Researchers at LSU have mapped a section of the water-containing sand layers of the Southern Hills Aquifer, something that can prove invaluable to the Capital Area Ground Water Conservation Commission as it decides how to deal with saltwater intrusion.
The map of the aquifer, which provides the Baton Rouge residents and businesses with water, is the result of years of work by Frank Tsai, professor in the Department of Civil and Environmental Engineering at LSU. It is included in a three-year project, which began last year and involved input from ExxonMobil and Georgia Pacific, the commission and the university.
“We really know how to help the commission plan their remediation designs,” Tsai said.
To get the data for the mapping, project workers took information from more than 500 wells to determine where sand layers occur. The layers aren’t uniform, rising and falling based on where the river deposited the sand.
The goal for the first year of work was to build the computer model for 11 layers of sand from 400 feet to 2,800 feet.
Tsai now will look at how to slow or stop the saltwater intrusion. Options include scavenger wells that help draw up salt water away from freshwater wells, freshwater injection that helps push away salt water, and horizontal drilling to get the most benefit for the least cost. All of these options will require the acquisition of property to locate the wells.
Tsai said the commission will recommend places for the wells, and he will run the information through the computer model to see if there are the right conditions underground.
The final year is set aside to fine-tune a plan to stem the flow of salt water. That would include deciding how much water needs to be removed, or pumped into the well, to optimize the desired result of keeping salt water at bay, he said.
The computer model also can be used to answer a variety of questions such as how much water flows in and out of the Baton Rouge portion of the aquifer. The model also can help manage groundwater resources.
“Our groundwater model can not only look into groundwater issues; we can also look at energy issues,” Tsai said.
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