A major consideration of animal lot management is prevention of pollution. Runoff from animal lots carries manure, soil, chemicals, and other contaminants, and may contaminate surface and groundwater sources. Animal feeding sites are a potentially significant source of high nitrates in homestead water wells. A system is needed for preventing lot runoff from leaving the owner's property, or entering surface water or groundwater, in a contaminated condition.

Along with addressing the potential of animal lots to contaminate water, other good reasons for improving management practices include improved animal health, ease of maintenance, and enhancing the quality of meat or milk.

Wells should be located in an elevated area upslope of the animal lot, so that runoff will not drain into the vicinity of the well. Washington regulations require a minimum separation of 100 feet between all potential pollution sources associated with existing animal lots and water-supply wells. In general, the farther the animal lot is located from the well, the less likely drinking water will become contaminated.

Minimum separation distances should guide new well installations and the distance from existing wells to new sources of contamination. Make every effort to exceed the requirements and strive to meet current recommendations whenever possible. For more information about separation distances, and how the condition of your well might affect the potential for groundwater contamination, see worksheet and fact sheet 1, Drinking Water Well Condition.

Many times, wells are located near animal facilities. If your well is near an animal lot, the best option is to move either the well or the lot to protect your drinking water. In many cases, however, this is not possible - financially or otherwise. Good management, such as keeping the lots clean and preventing any runoff from moving towards the well, can help protect your well water in these situations. Contact a specialist to help you design a system to protect groundwater and surface water sources. Plug any abandoned wells on your homestead to eliminate the direct passage they provide for contaminants to reach groundwater.

Soil characteristics are one important factor when considering groundwater protection in siting an outside animal yard. Important soil characteristics include surface and subsoil texture, soil depth, permeability, and drainage class. The best site has a deep, well-drained silt loam/clay loam soil with low permeability. A very poor site has shallow soil, a high water table, or a very sandy/gravelly soil with excessive drainage and high permeability. For more assistance in assessing your site's vulnerability to groundwater contamination, see worksheet 11, Site Evaluation.

For existing animal lots on poor sites, the best options for protecting groundwater might be eliminating the lot and using total confinement for the animals, or providing paved lots and liquid-tight basins to store lot runoff.

One way to reduce water pollution from animal lots is to reduce the amount of clean water entering the lot. In all cases, these structures need to be maintained.

• Waterways, small terraces, and roof gutters direct water away from animal lots.
• An earthen ridge or terrace can be constructed across the slope upgrade from an animal lot to prevent runoff from entering the lot.
• In some areas, if a diversion terrace is not practical, a catch basin with a tile outlet could be installed above the animal lot.

Careful site selection can minimize or eliminate the provisions needed to divert clean water away from the lot.

An outside animal lot without a runoff control system typically has an earthen surface compacted by animal traffic. This surface is not shaped for water drainage, so it is sometimes dry and sometimes muddy. Manure typically accumulates on the surface, and decaying manure is mixed into the soil by animal traffic.

Such a lot is difficult to manage, and the absence of runoff controls may lead to water quality problems. Runoff from adjacent cropland, pasture, roads, or building roofs can flush manure from the lot, possibly entering nearby bodies of surface water, or creating mudholes.

Contaminated runoff from an active feedlot that accumulates in areas adjacent to the lot may flow through the soil and threaten groundwater quality. This risk is particularly high on sites with high infiltration and percolation rates, such as sandy soils and other soils with good-to-moderate drainage.

Runoff control systems can remedy such problem situations. Figure 1 shows how curbing around an animal lot collects and channels runoff to a waste storage pond. After collection, runoff can be evenly applied to open grassed areas or filter strips, away from streams, ditches, waterways, and areas of permeable soils and creviced bedrock. Another option is to collect animal lot runoff, settle out manure solids, and direct the remaining water to holding ponds which collect and store runoff for later land application (Figure 2).

The need for runoff control facilities is dependent on several factors related to the size and type of animal operation as well as surface characteristics and management practices of the operation. Some operations, due to size and management, may not need structural controls.

The Washington Department of Ecology is the state agency responsible for administering surface water and groundwater pollution control laws, which include a waste discharge permit program for dairy farms that discharge pollutants to surface water or groundwater. (See State Water Pollution Control Act, Revised Code of Washington (RCW) Chapter 90.48.) Other concentrated animal feeding operations may require waste discharge permits, depending upon site-specific circumstances. More information is available by contacting the Department of Ecology regional office in your area (see contacts and references section).

Manure collection should be accomplished through "manure harvesting" rather than by "cleaning pens." Collect manure from animal lots regularly. The amount of manure on a animal lot depends on the number of animals and the hours per day animals spend on the lot. Scrape open lots at least twice per year. Heavy concentrations of animals will require more frequent manure removal.

The type of lot surface also affects lot management. Concrete surfaces are easier to scrape than earthen lots. Earthen lots are scraped when dry, so manure may be removed less frequently.

Lots should not be cleaned to bare dirt, but they often are. When earthen lots are scraped, a thin layer (1 to 2 inches) of manure pack should be left to seal the surface of the lot. Water moves very slowly through this compacted layer, minimizing the potential for leaching of nitrates and bacteria through the soil to groundwater. Collect all the manure from a lot when the lot is either no longer going to be used, or when it is to be left empty for an extended period of time.

The area needed per animal for minimizing the risk of groundwater contamination depends on the type of lot surface, lot slope, amount of rainfall, and other lot management factors. The amount of concrete surface area needed per animal is much less than that required for an earthen lot.

The concrete area needed is a balance between traffic on the lot and resting area provided for animals. Too large an area can result in manure freezing to the surface for long periods, while too small an area will result in animals having difficulty moving about. At least 50 square feet of concrete area per head is recommended for a cattle feedlot. Facilities for growing-finishing pigs in lots with open-front sheds should provide 12 to 15 square feet of outdoor lot space per pig.

For beef cattle operations, open feedlots are usually unpaved. Recommended slopes for good drainage are 2 to 4 percent. Minimum space recommendations are 150 to 250 square feet per head with 4 percent or greater slopes; 250 to 400 square feet with 2 to 4 percent slopes; and 400 to 800 square feet with slopes below 2 percent.

Mounds improve drainage and provide areas that dry quickly. Feedlot mounds should be about 3 to 4 feet high with 5 to 1 side slopes (horizontal to vertical). Mounds can be built down the center of the lot or at the fence line with half of the mound in adjacent pens. Besides improving drainage conditions, mounds provide a wind break from cold wind.

Lot management involves considerations other than surface and groundwater protection. In addition to decreasing the chance for groundwater contamination, a well-drained, dry lot improves animal comfort, health, and feed utilization. A combination of lot surfaces offers the most flexibility in adapting to weather conditions. Animal location can be chosen based on the amount of mud in the lot—on concrete in sloppy conditions, on an earthen surface in dry weather, and on a mound in intermediate conditions.

If bedrock is close to the surface where your animal lot is located, pave the surface with concrete, or totally confine animals.

In addition to the condition and management of your animal lots, your farm animal manure management should plan for manure storage and utilization. Worksheet and fact sheet 7, Animal Manure Storage, provide guidelines for minimizing the impact of animal manure storage practices on groundwater.

Animal manure can be a valuable fertilizer and soil conditioner. When managed properly, the nutrients in manure can be substituted for commercial fertilizers, saving money, and protecting groundwater and surface water. Matching nutrient applications to crop nutrient needs is critical. Worksheet and fact sheet 7 and the Livestock Waste Facilities Handbook, MWPS-18, provide more information on land application and utilization of animal wastes.

On active feedlots, the layer of organic matter mixed with soil at the surface lies over compacted subsurface soil, forming a layer through which water moves very slowly. Therefore, leaching of nitrate and bacteria through the surface seal and compacted layers is not likely within the animal lot. If animal lot runoff is discharged to permeable soils or bedrock, leaching may occur. Studies have found little nitrate in the soil beneath active feedlots. Nevertheless, abandoned lots can pose a particular groundwater contamination risk. As the manure pack breaks up from lack of use, water can leach through and carry nitrates to groundwater.

If you have a permanently abandoned lot, dig it up, spread the manure and soil combination on fields, and refill the former lot with other material. Another option is to till and plant the lot to a high-nitrogen-using crop, which will use the nitrogen released by soil and the manure decomposition process. Remove manure from a feedlot that will not be used for an extended period. Otherwise, cracks developing in the surface may allow leaching of nitrates.

Technical standards and design assistance
Your local Conservation District, Soil Conservation Service or Cooperative Extension office, or Cooperative Extension Biological Systems Engineering, (509) 335-2910.

Northwest: (206) 647-7000
Southwest: (206) 753-4089
Central: (509) 575-2809
Eastern: (509) 456-6198

Publications are available from sources listed at the end of the reference section.
Refer to number in parentheses after each publication.

Groundwater contamination, protection and testing
Washington Agriculture-Sustaining Water, Land and People EB1634 (1)
Regulation and Control of Odors from Livestock Facilities EB1184 (1)
Washington Groundwater: A Vital Resource EB1622 (1)
Protecting Groundwater: Managing Livestock on Small Acreage EB1713 (1)
Managing Livestock Manure to Protect Groundwater EB1717 (1)
Animal Manure Data Sheet EB1719 (1)
Defining Water Quality EB1721 (1)
A list of laboratories certified to conduct water sample analysis is available from your Cooperative Extension agent or local health district/department.

1. Your county Cooperative Extension office. There may be charges for publications, postage, and sales tax.

2. Your county Cooperative Extension office or the Midwest Plan Service, Iowa State University, Ames, Iowa, 50011, (515) 294-4337.

Home*A*Syst team members: Christopher F. Feise and Edward B. Adams, WSU Cooperative Extension Water Quality Coordinators; James D. LaSpina, Homestead Assessment System Project Associate.

Animal Lot Management Technical Reviewers: Ronald E. Hermanson, P. E., WSU Cooperative Extension Water Quality Project Leader and Agricultural Engineer; Andy Werkhoven, Dairy Farmer; Anne Schwartz, Washington Tilth; John A. Gillies, USDA-Soil Conservation Service; John W. Bernard, WSU Cooperative Extension Area Agent (Dairy); Philip A. KauzLoric, Nonpoint Source Specialist, Washington Department of Ecology; Daniel F. Caldwell, WSU Department of Animal Sciences.

Adapted for Washington from material developed by the Wisconsin, Minnesota, and Kansas Extension Services and Farm*A*Syst Programs. Washington Home*A*Syst development was supported by the National Farmstead Assessment Program.