Copyright Charleston Post and Courier
EDISTO ISLAND — Across 11 generations and more than three centuries, Tom Austin's family has called the area in and around this sea island home. As Austin drove his car down tree-shaded lanes, he talked excitedly about the landscape he loves. "This is something irreplaceable," said Austin, director of land conservation for the Edisto Island Open Land Trust. "It's my duty to try and make this place a better place for everyone who calls it home." On this warm summer day, he was working to fulfill that mission. Austin was helping a team of Clemson University and University of South Carolina Beaufort researchers collect water samples from across the island. This research trip represented a critical piece in a bigger puzzle — one which could impact the future of both Edisto and other rural communities across rapidly-growing Charleston County. "We're trying to figure out how to make septic systems sustainable in this rural landscape in a coastal community," Austin said. Leaky septic tanks are considered the “dirty hidden little secret” of the region’s development boom. Lax regulatory policies have led to a proliferation of the systems in recent years, The Post and Courier previously reported, even as climate change-fueled rising groundwater levels have made them less effective and prone to discharges. But in area such as Edisto, there aren’t any other options. "We are never going to get a municipal centralized wastewater treatment plant on this island,” Austin said. “It's 15 miles to connect to the one in Ravenel." And even if there were other choices, some residents in these rural areas view septic systems as a bulwark against over-development. A municipal sewage line could open Edisto to denser zoning — and there’s no guarantee it’d be environmentally friendly. Many municipal sewage systems experience overflows during high-intensity rainfall events. "When you have municipal water and when you have central municipal sewer systems, you can develop at higher densities," explained Grace Gasper, the executive director of Friends of Coastal South Carolina and a recently-elected member of the Awendaw town council. "Septic is the preferred alternative for rural areas because it is so ridiculously expensive to extend central sewer, and it does facilitate development." But a legal fight led by Gasper unfolding on Awendaw’s White Tract highlights that septic systems aren’t always a defense against dense development. That controversial project aims to construct a roughly 200-home septic-dependent subdivision on a piece of land sandwiched between the Cape Romain National Wildlife Refuge and the Francis Marion National Forest. The dilemma of waste management in coastal South Carolina’s rural communities is a Gordian Knot, and nobody seems to have a sword capable of slicing clean through the issue. But before leaders on Edisto and elsewhere can begin to address the dilemma, local policy leaders need clean, reliable data. Looking for a ‘smoking gun’ More than half of Edisto Island is under some form of permanent conservation protection. But Austin said residents still struggle with fecal contamination. " Development density is crazy low," he noted. "And yet 70 percent of our tidal creeks are closed to shellfish harvest because of elevated fecal coliform levels." The USC/Clemson team are trying to solve two separate mysteries with this project: Which mammals are responsible for the fecal contamination around Edisto, and what is the source of the water's cloudiness. "(The S.C. Department of Environmental Services) doesn't test for nutrients in estuarine waters," explained Amy Scaroni, a wetlands biogeochemist in Clemson's Forestry and Environmental Conservation Department. "So we don't know if the turbidity is just sediment eroding from a river or if it's from a fungal growth that would be fueled by nutrients." In brackish waters like these, one of those fueling nutrients might be nitrogen, which is a common runoff pollutant that can cause a myriad of water quality issues downstream, according to the Environmental Protection Agency. The other mystery — which mammals are causing the fecal pollution — is handled by the USC side of the team. Once they've finished collecting water samples from testing spots across the island, they’ll extract DNA from fecal contaminants to see whether it came from humans or other mammals. For more than a year, the team has been building a body of evidence. It started when Scaroni started crafting the island's watershed plan — a strategy to limit pollution in Edisto's waters — in 2020. "In the watershed plan, we were trying to determine what the causes of the turbidity and bacteria impairments were," she said. "It very much looked on paper that septic systems were the primary culprit, but we didn't have the smoking gun data to prove that." Fecal contamination can can come from many different sources. Pet waste is a not-insignificant contributor to water pollution, according to the EPA. Runoff from upstream communities also can be a problem. Fertilizers flushed into streams and rivers might increase turbidity. And it's not uncommon for septic tanks to quietly fail without anyone noticing. So it's hard to say with precision how many septic tanks might be polluting Edisto Island's waters. Scaroni emphasized that not every septic tank is an environmental menace. One 2022 study found that, between North and South Carolina, almost half of all residents are on some kind of septic system. "Septics are actually a great tool for managing wastewater in rural communities," Scaroni said. "The problem is just when they're not exactly maintained or when they're failing." Or, depending on whom you ask, when they're being put into an area where they don't belong. On the White Tract Up the coast from Edisto Island, another small community is facing its own septic struggle. In Awendaw's White Tract, developers are constructing a roughly 200-home septic-dependent subdivision. Sitting between the Cape Romain National Wildlife Refuge and the Francis Marion National Forest, that project has for years drawn criticism from local conservation groups. They worry that septic systems in Pulte Homes' new development will leech into the federally-protected Cape Romain National Wildlife Refuge. Friends of Coastal South Carolina and the South Carolina Environmental Law Project are suing to stop the development. But a hold on construction was lifted in June. So building can move ahead even as the courts weigh whether the project could harm the local ecosystem. "Once those systems are in place and once the developments are in, we're done," said Amy Armstrong, the Law Project's executive director. "You don't really unwind that. The amount of money it takes to get these old septic systems on sewer is incredibly expensive." Friends of Coastal South Carolina and the Law Project are asking the state Supreme Court to intervene in the case, and reinstate the hold as the lawsuit progresses. Pulte Group, Pulte Homes' parent company, did not respond to a request for an interview on the suit and the environmental groups' worries. Awendaw and Edisto are similar. The White Tract borders the Cape Romain National Wildlife Refuge. Edisto Island borders the ACE Basin National Estuarine Research Reserve. The two have roughly the same population. Both are coastal communities geographically defined by river estuaries. But, in Gasper's view, Edisto has done a better job of zoning than Awendaw. So it's unlikely they'll get a sudden infusion of new septic-dependent developments anytime soon. That's not necessarily the case for the region's other rural communities. "There's been a rash of these large suburban-style subdivisions in rural areas, thanks to these national homebuilding chains," Gasper said. Gasper described the issue as a "perfect storm." Charleston's urban core is becoming built out, so development is expanding into rural areas with weaker zoning policies. Advances in septic system technology mean that those tanks theoretically can be permitted on smaller lots, she said. Meanwhile, Gasper, Armstrong and many other environmental advocates contend the state's septic permitting system is flawed at its roots — and now it's being tapped to handle the aggressive growth. " When the groundwater level comes into contact with the septic system, it doesn't matter how great the system is," Armstrong said. " The state of South Carolina treats septic tank permitting the same across the entire state. It doesn't matter if you're in the higher elevation areas, if you're in the mountains, if you're in the Midlands or in the coast; the same standards apply across all of those areas." A changing world As sea levels rise, South Carolina's coastal septic systems likely will become less effective. Those rising waters are pushing up the groundwater in coastal areas, hindering septic systems' ability to filter wastewater before it leeches into the water table. Away from the coast, stronger hurricanes and heavier rainfall events threaten to saturate soil across the state and overwhelm septic systems. Austin expressed some anxiety about the island's future. Leaky septic tanks are just one entry on the list. Development, stemming from Charleston's growth, is a persistent worry. The island is transitioning from an agricultural economy to a more tourism-driven one. Meanwhile, rising tides have chipped away at the shoreline over the decades.
