Continuous Monitoring of Conventional Parameters to Assess Receiving Water Quality in Support of Combined Sewer Overflow Abatement Plans

Abstract

As part of its long‐term control plan for combined sewer overflow (CSO) abatement, the city of Buffalo, New York, maintained a network of Hydrolab Datasondes (Hydrolab‐Hach Company, Loveland, Colorado) to assess receiving water‐quality effects by continuously logging dissolved oxygen, pH, temperature, conductivity, and turbidity. Although the effect of individual CSOs could be visualized, turbidity levels entering the Buffalo River from the upper watershed often were greater than from CSO discharges. Turbidity data showed that the Buffalo River was a net‐sediment sink. Low dissolved oxygen levels were observed in the summer during dry weather, baseflow, and watershed‐wide storms and CSO events. Some CSOs did not produce dissolved oxygen sags in the receiving waters, but others did. This information, together with the sampling done for organic and inorganic contaminants, can aid the decisionmaking process when prioritizing outfalls for abatement work and provides a baseline against which receiving water‐quality improvements can be measured.