Simulated effects of climatic change on runoff and drought in the Delaware River Basin

Various projection of climatic change were applied to watershed models of the Delaware River basin. Simulations indicate that a warming could reduce annual runoff by as much as 25 percent if current precipitation patterns continue. Simulations indicate that the largest changes in basin drought are in response to relatively small changes in precipitation. Basin drought was less sensitive to increases in temperature, reservoir capacity, ground-water pumpage during drought, and consumptive water use--in that order of importance. The effects of global warming on basin runoff and drought cannot be determined precisely, as yet, principally because of the unreliability of precipitation projections.