Basin hydrologic response to changes in climate and land use: The Conestoga River Basin, Pennsylvania

Climate change and land-use change can significantly affect the hydrology of a drainage basin. This study examines changes in streamflow under three environmental scenarios in the Conestoga River basin and its five sub-basins using AVGWLF, a combined model of ArcView GIS and Generalized Watershed Loading Function. The results of the study indicate that climate change scenarios (Hadley Centre model and Canadian Centre model) are projected to increase spring streamflow by 5% to 18%. Mean annual streamflow is projected to decrease under the Canadian Centre model, while it is projected to increase by 11% under the Hadley Centre model. Urban growth is only projected to increase mean annual streamflow by less than 2%. The magnitude and direction of changes in streamflow are sensitive to watershed size and land-use scenarios. Smaller watersheds with higher proportion of impervious surfaces exhibit greater impacts than larger watersheds with relatively smaller urban areas. Assessing local hydrologic impacts of climate change and land-use change are thus important to identifying subtle changes in streamflow and to establishing future water-management strategies.