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Water Quality Facts for TN

Poor Water Quality Found in State Streams

The Tennessee Department of Environment and Conservation (TDEC) has estimated that about 30 percent of the state's streams are of such poor water quality that they cannot support a healthy population of fish and other aquatic wildlife, and almost 40 percent are not fit for human recreation. That means that many of our streams are not fit for our children to play in and that we can no longer catch the fish that our grandparents did.  It also translates into higher utility bills, with more resources going towards water treatment.

Urban Pollutants Wash into Streams 

Urban development typically brings a series of changes to a natural area that overwhelms a stream with a host of problems, such as the:

  • Sharp increase in impervious surfaces like concrete, asphalt and rooftops, which together create rapid runoff that pick up pollutants along the way to the nearest stream
  • Loss of watershed-wide vegetation, resulting in erosion and deposition of sediment into streams
  • Reduction of vegetated stream buffers that stabilize streambanks, absorb nutrients and cool streams by providing canopy cover
  • Decrease in native, deep-rooted vegetation that does a better job stabilizing soil

Tennessee's Changing Landscape

From 1992 - 1997, 68 acres of farmland were lost to urbanization EVERY day. During this same time period, Tennessee ranked seventh in the nation of total acres of land developed.
According to the 2000 Census, Tennessee's population was more than 5,689,000, a 14 percent increase from the 1990 Census.

Nonpoint Source Pollutants Originate from Residential Areas

Pollutants originating from no single source of discharge are called nonpoint source (NPS) pollutants and currently pose the greatest challenge to improving the health of Tennessee streams.

Nutrient runoff is, in part, from mismanaged fertilizer applications to lawns and the use of soaps that contain phosphates (washing the car, e.g.). When used on impervious surfaces, these chemicals result in nutrient-enriched runoff.

Sources of sediment input into streams is from bare spots on the lawn, exposed soils in gardens, eroded ditch lines and areas around the home that are under construction.

Toxic chemical sources include pesticides that have been misapplied or inappropriately stored outside. Household cleaning supplies that have been stored outdoors in open or leaking containers are also a souce of pollution. Another source of urban toxins are leaky cars parked on driveways or spilled car fluids.

How NPS Pollutants Impact Aquatic Wildlife

Pollutants affect aquatic wildlife in a variety of harmful ways:

  • Nutrients include nitrogen and phosphorus that act on algae in streams the same way they act on grass and garden plants, by increasing the growth rate and size. However, the decomposition process of large amounts of algae robs the water of oxygen, consequently smothering fish and other aquatic animals.
  • Sediment clogs fish gills, fills up aquatic habitat, including the cracks and crevices between streambed rocks where aquatic insect larvae reside. It also decreases the ability for fish to see for both mating and foraging purposes. In addition, sediment darkens our waters, resulting in increased heat absorption and escalating waterbody temperatures (just like when you wear a dark t-shirt versus a white one). It also causes flooding by reducing capacity channels.
  • Toxins can play havoc with aquatic animals' reproductive and nervous systems, among other effects. Birth defects and skin diseases are more common in fish inhabiting contaminated waters.


Pollutants Are Everyone's Responsibility

A recent study in the Beaver Creek Watershed in Knox County, Tennessee indicated that up to 40 percent of sediment entering Beaver Creek may be coming from residential areas.

Other studies indicate that residential areas also are contributing a relatively greater proportion of NPS pollutants to our waterways than in the past. In part, this is because there are simply more subdivisions in closer proximities, with more roads, more cars, and more lawn chemicals.

Because we are all, in some way, contributing to the problem of NPS polllution, the only way to stop the pollution is for all of us to take responsibilbity for our actions and adopt cleaner, greener methods of urban living. By each of us changing a few practices on the homefront we can together start to turn the tide so that our communities can continue to grow, but in a smarter, more sustainable way where conservation and development coexist.


Tennessee Smart Yards Gives You the Information You Need to Make a Difference

The Tennessee Yards & Neighborhoods program encourages homeowners to be part of the solution to Tennessee's water quality problems by adopting environmentally sound landscaping practices that are more in line with the natural water cycle. Your yard will absorb stormwater slowly, which, as it percolates downward, is cleansed naturally of toxins. The types of plantings you select will better endure the heat and dry spells and require less irrigation. In essence, you will:

  • Reduce the need for pesticides in your landscape
  • Conserve and protect water resources
  • Recycle and reduce organic wastes going to the landfill
  • Save energy

Want to see how your yard measures up to a Yard Done Right? Check out The Tennessee Yardstick Workbook.​​