The Land Steward’s Guide to Vineyard and Orchard Erosion Control Sonoma County Department of Agriculture/Weights & Measures 133 Aviation Boulevard, Suite 110, Santa Rosa, CA 95403 Phone: (707) 565-2371 Fax: (707) 565-3850 Website: www.sonomacounty.ca.gov/AWM The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 2 Acknowledgements This Guide was prepared by the Land Stewardship Division of the Sonoma County Department of Agriculture/Weights & Measures. It is a collective creation made possible by past and present staff whose contributions, insights, and perspectives have coalesced into The Land Steward’s Guide to Vineyard and Orchard Erosion Control. It is also a recompilation of existing material from numerous sources. We are deeply grateful to contributors, practitioners, and agencies who shared freely of their expertise and time. We thank the following reviewers for their thoughtful comments: North Coast Regional Water Quality Control Board Sonoma Resource Conservation District Russian Riverkeeper LACO Associates University of California Cooperative Extension We gratefully acknowledge the previous works of these Resource Conservation Districts (RCD): Sonoma RCD Goldridge RCD Napa County RCD RCD of Monterey County Marin RCD Upper Salinas – Las Tablas RCD This publication was supported by the U.S. Department of Agriculture’s (USDA) Agricultural Marketing Service through Grant 15-SCBGP-CA-0046. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the USDA. Contact Sonoma County Department of Agriculture/Weights & Measures 133 Aviation Boulevard, Suite 110, Santa Rosa, CA 95403 Phone: (707) 565-2371 Fax: (707) 565-3850 Email: [email protected] Website: www.sonomacounty.ca.gov/AWM Disclaimer The information provided in this Guide is to assist vineyard and orchard operators on general principles of erosion control. Use of this information does not relieve the user of the obligation to comply with other federal, state, or local laws and regulations, or from liability for damages against the County of Sonoma and its contractors, and agree to indemnify the County of Sonoma and its contractors from and against any claims, suits, or liabilities arising out of activities undertaken based on this material. Cover photo: Jordan Vineyard and Winery, Healdsburg, CA. The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 3 CONTENTS Acknowledgements 2 Contact 2 Disclaimer 2 Introduction 7 How to Use this Guide 7 The Need for an Erosion Control Guide 7 Erosion of Livelihood 8 Farm Planning and Erosion Control 8 Developing an Erosion Control Plan 9 Chapter 1: General Principles of Erosion Control 13 The Erosion Process 13 Types of Erosion 13 Factors Influencing Erosion 14 Land Use and Land Management Practices 15 Typical Causes of Erosion 17 Chapter 2: Managing Surface Erosion from Cultivated Areas 21 Irrigation 21 Source Controls 22 Treatment Controls 26 The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 4 Chapter 3: Managing Sediment Delivery from Roads 29 Roads vs. Avenues 29 Hydrologic Connectivity of Roads 29 Determining the Drainage Break 30 Reducing Hydrologic Connectivity Along Road Networks 30 Road Maintenance Best Management Practices 31 Chapter 4: Managing Stormwater Runoff 36 Runoff Management 36 Best Management Practices for Stormwater 37 Chapter 5: Managing Gullies and Shallow Landslides 40 Gully Formation 40 Shallow Landslides 40 How to Prevent Gullies and Shallow Landslides 41 How to Repair Gullies and Shallow Landslides 42 Bioengineering for Gullies 43 Chapter 6: Pollutant Control – Managing Pesticides 44 Basic Integrated Pest Management Principles 44 Integrated Pest Management Considerations 45 Best Management Practices for Pesticides 45 Chapter 7: Pollutant Control – Managing Nutrients 48 Determining Nutrient Needs of the Plant 49 Fertigation 50 Storing and Mixing Fertilizers 50 Use of Backflow Prevention Devices 51 Establishing Vegetative Barriers to Filter Runoff 51 The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 5 Chapter 8: Winterization and Sustainable Maintenance 52 Winterization 52 Riparian Areas and Streams 52 Monitoring and Maintaining Best Management Practices 53 Vineyard Waste 53 Glossary 54 Additional Resources 57 References 61 Image Credits 65 Appendix 1: Best Management Practices Selection Matrix 70 Appendix 2: Surface Erosion Control 71 Cover Crop 72 Straw Wattle/Fiber Roll 75 Mulch 77 Filter Strip 79 Hedgerow 81 Erosion Control Blanket 82 Straw Bale Sediment Trap/Check Dam 84 The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 6 Appendix 3: Road Best Management Practices 86 Reshaping the Road Surface 87 Rolling Dip/Critical Dip 91 Waterbar 94 Water Deflector 97 Channel Drain 98 Trash Rack 99 Appendix 4: Stormwater Runoff 101 Vegetated Swale/Grassed Waterway 102 Retention Basin 106 Diversion Ditch 107 Silt Fence 110 Engineered Drainage 112 Energy Dissipater 113 Appendix 5: Gullies 115 Headcut Repair 116 Rock Check Dam 120 Brush Layering 122 Willow Wattle/Wall 124 Live Willow Staking 127 Typicals for Gully Repair 129 The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 7 Introduction The Sonoma County Department of Agriculture/Weights & Measures established the Land Stewardship Division (Division) in 2015 to effectively manage several Sonoma County environmental programs and to meet increasing environmental regulations. The Division administers the largest of these programs, the Vineyard/Orchard Erosion and Sediment Control Ordinance (VESCO), a permit process which serves to sustain the agricultural community while protecting water quality, natural resources, and protected species. Through VESCO, the Division is working to assist the agricultural community in meeting State Water Board waste discharge requirements by leveraging ongoing practices designed to protect water quality. To further these efforts, the Division has produced The Land Steward’s Guide to Vineyard and Orchard Erosion Control (Guide). The purpose of this Guide is two-fold: To help landowners and land managers understand erosion processes To describe practices for repairing small-scale erosion problems common to agriculture The Guide has compiled pre-existing information about approaches and techniques for managing runoff from farmland and is intended to be improved upon as science and experience develop better stewardship tools. This Guide is intended to serve as a tool for voluntary, self-implementation of soil and water conservation practices. It is not the intent of this Guide to provide design criteria for engineered structures. If needed, third-party technical assistance in planning and implementation is available through your local Resource Conservation District, the Natural Resources Conservation Service, University of California Cooperative Extension, or any private consulting firm. How to Use this Guide To properly address runoff, a land manager must understand the fundamental processes of erosion, be able to correctly identify the source of the problem, and then select appropriate repairs. The Guide is designed to assist you with this methodology. Each chapter will cover important information to help you understand the source of your erosion. The appendices will assist in deciding how to effectively rectify the problem, maintain it, and achieve maximum effectiveness. The Need for an Erosion Control Guide Farms no longer have just a street address; they now have a watershed address. A watershed address represents the growers’ responsibility for eliminating offsite movement of soil, chemicals, and pathogens, therefore eliminating impacts on downstream water bodies, groundwater, and water users. Growers must understand that their farming decisions affect others in the watershed. There are numerous and serious environmental and economic costs of erosion. Erosion problems can include water pollution, loss of soil quality, increased flooding, degradation of habitat and loss of species, impairment of stream ecosystems, decreased groundwater storage, release of carbon, slope failures, and damage to downstream lands and properties, including the time and costs associated with addressing these issues. The Land Steward’s Guide to Vineyard and Orchard Erosion Control | 8 In addition to the harmful environmental impacts, soil erosion takes a huge toll on local and downstream economies. Accelerated accumulation of sedimentation in water impoundments and infrastructure poses unanticipated economic burdens necessitating costly cleanup and dredging programs. For the purposes of this Guide, however, it is the agricultural costs of erosion which warrant attention and action. Erosion of Livelihood Soil is one of the most critical resources on earth. As natural processes produce only one inch of soil every 500 ENVIRONMENTAL COSTS OF EROSION to 1,000 years, it is also a limited resource which, like Loss of hydrologic and ecosystem function. water, can be depleted and polluted. Initially, it is Loss of habitat. agricultural topsoil which is eroded. Topsoil, laden with the nutrients plants need for growth and the biological Deterioration of water quality. processes needed for health, is being lost at Increased flooding. unprecedented rates, leaving severly degraded and dead soils as the basis for our food production. The loss of soil ECONOMIC COSTS OF EROSION health poses economic burdens and serious crop quality Loss of topsoil. issues to agricultural managers. Dredging reservoirs,