Water temperature has significant and systematic effects on biological processes at all levels of organization
Water temperature shapes aquatic ecosystems in profound ways — influencing dissolved oxygen levels, biological activity, and the habitat ranges of cold-water species like trout and salmon. For power plant operators and water managers, modeling thermal discharge impacts is essential to protecting these systems and meeting regulatory requirements.
EFDC+ delivers a comprehensive suite of temperature sub-models, including surface heat exchange, solar radiation, a bed thermal model, and an ice sub-model for cold-climate applications. For thermal power plants, EEMS simulates once-through cooling system impacts — including forced evaporation — giving operators the analytical foundation to demonstrate and maintain thermal compliance with confidence.
A 3D EFDC+ model investigated flow velocity vs. thermal stability near a weir, finding the critical flow velocity to avoid persistent stratification is ~0.1 m/s.
Characterized Laguna Lake’s water temperature, finding it thermally unstratified with mean temps of 25–29 °C.
Directly evaluates how well different model settings reproduce lake thermal stratification.
Lake Washington’s steep bathymetry and decades of high-quality temperature observations make it a benchmark site for EFDC+‘s Sigma-Zed vertical layering. DSI constructed a 1,183-cell, 55-layer model that accurately reproduces the formation, persistence, and turnover of the lake’s thermal layers throughout the annual cycle. The model runs in real time and feeds a publicly accessible web portal — demonstrating both EFDC+‘s computational performance and its value as a transparent scientific communication tool. Additional resources: free grid and video walkthrough.
EEMS has been applied to the Delaware River for thermal and water quality assessment work, leveraging the model’s heat transport capabilities to evaluate temperature regimes, quantify impacts on aquatic ecosystems, and support compliance with state and federal water quality standards across one of the most industrially significant watersheds in the eastern United States.
DSI applied EFDC+‘s Sigma-Zed layering to Lake Mead, the Colorado River reservoir impounded by Hoover Dam, to test the model’s ability to resolve thermal structure in a large, deep, strongly stratified system. Results showed that EEMS accurately reproduces both the seasonal formation and the spatial evolution of temperature layers — a capability directly relevant to water supply forecasting, recreational management, and ecological assessment in the increasingly stressed Colorado River Basin.
