Spatial and temporal uncertainty in climatic impacts on watershed systems.

Evaluating the uncertainty of climatic impacts on watershed systems is critical in planning for water supplies, water allocation, and demand at multiple scales. With the increasing frequency of water crises worldwide, understanding the nature of climatic impacts along spatial and temporal dimensions is vital to the development of timely, and spatially relevant mitigation options. This study aims to quantify the nature of hydrologic uncertainties at a spatial and temporal dimension in a regional watershed system under scenarios of varying climatic uncertainties. Watershed-wide impacts of climate change under uncertain future scenarios are modeled with the Soil and Water Assessment Tool (SWAT) for the Connecticut River Watershed of northeastern USA. Changes in watershed flows are quantified for at subbasin scale. The results show that uncertainty in climate change, primarily through variability in precipitation and temperature can lead to spatial and temporal uncertainty in hydrologic processes in the watershed system. In general, the results show that uncertainty in climate can significantly impact the spatial and temporal characteristics in runoff, infiltration, evapotranspiration, and water yield of watershed systems. Strategies to enhance watershed resilience to climatic uncertainty need dynamic information on the vulnerability. Spatial and temporal strategies for adaptation to climatic change conditions could include forest cover and management practices in sensitive locations at local and regional scales.