Analysis of water temperatures in Conowingo Pond as influenced by the Peach Bottom atomic power plant thermal discharge

Numerical surface water hydrodynamic and transport models have been traditionally applied to predict power plant thermal impacts under design conditions. The need to understand both thermal impacts and receiving water biogeochemical impacts and associated ecological and health risks under highly variable transient conditions on seasonal to annual time scales necessitates the use of predictive multidimensional modeling systems. Over the last decade, three-dimensional hydrodynamic and reactive transport modeling has matured from a research subject to a practical analysis technology. Simultaneously, computational requirements for realistic three-dimensional modeling have changed from super computers and high-end workstations to economical commodity personal computers. This paper describes a three-dimensional surface water model system, the Environmental Fluids Dynamics Code (EFDC), capable of addressing a variety of power plant impact issues, including thermal transport, water quality-eutrophication, and toxic contaminant transport and fate, in surface water systems. The development history of the model and its previous applications, as well as its theoretical and computational formulations are presented. Model extensions addressing coupled near- and far-field thermal transport due to high velocity cooling water discharges are discussed in detail. To illustrate the model’s capabilities, preliminary results of thermal transport in Conowingo Pond associated with the Peach Bottom Atomic Power Station’s (PBAPSs) discharge are presented and compared with field observations.