During the last few months, two major infrastructure failures have impacted portions of Downtown Baltimore. Engineers from the Baltimore City Department of Public Works are using these problems as an opportunity to secure a long-term solution.

The first of the street collapses occurred April 23 when a large section of roadway collapsed in the 100 block of West Centre Street in the Mt. Vernon neighborhood. The cause was the failure of a 72-inch sewer line, specifically a four-foot hole in the top of it. On July 4 a collapse several blocks away, in the 500 block of West Mulberry Street, was also caused by a partial collapse of the same sewer trunk line that resulted in the Centre Street failure.

This line is over 100 years old, with previous failures on Park Avenue in 1997 and 2012. Therefore it was deemed best to rehabilitate a total of 4,100 linear feet of the sewer main with cured-in-place pipe (CIPP) lining to eliminate the possibility of another failure.

 Work at the Centre Street location has included stabilization, installation of bypass mains, clearing debris from the sewer, placement of scaffolding, lining 1,100 feet of sewer, capping the sewer main, removing the scaffolding, and partial backfilling. Some of the sewer bypass lines along Park Avenue are also being removed this week.

Repairs at this location have also begun on a 33-inch storm drain. This should be completed by the end of this week. City Conduit and BGE work will be done immediately after that. This will be completed by mid-October, to be followed replacement of an 18-inch water main, and additional backfilling and paving. Crews are looking into the possibility of reopening one lane of Centre Street prior to completion of all of the work. The estimated cost for this City work is placed at between $4 and $4.5 million.

 The Mulberry Street section of the sewer main is 80 inches in diameter and is made of brick and mortar. Sewer bypass pumping was briefly delayed while City crews coordinated with State Transportation officials in order to place the bypass under the Howard Street Light Rail tracks, and with CSX officials to place it over the railroad tunnel that runs beneath Howard Street.

 As occurred on Centre Street, the next step is cleaning the main. This will be done from West Saratoga Street and Martin Luther King, Jr. Boulevard, to the intersection of Mulberry Street and Park Avenue, and should be completed in mid-September. That will be followed by an intensive inspection of the line.

 Because of the history of failures on this aged sewer main, and while Mulberry Street is open, extensive lining will then be done to rehabilitate 3,000 linear feet of sewer from Martin Luther King, Jr. Boulevard to Park Avenue. Additional utilities will also be addressed as needed during this time.

 The preliminary estimated cost for this work is placed at between $6 and $7 million. The current estimate for reopening Mulberry Street is early November, with all work to be completed by early December.