, west of Walnut Creek Channel, east of I-680, and south of Suisun Bay. It is directly adjacent to the mouth of Walnut Creek.
The Pacheco Marsh Restoration project will restore tidal action to a previously diked and filled 123 acre parcel at the mouth of Walnut Creek. It will create quality habitat for endangered species and provide a staging area and trail linkages to the Delta DeAnza Trail and the Iron Horse Trail.
This restoration project will restore tidal action to a previously diked and filled 123 acre parcel at the mouth of Walnut Creek. It will create quality habitat for endangered species and provide a staging area and trail linkages to the Delta DeAnza Trail and the Iron Horse Trail. Finally, it will improve flood protection for the area by reconnecting the floodplain to the channel and by providing storage and conveyance areas for flood flows.
Drinking Water Supply
Water Quality Improvement
Habitat Protection and Restoration
The Pacheco Marsh Restoration covers many project types:
It provides flood flow conveyance and storage (Flood Protection).
It converts a diked and filled site into one that has 69 acres of high quality wetlands (Habitat Protection and Restoration).
By creating wetlands and providing flood storage volume, it encourages infiltration (Infiltration and Groundwater Benefits)
The creation of tidal marsh habitat restores natural biological processes and results in water quality benefits (Stormwater Improvements)
This project has good integration of flood protection and habitat. There is a CCCSD Sanitary Sewer outfall bisecting the site. There may be opportunities to further integrate with the Wastewater and Recycled Water functional area.
The site includes a staging area for two regional trails. Opportunities exist for LID design features of the parking lot, especially with wetlands being created directly adjacent.
Part 2 - Detail
The Pacheco Marsh Restoration will take a heavily degraded, diked and filled former tidal wetland at the mouth of Walnut Creek and restore it into a tidal marsh. The preferred restoration alternative will create approximately 69 acres of tidal marsh, 12 acres of transtitional habitat, and 42 acres of upland habitat (18 acres of which will consist of a parking / staging area and a utility easement).
The CCC Flood Control District has partnered with the Muir Heritage Land Trust and the East Bay Regional Park District in the initial acquisition and planning efforts for this site. The site is located directly adjacent to the Flood Control District's Lower Walnut Creek project site, and also at the future intersection of two major regional trails. There is great potential for habitat creation as well as public education.
The site will have balanced grading to avoid import or export of material from the site. The newly graded areas will be reconnected to tidal flows from both adjacent Suisun Bay and Lower Walnut Creek. The marshplain areas will consist of brackish marsh through graded, dendridic channels.
Pacheco Marsh Restoration Plan Final Report, PWA, 2004 is available at:
The Pacheco Marsh property has been filled, scraped, bisected, degraded and thoroughly abused by its previous owners. Quality salt marsh habitat has been eliminated. There is an abandoned sand processing site and weigh station that partially encroaches onto the parcel. Trash and abandoned cars and boats are sometimes left along the Waterfront Road entrance to the site. This project will change that.
The site is adjacent to higher quality wetland habitats that is home to ten special status plant and animal species including the Salt-marsh harvest mouse. This project is needed to better serve these special status species, as well as to provide interpretative opportunities for school groups and the public. The special partnership that has been forged between the regional flood control district, the regional park district and the local land trust has the expertise to satisfy this need.
If this project is not implemented, the site will continue to exist in a heavily degraded state and restoration will not occur. The connection of two regional trails will not occur.
Note that for planning purposes, the project his broken up in four quadrants, which can be phased depending on funding. This allows the project to be scalable.
i. Water Supply (conservation, recycled water, groundwater recharge, surface storage, etc.)
The creation of wetlands will assist in ground water recharge.
ii. Water Quality
The creation of wetlands will provide treatment of stormwater, especially when it overflows from adjacent Lower Walnut Creek, improving water quality before discharge into Suisuin Bay.
iii. Flood and Stormwater Management
The restoration of Pacheco Marsh will connect a floodplain to the adjacent channel and provide flood conveyance and needed storage during high flows. Currently the site is poorly protected from flooding by a low levee. The restoration would breach or remove this levee, acknowledging the low residual flood risk of the site.
iv. Resource Stewardship (watershed management, habitat protection and restoration, recreation, open space, etc.)
An important objective of the project is creation of habitat and restoration of ecosystem types that had historically existed on the site, but have long since been destroyed. The project includes a park staging area, recreational trails, and public education.
Portions of Martinez a mile west of the site are considered disadvantaged.
Increases Water Supply Reliability
Advances/ Expands Conjunctive Management of Multiple Water Supply Sources
Increases Water Use and/or Reuse Efficiency
Provides Additional Water Supply
Promotes Water Quality Protection
Reduces Water Demand
Advances/Expands Water Recycling
Promotes Urban Runoff Reuse
Addresses Sea Level Rise
Addresses other Anticipated Climate Change Impact (e.g. through water management system modifications)
Improves Flood Control (e.g. through wetlands restoration, management, protection)