Percentage of Surface Drinking Water from Intermittent, Ephemeral, or Headwater Streams in Tennessee Clarksville Johnson City Nashville Oak Ridge Knoxville Murfreesboro Columbia Memphis Chattanooga • s " ifcD STA l mj Miles. Key: Intermittent, ephemeral, and headwater stream miles as percentage of total stream miles contained in all SPAs for a given county ~ 0.42% - 44% ~ 45% - 56% ~ 57% - 69% | 70% - 86% | 87% - 100% ~ No Data Legend: This map highlights regional patterns of dependence on intermittent, ephemeral, and headwater streams for surface drinking water in Tennessee. In Tennessee, 18,464 total miles of streams provide water for surface water intakes supplying public drinking water systems; of this, 10,585 miles, or 57%, are intermittent, ephemeral, or headwater streams. Over 3.5 million people in Tennessee receive drinking water from public drinking water systems that rely at least in part on intermittent, ephemeral, or headwater streams. This analysis compared the stream length of intermittent, ephemeral, and headwater streams to total stream length within all mapped Source Protection Areas (SPAs) for each county. A SPA is an area upstream from a drinking water source or intake that contributes surface water flow to the drinking water intake during a 24- hour period. This is based on data that generally do not include streams less than one mile in length. Intermittent streams are streams containing water for only part of the year. Ephemeral streams flow in response to precipitation events. First-order streams have been used to represent headwater streams. ------- |