Capay Valley Riparian Vegetation Management Program

(funded by the CA Wildlife Conservation Board 2005-2009).

The Cache Creek watershed and riparian corridor hosts a wealth of wildlife and native habitat as it winds through publicly and privately managed wildlands and farmlands. While impressive bands of riparian and upland habitat remain along the section of creek that runs from the Yolo-Colusa county line to the Capay Diversion Dam, the habitat is significantly impacted by the dense stands of highly invasive Tamarisk (Saltcedar) and Arundo (Giant Reed). 

These stands completely displace native wildlife-friendly vegetation in some places, and exacerbate streambank erosion and flooding by constricting and deflecting flow in many locations on the creek.  As a result, many landowners have lost substantial acreage to the erosion, which has decreased valuable riparian habitat, farmable area and land supporting structures such as homes. 

Considerable effort and funding has already been directed towards managing these Tamarisk and Arundo infestations throughout much of the watershed.  The Bureau of Land Management is working on these weeds in Colusa and Lake Counties, and the Cache Creek Conservancy is doing an exceptional job removing infestations in the lower watershed.    The nearly untreated 33 mile middle stretch between the Yolo-Colusa county line and the Capay Dam, not only compromises the wildlife values and stability of the creek banks in Capay Valley, but also threatens the viability of the control work on the lower Cache Creek, by serving as a nursery of seeds, stems and rhizomes to re-infest sites downstream.

Treatment of this ‘missing link’ in the chain of riparian weed management and revegetation along Cache Creek represents an opportunity to not only enhance the viability of existing work and protect the resources of Cache Creek in Capay Valley, but to fully coordinate upstream and downstream vegetation management work as a unified watershed effort, ultimately the most logical and likely successful approach. The Wildlife Conservation Board is funding this important project to control Tamarisk, Arundo and Ravenna Grass along the creek.

A confluence of skills, relationships and opportunities has created an opportunity for successfully conducting weed management and restoration work in the Capay Valley:

• We have a high percentage of willing landowners along the creek who want to work with us.  The Yolo County Resource Conservation District (YCRCD) will assist by providing resources and institutional support with permitting and management techniques.
• The USDA Agricultural Research Service (USDA ARS) has focused years of research on the weed populations on Cache Creek and integrated control methods for Tamarisk. This includes two biological control test sites in the Capay Valley using the Tamarisk leaf beetle. They are committed to continuing this work in the future.
• The Cache Creek Conservancy has developed a highly successful model for landowner relations and Tamarisk and Arundo control on the section of creek immediately downstream of Capay Valley and is eager to lend expertise to support upstream work.
• Through watershed coordination support from the YCRCD, the Cache Creek Watershed Stakeholders Group (CCWSG) has developed a Capay Valley Watershed Stewardship Plan (CCWSG & Yolo RCD, 2003) that identifies Tamarisk and Arundo control along Cache Creek and its tributaries as a primary goal.
• The YCRCD has considerable institutional and staff expertise in weed management, native plant revegetation, and program management for private land conservation work.
  

We have secured the interest of over 30 willing private and public landowners representing more than 65 properties along Cache Creek and two tributaries in Capay Valley.  We are also coordinating with every other organization currently conducting vegetation management work in the watershed.  Part of this coordination is to develop a watershed-wide strategic plan for managing Arundo and Tamarisk and other riparian weeds. Through site visits, questionnaires and aerial survey analysis (supplied by USDA ARS) we have categorized major infestations along the creek and on the properties of cooperating landowners in terms of degree of infestation, related erosion, interest in revegetation and control.

Over the course of this project, we expect approximately 130 acres of creek will be treated in phase one, and a total of 760 acres over the life of the entire project. This number may increase due to increasing participation over time.  Restoration will be conducted on 20 acres in phase one, and a total of 150 acres during the larger project.

Capay Valley Watershed Coordination Projects

With funding provided by the California Department of Conservation Watershed Coordinator Program and the CALFED Watershed Program, the Yolo County RCD was able to hire a watershed coordinator in April 2001 to work primarily in the Cache Creek watershed. The position is currently funded through December 2007. While working towards the larger goal of providing a hub for Cache Creek Watershed information and creating a Cache Creek Watershed Network, the watershed coordinator focuses attention on working with the Cache Creek Watershed Stakeholders Group.

The Cache Creek Watershed Stakeholders Group formed in 1996 and has evolved into a locally-led, community oriented watershed group that is focused on the Capay Valley reach of Cache Creek.

Current issues of concern to the Stakeholders Group include:

•  Streambank erosion along Cache Creek and its tributaries;
•  Eradication and/or management of invasive plants such as Tamarisk, Arundo, and Yellow starthistle throughout Capay Valley;
• Investigating the effects of mercury in Cache Creek on wildlife and humans;
• Improving the current permitting system so that it does not serve as a hindrance to watershed restoration and management activities.

The Stakeholders Group’s vision is of “[a] healthy Cache Creek watershed with balanced uses of the natural environment for human benefit and conservation of local resources.”

Capay Valley Watershed Documents

The group has now completed a Capay Valley Watershed Stewardship Plan  (check our Resource Library folder to read or download  full document).

 The RCD has  also completed the Capay Valley Resource Conservation and Restoration Manual (check our Resource Library folder to read or download  full document) as a companion document. The Manual is an easy-to-use collection of resource conservation and restoration practices and provides project planning guidance for landowners.

This manual can also be purchased from the RCD  by contacting Sheila Pratt at (530) 662-2037 extension 117.