View of the sinkhole that has formed on W. Mulberry Street between Paca and Greene streets.
View of the sinkhole that has formed on W. Mulberry Street between Paca and Greene streets. (Barbara Haddock Taylor / Baltimore Sun)

Two street collapses above a century-old Baltimore sewer line near downtown are expected to cost the city at least a combined $10 million in repairs, the Department of Public Works said Tuesday.

A section of the 100 block of West Centre Street in Mount Vernon that fell into the 6-foot sewer line on April 23 is expected to reopen to traffic by Oct. 1 after $4 million to $4.5 million in repairs, the public works department said.


The more than four months of work has included stabilizing the roadway, installing bypass mains, clearing debris from the sewer, placing scaffolding, lining 1,100 feet of sewer, removing the sheeting and shoring, repairing and lining a 33-inch diameter storm drain and partial backfilling, the department said.

The repairs are almost finished, and follow-up work is expected to conclude on or about Sept. 23 before the road is resurfaced, striped and reopened, the DPW said.

The Mulberry Street work will be more complex.

The same ancient sewer line was responsible for a separate street collapse in the 500 block of West Mulberry Street on July 4, the department said. The section that broke there is 80 inches in diameter and made of brick and mortar.

Public works crews determined that the sewer needed 3,000 linear feet of cured-in-place pipe to fortify against any more collapses. The cured-in-place pipe will extend from Mulberry Street to the Centre Street collapse.

A portion of Franklin Street, one of the city's main thoroughfares, is closed for crews to dig sewer bypass tie-ins under the street, and state and CSX officials have coordinated with the city in order to bypass the Howard Street Light Rail tracks and the Howard Street Tunnel.

Then it will take three weeks to dig up the Mulberry Street sewer to clean it, which should be finished by the second week of November, officials said. Lining the sewer should take another three weeks.

Barring bad weather or other interruptions, Mulberry Street should be finished and reopened by mid-December. It is expected to cost between $6 million and $7 million.