An extreme flooding event in Detroit in 2014 exposed the outdated stormwater infrastructure in much of the United States. Since the event, various studies have shown that instead of mitigating flooding and its costly consequences, the antiquated sewer systems are actually worsening flooding events.
On August 11, 2014, the Metro Detroit area experienced record-breaking rainfall of 4.57 inches, more than doubling the previous record. The flooding event that followed caused many residents to lose power, streets, and highways to become inundated, and damage to thousands of homes, with the total cost amounting to $1.8 billion.
Researchers from the University of Michigan found that the current storm runoff system may have exacerbated rather than lessened the flooding. According to their report, a primary reason for this is the centuries-old system that targets highly localized solutions to stormwater runoff. As the country has grown and development boomed, the system in place cannot manage runoff from adjacent developed areas.
Additionally, flood maps developed by the Federal Emergency Management Agency FEMA only consider flood risk near bodies of water, while leaving out flooding data for cities located away from any such sources of water. This leaves towns like Warren, Michigan, without mapped flood risks and citizens unaware of the possible dangers.
Flooding also remains the most common and costly disaster, according to FEMA, and is becoming increasingly costly, with National Flood Insurance payouts increasing by 660% from the years 2000 to 2020 compared to 1980 to 2000.
From the 2014 event, researchers from the University of Michigan have developed a set of policy recommendations to be implemented nationwide. These include redesigning stormwater systems from a systemwide approach, including urban infrastructure in stormwater system design, further developing and mandating computer models that can more accurately represent runoff after a rainfall event, and creating flood hazard maps for areas not immediately adjacent to permanent bodies of water. Researchers, disaster management organizations, and citizen advocates believe that it is worth investing in new or updated stormwater systems and that these advancements will save taxpayers money in the long run.
By Sarah Ortega