The primary agricultural nonpoint source pollutants are nutrients (particularly nitrogen and phosphorus), sediment, animal wastes, pesticides, and salts. Agricultural nonpoint sources enter srface water through direct surface runoff or through seepage to ground water that discharges to a surface water outlet. Various farming activities result in the erosion of soil particles. The sediment produced by erosion can damage fish habitat and wetlands and, in addition, often transports excess agricultural chemicals resulting in contaminated runoff. This runnoff in turn affects changes to aquatic habitat such as temperature increases and decreased oxygen. The most common sources of excess nutrients in surface water from nonpoint sources are chemical fertilizers and manure from animal facilities. Such nutrients cause eutrophication in surface water. Pesticides used for pest control in agricultural operations can also contaminate surface as well as ground-water resources. Return flows, runoff, and leachate from irrigated lands may transport sediment, nutrients, salts, and other materials. Finally, improper grazing practices in riparian, as well as upland areas, can also cause water quality degradation.
CONFINED ANIMAL FACILITY -- Animal waste contaminates many of our waters with pathogens and nutrients. The management measure for ALL new facilities and existing facilities over a certain size is to limit discharges from confined animal facilities to waters of the United States by storing wastewater and runoff caused by all storms up to and including the 25-year, 24-hour frequency storm. For smaller existing facilities, the management measure is to design and implement systems that collect solids, reduce contaminant concentrations, and reduce runoff to minimize the discharge of contaminants in both facility wastewater and runoff caused by all storms up to and including 25-year, 24-hour frequency storms. This measure also specifies management of stored runoff and solids through proper waste utilization and use of disposal methods which minimize impacts to surface/ground water. Confined animal facilities required to obtain a discharge permit under the NPDES permit program are not subject to these management measures.
NUTRIENT MANAGEMENT -- This measure calls for development and implementation of comprehensive nutrient management plans. The fundamentals of a comprehensive nutrient management plan include a nutrient budget for the crop, identification of the types and amounts of nutrients necessary to produce a crop based on realistic crop yield expectations, and an identification of the environmental hazards of the site. Other items called for in the measure include soil tests and other tests to determine crop nutrient needs and proper calibration of nutrient equipment.
PESTICIDE MANAGEMENT -- This measure is designed to minimize water quality problems by reducing pesticide use,improving the timing and efficiency of application, preventing backflow of pesticides into water supplies, and improving calibration of pesticide spray equipment. A key component of this measure is use of integrated pest management (IPM) strategies. IPM strategies include evaluating current pest problems in relation to the cropping history, previous pest control measures, and applying pesticides only when an economic benefit to the producer will be achieved, i.e., application based on economic thresholds. If pesticide applications are necessary, pesticides should be selected based on consideration of their environmental impacts such as persistence, toxicity, and leaching potential.
LIVESTOCK GRAZING -- The goal of this measure is to protect sensitive areas. Sensitive areas include streambanks, wetlands, estuaries, ponds, lake shores, and riparian zones. Protection is to be achieved with improved grazing management that reduces the physical distance and direct loading of animal waste and sediment caused by livestock by restricting livestock access to sensitive areas through a range of options. In addition, upland erosion is to be reduced by either: (1) applying the range and pasture components of a Conservation Management System or (2) maintaining the land in accordance with the activity plans established by either the Bureau of Land Management or the Forest Service. Such techniques include the restriction of livestock from sensitive areas through locating salt, shade, and alternative drinking sources away from sensitive areas, and providing livestock stream crossings.
IRRIGATION -- This measure promotes an effective irrigation system that delivers necessary quantities of water yet reduces nonpoint pollution to surface waters and groundwater. To achieve this, the measure calls for uniform application of water based upon an accurate measurement of cropwater needs and the volume of irrigation water applied. When applying chemicals through irrigation (a process known as chemigation), special additional precautions apply. The measure also recognizes that states water laws that conflict with the measure will take precedence over the measure.
Section 6217 of the Coastal Zone Act Reauthorization Amendments of 1990 (CZARA) requires coastal states (including Great Lakes states) with approved coastal zone management programs to address nonpoint pollution impacting or threatening coastal waters. States must submit Coastal Nonpoint Pollution Control Programs for approval to both the U.S. Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA). Requirements for state programs are described in a document entitled "Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance" and are summarized in a separate fact sheet.
CZARA requires EPA, in consultation with NOAA and other federal agencies, to publish guidance specifying management measures to restore and protect coastal waters from specific categories of nonpoint source pollution. EPA has done so in a document entitled "Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters". State Coastal Nonpoint Programs must provide for implementation of these measures or alternative management measures in conformity with these measures in the coastal management area generally. "Management measures" are defined by law to be economically achievable measures that reflect the best available technology for reducing pollutants. States may select from a wide range of practices or combinations of practices that will achieve the level of control specified in the management measure. This fact sheet summarizes the management measures applicable to agricultural sources. Other fact sheets summarize the measures for forestry, urban areas, marinas and recreational boating, hydro- modification, and wetlands/riparian areas.