All living things depend on water for survival. For this reason, all living things are dependent on healthy watersheds. Water travels through watersheds across a variety of habitats and ecosystems and eventually will empty into the ocean (with the exception of the watersheds of the Great Salt Lake and the Dead Sea). Because watersheds affect all of the ecosystems in the world, they also affect all of the living things in the world. A contaminated watershed can be devastating to a large number of species in a variety of communities.

Water is easily contaminated because of its property as a universal solvent. This property is also one of the things that makes water so important to living things. Many substances dissolve in water. Because some substances have electrical charges that are attracted to the electrical charges of water molecules, the molecules of these substances will bond with the molecules of the water. This is what happens when salt or sugar is poured into a glass of water. The salt or sugar molecules will bond with the water molecules and, to the eye, seem to disappear. Because of this solvent property, water is necessary for digestion and for transporting substances around an organism’s body. In animals, water helps to break down food into its usable nutrients, and then the water in the blood helps to carry the nutrients to the various cells of the body as well as carry the wastes out of the body. 

This property that allows water to break down and transport nutrients in living things also breaks down and transports contaminants in watersheds. Chemicals or other impurities that are dropped into watersheds will be dissolved in the water and transported through the watershed, potentially across large areas of land. Anything that drinks this contaminated water will also be drinking the dissolved contaminants, with potentially unhealthy results for the organism.

Because a watershed can be as large as half a continent, contamination is never completely localized within a watershed. Contaminants released in a watershed near Greenville will travel across South Carolina to the coast through the Santee Watershed. Contamination on the Yellowstone River in Montana will eventually travel across the states to Louisiana and the Gulf of Mexico through the Mississippi River Watershed. For this reason, when thinking about how to improve the health of a watershed, the entire breadth of the watershed has to be considered.

Contaminants enter watersheds through a variety of means. One type is categorized as point source pollution. Point source pollution enters the environment from an identifiable source, such as from a discharge pipe of a factory. Industries that have identifiable discharges include livestock farms, landfills and water treatment plants. These industries discharge many different kinds of pollution, ranging from livestock manure to industrial chemicals. 

Half of the pollution in our nation’s waters comes from non-point sources. Non-point sources of pollution include you, me and everyone else that you know. Non-point source pollution is pollution that comes from sources that cannot be directly pointed out. An example of non-point pollution is the fertilizer that people put on their lawns. When excess fertilizer washes off of the lawn during a rainstorm it can enter the watershed as runoff. Runoff is water that flows on the surface across lawns, roads and other landscape features. Pollution can be carried or dissolved in runoff and enter the watershed. Once in a body of water, the pollution can be sensed with the proper equipment, but it can not be directly linked to any particular lawn in the community. Nonpoint pollution originates from urban areas, agriculture land, construction sites, lawns, and some industries, such as mining. The main elements of polluted runoff are heavy metals, salts, sediment, nutrients, and bacteria.

Sediment can also be a contaminant in watersheds. Runoff picks up soil as it travels over land. When vegetation is removed from land for farms, the roots that held the soil in place are no longer there, and the rainwater will easily erode it away. This sediment is eventually carried in to the watersheds and can make major changes in the quality and appearance of the water. For example the reddish-brown water we associate with the rivers of the Piedmont of South Carolina is not their natural appearance. These rivers were clear until poor farming practices were introduced into the Piedmont, and all of the exposed red clay soil in the fields began washing into the rivers and streams of the area.

Excess nutrients are considered contaminants in watersheds. Nutrients in watersheds are important because they support food chains in the aquatic communities. Too many nutrients can cause major problems, though. Excess nutrients can lead to algal blooms in which the fast-multiplying algae explodes in population because of the sudden influx of nutrients. The new algae will use up all of the oxygen in the ecosystem which in turn will lead to fishkills in which all of the animals in the aquatic ecosystem die because of lack of oxygen. Excess nutrients get into watersheds often through fertilizers that are put on farms and lawns. Fertilizers are artificial nutrients that are laid on fields and then brought into watersheds through surface runoff. These are then carried to coastal areas where they can cause algal blooms.

Most contamination in watersheds occurs on a steady continuing basis, but at times the contamination can be sudden and devastating. An example of this was when Hurricane Floyd hit the Coastal Plain of North Carolina in 1999. The deluge of water brought into this area by the heavy rains of the hurricane flooded the large pig farms and other farms of the area as well as the septic tanks of many rural homes. All the wastes from these farms and septic tanks began being carried by surface runoff into the PeeDee River Watershed. Along with the wastes came an abundance of bacteria known as fecal coliforms (the most famous one is E. coli) into the watershed. Because fecal coliforms are dangerous to animals, those who lived downstream of these farms and septic tanks in the Pee Dee Watershed around Myrtle Beach and Georgetown, could not drink untreated tap water for months because they would become seriously sick. This bacteria also affected wildlife, particularly filter feeders such as oysters. Many oyster beds have to be closed because the oysters have an abundance of fecal coliforms in their bodies.

Since over 50% of contamination in watersheds come from non-point pollution, students can do a great deal to help reduce contamination in local watersheds. Below are some examples of things the students or their parents can do to help local watersheds:

• Conserve the amount of water they use on a day-to-day basis. The less water used will reduce the amount of wastewater that will eventually enter the watershed.

• Recycle and compost. The less waste that enters landfills, the less contaminants that the landfills will be giving off.

• Pick up litter. Contaminants leach off of litter and enter watersheds or the litter itself will enter watersheds.

• Bury or flush pet wastes. Pet wastes left in lawns becomes homes to fecal bacteria that can be picked up by runoff and carried into watersheds.

• Only purchase and use environmentally friendly cleaners, pesticides, herbicides and fertilizers. The chemicals in many of these products can be very detrimental to living things and can be easily picked up by runoff and carried into local watersheds.

• Properly dispose of any chemical products. Never dump products such as oil, antifreeze, paint remover, cleaners and paint onto the ground or into storm drains. Contact local waste management professionals to find safe receptacles for these products.

• Plant native plants around the school and home. Because native plants are adapted to the local environment, they require less watering and fertilizer than exotic plants, and so reduce wastewater and runoff amounts.

• Educate others. The more people who understand the problems and solutions involved in watersheds and become involved in helping, the less non-point pollution will be produced.

• Become involved in watershed conservation projects. Projects such as the EPA's "Adopt a Watershed" allow students to become involved in an organized collective effort to continually improve the health of watersheds.

• Write public officials about issues related to watershed conservation. There are many ways to help watersheds that can be fostered with government support.

  • Preserve and create wetlands. Wetlands are very important for the health of watersheds. Wetlands slow the speed of runoff and reduce the amount of erosion that brings sediment into rivers and lakes. The vegetation and mud in wetlands also act as filters that hold impurities and so help clean watersheds. 

  • Preserve and create riparian zones. Riparian zones are areas of vegetation around rivers, lakes, wetlands and other bodies of water that act as buffer zones for watersheds. Like wetlands, riparian zones slow runoff and erosion as well as filter out impurities, helping to keep watersheds clean. Maintaining riparian zones helps to keep watersheds healthy.

  • Slow development that increases impermeable surfaces. Construction of roads and buildings creates impermeable surfaces on which water can not soak through. This increases the amount of runoff entering watersheds, much of it containing contaminants such as oil that collect on these impermeable surfaces. By reducing development, the contaminants entering watersheds will also be reduced.

  • Raise controls on the pollution emissions of industry. Waste given off by industry contaminates watersheds. By carefully controlling how industries dispose of their waste, less contamination will enter watersheds.

  • Increase wastewater treatment facilities. The water leaving our homes and businesses though our sinks, bathtubs and toilets are often full of contaminants. Sending this wastewater to a treatment plant helps to remove these impurities before they enter a watershed.

  • Conserve entire watersheds instead of just isolated habitats

This last idea is probably the most important. Watersheds connect habitats and ecosystems across a large area of land. For this reason, a section of a river cannot be conserved and expected to have healthy water quality unless the areas of rivers and streams upstream in the watershed are also conserved. Because watersheds are such large areas and inhabited by so many different species, maintaining the health of any watershed is of great importance. Because people often inhabit all areas of a watershed as well, it takes a collaborative effort on the part of everyone living on the watershed to help keep the watershed healthy. By being conscientious and by spreading the word to others, everybody has the opportunity to make a difference in improving the health of watersheds.