Thermal discharge effects on dissolved oxygen in an urban estuary

As part of the permitting process for power generation plant repowering, the impact of once-through cooling to estuary dissolved oxygen concentration was examined. This included field investigation of temperature and dissolved oxygen concentration with depth at various places in the estuary under different plant operating conditions, statistical analysis of the resulting data, calibration of a water quality model to the data set, and use of the model to predict the impact of the repowered facility under drought conditions. It was concluded that the once-through cooling operation had a positive impact on estuary dissolved oxygen by its destratification of the water column and its introduction of dissolve oxygen into the effluent by turbulent mixing