Impacts of Industrial Water Withdraws on Hydrodynamics and Salinity Transport in Calcasieu Water System

Xiao Han, Department of Chemical, Civil and Mechanical Engineering, McNeese State University; and Ning Zhang, Department of Chemical, Civil and Mechanical Engineering, McNeese State University,

A modeling tool for simulating hydrodynamics and salinity transport for Calcasieu water system has been developed in the past years. In the most recent study, the target area was extended, ranging from the city of Lake Charles as the north end to the Gulf of Mexico as the south end, including Lake Charles, Calcasieu Lake, Prien Lake, Gulf Intracoastal Waterway (GIWW) and entire Calcasieu Ship Channel. There are wetlands surrounding the Calcasieu Lake, which are the two National Wild Life Refuges. There are vegetated and various non-vegetated areas included in the simulation domain. Measured vegetation data are utilized in the vegetated areas and appropriate friction values are assigned to different types of non-vegetated areas. The wetland ecosystems could be affected by water level and salinity concentration. For agriculture, salinity affects plant growth resulting in lower crop yields and reduced agricultural production. For industry and for people living around, they could also be affected by the elevated salinity levels in the water. Because of the importance of salinity in this area, the focuses of this presentation are both hydrodynamic and salinity transport. Measurement data from NOAA and USGS are used as boundary conditions. Since these stations are not exactly located on the simulation boundaries, calibrations were performed to ensure the accuracy of the boundary conditions. Simulation results were compared with NOAA and USGS data in several locations. The good agreements prove the validity of the simulations. Lake Charles is one of the largest petrochemical industry centers in the country. Numerous plants uses tremendous amount of fresh surface water in the area. Recent expansions of several companies could increase the fresh water withdraws from the system significantly. One of the purposes of the study is to investigate the effects of increased water withdraw on the hydrodynamics and salinity in the system. The water withdraws come from two different locations, one through the north Calcasieu River inlet which is the north boundary of the simulation domain, and the other is from GIWW through the west boundary. Cases of different reduced flow rates at these two boundaries were tested, and the effects on hydrodynamics and salinity concentrations and distributions were analyzed. The optimal withdraw rates that have minimum impacts to the system were suggested from the results of the study. The results can be used as a guideline for industrial and city development in the areas.

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