An intensive quality of water study was conducted on Little Copiah Creek in the vicinity of Crystal Springs, Miss., from August 19 to August 21, 1980. The quality of water in Little Copiah Creek improved 7 miles downstream of a source of wastewater inflow. The mean total nitrogen concentration decreased from 17 to 1.1 milligrams per liter and the mean total phosphorus concentrations decreased from 5.8 to 0.39 milligrams per liter. The maximum five-day biochemical oxygen demand decreased from 14 to 1.4 milligrams per liter while the dissolved-oxygen concentration increased from 2.0 to 6.9 milligrams per liter. The maximum fecal coliform and fecal streptococcus densities at the upstream sampling site were 2,200 and 6,700 colonies per 100 milliliter, respectively, and were observed to decrease downstream to 160 and 1,500 colonies per 100 milliliters. The mean stream temperatures decreased downstream only slightly from 26.5 to 25.0 Celsius and the pH of the water ranged from 7.2 to 7.4 units upstream and 6.5 to 7.0 units at the downstream site. The average rate of dye travel through the upstream 2.3 mile reach was 0.08 miles per hour during the study. (USGS)