With Louisiana’s copious rain, it’s easy to assume where the tap water in your sink comes from. But the vast majority of water in Baton Rouge comes exclusively from groundwater sources deep below the earth, and now a University professor said the overuse of groundwater is causing problems.
Director of Louisiana Water Research Institutes Frank Tsai has spent the last five years working on a project, which will provide an estimate of the amount of groundwater left in the state. Tsai and a large group of undergraduate students are collecting large sets of geological data for all areas of the state, which they will use to create a statewide model of the groundwater channels, or aquifers.
Tsai said conservation of the state’s groundwater is important because the state’s economy and municipalities are heavily dependent on it. The agriculture industry uses more than 55% of groundwater in the state, Tsai said, and the various plants along the Mississippi River also rely on it for their operations. Overall, about 1.6 billion gallons are pumped each day.
“Groundwater in those irrigation areas is depleting,” Tsai said. “Groundwater levels are going down more and more and that introduces saltwater into the freshwater aquifer. Once they pump salty water, they cannot irrigate crops, and that creates a significant economic impact to Louisiana.”
Along with aquifers, Louisiana also has salt basins hidden below the ground. Tsai said that after too much groundwater is removed from an aquifer, salt from the basins will leak into the aquifers, creating saltwater. If pumping continues further, the saltwater will eventually totally replace the groundwater and ruin the supply of fresh water.
This process can also create land subsidence, which it has in both Baton Rouge and New Orleans. Tsai said the over-pumping of groundwater decreases the pressure that supports the soil, thereby creating a land subsidence.
Since almost all Baton Rouge residents get their water from groundwater sources through the Baton Rouge Water Company, this issue affects residents directly. Tsai said the company has already seen some salt intrusion in their water sources. BRWC has not returned comment by the time of publication.
Anthony Duplechin, Executive Director of the Capital Area Groundwater Conservation Commission, also said BRWC experienced saltwater intrusion at one of their pumping locations downtown. He said it installed a device called a scavenger well, which blocks the saltwater from contaminating the supply.
Part of the problem is the underground fault that roughly follows I-10 and separates freshwater and saltwater ground sources. Duplechin said the Commission’s opinion is that BRWC needs to move their wells further away from the fault when they rebuild them eventually, creating more distance between the freshwater and salt.
The Louisiana Office of Conservation’s website states that in 2001, Act 446 granted the state authority to regulate groundwater usage. However, Tsai said that people only have to report their groundwater usage if they pump past a certain amount. And the majority of people do not.
This means that other than the numbers reported by agriculture and other industries, the state does not know how much groundwater is actually being used. Duplechin said his office estimates that the average household uses about 400 gallons a day.
If, up to this point, industries are to blame for these issues, Duplechin said that they do not hold all the blame.
“Some people say, ‘Well, the industry is using it all up and wasting it.’ Well, that’s not what’s going on,” Duplechin said. “People have to be careful how they use it.”
Duplechin gave an example in the city of Baker. Several years ago, Baker residents paid $15 per month for water, and the city did not measure their usage. Duplechin said once the city put meters on all homes, it realized people were overusing water. Some people ran water over the roofs of their houses for hours during a hot day in order to save money on air conditioning. The meters greatly reduced water usage in the city, Duplechin said.
While groundwater conservation is important, Duplechin and Tsai both said the issue is not critical. They said plenty of groundwater is left, but that more research and conservation is needed in order to sustain one of the state’s most valuable natural resources.
Once Tsai’s project is complete in about five years, Louisiana will be the first and only state to have a complete geological map of aquifer layers across the state, aiding researchers and conservationists in protecting groundwater sources for the foreseeable future.
