Three-dimensional modeling of thermal stratification of a deep and dendritic reservoir using ELCOM model

The fate and transport of contaminants induced into a deep and stratified reservoir after flood events are largely governed by the thermal structure of the reservoir. For last two decades, diverse three-dimensional (3D) hydrodynamic and water quality models have been developed and applied for supporting reservoir water quality management, but validation of the models to simulate stratification processes in deep and dendritic reservoirs in monsoon climate region is rare. The study was aimed to evaluate the performance of a 3D hydrodynamic model, ELCOM, in a deep and dendritic reservoir located in Geum River of Korea for simulating heat fluxes and stratification processes. The model was applied to two different hydrological years; dry (2008) and normal (2009), and validated against extensive field data. The model showed satisfactory performance in simulating the water temperature profiles within the acceptable errors at all monitoring stations. The turbid density flows induced by flood events incurred a significant modification of the structure of thermal stratification, and which was well replicated by the model. In addition, the model reasonably captured the instant surface vertical mixings that observed during flood and strong wind events. The net heat flux across the free surface was positive (gain heat) from April to September, which resulted in the development of thermal stratification in the reservoir.

► We evaluate ELCOM for a deep and dendritic reservoir in monsoon climate area.
► We examine the model for different hydrological years; dry and normal.
► Flood flows incur modifications of thermocline and stratification structure.
► ELCOM captures instant vertical mixings observed during flood and strong wind events.
► ELCOM shows proper performance and simulates the observation within tolerable errors.