Assessing the water quality impacts of future land-use changes in an urbanising watershed

Abstract

An integrated watershed hydrologic model, the Soil and Water Assessment Tool (SWAT) was adopted in this study to simulate the water quality conditions under the current and the future land-use configurations. The findings were compared to determine the hydrologic consequences of future land-use changes. Results indicate that as the land use in the watershed shifts from predominantly agricultural to mixed rural and residential lands, a reduction in flow, sediments, and nutrients is detected. Although the projected average daily concentration of phosphorus is reduced by 47% under the future land-use scenario, it will still exceed the daily limit suggested by the US Environmental Protection Agency. From this study, it is evident that SWAT is a reliable water quality model, capable of producing accurate information for environmental decision-making. The model has a GIS interface and is coupled with the Better Assessment Science Integrating Point and Nonpoint Sources system. It is, therefore, a valuable tool for environmental informatics.

Keywords:

• BASINS
• hydrology
• land-use change
• SWAT
• water quality
• watershed management

Acknowledgements

We would like to thank J. Arnold of the USDA for his advice on the use of the SWAT model. We also thank J. Neal of the National Risk Management Research Laboratory of the USEPA for her helpful assistance.