Subsurface Salinity Variation in Lake Charles, Calcasieu Parish: An Investigation into Saline Sources

Alexandria Suding and Carol Wicks
[email protected]

One of the most pressing issues facing groundwater managers is saltwater intrusion. In coastal Louisiana this issue is especially prevalent. One location that is currently threated by saltwater intrusion is the industrial area of Lake Charles, Louisiana, where three high chloride bodies have been found within the underlying Chicot aquifer. There are three sand units of the Chicot aquifer in Lake Charles: the 200 foot (') sand, the 500' sand, and the 700' sand. Groundwater with elevated chloride concentrations was first noticed by industries in the early 1970's. An initial investigation determined that the northern and southern bodies had formed by upwelling of saline groundwater from the 700' sand. However, the origin of the salinity in the central body was not determined. The objective of this study was to determine the origin of the salinity for the central chloride body. Two sources of data were obtained from wells in the area: (1) spontaneous potential (SP) and resistivity logs from oil and gas wells and (2) water quality results from United States Geological Survey (USGS) monitoring wells. The result of this study was the creation of decadal isoconcentration maps that help illustrate the movement of the saline groundwater over time. Results from this study will hopefully aid in preventing further saltwater intrusion in the area by allowing for better placement of pumping areas.

AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63^rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013