Flood protection prevented significant damage in flood-prone Old Ellicott City

BALTIMORE - Flood protection prevented significant damage Sunday evening in flood-prone Old Ellicott City.

Those along Main Street and the low-lying areas around the Patapsco River were told to seek higher ground as downpours dumped inches of rain throughout Maryland.

A Flash Flood Warning has been issued until 12:45 a.m. for the area that has had several major flood events since 2011. 

County Executive Calvin Ball said the flooding alert was activated around 9:48 p.m. and again at 10 p.m., prompting police to shut down Main Street.

The storm brought about three inches of rain to Ellicott City in a short amount of time, and there was no apparent flooding to any of the businesses.

"While we remain vigilant, these storm events underscore the importance of our ongoing impactful investments in flood mitigation and prevention," Ball said. "While we still have much to do, we continue to make tangible and visible progress for our community." 

In 2016, rising floodwaters rushed through the historic city, turning Main Street into a torrent that carried away entire cars with drivers still inside, wiped out parts of roads and sidewalks, crippled homes and businesses, and had first responders working late into the night as they rushed from call to call, officials told reporters.

In 2018, in old Ellicott City, which sits in a gully, eight inches of rain in a few hours turned the street into a raging river. In some cases, water reached as high as the second floor of some buildings, stranding many seeking higher ground. More than 70 businesses were damaged.

Ways to mitigate flooding

In December 2018, Howard County Executive Calvin Ball first announced the Ellicott City Safe and Sound Plan, a comprehensive plan to mitigate the effects of flash flooding in Historic Ellicott City with retention ponds. 

The four focus areas of the plan include ensuring public safety, supporting business and property owners, maintaining Ellicott City's historic charm, and developing a more inclusive, community-driven process.

In 2022, a new retention pond opened upstream in a section near Baltimore National Pike and Route 29. Engineers say it's designed to trap about 4 million gallons of water.  

In 2023, another pond called Quaker Mill, which is just southeast, opened.

Howard County leaders recently broke ground on the North Tunnel project, which is one of the seven projects that are part of the Ellicott City Safe and Sound Plan.  

Once completed, it'll be able to collect and carry around 26,000 gallons of stormwater per second. The 18-foot diameter, one-mile-long tunnel will span from the west end of the city right into the Patapsco River.  

A tunnel boring machine, which has been named Rocky, will be the primary tool to create the tunnel. It'll be carving through the granite throughout the area's topography.

North Tunnel construction is aimed to be completed by Fall 2027.