Flood Mitigation Plans Bolstered By Construction Of 5,000-Foot-Long Tunnel In Howard Co.

HOWARD COUNTY, MD — A 5,000-foot-long tunnel will be built in Ellicott City as the largest and hopefully most impactful flood mitigation component of the Ellicott City Safe and Sound plan. The county has closed on a $75 million low interest federal loan through the Environmental Protection Agency’s competitive Water Infrastructure Finance and Innovation Act, which provides water project construction funding under favorable terms.

The EPA funding brings the total investment of county, state and federal dollars in Ellicott City to $167 million in the past four years, which is $138 million higher than during the previous four year period.

“This tunnel will be one of the most important and impactful public works projects in the history of Howard County,” Howard County Executive Calvin Ball said. “This game-changing project will carry 26,000 gallons of storm water per second, away from streets and foundations in Old Ellicott City and the West End and directly into the Patapsco River – about the amount of water in an in-ground pool every second. We are writing a new chapter in the long history of Ellicott City, making it a national model of resilience.”

County public works officials said they expect to complete design of the tunnel this year with construction starting as soon as possible. The project, known as the Extended North Tunnel, will be about 18 feet in diameter and run up to 100-feet underground, just north of Main Street. Howard County has already broken ground on two other major flood mitigation projects – the H7 and Quaker Mill ponds. Both projects are expected to be completed in the next year and will retain nearly 7.5 million gallons of storm water combined - about the size of a football field covered by 23 feet of water.

Components of the Ellicott City Safe and Sound Plan, which can be found at ecsafeandsound.org, also include:

• Seven major water retention and water conveyance projects, including the tunnel and the ponds being constructed
• Enhanced stream cleaning
• Tone alert warning system and signage
• Drainage improvements throughout the watershed