What is stormwater pollution?

Stormwater pollution is the untreated contaminated water that drains from the streets of North Augusta, and through the municipal storm drain system. The runoff eventually drains into the Savannah River.

The most common pollutants are:

• trash (fast-food wrappers, cigarette butts and Styrofoam cups)
• toxins (used motor oil, antifreeze, fertilizer, pesticides, sewage overflow and pet waste)

These pollutants can be picked up during rain storms. The polluted stormwater then enters the city’s storm-sewer system through catch basins and inlets located on our streets. From there, the stormwater flows through a system of pipes and open channels – straight to the Savannah River, untreated.

Basically, anything dumped or dropped on the ground or in the gutter contributes to stormwater pollution. Most of these common pollutants are not biodegradable and can be harmful to all living things in our local streams and waterways. Creatures especially sensitive to pollution are fish, amphibians, aquatic insects, wetland plants, and all animals that use the water to survive. Humans can be affected by stormwater pollution in several ways. Eating fish from or playing in polluted water can cause health problems. In addition, the Savannah River is where we get our drinking water. The city withdraws the water and then treats (cleans) it so it is safe and clean to drink. Polluted water is harder and more costly to clean. Having a beautiful river and clear running streams free from pollution is very important. These are a few of the many reasons that it is important for all of us to work together to protect our streams and river from pollution.

Other problems that can be created from stormwater pollution include increased flooding due to clogged storm drains, stream channel degradation from overflowing or blocked lines, and habitat loss or alteration. Sediment and erosion during flooding or heavy downpours can scour smaller stream channels and dump huge gravel and silt loads into them that can ruin fish and amphibian habitat. These loads can obliterate small streams, springs and wetlands. All of these activities affect ecosystem functions, biological diversity, public health, recreation, economic activity, and general community well-being.

The table below explains the categories of pollutants and what chemicals they can contain. Sediment is a key transporter of contamination since many of the pollutants listed will bind to the sediment and then will “wash off” when mixed with water in streams in rivers.

Sources of pollution

Vehicles:
Driving a car or truck contributes a number of different types of pollutants to urban runoff. Pollutants are derived from automotive fluids, deterioration of parts, and vehicle exhaust. Once these pollutants are deposited onto road and parking surfaces, they are available for transport in runoff to receiving waters during storm events.

Roads and Parking areas:
In many communities, most impervious cover is related to the transportation system. Material accumulates on these surfaces during dry weather conditions, only to form a highly concentrated load of pollution during the first flush (stormwater runoff during the first minutes during a downpour) during storm events.

Lawns & gardens:
Landscaping practices are another potential source of pollutants in urban runoff. Turf management chemicals including fertilizers used at home and on golf courses, cemeteries, and public parks can add nutrients to runoff. Monitoring has shown a direct link between the chemicals found in lawn care products and urban water quality. While there remain questions on some details of the contribution of turf management to receiving water quality, it is clear that the type, quantity, and timing of materials used make a significant difference.

One important variable is the quantity of chemicals being applied. Over or improper application at homes and other places is far too common. Experts estimate that residential fertilizer use accounts for one-third of the excess nitrogen entering the Sarasota Bay watershed in southwest Florida. Of particular concern is the application of fertilizers and pesticides just before an intense storm event, since they may not have had time to become fixed in the soil and thatch.

Similarly, harmful pesticides found in stormwater, such as chloropyrifos, 2,4-D, and diazinon come from golf courses, municipal parks, highway medians and roadsides, and residential lawns and gardens. The percentage of pesticide lost in runoff can be large; one study found up to 90 percent of the herbicide 2,4-D was lost in runoff after being applied a few hours before a storm event.

Since organic matter contains nutrients, raking autumn leaves or grass clippings into gutters or streets for municipal collection or otherwise facilitating the entry of these materials into the storm-sewer system also adds nutrient loads and oxygen-demanding substances to stormwater. Poorly maintained garden beds or lawns can be a source of sediment as well.

Construction Sites:
Construction activity is the largest direct source of human-made sediment loads. Results from both field studies and erosion models indicate that erosion rates from construction sites are typically an order of magnitude larger than row crops and several orders of magnitude greater than rates from well-vegetated areas, such as forest or pastures. Since erosion rates are much higher for construction sites relative to other land uses, the total yield of sediment and nutrients is higher. Studies indicate that poorly managed construction sites can release 7 to 1,000 tons of sediment per acre during a year, compared to 1 ton or less from undeveloped forest or prairie land. Construction activity can also result in soil compaction and increased runoff. Like nutrients, soil and sediment are, to a certain degree, a naturally occurring and functional component of all waterbodies. Yet human activities usually increase the amount of sediment entering our waterbodies to such an extent as to turn sediment into a water quality problem.

Illicit Connections to Storm Sewers:
Illicit connections from toilets to storm sewer pipes can add pathogens to stormwater. Pathogens are viruses, bacteria, and protozoa harmful to human health. Coliform bacteria, which come from human waste, is commonly used as an indicator that harmful pathogens may be present in the water. Studies have found high levels of coliform bacterial in stormwater. Illicit sanitary connections can also add nutrients such as nitrogen and phosphorus to stormwater. Human waste also contributes to biological oxygen demand (BOD) in our waters. Leaking sanitary sewer lines located near storm sewer lines can pose the same problems as illicit connections. Businesses that illicitly connect pipes containing wastewater from industrial processes to the storm sewer system rather than to the sanitary sewers can add metals, solvents or other contaminants to stormwater

Uncovered storage of materials:
Rain can erode piles of uncovered bulk material, such as sand, loose topsoil, or trash if left uncovered, adding sediment, oils or other pollutants to nearby waterbodies. Likewise, precipitation can wash contaminants off leaking or dirty objects left outdoors such as oil drums, paint cans, herbicide/pesticide containers, trash containers, or other items that are not sealed.

Pets and wild animals:
Waste from domestic and wild animals is a source of pathogens, nutrients and BOD in stormwater. In one study, the Northern Virginia Soil and Water Conservation District estimated that each day, dogs leave 180,000 pounds of waste on the ground in Fairfax County, Virginia, alone.Waste from birds such as pigeons, geese, and gulls that are attracted to human activity can also be a problem. Wild geese that congregate in large numbers on cultivated turf adjacent to bodies of water also contribute to pathogen, nutrient and BOD loadings.

Littering:
Not only does stormwater frequently receive no treatment, it also often does not even have the benefit of simple filtering or screening for visible objects. As a result, paper cups, cigarette butts, virtually anything made of styrofoam, newspaper, and other materials that people toss on the ground are carried into storm sewer systems -- and eventually into our waterways.

Source: NRDC report “ Stormwater Strategies Community Responses to Runoff Pollution”.