Modelling fresh water inflow to an estuary

D. W. W. Urish
J. G. de Meneses


The Pettaquamscutt Estuary is a unique and valuable environmental feature of coastal Rhode Island. Two deep stratified lakes trap dense sea water and greatly limit the ability of the system to attenuate or to flush out pollutants which may enter. Water quality investigations reveal a wide range of pollutants entering the estuary system from watershed fresh water input, both as stream runoff and as groundwater outflow. A deterministic computer model has been developed which is capable of simulating existing conditions under a complete set of seasonal scenarios, and able to predict the pollution potential due to alternative land uses. The model is a hybrid model which combines conventional surface runoff solutions with newly created groundwater outflow quantification techniques. Linkage is provided for coupling the freshwater inflow model with estuary mixing and flushing models. The model provides a valuable management tool for use by the three towns situated along the watershed in their evaluation of land use practices and the effectiveness of possible solutions. (A)