Howard County Executive Calvin Ball (D) announced Monday that his flood mitigation plan for Ellicott City would cost an estimated $113.5 million to $140.5 million. (Katherine Frey/The Washington Post)

Howard County Executive Calvin Ball (D) has selected a five-year flood mitigation plan for Ellicott City that includes building a tunnel and tearing down four buildings in the historic district.

The plan, which officials estimate will cost $113.5 million to $140.5 million, is intended to reduce the risk of flooding after two “1,000-year floods” sent water roaring down Ellicott City’s main street.

The floods in 2016 and 2018 were so intense that the National Weather Service found that the chance of them happening in a given year was less than one-tenth of 1 percent.

Debate over flood mitigation plans was a point of contention in the race for county executive last year, in which Ball defeated incumbent Allan H. Kittleman (R).

Kittleman proposed a $50 million plan that would have required razing 10 buildings — a move strongly opposed by preservationists and some community members. Ball said the plan was rolled out too hastily.

But many of the business owners affected by the floods said they supported Kittleman’s plan and wanted to see swift action.

“The time for Band-Aid fixes is over, this is an innovative long-term solution that can only happen if we come together and get to work with everyone’s support,” Ball said in a statement Monday, noting that the first anniversary of last year’s flood will occur on Memorial Day weekend. Eddison “Eddie” Hermond, a National Guard sergeant, died trying to rescue a woman trapped by rapidly rising water across the street.

Ball presented five flood mitigation plans to the community last month, saying he wanted public input on the best way forward. All of the options included razing at least four buildings. The structures that will be destroyed are home to Phoenix Emporium, Discoveries, Bean Hollow and Great Panes Art Glass Studio.

A request for proposals for construction of the tunnel will be issued this year.

Ball’s office says the measures will reduce the amount of flooding on Main Street from storms like the one last year to less than a foot of water.