Ten years ago on the night of July 30, 2016, the first of two “1,000-year floods” to devastate Ellicott City, Maryland, within two years killed two people and severely damaged dozens of buildings in the popular historic district.
Now, in 2026, construction continues on a tunnel that aims to keep stormwater from running downhill in the hilly former mill town onto Main Street and instead dump it into the nearby Patapsco River.
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In 2016 more than six inches of torrential rain fell in less than two hours, causing flash flooding that swept away hundreds of cars. Two people, Jessica Watsula and Joseph Blevins, were killed in the flooding.
Two years later, in 2018, another “once in a millenium” flood struck Ellicott City, killing Edison Hermond, who was swept away while trying to help rescue a woman on Main Street.
Then new Howard County Executive Calvin Ball announced the “Ellicott City Safe and Sound” plan, projecting to cost $140 million, to be finished by mid-2025.
Since then, the county has installed a new outdoor tone alert system to warn people when a flood is imminent. New evacuation routes have also been developed, with signs posted in Ellicott City.
Three of five planned upstream retention ponds have been built to intercept stormwater before it runs downhill to Main Street. Three tributaries run through the watershed: Tiber Branch, Hudson Branch, and New Cut Branch which have funneled stormwater toward Main Street during flash flooding.
One mile up Main Street is the construction site for the North Tunnel Project, designed to carry 26,000 gallons of water per second underground, and away from Main Street. Tunnel boring machines have been cutting through granite to create the 18-foot-diameter tunnel.to the Patapsco River.
By July 2026, the broader flood mitigation program had grown from an originally projected $140 million to about $386 million, based on inflation and extending the tunnel further uphill than initially projected.
The North Tunnel Project is now expected to be completed by late 2027.
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