Napa Resource Conservation District

In March 1999, the CIWMB  (now known as the Department of Resources Recycling and Recovery or CalRecycle) awarded contracts to two partnerships in the Napa/Sonoma area to demonstrate the effectiveness of mulch on hillside erosion control in vineyards. Both groups spread mulch made from yard trimmings on hillside vineyards in the winter of 2000 and monitored erosion after each major storm event until May 2001. The partnership headed by the Napa Resource Conservation District (RCD), which received $99,148 in project funding, applied mulch within the vine row and cover crops and was used between vine rows. Members of this partnership provided matching funds in excess of the contract funding. 

An article from August 1999 Wine Business Monthly discusses the studies and the importance of erosion control in hillside vineyards.


  • Develop markets for mulch made from municipal yard trimmings.
  • Increase the use of mulch in agriculture.
  • Create public/private partnerships that will produce meaningful and credible study results.

Partnership Organization

  • Fiscal Agent: Napa RCD.
  • Contract Manager: Will Bakx, Sonoma Compost.
  • Key Partners: Napa RCD, Sotoyome RCD, University of California Cooperative Extension, USDA– NRCS, Sonoma Compost, Napa Garbage Company, and the City of Napa.
  • Participating Vineyards: Beringer Wine Estates, Walsh Vineyards Management, Iron Horse Vineyards, and Everett Ridge Vineyards.

Project Components

  1. Partnership Development and Implementation of Work Plan. The partnership team met periodically and developed a detailed work plan for evaluating the use of mulch for erosion control in vineyards. Erosion control was monitored through the spring of 2001.
  2. Development and Dissemination of Information. During the course of the contract, the partnership team developed and disseminated news releases, fact sheets, and other outreach materials.
  3. Coordination of Field Days and Workshops. The partnership conducted at least two field days or workshops while work is in progress and at least one workshop for wine-grape growers at the conclusion of the demonstration.
  4. Project Evaluation. Throughout the project, the team evaluated soil loss and changes in the physical properties of the soil.
  5. Submission of Quarterly and Final Reports. Quarterly reports convey project progress while the final report summarizes project protocol and findings.


  • Demonstrate the value of mulch for hillside erosion control in vineyards, specifically within the vine row.
  • Disseminate the results of the demonstration project to wine-grape growers in Napa and Sonoma counties.