Suisun Creek Watershed Program
The Suisun Creek watershed encompasses 53 square miles in Napa and Solano counties. Three major creeks—White Creek, Wooden Valley Creek, and Suisun Creek—drain a watershed of steep, mountainous terrain and several large valleys into the Suisun Marsh and Suisun Bay. Steelhead trout (Oncorhynchus mykiss), a federally listed threatened species, have been found in the three main creeks of the watershed. This watershed has been named one of the primary “anchor” watershed streams with essential habitat for steelhead trout in the Bay area (CEMAR 2007). The City of Vallejo owns and operates the 10,000 acre-foot Lake Curry located on the northern end of Suisun Creek. Land use in the watershed is almost entirely rural: cattle grazing and irrigated agriculture consisting of winegrapes, fruit and nut orchards and row crops. The watershed has no urban areas.
In 2001 the California Sportfishing Protection Alliance (CSPA) working with Laurel Marcus & Associates (LMA) received a grant from the California State Coastal Conservancy to prepare a watershed enhancement plan for the Suisun Creek watershed. Water temperature, water quality, and geomorphic monitoring were carried out between 2001 and 2003. Mapping of riparian forest and field studies of aquatic habitats was also completed. Extensive landowner outreach was also completed. The Enhancement Plan identified a number of priority actions and projects including:
- Restoring riparian forest on denuded channel areas to reduce water temperatures
- Eradication of invasive species in the riparian corridor to enhance the corridor and reduce water temperatures and create wildlife habitat
- Giant Reed (Arundo donax) mapping, eradication strategy and implementation of removal projects
- Native riparian revegetation and invasive plant removal projects
- Reducing fine sediment in creeks and improving land management measures using:
- Farm Conservation Planning through the Fish Friendly Farming program
- Community workshops for rural residential landowners
- Evaluation of Lake Curry releases to enhance cold water habitat in Suisun Creek
- Continued monitoring to identify additional needed projects and limiting factors for steelhead trout
In 2004 CSPA, working with LMA, received a grant from the CALFED Watershed Program for implementation of the recommendations of the watershed plan. In 2007 the Californian Land Stewardship Institute took over the Suisun Creek watershed program and received a variety of grant funds to implement the priorities of the watershed plan.
As of April 2012 the following projects have been completed or are underway:
- Arundo removal and revegetation with native plants on 5 miles of Suisun Creek; ongoing removal is occurring on an additional 9 miles of Suisun Creek.
- Removal of other invasive plants on all three creeks with installation of approximately 2,300 native plants and revegetation along three miles of Suisun and Wooden Valley Creeks; ongoing revegetation of White Creek.
- An estimated 1,133 tons of sediment/year have been reduced through the implementation of BMPs on 3700 acres of agricultural lands enrolled in the Fish Friendly Farming Environmental Certification Program.
- Survey for steelhead trout juveniles and predatory warm water fish species
- Workshops for rural residents to reduce pollutants;
- Workshops for farmers and ranchers on riparian revegetation and creek corridor management
- Development of an engineering model to evaluate re-operation alternatives for Lake Curry with recommended next steps for implementation.
- Ten years of monitoring of water quality and water temperature at 34 stations on Suisun Wooden Valley and White Creeks
- A 3month experiment involving monitoring of water temperatures at 16 stations and stream flow at 2 stations on Suisun Creek under various rates of water release from Lake Curry to evaluate effectiveness of Lake Curry releases on reducing water temperatures for steelhead trout.
- Monitoring over a 10-year period of bed composition, channel form, gravel permeability and aquatic insects.
- Quantitative assessment of riparian canopy cover for six miles of Suisun Creek
- Quantitative assessment of erosion and sediment delivery along the primary public roads in the watershed including evaluation of all culverts.
CLSI continues to implement the watershed plan and move forward with additional projects and programs.