EFFECTS OF CLIMATE-CHANGE ON WATER-RESOURCES IN THE DELAWARE RIVER BASIN

The effects of potential climate change on water resources in the Dela ware River basin were determined. The study focused on two important w ater-resource components in the basin: (1) storage in the reservoirs t hat supply New York City, and (2) the position of the salt front in th e Delaware River estuary. Current reservoir operating procedures provi de for releases from the New York City reservoirs to maintain the posi tion of the salt front in the estuary downstream from freshwater intak es and ground-water recharge zones in the Philadelphia metropolitan ar ea. A hydrologic model of the basin was developed to simulate changes in New York City reservoir storage and the position of the salt front in the Delaware River estuary given changes in temperature and precipi tation. Results of simulations indicated that storage depletion in the New York City reservoirs is a more likely effect of changes in temper ature and precipitation than is the upstream movement of the salt fron t in the Delaware River estuary. In contrast, the results indicated th at a rise in sea level would have a greater effect on movement of the salt front than on storage in the New York City reservoirs. The model simulations also projected that, by decreasing current mandated reserv oir releases, a balance can be reached wherein the negative effects of climate change on storage in the New York City reservoirs and the pos ition of the salt front in the Delaware River estuary are minimized. F inally, the results indicated that natural variability in climate is o f such magnitude that its effects on water resources could overwhelm t he effects of long-term trends in precipitation and temperature.