A 1-D tidal, salinity and water quality model that analyzes the general effects freshwater diversions have on the water quality of the Pontchartrain Estuary over a 17-year period is presented here. Using the modeled live algae concentrations in conjunction with the algal bloom probability model results produces an accurate prediction of algal bloom occurrences between 1990 and 2006. The model predicts that the addition of freshwater diversions into Maurepas swamp and increases to flow in the Bonnet Carré Spillway may cause more intense and frequent algal blooms to occur around the Pontchartrain Estuary. The model also predicts that high nutrient input events that occur earlier in the year (January/February) will not likely have algal blooms associated with them. When nutrient input events (even small events) occur in the late spring or early summer, algal blooms have a high probability of occurring when the salinity, temperature and light levels are sufficient.

A 1-D tidal, salinity and water quality model that analyzes the impacts of freshwater diversions with median and high flow on the water level, salinity and nutrient concentration of the Barataria Basin over a 2 period is presented here. The model predicts that the salinity of Lower Barataria decreases with the introduction of freshwater diversions. The model also predicts that nutrient concentration increases in Barataria Basin and decreases in Northern Gulf of Mexico with the introduction of diversions. The model shows the impact of freshwater diversions on water level except in the neighborhood of the diversion sites are small.

On April 20, 2010 a tragic explosion aboard the Deepwater Horizon (DWH) drilling rig marked the beginning of one of the worst environmental disasters in history. For 87 days oil and gas were released into the Gulf of Mexico. In August 2010, anomalous phytoplankton activity was identified in the Northeastern Gulf of Mexico, using the Fluorescence Line Height (FLH) ocean color product. The FLH anomaly was bound by approximately 30-28 degrees North and 90 and 86 degrees West and there was a suggestion that this anomaly may have occurred due to the presence of oil. This study was designed to examine alternative explanations and to determine what influence the Mississippi River and the freshwater diversions, employed in the response efforts, may have had on the development of the FLH anomaly. The combination of the anomalously high flow rate in the Mississippi River observed in June-August 2010, the use of freshwater diversions, and three severe storms increased the flow of water through the adjoining marshes. We propose that these conditions reduced the residence time of water and nutrients on the wetlands, and likely mobilized nutrients leading to increased fresh water and nutrients being discharge to the coasts around the Mississippi Delta. Salinity contour maps created from data collected by ships operating in the Northeastern Gulf of Mexico showed that the 31 isohaline was upwards of 250km east of the Mississippi River Birds Foot Delta in August 2010. The American Seas (AmSeas) numerical circulation model was used to examine the dispersal and distribution of water parcels from the Mississippi River and freshwater diversions. Two virtual particle seeding locations were used to trace particles to obtain a measure of the percentage of particles entering a Region of Interest (ROI) located in the center of the FLH anomaly, i.e. 150 km east of the Mississippi Delta. All environmental data examined suggest that the eastward dispersal of the Mississippi River water including that derived from freshwater diversions and storm activity contributed to the development of FLH anomaly in August 2010. Chapter two examines the spectral characteristics of water and oil collected by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Several peaks in the spectral features of the total radiance of surface oil between 1907nm and 2400nm appear to be absent for water. An algorithm (Spectral Line Height) was created to measure the height of the peak at 2142nm relative to a baseline between 2013nm and 2390nm. A normalized difference technique developed by the USGS was used as a validation tool. Preliminary results of the SLH technique appear to compare favorably with the results derived using the USGS technique. The SLH technique worked in areas that did not show sunglint or shallow bottom features. Sunglint areas would require additional correction to remove the effect of specular reflection. The SLH technique shows promise but will require validation to develop into an operational remote sensing method.