In order to prevent the city of New Orleans from flooding, the high floodwater of the Mississippi River is diverted into the Lake Pontchartrain via the Bonnet Carré Spillway. During a flood release, a large amount of freshwater, nutrients, sediment, etc. is discharged into the Lake and causes environmental problems.
To evaluate the environmental impacts of the floodwater on lake ecosystems, CCHE hydrodynamic and water quality models were applied to simulate the flow circulation, sediment transport and the water quality process in the Lake Pontchartrain. The effects of nutrients and suspended sediment concentration on the growth of algae were considered. The figure shows (a) the observed algal bloom distribution obtained from remote sensing imagery acquired on June 13, 1997; and (b) simulated chlorophyll a concentration. The general distribution of the chlorophyll a concentration is found to be consistent with that of the algal blooming imagery.