Time-series plots of the data found fecal coliform improving and no longer a concern. Due to the limited amount of data collected, causes for the remaining concerns and possible concerns could not be determined. The North Sulphur River, which flows through primarily undeveloped areas, is the headwater tributary of the Sulphur River. This segment receives drainage from the cities of Paris and Honey Grove. The main tributary of note to the North Sulphur River is Auds Creek, which receives some wastewater discharges.
Dairies are present in the upstream portion of the river, south of Paris.
The other undeveloped areas in the basin are used primarily as cropland. Due to elevated levels of fecal coliform bacteria, the lower 25 miles of the segment do not meet the contact recreation use. The upper portion of the South Sulphur River is the major tributary to Cooper Lake and receives drainage from the city of Commerce. Land use in this watershed is primarily agricultural, with cropland in the upper portion of the segment, rangeland in the lower portion, and forest lands immediately adjacent to the river. Numerous dairies are located on the south side of the river.