Climate variability and the sensitivity of downstream temperature to treated wastewater discharge: a simulation analysis

Abstract

Anthropogenic influences and climate variability and change pose a challenge to conserving cold-water resources and associated biota in the US Rocky Mountain region. State and federal regulators set temperature standards for point-source wastewater dischargers to maintain healthy stream conditions. Regulators use recent receiving water data and temperature standards to calculate permitted effluent temperature and discharge. Thus, changes in receiving waters, especially stream temperature or discharge, may have a significant effect on permit levels for a wastewater treatment facility. Therefore, understanding the effects of climate variation on stream discharge and temperature is important in assessing potential changes to future wastewater effluent permits. In this study, we analyzed the challenge of keeping downstream temperatures below established maxima in the face of climate-induced variations in stream discharge and temperature.