Many people in Washington raise livestock and horses on small farms. Overgrazed pastures, uncontrolled animal access to stream corridors, and manure, fertilizer, or pesticide application and disposal all can degrade water quality. Management practices can reduce water pollution from farms and contribute to the overall improvement of water quality. Sound livestock management keeps contaminants such as sediments, fertilizers, animal waste, and pesticides out of water sources.

Contaminants produced by small farm operations can find their way into groundwater and surface water. Groundwater, the primary source of drinking and irrigation water, becomes contaminated when pesticides and fertilizers leach through porous soil. This leaching may occur on or off farms when surface water carries contaminants into contact with groundwater.

Overloading causes most of the water quality damage from small livestock farms. Overloading occurs when small farm operators keep too many animals on too few acres. Choice of livestock management system can affect how many animals the acreage will support. Experienced producers, extension agents, and conservation district personnel can guide managers in estimating livestock carrying capacity for small farms.

Even small farms with only a few animals can degrade water quality. Shoreline damage from livestock trampling increases erosion, resulting in siltation and loss of fish spawning sites. When livestock have unlimited access to streams, they can destroy the shoreline vegetation needed for shading the streams.

Water quality improvement and protection require action at the local level. To put protective measures to work successfully, individuals and communities must become involved. Small farm owners often are unaware of the local effects of poor management practices and how they can change practices to protect water quality.

Best Management Practices (BMPs) can improve or protect surface and groundwater quality. Farm owners must carry out BMPs on a long-term basis to maintain the productive life of the farm.

• Range from making simple operational changes to building waste containment structures.
• Consider how all the parts of a livestock enterprise interrelate.
• Stress practical and feasible implementation.
• Recognize that the practices may be modified to fit individual livestock and horse operations.

Local Washington State University Cooperative Extension (WSU Cooperative Extension), USDA Natural Resources Conservation Service (USDA-NRCS) and Conservation District personnel can help select suitable manure handling systems for your farm. Cost sharing programs for some livestock waste control measures may be available through your county Farm Service Agency (FSA).

Specific ways to reduce contamination from livestock wastes follow.

• Divert uncontaminated land surface runoff and roof runoff away from livestock facilities to reduce the amount of waste-contaminated water to be handled.

- Install diversion ditches or terraces around livestock areas so water from fields or the farmstead does not mix with manure and feed.

- Install gutters and downspouts on roofs that drain into livestock areas. Pipe or ditch rainfall and snowmelt runoff away from the livestock areas (See Fig. 1).

Fig. 1. Roofing the feeding area and installing rain collection pipe systems and gutters reduce contaminated runoff.

• In heavy rainfall areas, reduce the amount of manure exposed to rain.

- Consider indoor feeding for animals, a practice which keeps more total manure under a roof.

- Cover manure storage and direct roof water away from livestock (Fig. 2). For a small farm, you may find tarpaulins are adequate if weighted down against wind. You can retain the fertilizer value of covered manure by preventing leaching.

- Pave outdoor livestock areas.

- Scrape manure regularly from paved area or yard to a protected stockpile.

Fig. 2. Roofing of manure structure reduces contaminated runoff and seepage.

• Develop a waste handling system that will accomplish the following.

- Collect and store untreated runoff and seepage from waste storage areas.

- Store manure and bedding waste for field spreading.

- Provide for field spreading when soil is not frozen, but firm enough to prevent soil compaction by spreading equipment, and dry enough to avoid contaminant runoff.

- Apply manure to pasture or crops to meet plant nutrient needs. Avoid excess manure application to prevent leaching.

• Maintain a grass buffer between cropland and a waterway to filter out some contaminants from field runoff. Size of adequate buffer will vary with slope, runoff volume, vegetative cover, and individual situation.

Pastures are an important part of most small farm operations. Proper pasture management will contribute significantly to the protection and enhancement of water quality.

• Permanently defines the pasture perimeter.
• Divides pastures into temporary plots for rotational grazing.
• Keeps animals out of environmentally sensitive areas.
• Protects stream banks from overgrazing, trampling, and contamination.
• To water livestock from a stream:

- Pipe water by gravity or pumping to a trough well away from the stream (Fig. 3).
- Limit stream damage by fencing along the bank top, yet leave some areas for livestock watering access (Fig. 4). Keep in mind that water levels can fluctuate throughout the grazing season.

Fig. 3. Gravity flow or pumped water provides a drinking area away from stream bank.

Fig. 4. Limit stream access to small areas for watering.

In productive grazing management schemes, you can protect and enhance water quality when you maintain healthy and vigorous plant cover. The plant cover prevents soil erosion and reduces the need for chemical weed control. It also serves as a filter for runoff and aids in the percolation of surface water to groundwater. Grazing management depends on the land's carrying capacity­how many animals it can feed. Factors such as animal species, forage variety, soil type, soil fertility, and climate dictate capacity.

Limit grazing while grass regrows and during the fall and winter when grass is dormant. Grazing on overly wet soil can compact soil and destroy sod. Feed livestock hay or other feedstuffs in a holding area when pasture forage is short.

When animals graze pasture down to 3 inches or less, they significantly reduce the leaf surface, which is needed for photosynthesis. When less photosynthesis occurs, plant growth slows. If allowed to regrow, the plant can regenerate necessary leaf surface and root stores. Repeated overgrazing weakens the plant and makes it susceptible to competition from weeds.

• Implement a grazing management program for maximum productivity.
• Divide grazing areas into three or more equal sized units.
• Start grazing when grass is 8 inches to 10 inches tall.
• Allow animals to graze pasture down to 3 inches to 4 inches, then move them to another grazing area or holding area.
• Clip tall weeds and old grass to control weeds and to stimulate grass regrowth.
• Drag pastures to spread animal droppings, to level mole and gopher hills, and to promote uniform grazing.
• Let pasture regrow to 8 inches to 10 inches before allowing regrazing.
• Base number of animals pastured on the amount and condition of forage available in mid-summer.
• If needed, supplement manure from grazing animals by using additional fertilizer or manure as indicated by soil tests and plant behavior.

Soil forms a bed for grass production and a filter for water and water soluble materials. Generally, sandy highly porous soils have little water holding capacity; pesticides, fertilizers and animal waste easily infiltrate through the soil to ground and surface waters. Clay soils absorb water slowly, so nutrients and pesticides can wash off pastures during heavy rains. Loamy soils have good inflitration rates and water-holding capacity, so neither runoff nor percolation to groundwater are excessive. Loamy soils protect surface water from contaminated runoff and groundwater from leaching of agricultural chemicals. Pastures with steep slopes often erode and lose surface nutrients. For more information on soils and water quality, see EB1633, Role of Soil in Groundwater Protection.

Soil fertility tests provide specific information on soil amendments needed for improved crop production. To maintain highly productive, healthy pastures, you may need to supplement soil nutrients. Manure and chemical fertilizers usually meet most pasture nutrient needs.

Do not guess on fertilizer use. Too much fertilization is costly and leaves excess nutrients in the soil to be leached to groundwater or washed away to contaminate water resources. Too little fertilization restricts pasture development and growth. Follow soil test recommendations to increase forage production at minimal risk to water quality.

You can control most pasture weeds by practicing responsible pasture management, using controlled grazing, clipping, dragging, and fertilizing. Some weed seeds remain viable in the soil for decades, so any control program includes repeated treatments to control newly emerging weeds.

When pastures become weedy, chemical weed control can often extend pasture life and delay costly renovation. Chemical control uses specific herbicides on specific weeds to eliminate or prevent them from spreading. Correct use of herbicides is vital to water quality maintenance.

• Identify the weed(s) to be controlled.
• Pick an appropriate control method (mechanical, biological, chemical, or a combination). If you choose chemical control:
• Select a herbicide suitable for the specific weed(s).
• Read, study, and follow the label instructions.
• Select a spraying system­spot or broadcast spraying, depending on the percentage of weeds and the size of the site.
• Select spray equipment­from backpack sprayer to spray booms on a tractor or all-terrain vehicle.
• Be cautious­spray drift or runoff can contaminate surface water. Herbicides carried off target by wind or runoff pose major threats to water quality.
• Avoid spraying before, during or immediately after a rainfall.

• Time renovation to avoid having bare soil exposed during runoff season.
• Use cover crops when you cannot complete renovation before runoff season.

Partial funding for publications in this series on Groundwater Protection was obtained through U.S. Environmental Protection Agency nonpoint source pollution grants administered by the Washington State Department of Ecology.

Reference materials include:

Other Clean Water for Washington fact sheets.

Soil test information:

Water Quality Guide­Recommended Pollution Control Practices for Homeowners and Small Farm Operators, Washington Department of Ecology, 87-30 revised.

Livestock Waste Facilities Handbook, MWPS-18. (Available from Midwest Plan Service, Davidson Hall, Iowa State University, Ames, IA 50011. Design and planning information. $8.00)

County Soil Survey available from WSU Cooperative Extension or the Natural Resources Conservation Service office.

The authors acknowledge the contributions of Christopher F. Feise, Ph.D., Cooperative Extension Liaison to EPA, U.S. EPA Region 10, Seattle, WA; John H. Pedersen, Ph.D., P.E., consulting technical editor; and Ronald E. Hermanson, Ph.D., P.E., WSU Cooperative Extension Agricultural Engineer and Water Quality Project Leader, WSU­Pullman.

Janet L. Schmidt is Washington State University Cooperative Extension Agent, Whitman County; Blair F. Wolfley is WSU Cooperative Extension Chair, Clark County.

Figures adapted from Prather, Steven S., 1978. Livestock and Water Quality, Clark County Conservation District. Original sketches from Farm Water Quality Management Manual, prepared by URE Company for ENOMET/King County 208 Program, 1977.