Researchers have finally been able to determine just how much impervious surfaces exacerbate flood levels
Blockbuster flooding events such as Hurricane Harvey grab headlines, but urban flooding is a routine—and growing—problem: in a 2018 report, 83 percent of municipal stormwater and flood managers surveyed in the U.S. reported such inundation in their areas. Although heavier downpours fueled by climate change are a factor, the expansion of pavement and other impervious surfaces is making the situation worse because it prevents the land from absorbing these torrents of water. On that broad point, researchers largely agree. What they have not agreed on is how much worse.
