By Linda Poon
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The Memorial Day weekend downpour that struck Ellicott City, Maryland, on May 27, 2018 was a “1,000-year storm”—a rain event so intense that, in any given year, it has a 1-in-1,000 (or 0.1 percent) chance of happening. On that day, back-to-back thunderstorms dumped more than eight inches of rain in just three hours, overwhelming the three streams that converge on the town’s Main Street and sending water crashing down the hill. By evening, according to rain gauges to the north, as much as 15 inches had fallen. The resulting flash flood devastated the historic downtown and killed Eddison “Eddie” Hermond, an Air Force veteran and Maryland Army National Guardsman who was swept away trying to rescue a woman trapped by the floodwaters.
Flooding in Ellicott City is hardly new—the mill town has had at least 18 major floods since it started recording them in 1789. This one, however, was different: It was the second such 1,000-year storm in less than two years. On a Saturday night in July 2016, thunderstorms dropped six inches of rain on the city, triggering flash flooding that killed two people and caused an estimated $22 million in damages, plus $42 million in lost economic activity.
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The notion of “flood-proofing” a place like Ellicott City, where regular inundation has been all but engineered into the town’s foundation, involves setting reasonable expectations for success. Over the years, the town had added countermeasures like flood alerts. But when the 2016 disaster was repeated less than two years later, finding a way to bring water levels down became an existential priority. “We had come so far so quickly,” [Howard County councilman Jon] Weinstein says, referring to how swiftly the town recovered in 2016. “But, now, unless we do something huge, this town is never coming back.”
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In May, with the anniversary looming, [County Executive Calvin] Ball put five new flood mitigation options on the table as part of his EC Safe and Sound plan, with price tags ranging from $91.5 million to $175 million. On May 12, Ball announced that the county would go with the second-costliest option. Four buildings will be knocked down, to open up the area for water to flow through. The scheme also includes boring a tunnel further up the hill that engineers say will divert water away from Main Street, and building several retention ponds within the Hudson-Tiber watershed. With a storm as powerful as 2016, the county estimates it can bring down the flooding on lower Main Street to about three feet.
The plan is ambitious, by the county’s own admission, and is expected to take at least five years. To come up with the $140 million price tag, the county will have to work with state and federal partners. “We know that while our plan costs more, it does a better job of actually addressing the problem,” Ball tells CityLab. “And our plan costs less than rebuilding every time we have a major storm.”
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