West Ashley flooding

The Shadowmoss subdivision of West Ashley is part of the Church Creek drainage basin and has seen repeated flooding, most recently from Tropical Storm Irma. File/Brad Nettles/Staff

The city of Charleston is posed to extend a development moratorium for another six months in northern West Ashley, and if City Council agrees, the staff has a plan that would allow development to resume there by Dec. 1.

The extension will give the city's staff more time to coordinate new stormwater rules in the Church Creek Drainage Basin, evaluate possible infrastructure improvements there and continue buying out the most flood-prone homes.

Stephen Julka, the city's floodplain manager, said the six-month extension "gives us an opportunity to test our ideas and work through them."

Since its first moratorium there took effect last year, the city's goal has been not to take any steps, such as permitting new development, that would make the area's flooding worse, said Mark Wilbert, Charleston's chief resilience officer.

The city soon plans to model simulated development under the new stormwater rules to get a sense of where water would go, and whether there would be any harm. Wilbert is leading a team of about a half dozen city staff reviewing the basin and eyeing next steps there.

"We've got some work to do, but we've got this laid out," he said.

City Council first passed a temporary moratorium in the Church Creek Drainage Basin in May 2017 after two consecutive years of fall floods there. Before it expired in February, council members agreed to extend it to May 31.

On Thursday, council members will consider extending it yet again, until Nov. 30, to allow time for field testing and public vetting of new changes to the city's stormwater rules.

While some council members have bristled against a moratorium on new hotels downtown, they have been much more supportive of blocking new development in Church Creek.

City Councilman Harry Griffin, who represents much of the Church Creek area, said the moratorium has been justified and he supports extending it for six months, “but I want us to get something done in that six months.”

“We’ve to get this right,” he added.

In November, council was presented with a long-range plan to buy 350 flood-prone properties in the Church Creek area.

The $50 million to $70 million buyout would be in addition to $8 million already approved to buy and demolish 36 homes hard-hit by area flooding, including 32 residences in the Bridge Pointe townhouse community.

The federal government is paying $5.8 million and the city $1.9 million for that.

Wilbert said the city hopes to buy out about five more properties soon, a smaller number that reflects the amount of state and federal funding available.

Also last year, consultant Bob Horner of Weston & Sampson Engineering also presented $44.3 million worth of possible projects to control Church Creek flooding, including tidal gates and pumps to speed water toward the Ashley River.

"We've got a huge price tag," Mayor John Tecklenburg said at the time. "Coming up with the money is going to be a huge challenge."

Wilbert said the city's approach to the Church Creek Drainage Basin would serve as a model to address concerns about development and flooding elsewhere in the city.

Reach Robert Behre at 843-937-5771. Follow him on Twitter @RobertFBehre.