Minimize Pollutants. Significant stormwater pollution can be avoided by removing pollutants from the watershed, using alternative chemicals, using alternative practices, recycling or reducing the use of polluting chemicals and other materials. In addition to the management methods presented here, many innovative ideas can be used to reduce pollutants at specific sites. Managers of industrial and commercial sites and residents of residential areas are in the best position to devise alternate and innovative procedures and new techniques that avoid or reduce pollutants. Industries, municipalities and the public can minimize pollutants. The number of ideas is unlimited. Good examples of pollutant minimization are:

Community hazardous waste and waste oil recycling centers. These activities remove some of the most polluting substances from places where the substances can enter stormwater runoff.

Connecting the drains from vehicle washing areas to the municipal sewer or sanitary sewer system to prevent discharge of the wash water into a nearby stream, if permitted by the local government.

Implementing "Just-in-Time" (JIT) management of materials and finished products to minimize the amount of materials in the stockyard and at the loading dock. JIT management uses very precise scheduling and intensive management to keep the amount of raw or finished products to a minimum, reducing waste, storage costs and clutter. It is intended to reduce overhead and make the workplace more efficient; however, it can also reduce stormwater pollution by reducing exposure of materials to rain.

Using non-toxic or non-hazardous materials in place of hazardous materials, such as water-based degreasers and water-based inks to reduce the amount of solvents and chemicals that enter the environment.

Maintain a clean site to reduce the amount of pollutants available to enter stormwater. Recycle empty drums and remove hazardous substances and wastes as soon as possible. Old stockpile areas and bare areas should be graded and seeded to reduce erosion and improve appearance. Keep loading, unloading and processing areas clean. Sweep parking lots and roads, and dispose of old, unused equipment to reduce the amount of dissolved pollutants that can enter stormwater from the site.

Maintain all pollution control devices in good working order. This will help to reduce pollution in all areas; for instance, air pollution control devices can reduce the amount of toxic substances and particulates, which can get washed into stormwater runoff. Use preventive maintenance to reduce leaks, breakdowns, spills and accidents. Replace worn seals, fittings and other parts before they leak or break.

Begin a spill prevention and response program to train employees how to prevent and respond to spills. Provide employee training to enable all employees to recognize and avoid situations such as spills or accidents which could cause stormwater pollution.

Education programs. Too much pollution enters streams, rivers and lakes through carelessness or ignorance. Many people will adapt new methods or use alternative materials if they are better informed of techniques that can reduce the impacts on receiving waters.

Industrial employees can learn proper methods to handle and store materials and dispose of industrial wastes through in-house training courses, videotape presentations and interactive seminars. Local libraries and government agencies, such as the Cooperative Extension Service and the Industrial Extension Service at North Carolina State University, often have educational materials to use in training.

Municipalities can sponsor public presentations, school programs and mailings. Citizens should learn proper disposal of litter, yard waste, used motor oil, and other household wastes. Education programs may reduce the size and expense of stormwater control facilities by reducing the pollutants at the source.

Citizen's groups can sponsor programs to teach the public ways to protect water quality.

Landscaping and lawn maintenance controls. Significant amounts of fertilizers and pesticides enter the water from lawn maintenance and landscaping activities. Plant fertilizer promotes eutrophication, or the over fertilization of aquatic plants in water. The fertilizer causes excessive growth of plants in the water, choking out desirable plants and animals and reducing the recreational value of the water body. Many pesticides can kill aquatic animals and contaminate drinking water supplies.

Both homeowners and professional services may over-apply fertilizers and pesticides in home landscapes creating potential for water pollution. A bright, emerald-green lawn usually has received too much fertilizer and pesticides and will lose these pollutants to runoff. Low maintenance plants and shrubs can be used to reduce the amount of fertilizer and pesticide necessary. Fertilizer or pesticides should not be used near water bodies unless absolutely necessary because the runoff will carry the fertilizer and pesticides directly into the water. Application procedures require special attention when applying pesticides near water.

Contracts for maintenance of industrial grounds can specify minimal fertilizer and pesticide use. Managers may investigate the use of hardy perennials which do not require as much fertilizer as less-hardy vegetation. In addition, fertilizer should be applied only during the growing season at the minimum amounts necessary to obtain the desired results.

Local governments should reduce their use of fertilizer and pesticides to the minimum to maintain property. Ordinances may be used to control the use of pesticides and fertilizer by professional landscaping services. Particular attention should be paid to certain areas of high-intensity landscaping, such as cemeteries and golf courses, which may contribute large amounts of excess fertilizer and pesticides to runoff.

Local governments can start programs for area-wide composting using yard wastes picked up at the curb. The compost can be sold or given to local gardeners and lawn maintenance crevices. Homeowners can dispose of yard wastes through composting at home or through area composting services.

Animal Waste. Animal wastes contribute significantly to the bacteria in stormwater runoff.

Industries that generate animal wastes should dispose of the wastes in an approved manner. Under certain conditions, spreading of animal manure on fields can cause severe nonpoint source water pollution problems. Assistance in determining proper disposal can be obtained from state agencies, local universities and the Cooperative Extension Service.

Pet wastes are a source of bacteria that can be controlled through ordinances requiring collection and removal of the waste from curbside, yards, parks, roadways and other areas where the waste can be washed directly into receiving waters. The ordinance should include instructions for proper disposal of animal wastes. Pet owners should remove wastes from street gutters and dispose of the waste where it will not be washed into streams. Wastes can be buried or flushed down the toilet.

Eliminate Curbing. The elimination of curbs has been shown to reduce pollution entering the aquatic environment. Because curbs function as channels for both vehicles and stormwater, runoff flows at high velocities in curbs, carrying with it many pollutants and much sediment. Without curbs, runoff can be spread over much larger areas, which are generally covered with vegetation. If dispersed over large vegetated areas, runoff velocities are reduced and many pollutants settle out or can be taken up by plants.

Curbs do not have to be completely removed to aid stormwater quality. Sections of curb can be removed and curb outlets can be installed at regular intervals or in appropriate areas to allow the stormwater to flow onto well-vegetated areas. To avoid erosion, flooding and trash accumulation, the areas to install curb outlets should be carefully chosen. On the other hand, curbs can be beneficial to stormwater quality because they keep accumulated debris where it can be easily collected by street sweeping, thus helping to remove potential pollutants from runoff.

Curbs along industrial and commercial access roads, city streets, residential streets, and around parking lots can be eliminated or interrupted with outlets. Outlets for runoff should be chosen so that the stormwater flows onto stable, well-vegetated sites where it will not cut channels, cause erosion or flood private property.

Regular street cleaning can reduce pollutants in runoff as well as improve the appearance of streets and access roads. Cleaning also keeps pipes and outlets in detention structures and ponds from becoming clogged. Additionally, street cleaning reduces bacteria in runoff by removing animal wastes from the curbsides before the wastes enter the water and reduces food sources and breeding areas for insects and rodents. Street cleaning also reduces accumulation of floating material in detention basins and retention ponds, improving the appearance of the basins and reducing the need for frequent cleaning of trash racks and grates over inlets and outlets. New street sweeping machines pick up much finer materials than older models, a feature designed to help reduce the transport of sediment-bound pollutants.

Disposal of street sweeping wastes may pose a problem because of possible high levels of lead, copper, zinc and other wastes from automobile traffic. Testing of street sweepings may be appropriate to determine appropriate disposal or reuse alternatives. Some municipalities and industries have found that street sweepings can be used as cover in sanitary landfills. Street sweepings can be handled as dry solids rather than wet sediment from a detention basin.

Industries should schedule frequent sweeping of access roads, parking lots, truck aprons and loading dock areas. Trash should be cleaned up before it accumulates and shows up as floating debris in the stormwater discharge from the site.

Residents should not use streets and curbs as a disposal areas. Yard wastes and grass clippings should be disposed of in compost piles and the compost used around shrubs and in flower beds.

Debris removal. Stormwater control and conveyance structures need frequent cleaning or these structures may fail if too much debris is allowed to accumulate in them. Litter and yard wastes can clog inlets and outlets and make these devices ineffective in stormwater pollutant removal and an eyesore. Clogged inlets and outlets can lead to overflows, erosion and unintended flooding. Also, when debris is present, streams are more prone to flooding and are aesthetically unappealing. Proper maintenance is the key to long-term operation and pollution control.

Grates on inlets and outlets must prevent entry by children but should be easy to clean.

Forebays, separate sections of detention basins or retention ponds where the incoming water enters, are very useful in promoting proper maintenance and cleaning. It is much easier to clean a forebay than to clean the entire pond. Also, much sediment and debris is removed in a forebay, reducing the pollutants in the water that flows into the main basin. Paving portions of the forebay or the main part of the pond allows quick and easy entrance for maintenance equipment such as backhoes and power excavators. The hard surface is much easier to work from with heavy equipment, which can encourage proper maintenance.

Permeable bottoms for ponds that can support heavy vehicles can be created by using turf blocks or flexible revetment. Such bottoms allow much easier access and thus promote proper cleaning and maintenance.

Reduce Use of Road Salt. Most of North Carolina usually has little problem with the use of road salt. In those areas where salt is used, reduced application or alternative agents, consistent with the need for safety, will reduce pollution of the nearby water bodies. Road salt use should be reduced on all city, state, industrial and commercial roads. Alternatives not only reduce pollution but also reduce corrosion and other damage to vehicles, pavements and bridges. Sand is less harmful to vegetation and aquatic life.

Construct storage facilities to prevent salt exposure to rainfall, thereby reducing pollution of surface and ground water.

Alternatives to salt should be used for driveways and sidewalks. Salt can damage valuable plants if runoff transports the salt to the plant roots.

Catch basin cleaning. Catch basins were originally used to prevent clogging of sewers and provide a water seal to reduce odors from sewer gases. A certain amount of debris and solids collects in catch basins over time. This debris can easily be carried with the stormwater in the next rainfall event, contributing to a "first flush," or a wave of pollutants entering streams during the initial stages of a storm event. If the catch basins are part of a combined sewer system (a sewer system that carries both sanitary wastes and stormwater) the collected debris contains human waste as well as leaves, yard wastes and pet droppings. The debris is often foul smelling and has high concentrations of bacteria.

More frequent cleanings can reduce the impact of resuspended materials that have collected in catch basins, especially near sensitive water resources. Local governments and industries with catch basins in storm sewers or combined sewer systems should consider cleaning catch basins frequently to reduce odors and water pollution.

Return to Surface Water Pollutants and Stormwater Runoff

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Last Modified: 07/10/96