The Wolf River is one of several western Tennessee-northern Mississippi streams that flow northwest from Coastal Plain uplands to the Mississippi River. The origin of the Wolf River is typically attributed to small, spring-fed Bakers Pond, in northeastern Benton County, Mississippi. From its origins, the Wolf River flows approximately 100 miles through Benton County, Mississippi, and Fayette and Shelby counties in Tennessee to discharge into the Mississippi River. The Wolf River watershed comprises 522,000 acres, including much of the city of Memphis, which relies on the underlying Memphis Sand aquifer, recharged in part by the Wolf River watershed, as its public water source. Primary tributaries of the Wolf River include the North Fork of the Wolf River, Indian Creek, Shaws Creek, Grays Creek and Fletcher Creek from the north, and Grays Creek (Mississippi) and Clear Creek from the south.
The Wolf River is a low-gradient, sandy bottomed stream with a sinuous and sometimes braided channel and high-quality riparian wetlands in its upper reaches. The river is channelized for 7.5 miles in Mississippi, and for its last 23 miles in Shelby County, Tennessee. Portions of the upper, rural Wolf River are included in the list of Exceptional Waters of Tennessee, though the final third of the river – the urban Wolf from Collierville to the Mississippi River - is on the Tennessee Department of Environment and Conservation’s (TDEC) 303(d) list of impaired waters, meaning water quality is impaired by such issues as storm water runoff, sedimentation exacerbated by channelization, and historic industrial contamination. Water quality can be thought of as a measure of the suitability of water for a particular use based on selected physical, chemical, and biological characteristics. To determine water quality, scientists first measure and analyze characteristics of the water such as temperature, pH, dissolved oxygen, and number of bacteria. Selected characteristics are then compared to numeric standards and guidelines to decide if the water is suitable for a particular use.
Water quality is important in both surface water in rivers, streams, lakes, and wetlands, and groundwater present underground in soil, sand, gravel, or rock formations. In general, the water quality of the rural Wolf River is better than that of the urban Wolf River. The quality of water stored in the Memphis Sand Aquifer, while generally excellent, is the subject of ongoing research by the University of Memphis (CAESER); all drinking water pumped from the aquifer is tested by Memphis Light, Gas, and Water before.