Ramboll has been engaged to assist the Department of Energy and Environment in assessing the effect of flooding from the large Potomac River, that flows though the city centre, in terms of rising sea level and storm surges, as well as extreme rainfall.
The Potomac River is among the wildest rivers in the world and it relatively often reaches flood stages because of events in distant areas of its watershed.
“Through advanced hydraulic modelling we illustrated that the planned level of resiliency towards storm surge and sea level rise only has limited effect on reducing flooding in the future,” says Trine Munk, climate adaptation and resilience specialist at Ramboll, adding:
“We are now conducting a cost-benefit analysis (CBA) for the currently proposed protection level and for a recommended higher protection level, to illustrate the value of increasing resilience compared to the curerntt situation, both in terms of reduced risks, but also in terms of added value.”
The riverine protection measures are proposed as a mix of grey infrastructure and BGI. Added value includes an extension of an existing Riverwalk trail, additional green space, living shoreline concept and increased access to the river.