Water Quality of a Limited Segment of the Big Blue River in Nebraska

A water quality study was conducted on the Big Blue River in Nebraska, U.S.A., from the city of Seward to the Kansas state line. Fifty-one sites were sampled in a five-day period in August 1973; limited sampling was also done in May 1974. The primary purpose was to evaluate the effects of the effluent of eight sewage treatment plants, located along 196 km (122 miles) of the river upon water quality of the river and to collect baseline ecological data. The following water quality constituents were evaluated: total P, NH3-N, N03-N, 02 (dissolved), pH, temperature, conductance, biological oxygen demand (BOD), coliform bacteria, phytoplankton numbers, pollution-indicator taxa, macroinvertebrate numbers, biomass, and diversity and pollution-tolerant taxa. Phosphorus and total nitrogen levels were not markedly higher below the sewage treatment plants (STP). Also, STP effluent seemed to have little effect on temperature, pH, conductance, oxygen, or BOD of the river water. Coliform bacteria levels were elevated downstream from some SIPs, and were generally higher than the limit for Class A water quality. Macroinvertebrate indices showed the Seward sites to have the best water quality, with deterioration of water quality especially prevalent at the Milford and Crete sites