ANNAPOLIS, Md. — With another extreme hurricane season about to start, a new study found roadway flooding in Maryland occurs not just on the coast but throughout the state, impacting almost a half-million residents with lane closures and traffic slowdowns.
The report from consulting firm ICF found flooding on 15,000 miles of Maryland roads caused hours of lost productivity and damage to roads.
Matthew Fuchs, flood-prepared community initiatives officer for the Pew Charitable Trusts, which supported the study, said the disruptions have serious economic implications.
“User delays captured in this report, which include the value of lost work time and delayed deliveries, cost about $15 million per year in Maryland, for a total of over $230 million over the years 2006 to 2020,” Fuchs explained.
He noted the figures do not include the cost of road repairs. Despite flooding problems, he pointed out Maryland is a national leader for building flood resilience and other states could learn from its efforts.
For example, the Maryland Department of Transportation (MDOT) uses climate data to assess the vulnerability of hundreds of structures to sea-level rise, storm surge and increased rainfall. ICF used MDOT’s roadway flooding incident data as the basis for the report.
Sandy Hertz, assistant director of the Office of Environment for MDOT, said the past few decades have seen more frequent and more extreme rain events in the state, such as the Ellicott City floods in 2016.
She thinks it’s critically important for states to have the best data available on rainfall, as Maryland does, to help decide flood-mitigation projects.
“That data helps inform design decisions for how we size our stormwater infrastructure,” Hertz stated. “It can, and also does, influence the stormwater management regulations that are done at a state level.”
Cassandra Bhat, director of climate resilience for ICF and co-author of the report, said they came to their findings by using road-delay data that consistently tracked flooding incidents, which some states may not track.
“Our intention with this analysis was to raise awareness of the scope and magnitude of flooding impact on the transportation system,” Bhat outlined. “I think it’s something people understand anecdotally at some level, but there isn’t always that quantified side of how much is this actually costing in terms of dollars and times.”
The report identified more than 100 locations along state highways that are especially flood-prone, to help policymakers target infrastructure-resilience strategies or relocation investment.