Connect flood control with urban design
Over the course of four days in mid-September, Hurricane Florence dumped a record-breaking 34 inches of rain on Swansboro, N.C. — a city that usually gets 57 inches in an entire year. In 2017, Hurricane Harvey caused the worst flood in Houston’s history. In 2012, flooding from Superstorm Sandy — considered a once-in700-year event — devastated coastal New York and New Jersey.
These and other events are typically called natural disasters. But overwhelming scientific consensus says they are actually the result of human-induced climate change and irresponsible construction in floodprone areas.
Most scientists agree that global warming is causing sea levels to rise, while increasing the frequency, intensity, and duration of extreme weather events. At the same time, the rapid urbanization of coastal areas is putting more people and property in harm’s way.
Given this new normal, it is time to rethink our approach to floods. We typically deal with only the symptoms of the problem, by evacuating residents before a disaster, housing them temporarily in emergency shelters, and paying insurance so that they can rebuild afterward.
But this is tremendously costly, both in human and financial terms.
Moody’s Analytics has tallied at least $17 billion in property damage from Florence so far. Harvey cost $125 billion and the tally for Maria in Puerto Rico is $139 billion. Katrina destroyed $161 billion in property.
Fortunately, the right infrastructure can prevent flooding, rather than treat it after the fact. Prevention is cost-effective: The National Institute of Buildings Services estimates that every dollar spent on the reduction of a community’s vulnerability to disasters saves approximately $6 in economic losses.
As an architect and urban designer working on large-scale projects, as well as a native of the Netherlands, a low-lying country that wouldn’t exist without flood-management infrastructure, I have been intrigued by recent, innovative solutions to flood prevention.
For example, the beach town of Cleveleys, in England, chose not to build a standard concrete seawall, which has all the charm of a military bunker and can block human access to the shore. Instead, the city built a structure with amphitheater-like viewing spaces and steps. The steps accentuate the beautiful curvilinear shapes, while creating access to the beach and adding public space, which is important for a coastal town that relies on tourists.
Flood protection can even be integrated into buildings. The Dutch coastal town Katwijk aan Zee integrated a levee with a parking garage, and covered it with landscaping.
Finally, some of the best solutions rely on an ancient flood protection device: dune grass, a saltwater tolerant plant that stabilizes dunes and prevents erosion. In contrast to reinforced concrete defenses that take the full force of waves until they are worn away by the sea, dunes absorb the waves’ velocity, while beautifying the landscape and providing habitats.
By marrying flood management with creative urban and landscape design, infrastructure can become a strategic civic asset. In addition, it can pay for itself by unlocking the real estate and economic development potential of newly protected areas. The new normal of flooding and sea-level rise poses great challenges, but it also offers opportunities to improve our urban areas and landscapes.