Groundwater dwindles as farms increase irrigation east of Columbia, agency says

With groundwater levels dropping in parts of central South Carolina, the state is looking to control withdrawals from farms, industries and public water systems that have for years slurped as much water as they wanted without oversight.

But the state’s effort to oversee groundwater withdrawals sets up a potential conflict involving cities that supply drinking water and large farms that are increasingly irrigating crops, mostly in Sumter and Clarendon counties.

The S.C. Department of Health and Environmental Control, in a plan discussed Thursday by the agency’s board, proposes requiring major groundwater users in a six county area to notify the public about future withdrawals and obtain state permission to take large amounts of water.

Water planners have for 17 years urged controls over groundwater withdrawals in South Carolina’s coastal plain, a broad flat area between Columbia and the ocean. But for years, the state failed to include controls in an area of the coastal plain from Aiken through Columbia to Sumter and Clarendon counties.

Now, the state is proposing controls for Richland, Sumter, Clarendon, Lee, Kershaw and Chesterfield counties.. The region would become the last in South Carolina’s coastal plain where the state would oversee major groundwater withdrawals. The rest of the coastal plain has restrictions.

The state imposed oversight of water withdrawals in the Aiken and Lexington areas west of Columbia three years ago after an outcry over the impact mega vegetable farms were having on groundwater. The State examined the threat in a 2017 series about industrial-scale farming in the Edisto River Basin.

While the latest set of rules would apply to one of the state’s largest counties — Richland — they would potentially have the biggest impact in the farm-rich communities of Sumter, Clarendon and Lee counties.

“Right now, there is no regulation on limiting agricultural withdrawals,’’ DHEC staff member Alex Butler said when asked by a board member about farming. “They can take as much as they would like.’’

Farmers in Sumter and Clarendon have relied increasingly on irrigation in the past 20 years as a way to ensure their crops succeed during droughts or times of sporadic rainfall, according to DHEC. But cities in those areas also use groundwater to supply the public.

As irrigation has increased, groundwater levels in some parts of those counties have dropped. Groundwater levels have fallen 60 to 80 feet in two aquifers in Sumter and Clarendon counties, statistics show. Drought and agriculture use are suspected to have caused much of the problem.

Lower groundwater levels caused the city of Manning to spend more than $150,000 recently to make improvements to its main water supply wells, city manager Scott Tanner told The State. The city had to lower pumps deeper into its wells because water levels had dropped, he said.

“We had to do that just to give us adequate supply,’’ he said.

Al Harris, an assistant city manager in Sumter, told the DHEC board Thursday that he understands the need by farms to irrigate, but his city also needs water. The city of Sumter, with 30,000 taps, provides water to both city residents and many who live in the county.

“We are seeing that increase in wells,’’ Smith said, referring to increasing demand for groundwater. “We are seeing some issues going on around the community and other areas. So we have a great concern.”

DHEC says the state needs to gain control over withdrawals with a system that requires anyone taking 3 million gallons or more per month to get a permit. That would not necessarily prevent farms or cities from taking groundwater, but it would allow DHEC an opportunity to scale back withdrawals that might be excessive.

The agency board took no action on the plan to oversee groundwater withdrawals in the six-county area. A decision is expected later this year. Utilities that use large amounts of groundwater, as well as industries, would be affected by the rules.

Not everyone is happy with DHEC’s plan — namely the South Carolina Farm Bureau. The bureau, which criticized groundwater rules for the Aiken area, has also expressed concern about the latest round of water regulation.

The bureau, which represents farms and has a powerful lobby, has urged DHEC to go slow because permits would be good for only five years. The farm bureau argues that many water levels rise after the agricultural season ends in the fall.

“An agricultural user of water is not making widgets that can just be stopped when DHEC asks everyone to reduce water amounts per groundwater regulations,’’ the Farm Bureau’s Gary Spires wrote DHEC this past winter. “Crops need a specific amount of water and and often that is in times when rain is at the least and water tables are at their lowest. Without the right amount of water on a crop, it dies and both farmer and consumer loses.’’

In addition to concerns about drinking water in Sumter County, DHEC’s proposal also is significant because central South Carolina aquifers replenish groundwater supplies throughout much of the coastal zone.

Rainfall gets into aquifers in the state’s mid-section more easily because they are closer to the surface. The water then flows to other aquifers farther away. Groundwater supplies farmers and public water systems, but it also helps keep rivers flowing by seeping into them.

“We’re supportive of it,’’ Congaree Riverkeper Bill Stangler said of the plan to regulate groundwater . “Much like surface water, groundwater is a shared resource. Having a better understanding of how it is being used and keeping an eye on it to make sure we are not depleting it as a common resource is important.’’