Streams and Waterbodies in Tennesse The National Hydrography Dataset ^ a w^mmmSfrmWLl mgam iiSSIKi |« WW&Mi This map displays the pattern of different surface water feature types across the state of Tennessee, including perennial, intermittent and ephemeral streams. Perennial streams generally contain water throughout the year, except for periods of extreme drought. Intermittent streams contain water for only part of the year, while ephemeral streams flow only in response to precipitation events. Although the intermittent and ephemeral stream classifications are distinguished from each other in the dataset, many ephemeral streams are included in the "intermittent" category. In addition, some ephemeral streams in the Southwest have been classified as washes. Only recently, and mainly on U.S. Forest Service land, have streams been added to the dataset under the "'ephemeral" category. No streams in the state have yet been classified in the ephemeral category (data current as of October 2009). The map highlights the distribution of intermittent and ephemeral streams across the state. Of the 100,946 miles of linear streams in Tennessee, 32 percent (31,851 miles) are intermittent or ephemeral. Less than 1 percent of streams are ditches (679 miles), which are not classified by their flow duration in the dataset. The water features on the map are from the National Hydrography Dataset (NHD) at high resolution (1:24,000 scale or higher). Many smaller waters are not included in the NHD because they could not be detected on the original aerial photos used to create the dataset or were excluded from the maps from which the dataset originates. The majority of perennial and most intermittent streams are captured at this resolution. However, most ephemeral streams are not captured unless they are in the arid west. Additional information on the NHD can be obtained from the NHD website at https://nhd.usgs.gov. EUSGS Uffiy science for a changing world pro^g^ SURFACE WATER FEATURES ~ STREAM/RIVER - PERENNIAL ~ STREAM/RIVER - INTERMITTENT ~ STREAM/RIVER - UNCLASSIFIED ~ CANAL/DITCH ~ LAKE/POND OR RESERVOIR ¦ SWAMP/MARSH ~PLAYA ~ WASH EZI STATE BOUNDARY 0 25 50 100 Miles This map relies exclusively on USGS data for mapping water resources such as streams and other waterbodies. Due to the resolution of the map, it does not distinguish effectively between land and water and thus Prepared by INDUS Corporation under contract with makes waters appear more prevalent than is actual. This map does not depict the scope of waters protected under the Clean Water Act or the scope of waters that would be protected under the Army/EPA proposed U.S. Environmental Protection Agency , . , . , , . . Office of Water - Washington, DC rule. This map has not been used tor any regulatory purpose. , ° F j f f October 2013 ------- |