High-Resolution Integrated Hydrology-Hydrodynamic Model: Development and Application to Barataria Basin, Louisiana

iii DISCLAIMER This report was prepared under contract between the Minerals Management Service (MMS) and Louisiana State University. This report has been technically reviewed by the MMS and approved for publication. Approval does not signify that the contents necessarily reflect the view and policies of the Service nor does mention of trade names or commercial products constitute endorsement or recommendation for use. It is, however, exempt from review and compliance with MMS editorial standards. ABSTRACT This is the final report of our effort under Coastal Marine Environmental Modeling: Part III. Coastal Marine Environmental Modeling targets the development of numerical models of estuarine shelf interactions with the ultimate objectives of formulating a coupled hydrodynamic-ecological model that includes biological and sedimentological components. Under Part II, a two-dimensional depth-integrated hydrodynamic model, that includes baroclinic pressure gradient, was developed. This model has been applied to various estuaries in Louisiana, namely, Terrebonne/Timbalier Bay, Barataria Bay, Chandeleur-Breton Sound and Fourleague Bay. A simplified version of the hydrodynamic model has been coupled to a simple ecological model that includes suspended sediments, nutrients and phytoplankton, to simulate a spring bloom in Fourleague Bay. In this report, development of a high-resolution integrated hydrology-hydrodynamic model of Barataria Basin is presented. First, a hydrology model that explicitly accounts for the local hydrological cycle over the surrounding drainage basins for the Barataria Basin is developed. Using observed precipitation and estimated evaporation over the surrounding drainage basins, the hydrology model provides estimates of local runoff. The hydrology model is coupled to a high-resolution (O (100m)) two-dimensional depth-integrated hydrodynamic model of the Barataria Basin in order to simulate the hydrodynamic response of Barataria Basin to hydrological, tidal, and wind forcing. A flood event during tropical storm Allison in June 2001 resulted in significant rise in sea-level heights especially in the upstream region of the basin, thus, providing a rare opportunity to test the model. It is shown that the integrated model is capable of capturing a significant portion of the observed sea-level variations during the flood. The integrated model was also used to simulate a typical dry summer condition, namely the 30-day period during the summer of 1999. Despite the relatively crude salinity initial condition used (based on only eight observations), the model appears to do reasonable job of simulating time evolution of salinity fields inside the bay. The model was then used to simulate potential impact of freshwater diversions at Naomi, West Pointe …