What does this measure?
The number of streams designated as impaired, defined by the Tennessee Department of Environment and Conservation as having high levels of particular pollutants, nutrients, pathogens, acidity, silt, or altered habitats.
Why is this important?
The health of waterways impacts wildlife, agriculture, and recreation, and is also an indicator of land health. Although some water pollutants come from industrial discharges, many arise from increased runoff from development and impervious surfaces, such as roads and rooftops, pollution from agricultural operations (including animals causing erosion of stream banks and eliminating waste into the water), and channelization.
How is our region performing?
In 2014, there were over 2,000 miles of impaired streams in our region, up 31% from 2004. Of the counties in the region, Knox had the highest number of impaired stream miles, 391, followed by Blount with 287. Union had the fewest miles of impaired streams in 2014, but experienced an increase of 172% since 2004, the fastest rate of increase of any other county in the region.
Notes about the data
Assessed streams are designated as unimpaired or impaired based on whether a stream supports all intended uses. Uses may include drinking, industrial processes, agriculture, irrigation and recreational activities such as fishing, boating and swimming.