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Updated: December 21, 2021 @ 6:23 am
Charleston plans to set aside $500,000 for a Comprehensive Water Plan that will create a citywide strategy for flood mitigation projects. Currently, flood projects are planned on a case-by-case basis. Brad Nettles/Staff

Charleston plans to set aside $500,000 for a Comprehensive Water Plan that will create a citywide strategy for flood mitigation projects. Currently, flood projects are planned on a case-by-case basis. Brad Nettles/Staff
It has been nearly 40 years since the city of Charleston mapped out a citywide flood-prevention strategy. 
The 1984 Charleston Master Drainage and Floodplain Management Plan laid out where new or expanded drainage systems could help ease flooding across the city.
“That drainage plan, as important as it was, is outdated and it isn’t comprehensive,” Charleston Chief Resilience Officer Dale Morris said.
Since then, projects and studies have been commissioned, but a new plan aims to stitch them together. 
In the proposed $254 million 2022 budget, Charleston officials have set aside $500,000 of the city’s federal pandemic relief funds to commission a Comprehensive Water Plan. The thrust, which will be mapped out by consultants, would look at the city as a whole to see what types of flood mitigation are needed most and where they would have the most impact. 
Instead of trying to drain water as quickly as possible, Morris said the city’s main strategy should be to effectively store floodwater, such as in detention basins, and let it slowly disperse. One advantage of this approach is that it helps prevent a sinking effect called subsidence. Shifting ground levels due to the movement of groundwater threaten buildings’ foundations and worsen flood risk.
In New Orleans, where consultants with engineering and architectural firm Waggonner & Ball designed a water plan in 2013, the city was already facing significant subsidence.
“We had created this system of pipes and pumps and the land couldn’t handle it,” said David Waggonner, founding principal of Waggonner & Ball.
A sense of urgency in New Orleans fueled the push for a water plan, he said. 
“There was a sense that if New Orleans doesn’t do better with water, it won’t exist,” he said. “Charleston isn’t quite at that point but I fear it will be.”
In Charleston, tidal flooding, subsidence and storm risk all impact how much water collects in undesired places such as homes, businesses and cars. 
The aim of a water plan is not to eliminate flooding, Morris said, but to find ways to direct it away from where it can do the most damage. More detention can be planned in areas of town where there is already more open space to work with or can be added at public parks. 
It would also allow the city to use funding for flood mitigation more efficiently.
“If you can store some of the storm water, it doesn’t need to be pumped out as quickly. You don’t have to oversize your pump,” Morris said. 
That doesn’t mean that Charleston won’t need more drainage projects at all however, especially on the peninsula.
“Its going to be hard to say, ‘Hey we’re going to knock these buildings down to build detention ponds,'” Morris said of the peninsula. “Because it’s already so dense.”
Groups like the Historic Charleston Foundation and the city’s sea wall advisory committee support funding for a water plan.
Members of the sea wall committee recommended the city form a water plan after evaluating the flood risk the city faces, with or without, a sea wall. 
Historic Charleston got involved, too.
“We wanted to be at the forefront of the conversation,” said Cashion Drolet, Historic Charleston’s chief advocacy officer. “There is a lot of historical value in the city at large that is at risk.”
City Council on Dec. 21 will take its final vote on the budget proposal, including the $500,000 allocation for a water plan. 
Reach Emma Whalen at 843-708-5837. Follow her on Twitter @_emma_whalen. 
Emma covers the city of Charleston for the Post and Courier. Previously, she covered city hall and general assignments for newspapers in Houston and Austin. She is a Boston-area native, former student athlete and graduate of The University of Texas.
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