HYDRODYNAMIC MODELING OF FRESHWATER INTRODUCTION AND RESIDENCE TIMES IN A SHALLOW ESTUARY

摘要

In coastal Louisiana, the growing restoration efforts have focused on the need for the reintroductionof freshwater and sediment from the Mississippi River to the endangered wetlands. With theerosion and land loss rates approaching km~2/yr, multiple high flow diversions are being considered. Onepossible locations for diversions is the Bonnet Carré Spillway, a floodway structure that diverts floodwaterfrom the Mississippi River into Lake Pontchartrain. The purpose of this paper is to discuss the hydraulicresidence times, flushing and general water quality impacts from such diversions on Lake Pontchartrainand Lake Maurepas. This exercise includes the use of two pre-calibrated numerical models for the area.Specifically, the models used are the two-dimensional depth-integrated RMA2/RMA4hydrodynamic/transport model developed by the United States Army Corps of Engineers and a modifiedversion of the Princeton Ocean Model, a three-dimensional primitive equation hydrodynamic and transportmodel.