The U.S. Army Corps of Engineers is proposing to build a flood wall to protect Baltimore's Fort McHenry and Harbor Tunnel entrances as the risk of flooding increases due to climate change.
The project, estimated to cost $77 million, follows a three-year study of Baltimore's storm risks, particularly to critical infrastructure along the Patapsco River.
If completed, motorists can expect to see new walls rising 2.5 to 6.5 feet above the ground along the southern entrances of both tunnels, Army Corps Baltimore District spokesperson Cynthia Mitchell said in an email.
Mitchell said the existing walls at the tunnel entrance are not able to withstand flooding and engineers will determine whether they need to be replaced during the design phase of the project.
The two tunnels will receive approximately 9,500 linear feet of floodwall to protect each tunnel's entrance and ventilation buildings, according to an Army Corps news release Monday. The walls will include enclosed structures ranging in length from 20 to 50 feet. Mitchell said the shutdown device can be left open when not needed.
According to the study, this height was chosen based on “intermediate” estimates of sea level rise — between the most extreme and least extreme projections of average Patapsco River levels over the next few decades. The move is intended to reduce the risk of flooding from a once-in-a-century severe storm event, according to a release Monday.
According to a 2015 Army Corps study called the North Atlantic Coast Comprehensive Study, Baltimore's mean sea level is projected to increase by 1, 2.1, or 5.4 feet by 2100 (under the low, medium, and high scenarios, respectively).
Higher water levels may increase the risk of storm-related flooding in the Baltimore area. According to the Army Corps, the region's steady population growth and continued shoreline development mean the risk of injury, loss of life and property damage also increases.
The Fort McHenry Tunnel on Interstate 95 connects Locust Point in South Baltimore to the Canton industrial area on the city's east side and is used by approximately 45 million vehicles annually, while the Harbor Tunnel on Interstate 895 connects South Baltimore Joe Bieberich, program manager for the Army Corps' storm risk study for Baltimore, said communities ranging from Brooklyn to southeast Baltimore are used by about 27 million vehicles each year.
Baltimore Sun Photo: Amy Davis
The third annual Fort McHenry Tunnel 5K Run/Walk begins through the right northbound tunnel tube to benefit Special Olympics Maryland.
“It is important to ensure these critical transportation routes remain open during coastal storm events, keeping jobs, commercial transportation routes and emergency services flowing,” Biberic said in a news release Monday.
The coastal flood risk area studied by the Army Corps covers all of the city's Patapsco River shoreline, including the Inner Harbor, Federal Hill, Fells Point, Canton and an area of South Baltimore. The Army Corps also evaluated Martin State Airport in Baltimore County during the study.
Mitchell said the tunnel projects were chosen based on cost-effectiveness and need, but they are considered a “first bite” and future conservation actions may come later.
Officials say the importance of infrastructure protection was highlighted when a ship strike in March led to the collapse of the Francis Scott Key Bridge, killing six construction workers.
“The people of Baltimore know all too well the impact when critical transportation infrastructure is lost. This project will increase the resiliency of the tunnels, a critical route for the movement of goods and services throughout Maryland and along the Eastern Seaboard,” Army Gen. Scott A. Lieutenant General Spellmon said. in a press release on Monday.
The Army Corps recommends that Congress approve funding for 65 percent of the program's costs. The other 35 percent will be borne by the Maryland Transportation Authority, which owns and operates both tunnels. Spelmon signed the recommendation during an Aug. 5 ceremony at Army Corps headquarters in Washington, D.C.
The study, co-funded by the Army Corps and the Department of Transportation, said costs could be expected to increase if contamination is found in soil near the tunnel. The construction would also require a right-of-way agreement with the landowner, which can be “difficult and time-consuming, particularly on railroad property,” the study noted.
But if all goes according to plan, construction could begin in 2027, according to the release. Design work may begin later this year.
It is estimated that new floodwall infrastructure will cost the transit authority approximately $60,000 per year in the Fort McHenry Tunnel and approximately $130,000 per year in the Harbor Tunnel.
