Johns Island Drainage (copy)

Contractors clear land on River Road and prepare to hall away the topsoil of a new subdivision on Johns Island. Brad Nettles/Staff/File

Amid rising concerns about flooding on Johns Island, city of Charleston leaders on Monday asked legal staff to draft a new moratorium proposal that would temporarily halt developments in the island's flood-prone areas. 

At the Public Works Committee meeting Monday, Mayor John Tecklenburg and council members agreed that the city needed to update its stormwater standards, and projects planned in low-lying areas on Johns Island shouldn't be able to move forward until those new rules are in place.

City attorney Frances Cantwell said that sounded like a feasible approach, but it will require further study to outline which properties would be affected. Tecklenburg said it's too late to get the proposal to City Council on Tuesday, but that staff could have a draft ready by the next meeting on May 8.

The mayor proposed a six-month building moratorium on the island in mid-February to give the city time to coordinate with Charleston County on planned infrastructure projects, but it was deferred. Residents and council members complained that it wouldn't have stopped construction of projects that were already approved, and that the goals of the moratorium weren't specific enough.

Councilman Keith Waring, who chairs the Public Works Committee, said he wanted to revive the discussion about the moratorium after the Planning Commission's decision last week to allow a new dense subdivision in a floodplain on the Stono River. 

He said if it was possible to pause development in outer West Ashley to study the Church Creek drainage basin's issues over the past year, the same thinking could be applied on Johns Island.

"We’re in the process of redoing drainage standards out in the Church Creek basin, but obviously there are the same concerns over in Johns Island as well," he said.

The city hired an engineer last year to study that area's flooding issues and suggest ways to fix them. The full report is expected by the end of May. In addition to the policy changes recommended in that study, the city is about six months into an 18-month process to review and update its citywide stormwater manual. 

Waring said it's possible that new projects on Johns Island could be approved before the city has a chance to implement better stormwater standards. 

"It would be in everybody’s best interest if those new developments adhere to those new standards," he said.

Councilman Marvin Wagener, who represents Johns Island, agreed. He said recent research by College of Charleston ecologist Phil Dustan showed that new developments are disrupting the island's natural capacity to handle storm water.

"We probably need to think about some of what Dustan is saying," he said. "When we build something on Johns Island, there is a synergistic effect. It is going to impact someone upstream, downstream or somewhere in close proximity."

Waring suggested that the revised moratorium could apply to projects in places the Federal Emergency Management Agency defines as low-lying floodplains. Wagener said that might not be strict enough because FEMA's maps use data from past weather events to determine the most at-risk areas, not future predictions for storms or rising sea levels.

"Who knows what’s yet to come? I think that’s too loose of criteria," he said.

Only a small percentage of Johns Island is included in the high-risk flood zone in FEMA's updated maps for Charleston County.

Tecklenburg said the discussion Monday was "timely" because he recently convened the Johns Island Growth Management Committee, which met for the first time last week. 

"I thought when we got to the public comment period that most folks would address traffic and that kind of infrastructure, but in fact folks were a little more mindful of drainage and flooding infrastructure, or lack thereof," he said.

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Reach Abigail Darlington at 843-937-5906 and follow her on Twitter @A_Big_Gail.