With the help of an ecological restoration company, they coaxed back to the surface the stream that had been diverted through stormwater pipes and built a cascading streambed, with step pools and weirs—low dams to slow water flow—to filter the water as it makes its way toward Back Creek.
…In an age of climate crisis, marshes like this one are critical: As sea levels rise, marshes engage in a kind of dance with the rising tides through a process called accretion. …The marsh is also a carbon sink, more effective at sequestering carbon than the equivalent area of dry land.
By restoring their land to serve its intended purpose, the church created a climate sanctuary: absorbing higher tides, filtering polluted stormwater from extreme rain events, hosting displaced creatures, and drawing carbon out of the air.
…Three hurricanes, in 2015, 2016, and 2017, pummeled Crosstowne, each dumping enough water to require a massive rebuild of the sanctuary. After the third flood, the church interior was rebuilt in two weeks, but the church recognized that rebuilding wasn’t enough. The leadership team at Crosstowne decided to do something unusual for a church: gather scientific data. They hired a hydrology team and an environmental lawyer to analyze the onshore causes of the flooding so that the church could serve as a trustworthy hub of communication with their neighbors and the city.
The study found that as climate change exacerbates rainfall intensity, unsustainable development results in water flowing over concrete rather than percolating into the soil. When rain falls, streets and storm drains are inundated with more water than they can handle, and the excess water ends up 3 feet deep in the sanctuary of Crosstowne. According to the Fourth National Climate Assessment, by the end of the century heavy rainfall events in the Southeast U.S. are expected to double, and the amount of water falling on extreme rain days will increase by 21 percent. As more rain falls on hard surfaces around Charleston, Crosstowne has realized it will be underwater more frequently.
With their data-driven study, Crosstowne became experts on flooding in the area around Charleston’s Church Creek Basin. Rienzo worked with the city to develop new stormwater retention guidelines, reshaping how development is done in Charleston. The benefits of Crosstowne’s work extended beyond its walls, to local homeowners who “were looking at buyouts, flooding, delays,” Rienzo told the local Live 5 News. “So we began to see we were not just doing this study for ourselves. It was a study to do for the community around us.”