State Water Resources Research Institute Program (WRRI)
Start Date: 2006-03-01 End Date: 2007-02-28
Total Federal Funds: $19,800 Total Non-Federal Funds: $40,253
Principal Investigators: Zhi-Qiang Deng
Abstract: The pumping of New Orleans floodwaters from Hurricanes Katrina and Rita into Lake Pontchartrain has raised serious environmental concerns regarding adverse impacts of the contaminated floodwaters and sediments on the water quality of the receiving lake. Although water quality sampling programs have been initiated by Federal and State agencies for Lake Pontchartrain, no existing efforts can effectively predict temporal and spatial variations of the pumped contaminants in the lake. This information is crucial to guiding water and sediment quality sampling and to assessing short-term and long-term environmental impacts of the pumped floodwaters and sediments on Lake Pontchartrain. The goal of this project is to develop a GIS-aided water quality monitoring and assessment system for Lake Pontchartrain. The system can be employed (1) to simulate temporal and spatial variations of water temperature and dissolved oxygen in the lake, (2) to provide guidance to water quality and sediment sampling in the lake, (3) to visualize modeling results, and (4) to provide necessary scientific information for assessment of short-term and long-term environmental impacts of the pumped New Orleans floodwaters on Lake Pontchartrain. To achieve the primary goal of this project, the research is split into six specific objectives: (1) Modeling of New Orleans floodwater plume trajectory and sediment deposition in Lake Pontchartrain, (2) Water and sediment quality sampling, (3) Development of multi-layered water quality database, (4) Development of lake temperature model, (5) Development of dissolved oxygen model, (6) Integration of numerical models and GIS interface. The proposed strategy is to combine field sampling and GIS-based numerical modeling. The field water and sediment quality sampling provides inputs for GIS-based numerical modeling which, in return, guides field sampling by providing information on where and what data are most needed to effectively assess and rapidly restore the environmental damage. The software D-CORMIX will be used to simulate the trajectory and fate of the pumped floodwaters and thus to determine the deposition distribution of the pumped sediments in Lake Pontchartrain. The sampling effort of this project will be combined with that of Louisiana Department of Environmental Quality. The multi-layered water quality information will be superimposed on the base layer in the Lake Pontchartrain GIS to be developed in this project due to the georeferenced nature of the data. The lake temperature model will be a one dimensional advection-dispersion equation containing a term of thermal-energy exchange at the water-air interface. The dissolved oxygen model involves two separate oxygen concentration models for the epilimnion and the hypolimnion due to summer stratification in the lake. The oxygen transfer from the epilimnion to the hypolimnion is modeled by a turbulent diffusion term. The influence of bottom sediment oxygen demand on the dissolved oxygen in water column is also included in model. The multi-layered database, numerical models, and GIS interface will be linked together using ArcView GIS software to form a fully integrated GIS-aided water quality monitoring and assessment system for the lake. The proposed research is of broad significance. The GIS-aided water quality monitoring and assessment system is capable of providing an efficient and cost-effective tool for water and sediment quality sampling and modeling of the lake. It is therefore of great interests to the understanding and restoration of adverse impacts of the pumped floodwaters on Lake Pontchartrain. The project also provides research and educational training opportunities for graduate and undergraduate students.