The need to protect surface and groundwater quality is a serious environmental issue. Good design can prevent or minimize erosion and runoff. Good design provides buffers and naturally vegetated areas near streams, wetlands, and other fragile areas. Good design also minimizes the development of gullies, the redirection of streams, and the unnecessary disruption of the natural landscape, especially around drainage ditches and stream banks.

Proper management practices can protect this environment. The purpose of this publication is to provide professional turf managers with management strategies that preserve and protect water resources.

Every turf maintenance decision you make in managing a turf area will have an effect on the ecosystem. Best management practices, or BMPs, are cultural practices designed to maximize resources, while also minimizing the risk to the environment. The BMPs include important aspects of turf management from the original design of the area to its daily maintenance. This publication discusses some BMPs that are applicable to the creation, protection, and maintenance of a turfgrass ecosystem.

Without proper turfgrass cover, bare soils and steep slopes are highly susceptible to erosion. Sediment from erosion is the leading cause of stream impairment and pollution. Sediment destroys fish spawning beds, reduces useful storage volumes in reservoirs, and increases filtration costs for municipal water supplies. Pesticides and nutrients, such as nitrogen and phosphorus, can be moved in water that contains sediment. A healthy stand of turf can control erosion and reduce runoff, but it must be properly constructed in order to protect water quality.

North Carolina requires that an erosion and sediment control plan be submitted to the Division of Energy, Mineral, and Land Resources, Department of Environmental Quality Regional Office in your area, thirty days before the start of clearing or grading for areas larger than one contiguous acre.

Here are several methods of reducing and managing erosion and sedimentation during construction.

Erosion and Sedimentation BMPs

• Plan construction activities to minimize the duration of exposed soil.
• Limit the area of soil disturbance at any one time.
• Construct sediment traps and basins before other land-disturbing activities.
• Establish soil stabilization with plant materials as soon as possible after soil disturbance.
• Manage runoff and keep velocities low through controlled irrigation.
• Break long slopes with diversions.
• Divert storm water runoff to and from disturbed areas to sedimentation containment systems by using dikes, diversions, and waterways.
• Inspect the erosion and sedimentation control systems frequently.

Further information can be found in the North Carolina Erosion and Sediment Control Planning and Design Manual that is available online on the North Carolina Environmental Quality website. The Field Manual, a condensed version of the design manual, is also located on the website or a printed copy can be ordered for $13 by contacting the Division of Energy, Mineral, and Land Resources, 1612 Mail Service Center, Raleigh, NC 27699-1612.

Wetlands serve as filters for surface and groundwaters, provide vital habitat for many species of plants and animals, serve as recreational areas, and help in natural flood control. The 1979 Clean Water Act defines wetlands as "areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions."

Wetland areas must be defined and delineated at the beginning of the site design process. During construction, these areas need to be protected from excess water and sedimentation. After the site is built, the wetland areas should be managed as natural areas that are protected from abnormal amounts of water, nutrients, or pesticides.

Here are actions that can reduce the impact of construction on wetlands.

Wetlands BMPs

• Maintain borders of low-maintenance turf or natural vegetation within 50 ft of wetland boundaries.
• Minimize the flow of irrigation water into the wetlands. This will also reduce the possibility of nutrient and pesticide movement into those areas.
• Stabilize and maintain stream banks and ditches to limit erosion.
• Limit the application of fertilizers and pesticides to turf near the wetlands boundary areas.
• Locate pesticide, fuel, fertilizer, and chemical storage mixing and loading areas away from sites where possible transport from runoff and spills to wetlands could occur.
• Install and maintain wash-down and mixing pads where waters from these operations are contained, reused, or filtered.
• Use a sound integrated pest management (IPM) program on wetland areas of the turf site.
• Avoid direct runoff from parking lots and drives directly into wetlands
• Design the site to inhibit intrusion into wetland areas.

Further information on the subject of wetlands may be found in the Extension publications, Wetlands and Water Quality, AG-473-15.

Surface water of ponds and lakes must also be protected. Effective erosion control and turf management practices can help prevent sediment and nutrients from contaminating lakes and ponds. Design considerations at pond and lake areas should include a site selection that minimizes the surface runoff and downward seepage through the soil.

The Agricultural Handbook, number 590, Ponds Planning, Design, and Construction, published by the USDA Soil Conservation Service (SCS), provides guidelines for pond construction. You can also refer to Extension publication, Pond Management Guide, AG-424.

Ponds and Lakes BMPs

• Choose a site that minimizes disturbance and can accommodate runoff from the immediate surrounding area.
• Maintain an unfertilized buffer zone at least 50 ft wide, or wider if the slope is steep.
• Construct a small sedimentation pond upstream to reduce nutrient and sediment deposits.
• Be careful not to introduce undesirable plant material into the ponds and lakes.

Turfgrass selection is an important element of a BMP system that can have a major impact on water quality. Using weed-free planting material can minimize future weed problems and the need for herbicides. Adapted, improved grasses often require less fertilizer, pesticides, and water. Healthy plants are better able to ward off pests and recover from pest injury or environmental stress.

Grasses differ in adaptation, cultural requirements, and performance. Base your selection on existing environmental conditions (soil pH, soil type, level of moisture, degree of sunlight, and topography), the purpose for which the grass will be used, and the expected management intensity. Consult with a turfgrass specialist or your county Extension center to identify the grasses that perform best in your area or refer to Extension publication, Carolina Lawns, AG-69.

The primary objective of a fertility program is to create a soil environment in which sufficient nutrients are available for optimal plant health with minimal risk to water quality. Since nutrients are not found in adequate supply in the soil, most turfgrasses require regular fertilization.

Improper fertilization practices can pose a risk to surface or groundwater quality. You must have a working knowledge of how the plant uses nutrients and the fate of nutrients in the soil. With this information, you can implement a fertilization program that benefits the turfgrass and minimizes risks to water quality.

Nitrogen and phosphorus are the nutrients most likely to affect water quality. Carefully planned applications are important to the health of the plant and the environment.

Phosphorus is critical in establishing and rooting plants. However, through erosion or sedimentation, an improper application of phosphorus can cause undesirable algal blooms and excessive growth of aquatic plants in lakes and ponds.

Nitrogen is required for plant growth and is often associated with the green color in plants. Nitrogen deficiency causes poor growth and susceptibility to pests, diseases, and slow recovery from stresses. Excessive nitrogen may cause restricted root systems, an overaccumulation of thatch, an increase in the occurrence of disease, a decrease in the tolerance to environmental stress, and reduced wear tolerance.

Nitrogen Carriers

The carrier of nitrogen, or the form in which it is supplied to the soil, can affect the degree of runoff or leaching. The nitrate ion (NO₃) has the highest potential to leach or runoff into water sources. Runoff is not likely, but it can occur if the nitrogen is applied at high rates to frozen ground or slopes, or before an excessive rainfall or irrigation. Leaching is likely if the soil is sandy, has insufficient organic matter, or is saturated through intense irrigation.

Table 1 outlines the characteristics of many nitrogen carriers available on the market today. Generally, nitrogen sources are separated into quickly available and slowly available categories.

Quickly available forms release large quantities of nitrogen into the soil and cause a rapid response by the plant. Inorganic salts, such as ammonium sulfates, dissociate rapidly in the soil water and provide large amounts of plant-available nitrogen in a short period of time. Urea is a quickly available, organic nitrogen source that is commonly applied in a liquid or granular form. Upon entering the soil, several reactions take place rapidly to convert the urea to the plant-available nitrate form. However, leaching potential is high because of the rapidity of these reactions.

Slowly available products such as urea formaldehyde rely on chemical or microbial activity for release of plant-available nitrogen. Some urea formaldehyde products are available as solutions or suspensions that can be applied in liquid form. Coated urea products such as sulfur-coated urea and polymer-coated urea rely on the coating to control the release of plant-available nitrogen into the soil solution.

Natural organic sources are composed of material such as processed municipal sewage sludge, composted plant and animal debris, or various other organic wastes. Plant-available nitrogen is released from these products through chemical and microbial processes in the soil. As a result, temperature and moisture are important factors that govern microbial activities and the ultimate release of available nitrogen. Warm, moist conditions favor high levels of microbial activity. The release of nitrogen will be affected as temperature and moisture levels move toward either extreme.

Overall, slowly available nitrogen sources provide a more controlled release of nitrogen with longer residuals and are less likely to affect groundwater through leaching than quickly available products.

Fertilizer Management BMPs

Base fertilizer applications on a soil test. A soil test will show the types and levels of nutrients in the soil. Most newly planted areas should be tested during the construction phase and every one to two years, depending on the type of turf being grown.

• Wait a minimum of three to four weeks after the last fertilization before sampling.
• Be careful to submit a sample for analysis that is truly representative of the area.
• Make sure the equipment used to obtain the sample is clean and free of contaminants. Clean equipment between samples.
• Sample to a uniform depth—preferably to 3 or 4 in.
• Take 15 to 20 soil cores from each area being tested, use a one in. diameter soil probe, and thoroughly mix them in a plastic container or paper bag. Do not use a metal bucket which may affect results.
• It may take several weeks before you receive the results of your test, so plan to submit your samples far enough in advance.
• Submit samples to a reputable laboratory for testing and interpretation. The North Carolina Department of Agriculture & Consumer Services (NCDA&CS) provides soil testing. During peak season (December through April), there is a $4.00 fee per sample. In the off season, the soil testing is free. You can submit samples to the Agronomic Division – NCDA&CS, 4300 Reedy Creek Road, Raleigh, NC 27607-6465.

Supplement the soil test with a plant tissue analysis. A plant tissue analysis is a diagnostic tool that can be used by a turf manager to identify potential nutrient problems. The analysis measures the concentrations of different nutrients in the tissue and can indicate adequacy or deficiency. For more information, visit NC Department of Agriculture & Consumer Services – Plant Tissue Analysis or contact your Cooperative Extension center.

Core aerify compacted soil. Coring and aerification at the time of fertilization can aid the fertilizer getting into the soil. This is especially important for phosphorus. Coring compacted, sloped areas will reduce runoff.

Minimize fertilizer rates on slopes. The application of high rates of nitrogen and phosphorus fertilizer on slopes near surface water increases the risk of a negative impact on water quality. Use no more than 0.25 to 0.50 lb of nitrogen or phosphorus per 1,000 sq ft per application.

Do not apply fertilizers directly into lakes, drainage areas, and other bodies of water. Maintain a buffer zone of low maintenance grasses or natural vegetation between areas of highly maintained turf and water. This prevents erosion and produces a trap or filter for unwanted nutrients.

Consider using iron as a supplement to nitrogen for greening response. Iron can be used alone or in combination with nitrogen to provide a greening response. Reduced nitrogen applications will minimize possible nitrate leaching into groundwater. Rates vary with grass type and environmental conditions, so it is best to follow directions on the label.

Use a slowly available carrier on sandy soils. Sandy soils put groundwater at greater risk of contamination. Slowly available nitrogen fertilizers are less likely to be leached below the root zone than quickly available sources on highly leachable soil.

If you use quick-release nitrogen on sandy soils with little organic matter, or near shallow water tables, use no more than 0.25 to 0.50 lb nitrogen per 1,000 sq ft per application. Plant response is often better with a program of lower levels of nitrogen and more frequent applications.

Time applications carefully. Quickly available sources should not be applied before a heavy rainfall. Nitrogen has the highest chance of leaching during cool and wet weather. Cold temperatures (55° to 65°F) slow microbes and plant uptake, as well as loss through volatilization and denitrification.

Irrigate after each application of quick-release fertilizer. Irrigation of 0.25 to 0.50 in. of water moves the fertilizer off the foliage and into the ground where it can be used by the plants. This decreases loss by runoff and volatilization, and minimizes the risk of foliar burn.

Irrigate to replace lost water. Provide only enough water to compensate for the water lost by evapotranspiration. Overirrigation will produce water movement beyond the root zone, which increases the potential for leaching.

Recycle grass clippings (grasscycling). When possible, clippings should be allowed to remain on the turf area to decompose and recycle nutrients back into the turf. Clippings that are removed should not be blown into ditches, streams, lakes, or placed in areas such as ditches or concrete areas where they have a high probability of running off into surface water.

Use a drop or gravity spreader near bodies of water or impenetrable areas. Centrifugal or rotary spreaders should not be used near bodies of water because of the potential of heavy granules entering the water.

Determining the appropriate level of irrigation for an area of turfgrass is vital to the health of the plant and the preservation of water quality. Underirrigating produces wilt and desiccation. Overirrigating increases the potential for leaching and surface runoff, weakens the turf, and makes it more prone to pest attacks and environmental stress.

A properly designed and installed irrigation system will apply a uniform level of water at the desired rate and time. The amount and frequency of irrigation should be based on the needs of the grass, soil conditions, and expected weather conditions. The goal is to wet the soil to a depth just below the existing root zone to encourage further rooting. Watering deeper than that does not benefit the plant and may leach contaminants into the groundwater.

While it is obvious that a plant needs a certain amount of moisture to function, determining the appropriate amount and frequency of water to apply is not easy. Several programs have been developed to aid irrigation scheduling. The publication Water Requirements of NC Turfgrasses, AG-661.

Consumptive use approaches to irrigation are based on the premise that evaporation from water exposed to the atmosphere is proportional to the amount released from the plant. Temperature, wind, relative humidity, and soil moisture are factors that determine the amount of water available for use by the plant.

Irrigation BMPs

• Water to a depth just below the root system. If you observe runoff, shut the system off and wait for the existing water to enter the soil. Go back and re-wet until the water reaches the appropriate depth.
• Do not irrigate again until you see visual signs of wilt or footprinting. A soil probe can aid in the visual estimate of moisture content.
• Use short, frequent intervals to irrigate sloped areas, compacted soils, and sandy soils.
• Water in the early morning to increase irrigation efficiency and to decrease disease potential. Avoid midafternoon watering to reduce irrigation water loss from evaporation and reduce the time the turfgrass surface is moist.
• Do not be alarmed at brown, withered leaves that result from drought. These are normal signs of dormancy on cool season grasses. Lawns allowed to go dormant should be watered every three weeks in the absence of rainfall to prevent injury to grasses from heat and drying.
• Do not water a surface before it is used by heavy traffic. Heavy traffic on a wet soil leads to compaction, which may lead to runoff.
• Periodically test the irrigation system to make sure it is producing an acceptable level of uniformity. The Extension publication AG-838, Landscape Irrigation Auditing Made Simple, provides helpful information about managing irrigation systems.

Maintaining the appropriate grass height encourages deeper roots, reduces the potential encroachment of certain weeds that need high light intensity for germination, such as crabgrass, and cools the surface of the grass.

Thatch is a layer of partially decomposed organic matter situated above the soil surface. This layer can be effective in capturing and breaking down pesticides, but it can also be damaging when it has become too thick (¹⁄₂ in. or more) and has created a favorable environment for insects and plant pathogens. The thickness can be reduced by vertical mowing, coring, and topdressing.

Mowing BMPs

• Use the highest acceptable mowing height for the grasses being grown. Never remove more than 33% of the foliage at one time.
• Do not mow when the grass is excessively wet to avoid compacting the soil, clumping of clippings, and spreading of disease.
• Practice grasscycling. Every 100 lb of dried grass clippings contains 4 lb of nitrogen, ¹⁄₂ lb of phosphorus, and 2 lb of potassium. Grasscycling may enable you to reduce your fertilization requirements by 25%.
• Compost if you collect your clippings. Use the compost as a soil modifier or mulch.

An integrated pest management (IPM) program is a multidisciplinary, ecologically based pest management system that uses all available methods to keep pests at acceptable levels, while also minimizing the effect on people, the environment, and turf. Pesticides are only one of several options available to you for use in pest management. Other options include genetic, regulatory, physical, biological, and cultural solutions.

A sound IPM program is based on the acceptance and tolerance of pests at a damage level which does not significantly reduce the acceptability of the turf. It is this reduced reliance on pesticides which is an important factor in managing turfgrass sites for water quality.

A sound IPM program will include:

A knowledgeable manager. Knowledge is the cornerstone to any successful IPM program. You should know about the grasses being grown, the pests that are likely to be a problem, and the conditions that may affect the pests and the grasses.

A written plan. This plan should include objectives for each section of the site and the degree of acceptable injury from pests. It is important to define pest threshold levels, and to include specific management practices for non-chemical control, which will vary with each section of the site.

Defining pest threshold levels. Determine what is acceptable for your site, such as if weeds should be allowed in low maintenance settings or the number of insects that can be tolerated per square foot. Recommendations are available for threshold levels for certain insects.

Implementing appropriate cultural practices. The use of agronomically sound cultural practices results in a healthy, dense, vigorous turf that is better able to ward off pests and pest injury.

Monitoring pest activity. Most pests are easiest to manage when they are immature and few in number. Frequent scouting can help determine the stage of pest activity or injury.

Maintaining accurate records. Keeping accurate and current records of pest activity, actions taken, and the results of those actions will assist in future planning.

Pesticides are sometimes necessary to keep pests at tolerable levels. These chemicals will continue to be an integral part of any IPM program. However, sole reliance on chemical control can no longer be justified because of rising chemical costs, increased resistance to pesticides, and environmental concerns. Some pesticides can also enter the surface of groundwater from leaching or runoff.

The selection of pesticides should be based on criteria that include the pest to be controlled, the turfgrass species the pest is infesting, the season and growth stage of the pest, the level of control desired, the application method required for the pesticide, the duration of control from the pesticide, the possibility of environmental contamination, and the need for frequent rotation of pesticides of different modes of action for the targeted pest to avoid pesticide-resistant plants, insects, and diseases. After all these factors are considered, there may be two or three possible options of pesticides that can control the pest.

You should then select the pesticide based on the pesticide leaching potential rating (PLP). (See Tables 2, 3, and 4.) A pesticide with a low rating would be very unlikely to move into groundwater or surface waters. A pesticide with a high ranking may be easily transported offsite, leach into groundwater, or may persist long enough to allow it to enter surface or groundwaters even though it moves more slowly.

The PLP values in the following tables are based on the soil retention, persistence of the pesticide, rate of application, and percent pesticide that reaches the groundwater. You should be aware that the PLP rating may change from site to site depending on microbial decomposition, soil pH, soil type, photodecomposition (degradation from sunlight), or transformation of chemical properties due to exposure to light, volatilization (changing of solids and liquids into gasses), and water volumes applied after pesticide application.

You should also keep in mind that leaching is only one of many considerations in selecting a pesticide. There will be some instances where a pesticide exhibits low leaching potential but because of its high potential toxicity to wildlife, such as fish, extra precautions may be necessary around water. These precautions should be described on the label.

Pesticides currently available for use on agricultural, turfgrass, horticultural, and residential pests in North Carolina have been thoroughly tested by the pesticide manufacturer and approved by the United State Environmental Protection Agency (EPA) before registration and release to the public. Pesticide applicators should be aware that the pesticide label is an official and binding contract between the chemical manufacturer, the EPA, and the purchaser of the product. If the label directions are not followed, the applicator may be subject to prosecution that results in penalties that may include fines and imprisonment.

Pesticide Selection and Use BMPs

• Select turfgrasses which are insect and disease resistant.
• Use pesticides which have a low pesticide leaching potential (PLP) index, whenever possible.
• See Tables 2 to 4 for pesticides approved for use in North Carolina on turf. Rates of pesticides applied are based on the maximum reported application rates in Extension publication, North Carolina Pest Control Recommendations for Turfgrass Managers, AG-408. The pesticide leaching potential (PLP) value was computed based on formulas defined by R.L. Warren and J.B. Weber in Evaluating Pesticide Movement in North Carolina Soils. Trade names listed are examples because pesticides may be sold under other trade names.
• Develop and implement a quality IPM program.
• Train employees in proper pesticide application techniques.
• Determine the size of the area of application and mix only the quantity of pesticide needed in order to save money, avoid disposal, and protect the plants.
• Spot treat whenever possible.
• Read and follow all label directions. The label is a legal document.
• Only apply pesticides labeled for the turfgrass being grown and for the area being treated.
• Apply the pesticide correctly at the right time.
• Note groundwater advisories on the label.
• Mix the pesticide and load the spreader or sprayer carefully to avoid spills.
• Mix pesticides in areas where spills may be safely contained.
• Do not mix, apply, or dispose of chemicals within 100 ft of your well.
• Consider closed systems for loading and mixing.
• Triple rinse containers, pour rinsate into tank, and spray excess on turf area. Do not exceed label rates.
• Calibrate your spreader or sprayer. Refer to information provided with your equipment and to Extension publication AG-934, Water Quality and Sprayer and Spreader Calibration, for complete calibration instructions.
• Fill the spray tank away from the well or any body of water.
• Prevent back siphoning by keeping the fill hose above the solution level of the spray tank. Use an anti-backflow device or check valve on the fill hose.
• Store all pesticides in properly built and maintained storage facilities.

The best way to manage pesticide storage and disposal is to reduce the amount of pesticides left over after applications through proper planning and equipment calibration. Faulty or improperly managed storage facilities may result in direct runoff or leaching of pesticides into surface and groundwaters. You and others may be held liable for damages incurred from improperly stored or disposed of pesticides.

A good storage facility should possess the following features:

• A secure area where unauthorized persons are restricted from entering
• Proper labeling such as No Smoking and Warning Pesticide Storage signs
• Limited opportunity for water damage
• Temperature control
• A location at least 50 ft from any body of water or stream
• Nonporous floors
• Adequate lighting and ventilation
• Capability of containing runoff from spills
• Source for clean water
• Absence of combustible materials or debris
• Materials and equipment to contain and cleanup pesticide spills

One option for disposing of leftover chemicals is to spray the excess on another site which is considered safe according to the requirements on the label. Another is to take the leftovers to an approved landfill. There are also companies whose business is to correctly dispose of pesticides.

Additional information on pesticide storage and disposal is available through the NCDA&CS – Pesticide Disposal Assistance Program, 919-733-3556 or your local Cooperative Extension center.

Pesticide Storage and Disposal BMPs

• Maintain and follow labels on all pesticide containers.
• Store pesticides only in original containers, or make sure the new container is properly labeled.
• Store similar pesticides together. For example, store herbicides with herbicides, and fungicides with fungicides.
• Keep containers closed tightly.
• Watch for damaged containers.
• Store pesticides separately that may be flammable.
• Maintain an up-to-date inventory of pesticides.
• Purchase only the amount you need.
• Comply with Emergency Planning and Right-to-Know regulations.
• Triple rinse empty containers and puncture, crush, and recycle them. You can also take them to an approved landfill.
• Apply the rinsate to a labeled site at no more than labeled rates or save rinsate and use it to make up water for similar applications.

Unmanaged spills may quickly move into surface waters and cause injury to plants and animals. It is essential that you are prepared for major or minor spills.

Pesticide Spill BMPs

• Locate and control the source.
• For small spills, use kitty litter, vermiculite, shredded newspaper, adsorbent pillows, clean sand, or pads.
• Direct large spills away from ditches, storm drains, ponds, or wells through dikes.
• Place contaminated material in a plastic container(s) for disposal.
• Encourage employees to report spills as soon as possible.
• Call Chemtrec, a 24-hour emergency service for spill management, for specific instructions on site neutralization (800-262-8200).

Underground storage tanks are frequently used in turf site maintenance for petroleum storage. A leaking underground storage tank represents a fire and explosion hazard, as well as a fume hazard, and is a serious threat to groundwater. Environmental contamination of groundwater with hydrocarbons increases the potential exposure to benzene and ethyl dibromide, which are suspected cancer-causing agents.

Piping failure, spills and overfills, and tank corrosion are the main causes of leaks from underground storage tanks. The EPA estimated that 80% of all spills were the result of failure or fatigue of piping systems. Many of these failures were caused by improper installation and maintenance. The corrosion of tank walls and the failure of fiberglass-reinforced tanks are other leading causes.

An aboveground storage tank with containment walls is the preferred method for storing chemicals. For more information, contact your fire marshal.

Given the difficulty and the cost of cleanup, underground storage tanks at your site should be monitored closely. Specific preventive measures including installation of double-walled tanks, early detection of leaks, inventory control, monitoring, and tightness testing can avoid leaks.

Water quality should be considered in all stages of turf area design, construction, and maintenance. Some factors to consider have been outlined in this publication to help protect water quality — one of our most precious resources.