Date of this Version
Physiochemical and bacteriological conditions along with the macroinvertebrate community structure were studied to evaluate water quality of the Big Blue River, in southeastern Nebraska. Samples were taken between November 7, 1978, and December 19, 1979, at six stations from the headwaters to lower reaches of the river. Some sample sites were below specific municipal and industrial effluents to evaluate better their impact on water quality. Parameters measured included pH, temperature, dissolved oxygen, suspended solids, conductivity, biochemical oxygen demand, nitrate, ammonia, and fecal coliforms. Dissolved oxygen and nitrate were significantly different (p<0.05) between stations, with the headwaters station exhibiting the greatest difference in water quality. Fecal coliforms were substantially higher at stations below Crete. The macroinvertebrate fauna comprised 42 and 66 taxa collected with Ekman grabs and multiplate artificial substrates, respectively. Average diversity values, using the Shannon-Weaver index, indicated all stations would be categorized as moderately polluted. Taxa collected at the stations showed a great deal of homogeneity. An exception was the headwaters site where pollution-associated taxa were found in abundance. Seasonal changes were an apparent factor affecting diversity of the macro invertebrates. The results collected provide useful baseline information for future evaluation of water quality trends of the Big Blue River.