Memphis Water: Does Vast Resource Need Better Protection?

Dec 15, 2016

A pair of large mouth bass mailboxes stand outside the construction area of the TVA's new Allen Combined Power Plant in Memphis.
Credit Christopher Blank/WKNO-FM

Mid-South environmentalists are concerned about tapping the vast Memphis Sand aquifer for some industrial uses, and whether the pumping is safe. The Sierra Club's recent legal dispute with the Tennessee Valley Authority over the use of water to cool a natural gas power plant has some Shelby County citizens asking if government should have more oversight.

The Allen Combined Power Plant under construction in South Memphis will be one of the most efficient and advanced in TVA's fleet. It will reduce air pollution and increase power output. But it will also require more than 3.5 million gallons of fresh water each day for cooling.

At the Ghost River Brewery in Memphis, head brewer Jimmy Randall is serious about the flavors that go into making his beer. That includes the taste and quality of his main ingredient: Memphis tap water.

“It is a very soft, pure water,” he says. “It has a low mineral content, which allows me to replicate global water characteristics.”

With this “blank canvas,” Randall can experiment with different styles easily.

The water used in Memphis’ growing craft beer and distillery scene is the same that comes out of every faucet in town, pumped constantly by Memphis Light, Gas & Water out of the Memphis Sand aquifer.

Discovered in 1887, a vast water supply lies underneath the county, filtered through sand over thousands of years. Its purity has brought businesses to Memphis. The water is good enough to be bottled. Much of it is flushed down toilets.

And that has some people asking: what’s the best use for some of America’s cheapest and highest quality water?

“People are becoming aware that water is a limited resource,” says Scott Banbury of the Sierra Club’s Tennessee Chapter. “People are waking up to it.”

The conservation group wants more protections for this municipal resource.

The Sierra Club sounded an alarm in a recent public dispute with the Tennessee Valley Authority, the federal corporation that provides electrical power to the region’s utility companies.

The environmental group doesn’t like that TVA’s new natural gas power plant in Memphis will use around 3.5 million gallons of pristine aquifer water each day, and sometimes more than double that amount.

“Nobody wants to see our drinking water used for cooling purposes,” Banbury says.

But in the case of this new power plant, some maintain that the use of clean water makes the most sense.

Construction is well underway on the new Allen Combined Cycle Plant just south of downtown.

By every measure, this natural gas plant is better than the coal-burning plant it will soon replace. It generates more power and far less waste. Memphis’ notoriously bad air could see a marked improvement. Carbon emissions will drop 60 percent; sulfur dioxide by nearly 100 percent. Project Manager Dan Tibbs says it’s what environmentalists have lobbied for, and is part of TVA’s long-term plan to close most of its coal burning plants.

“This’ll be the most efficient combined cycle plant we have in our fleet,” says Tibbs, “And among the most efficient plants in the world.”

But one green feature was dropped from the final blueprint.

TVA originally proposed using gray water from a nearby wastewater treatment plant to cool its machinery. But the corporation balked at the annual costs of treating the water.

Some water industry experts such as Tom Volinchak, author of the blog, say that cleaning out the sewage with chemicals would have traded one environmental problem for another.

“Then you’re going to have gas-driven vehicles hauling this sludge away, sending it to landfills where it’s going to go back into the environment contaminating the groundwater anyway.”

The Shelby County Health Department approved TVA’s request to draw its cooling water from the Memphis Sand aquifer. MLGW already pumps more than 200-million gallons a day from it, so to some, 3.5 million a day for the power plant looks more like a drop in the bucket.

How much water is in the Memphis Sand aquifer? Some experts estimate that there’s enough to fill a lake the size of Shelby County as deep as a 33-story building, the height of Memphis’ Clark Tower.

For scientists such as groundwater expert Brian Waldron, a professor at the University of Memphis, the main public concern at this point isn’t the amount of water being used, but the methods and procedures used to extract it.

A top layer of clay protects the aquifer from most contaminants. But there are some large holes in that layer across the county. Too much pumping near a hole can create a suction.

“It could pull water of poorer quality (such as Mississippi River water) down into our drinking water supply and impact its quality.”

At a recent hearing, activists argued that the TVA’s toxic coal ash disposal ponds are close enough to its new pumps that chemicals such as arsenic eventually could be drawn down into the aquifer. TVA dismisses that danger, and is abiding by current federal guidelines. But the Sierra Club’s Banbury believes the concerns at least warrant further study and discussion.

“As soon as it was brought to their attention that there could be contamination of our groundwater, it should have been brought to the public,” Banbury says.

A new citizens’ group called is petitioning elected officials to explore stronger water regulations. Organizer Randy Blevins says that after recent events in Flint, Michigan and in North Dakota, it’s time to be more vigilant.

“Why run the risk?” he asks. “You can only pollute the aquifer one time. Once you pollute the aquifer that one time, it’s over.”