What is TVA's plan to drill into the Memphis aquifer and why does it matter? Here's a primer on the latest environmental order for Shelby County.
Despite resistance from the Sierra Club and other environmentalists, the Tennessee Valley Authority’s plan to pump about 3.5 million gallons of water per day from the Memphis Sand Aquifer was approved by the Shelby County Groundwater Quality Control Board on December 1. Here’s what you missed:
Cost-efficient, safe, and legal
- In April 2011, to comply with EPA Agreements, the Tennessee Valley Authority (TVA) proposed to replace Memphis’ existing coal-fired Allen Fossil plant by constructing and operating a new natural gas plant, called the Allen Combined Cycle plant.
- After TVA reviewed public comments on its original environmental assessment, they issued a final assessment in August 2014 that proposed the new plant would use greywater from a nearby water treatment plant.
- However, in January 2016 TVA confirmed that they were considering obtaining the water to cool the natural gas plant from the Memphis Sand Aquifer, which provides Memphis’ drinking water, instead.
- Despite attempts by environmentalists to block this change, the Groundwater Quality Control Board voted unanimously to reject the appeal, 7-0.
- TVA says there is no evidence that pumping from the aquifer will cause damage to the water quality or have any effect on groundwater users. They also asserted that minerals in the greywater would have required advanced, costly treatment to be used for cooling water at the gas plant, whereas the aquifer water itself is pure enough for immediate use.
- At hearings on December 1, TVA provided a geologist who said the plant isn’t close enough to a gap in the protective clay layer, which would have to be penetrated to affect the groundwater, to likely cause contamination of the aquifer.
Possible contamination, private use of public resources
- Although they did not disclose their decision to use aquifer water instead of greywater up to public comment, they said in a July 2016 email to the Sierra Club’s Scott Banbury, conservation program coordinator of Tennessee's Sierra Club chapter, that they are not required to do so by law. Additionally, TVA did not feel there was enough public interest in the stated intention to use greywater to open the supplemental environmental assessment for further comment.
- An August 2016 Memphis City Council resolution suggested using the Mississippi Alluvial Aquifer as an alternative or to purchase the water from Memphis Gas, Light & Water and report its water use to MLGW and the City of Memphis. However, TVA maintained that they could not purchase enough water from MLGW to run the Allen Combined Cycle plant.
- The Sierra Club said that the massive daily water withdrawal might contaminate the aquifer. The conservation nonprofit cited a U.S. Geological Survey report about the project that warns, “This report does not address the potential effects of water leakage from the shallow aquifer on groundwater quality in the Memphis Sand Aquifer. Water quality changes due to the leakage of water from the shallow aquifer have been noted in nearby MGW well fields at Davis and at Allen.”
- The Sierra club also cited known breaches in the clay layer between the sand aquifer and the shallow groundwater aquifer above it at the Davis and Allen sites named by the USGS as well as at President’s Island.
- They assert that the plan violates the rules and regulations of wells in Shelby County, specifically the limitation section which limits use of water to “reasonable use” as well as the availability section, which deems public water available for use. The Sierra Club hoped the latter would be cause for TVA to buy the water from MLGW and provide oversight for the TVA’s use.
- The Groundwater Quality Control Board said that, as TVA met the requirements, they “had no choice” and were required to issue the final permits.
- The board’s rejection of the Sierra Club’s appeal means TVA has all the required permits to draw the daily water from the Memphis Sand Aquifer.
- The board did express interest in changing well regulations to protect the Memphis Sand aquifer in future.
- The new plant is expected to be operational by June 2018.