Endangered Bats Have Slowed, But Not Stopped, a Waterfront Mega-Development in Charleston. Could Flood Risk?

Flooding the Market: Third in a series about climate change and coastal threats in South Carolina.

In March 2023, the Fish and Wildlife Service (FWS) uplisted northern long-eared bats from threatened to endangered, citing one specific disease and habitat destruction as driving factors in the bats’ rapid population decline. By some estimates the species will be completely extinct by 2060. 

Within a few months the relisting reverberated in South Carolina, at the very southernmost limit of the bats’ East Coast range. In July 2023, a 9000-acre mega-development over a decade in the making on Cainhoy Peninsula, neighboring downtown Charleston, screeched to a halt while biologists descended to survey for the endangered bat. 

As little as two decades ago, Joy O’Keefe, a bat biologist, could leave a net over a forest trail and catch the small, furry mammals to study with relative ease.

But this summer after a year of surveying—which confirmed the development’s impact on northern long-eared bats, neighboring Francis Marion National Forest and 180 acres of wetland—the Fish and Wildlife Service determined the project could go ahead largely as planned. 

Environmentalists continue to appeal the decision for the bats’ sake, but the project’s supporters say it meets the state’s booming demand for waterfront housing. Meanwhile, urban planners question the wisdom of building housing for over 20,000 people in a floodplain already facing rising seas and worsening storms.

Catherine Wannamaker is a senior attorney at the Southern Environmental Law Center (SELC), who has led litigation against the development plans since 2022. “This is a huge project and it has a textbook array of impacts: from a massive amount of wetlands filled to housing in the floodplain to multiple endangered species—there are lots of pieces to it,” Wannamaker said on Oct. 10, the same day the South Carolina Court of Appeals denied the SELC’s request for an injunction to stop tree felling. 

Since developers first applied for a federal permit to build on wetlands in 2018, “it’s been one twist and turn after another,” Wannamaker said. After six years the U.S. Army Corps of Engineers granted a permit finding the project would have no significant environmental impact, despite the peninsula playing home to another endangered species, the red-cockaded woodpecker. 

Construction was halted to resurvey for bats in 2023, then resumed. The state’s Fourth Circuit court ordered a weeks-long pause this summer to hear the case for an injunction, which was denied in October.

“We thought we had a break, but we don’t,” Wannamaker said of the court’s decision, rubbing the bridge of her nose. “We’re back to writing briefs.” Satellite images suggest just under 200 acres have been felled so far. 

Protecting the Bats’ Habitat

Cainhoy extends into the Wando River 20 miles northeast of downtown Charleston, with one other peninsula, Daniel Island, between the two. But unlike its neighbors, Cainhoy—apocryphally named after freedman Cain Walker, who ran a ferry onto the peninsula after the Civil War—has remained largely untouched by construction. 

Once a lumber plantation, businessman-heir Harry Frank Guggenheim bought most of Cainhoy in the 1930s. He passed the land in a trust to his descendants, who formed Cainhoy Land & Timber LLC in 2005, then gave management of the land to Daniel Island Development.

DI Development, which has not replied to repeated requests for comment since April, began applying for permits on Cainhoy a decade ago: first with the City of Charleston and state officials, then in 2018 for federal approval from the U.S. Army Corps of Engineers, required under the Clean Water Act for any construction on wetlands. The Army Corps approved the permit in 2022, acknowledging the development’s “potentially significant impacts” in its decision.

That was upended the following year when the northern long-eared bat was uplisted and the Fish and Wildlife Service returned to resurvey the tract for the newly endangered species. At the time, advocates at SELC approached the decision with cautious optimism. 

“It remains to be seen whether it’ll be enough, but the agencies are going to come up with some additional conditions to protect the bat,” Christopher DeScherer, director of the SELC’s South Carolina office, said on a visit to Cainhoy in April, while the surveying was still underway . But when the Army Corps issued a modified permit on July 12 this year, DeScherer and Wannamaker said the permit didn’t seem that meaningfully modified: allowing felling and construction across the entire tract originally proposed with seasonal limitations but no limit on the number of bats that could be displaced.

In their reevaluation following the uplisting, experts from the FWS argued the impact on northern long-eared bats of developing Cainhoy could only be minimal because the 9,000-acre tract represents just 0.003 percent of the species’ total habitat in South Carolina alone. 

SELC argued in their injunction request to stop tree felling on Cainhoy this summer, that that percentage was calculated by including cities like Charleston in the bats’ total possible range, when northern long-eared bats only live in forests.

The figure also understates the potential importance of warm, coastal habitat for bats under attack from white-nose syndrome, Wannamaker said in the emergency filing. Northern long-eared bats and other cave hibernating species only catch the fungus sleeping in the winter. In Cainhoy and along the coast, recent research suggests the climate is warm enough for bats not to hibernate at all, making the peninsula a refuge for a species battling a cold-loving disease. 

Staff from the FWS’s South Carolina field office who surveyed for the bat and decided developing Cainhoy would not affect the species declined to comment on their decision or the development. Jill Utrup, the FWS’s national recovery lead for northern long-eared bats, said that research into how northern long-eared bats behave in warmer climates is “very recent,” but that experts now think bats stay active year round only in the far southern part of their South Carolina habitat. 

“We’re still learning about where the edge of the year-round active part of the [bats’] range is,” said Utrup, who authored the species’ uplisting in 2023, “but it would include parts of Louisiana, parts of the Carolinas in the far southern part of their range.”

“Adding a Small City to Charleston”

Looking at Cainhoy from the water, bats aren’t the most obvious wildlife. On a boat visit to the peninsula earlier this year, DeScherer looked out and saw a pod of dolphins spouting close enough to hear the water spitting over each gush of air. “It’s crazy, you’re in downtown Charleston, then 15 minutes away there’s dolphins and alligators,” he said. “You come down here and you don’t see hardly anybody and it’s so quiet. It’s a pretty wild spot.”

Gates Roll, a boat pilot with a streak of gray running through the stubble over his Adam’s apple, kicked the engine back into gear: “You’ll want more time up there so I’ll bomb it.” Four creeks cut into the peninsula, one with palmettos and pines right up to the bank. But others have hundreds of yards of marsh before turning to solid ground. Roll drops an electric motor off the front of his boat, because it makes less noise. A green heron takes off out of the reeds.

The difference to Ralston Creek, cutting into Daniel’s Island opposite Cainhoy, is obvious. At the end of each waterfront house on Ralston are private docks; at the end of most docks, boats with triple outboard motors sit in net slings to stop barnacles growing attached. Roll has been running fishing trips up Charleston’s creeks for 15 years and remembers Ralston before it was developed. “You can walk down the creek jumping dock to dock these days,” he says, idling under a bridge with rusting metal legs and a graffiti Homer Simpson. “It’s Dock Creek now.”

DeScherer is used to making the eloquent, green case for Cainhoy. “This is one of the most ecologically valuable, undeveloped tracts left in coastal South Carolina,” he says from the boat. “It is truly special in terms of its size, adjacent to the national forest, wildlife species, the marsh.” But he also knows that appealing to a marsh or endangered bat is not equally persuasive to everyone. He’s worked as an environmental attorney since 2000; the ringtone on his phone is a cricket chirping.

For him, the case for developing Cainhoy sustainably is as much about urban planning. “Even if you don’t care about wetlands, wildlife—protect people. The roads are going to be underwater even if the houses aren’t.” The water in Charleston Harbor is expected to rise over a foot by 2050, according to federal scientists. By then other studies suggest tidal flooding will be a common occurrence two days out of three. “That’s already the reality in Charleston,” Roll said. “The sun’s out and it’s flooding.”

“You can walk down the creek jumping dock to dock these days. It’s Dock Creek now.”

— Gates Roll, boat pilot

Under its current plan, almost half of the development’s 9,000 houses will be built in a 100-year floodplain: a designation for land with a 1 percent chance of experiencing a catastrophic flood every year with current sea levels.

“They’re basically adding a small city to Charleston,” DeScherer said, motoring with Roll back down toward the city, “and no one has taken a holistic assessment of all the ways this is going to impact not only this tract of land but Charleston in general. It’s shortsighted.”

Even from 20 miles away, SELC believes the project will affect Charleston by building on top of 182 acres of wetland. According to the EPA, every acre of wetland absorbs 1 million to 1.5 million gallons of water during a flood, then releases it slowly like a sponge. While the wetland in Cainhoy only constitutes a small fraction of the state’s total, it is enough to hold 270 million gallons of floodwater: the equivalent of over 400 Olympic-sized swimming pools. 

More recent research from the University of California, Berkeley, attempting to quantify how wetlands protect us from flooding, suggests that every lost hectare of wetland near developed areas causes an additional $8,000 of flood damage annually. If that national average holds true in Cainhoy, the development stands to create almost $600,000 in additional flood damages each year.

That figure does not include new infrastructure built in the path of flooding. At Cainhoy almost one in two of the new homes is planned for construction in a floodplain. According to DI Developments, that amounts to just over 20,000 new residents living in the 100-year floodplain.

Robert Young is a geology professor and director of the Developed Shorelines study program at Duke and Western Carolina Universities. He has followed the project through its permitting and says it represents disjointed thinking about climate risk.

“The City of Charleston wants over a billion dollars of federal money to build a sea wall around the peninsula, and at the same time, with a straight face, they want to put all these houses in an area where almost all of it is in a flood zone,” Young said.

In 2022, Congress approved plans to build a $1.1 billion seawall stretching eight miles around Charleston Peninsula; city officials (who prefer to call it a “battery”) are now hashing out design details with the Army Corps of Engineers, which approved permits for the Cainhoy development in the same year. 

There’s an incongruity that “just drives me crazy,” said Young. “It should be one or the other. We’re spending billions of dollars to protect already developed areas. Why would we make the problem worse?” The Corps did not respond to a request for comment.

Young acknowledged the growing demand for housing on South Carolina’s coast. “I’m not anti-development,” he said. “I’m just ant-stupid development.” 

“The City of Charleston wants over a billion dollars of federal money to build a sea wall around the peninsula, and at the same time, with a straight face, they want to put all these houses in an area where almost all of it is in a flood zone.”

— Robert Young, Duke and Western Carolina Universities geology professor

In 2019 SELC and the South Carolina Coastal Conservation League commissioned a town planning firm to assess whether the development could go ahead without destroying as much wetland area. 

The report found that reducing the number of homes by a third, and resituating some others could allow it to go ahead “with zero wetland impacts.” If all 9,000 houses remain the goal, the report suggested three different layouts that would disturb just 14 acres of wetland and keep all but 10 percent of the houses out of the floodplain.

“This report is not an endorsement of the development of Cainhoy,” it says. “However, we understand the development pressures facing the Charleston area. This report is meant to … facilitate a desire for growth and expansion while avoiding and minimizing negative impacts to the wetlands and floodplains integral to this region’s flood defenses, and minimizing the number of our future neighbors placed into vulnerable tracts.”

Wannamaker agreed with Young’s assessment that the development was luring too many new homeowners into the flood plain. “We’re not saying ‘no development,’ but we’re saying it should be better than this and it should have fewer impacts,” Wannamaker said. “We tried to make that argument to the Corps of Engineers before they issued this permit but unfortunately it fell on deaf ears, so we are left with the court system as our backstop.”

While tree felling continues, the Court of Appeals is expected to begin hearing SELC’s full case against the permit early in 2025. Even after this month’s decision, Wannamaker was hopeful for a reviewed decision from the Court of Appeals. 

“Is the system working? It’s really unpredictable,” she said. “The system is working in letting us proceed with our case in court. What that means for the ultimate outcome is very hard to say.”