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The cookout area at Hawthorne Westside Apartment Homes West Ashley, was still flooded Tuesday morning from the aftermath of tropical storm Irma. Leroy Burnell/staff

The moratorium on development in the Church Creek basin in West Ashley served its primary purpose. It gave city officials enough time to come up with new rules designed to prevent future drainage problems in one of the region’s most flood-prone areas.

But the true test will likely start when the moratorium expires and Charleston City Council approves the new building guidelines.That was set to happen on Tuesday, but Hurricane Florence intervened.

About 80 percent of the Church Creek basin has already been developed, but at least 352 new residences can soon move forward, according to a recent report by The Post and Courier’s Abigail Darlington.

In the past, a lack of data on water movement, poor planning and overambitious development led to flooded homes. As building continued, the added impervious surface area and new impediments to natural water flow made the problem worse.

Today, more than 70 homes in the basin have been repeatedly damaged by flooding. A few dozen are in the process of being bought out, and will be razed and turned into green space.

For decades, new developments have involved adding tons and tons of fill dirt to raise properties above the flood line. That might save a new house, but the water flowing downhill pooled around others.

The new rules still allow filling. But they specify that developers have to dig ponds to retain water on site and use looser dirt that allows water to sink in more quickly. Hopefully that will be enough.

New guidelines also call for developers to work with city officials to build identified infrastructure needs. They set standards for culverts and drainage into tidal waters and rules for how water should be managed during severe storms.

With new guidelines in place Church Creek area could have some of the most rigorous stormwater rules in the area. That’s essential.

Church Creek is a small waterway. It’s only about 10 feet wide for most of its length. But it handles runoff from a massive formerly swampy basin that stretches over 5,000 acres. The whole system is complex and fragile, and seemingly minor human interventions have had dramatic and unpredictable consequences.

Even with new guidelines, developers must proceed with caution. A light touch is the only responsible approach in such a delicate Lowcountry ecosystem.

We already know the alternative. After multiple problem floods, some homeowners are waiting on a buyout program using local and federal dollars. And with Hurricane Florence threatening to drop torrential rain in Charleston, more headaches could await residents who have already dealt with repeated and costly frustrations.

It’s a dangerous situation that has caused tremendous loss and heartache.

The Church Creek moratorium served its purpose. That’s hopeful news. But there is still a lot of work to do in order to keep residents high and dry. And not just in West Ashley.