Modeling Landscape Change Effects on Stream Temperature Using the Soil and Water Assessment Tool

Area of Science:

• Environmental science
• Hydrology
• Ecology

Background:

• Stream temperature is critical for fish behavior and habitat.
• Accurate stream temperature modeling is vital for predicting impacts of climate and landscape change.
• Existing models often lack detailed radiative heat exchange components.

Purpose of the Study:

• To extend the Soil and Water Assessment Tool (SWAT) stream temperature model by incorporating radiative flux components.
• To improve the realistic simulation of radiative heat exchange in stream ecosystems.
• To assess the model's performance in simulating land use impacts on stream temperatures.

Main Methods:

• Extended the mechanistic stream temperature model within SWAT.
• Explicitly incorporated radiative flux components to account for radiative heat exchange.
• Tested the model on the Marys River, Oregon, comparing results with observed data and previous model estimates.

Main Results:

• The extended model successfully simulated higher stream temperatures in agricultural compared to forested sub-basins.
• The model's inclusion of radiative components improved simulation of observed data trends.
• Overestimation and increased noise were observed due to highly variable radiative forcing components.

Conclusions:

• The enhanced radiative stream temperature model provides a more realistic simulation of heat exchange, particularly for land use change impacts.
• Further research is needed to improve temporal resolution (hourly timesteps) and validate the model across diverse watersheds and climates.
• The model shows potential for assessing ecological impacts of environmental change on stream ecosystems.