Tetra Tech scientists co-authored, with colleagues from the U.S. Environmental Protection Agency Office of Research and Development, the paper “Modeling Streamflow and Water Quality Sensitivity to Climate Change and Urban Development in 20 U.S. Watersheds,” published on the Journal of American Water Resources Association website.

The paper summarizes Tetra Tech’s work with U.S. Environmental Protection Agency (EPA) researchers over a 5-year period to analyze the effects of water quality and streamflow in response to climate change and urban development in the United States. Using data sets from 20 large-scale watersheds, Tetra Tech developed detailed models of 20 large watersheds (approximately HUC4-scale) using the Soil and Water Assessment Tool (SWAT) and modeled responses to a suite of future climate scenarios. The results showed a pattern of decreasing streamflow volume in the central Rockies and Southwest, with increased volume on the East Coast and Northern Plains. Changes in pollutant loads follow a similar pattern but with increased variability. Sensitivity to potential climate change outweighs the sensitivity to land-use change at the large basin scale (largely due to the uncertainty in forecasts of future precipitation regimes), but land-use change can be a significant driver at more local scales.

The entire article is available here.