Simulated Effects of Water Withdrawals and Land-Use Changes on Streamflows and Groundwater Levels in the Pawcatuck River Basin, Southwestern Rhode Island and Southeastern Connecticut - Usgs Scientific Investigations Report 2009-5127 (Paperback)

The Pawcatuck River Basin, in southwestern Rhode Island and southeastern Connecticut, is an important high-quality water resource that provides water for domestic and public supplies, irrigation, recreation, and a rich aquatic ecosystem. Streamflow records for several rivers in the basin indicate that during the summer, withdrawals could be affecting aquatic habitat and diversity, water quality, and the value of the rivers as scenic and recreational resources. Concerns over the effects of water withdrawals on streamflow, pond levels, groundwater levels, and aquatic habitat in the basin prompted the development of surface-water, groundwater, and conjunctive-management models. Separate models were developed because linking surface-water and groundwater models was not feasible in this geologic setting. Each individual model provided an accurate representation of the part of the hydrologic system under consideration. A precipitation-runoff model was developed for the entire basin on the basis of the Hydrologic Simulation Program-FORTRAN (HSPF) model. Groundwater-flow models were developed for the lower Wood River and the eastern Pawcatuck River areas in the basin on the basis of groundwater-flow models (MODFLOW). In addition, conjunctive-management models were developed for subareas of the two groundwater model areas. These models were used to evaluate current conditions, long-term conditions, water-management alternatives, and land-use changes in the basin. Additionally, the results from MODFLOW were compared to the results of a streamflow-depletion algorithm in the HSPF model.