Saving BR’s Water
March 19, 2014
The city’s main source of drinking water, some of the best in the world, is in danger of becoming undrinkable.
As more and more industrial and civilian pumping takes water from the Southern Hills Aquifer, salt water is pulled into the fresh pure water that Baton Rouge drinks. LSU’s Department of Geology and Geophysics has documented this concern for the last 50 years, though activists say that this problem has persisted since the 1930s.
“As we pull fresh water from the aquifer for use it pulls the salt water in the southern portion of the aquifer north and currently the saltwater is threatening to overtake the drinking water wells for the city of Baton Rouge in the near future and the government has been warned of this for quite some time,” said Paul Orr, a Lower Mississippi Riverkeeper and communications director for the Louisiana Environmental Action Network.
The Southern Hills Aquifer is actually a system of ten or eleven pockets of sand and clay that capture rainwater and filter their impurities, resulting in delicious pure water. These pockets are situated more or less directly under the city – the shallowest rests at a depth of 400 feet and the deepest at 2,800 feet. While it’s unknown exactly how much water is contained within the aquifer, a report from the U.S. Geological Survey released last July said that in 2010 an average of 23.9 million gallons a day was pumped from the system. According to that same report, 66 percent of that water went toward industrial use.
“Currently large industrial users in the Baton Rouge area – ExxonMobil and Georgia Pacific being the vast majority of this – are using at least the same amount of groundwater from the aquifer as the citizens of Baton Rouge,” said Orr. “These facilities are using clean drinking water for polluting industrial processes while sitting on the largest river in North America. If industry switches from groundwater to Mississippi River water it will reduce the usage pressure on the aquifer by at least half.”
Orr pointed to a another report filed by the Louisiana Water Science Center, which stated that if industries switch to using already polluted river water – which is no danger of running dry – for manufacturing purposes it would “have a pretty dramatic effect.”
“It is just common sense that industry should switch to river water so that we can preserve the clean aquifer water for citizens to drink, bathe and cook with for as long as possible,” said Orr. “Industry representatives have claimed that it is not fair to make industry spend a little more money to use river water, but is it fair for industry to use up the clean drinking water that the citizens of Baton Rouge rely on twice as fast when there are alternatives available?”
According to Patrick Courreges, a policy analyst for the Department of Natural Resources, there’s a simple explanation: money.
“Generally speaking, the problem with drawing from the river is paying for the set up that would take the water into their facility,” he said. “They would also have to treat the water because they require a certain level of purity for the chemical processes they use.”
However, industry is not pumping the city’s drinking water directly out from under it. Municipal drinking water mostly comes from the 1,500 and 2,000 sands (primarily the 1,500) while these companies – like ExxonMobil and Georgia Pacific – draw only from the 2,000 and 2,400 sands. Also, these aquifer sands barely flow into one another, if at all.
Drying up isn’t the primary concern, however. Over-pumping that leads to salinization is.
Courreges said that his department was first asked to intervene in this issue in 1974, and since then they have adopted a policy of cut and cap to reverse or slow salt water intrusion. In 2013, it was voted to cap industrial pumping from the 2,000 sands from 17.25 million gallons a day to 15.25 million gallons a day. So far, everyone in the industrial district is in compliance of this ruling. But Courreges think that the big problem isn’t the amount of pumping – it’s where the pumping is taking place.
“One of the biggest problems we have is the concentration of pumping that’s going on,” he said. “Lots of centers are too close to the fault – especially Baton Rouge Water pumping centers, which are nearly on top of it.”
That fault that Courreges is talking about runs through the entire state, roughly along I-10 and right through downtown Baton Rouge. Simply put, that fault is what separates the salty ground water from the fresh water in the aquifers. Salt water is heavier than fresh, and when companies take water from the deeper sand so close to the fault it makes it easier for that salt water to flow up the fault and take the place of the fresh water.
At a glance, stopping pumping close to this fault altogether seems like the only way to keep salt from polluting BR’s drinking water in the future. However, the USGS (and hydrophysics) has determined that ceasing all industrial pumping outright could make the problem worse.
“A computer model provided the Geological Survey shows us how the salt plumes in and out of the freshwater aquifers,” said Courreges. “We made the model show us what would happen if we stopped industrial pumping near the fault altogether and things got much worse around the Government street area.”
Courreges said that solutions are in the works, though. Several water companies, including Baton Rouge Water, have begun using scavenger wells, which can separate the fresh water from the saline water. But whether or not they can slow or stop the intrusion of saltwater into BRs drinking water is yet to be seen.
“[Scavenger wells] aren’t necessarily our way out of this problem – there’s still a question of how effective they will be,” said Courreges.