Flood Mitigation Policies and Practices17 Dec 2021, Posted in All Posts, Blog Posts
As the U.S. comes out of hurricane season and the Infrastructure and Jobs Act allocates multi-million dollar resources for infrastructure repairs, flood mitigation infrastructure stands to benefit from a long-awaited influx of funds. Dam failures and massive flooding have struck numerous communities on the coast and inland as the impacts of heavy downpours have increased in the last fifty years.
Sea level rise has also caused increased flooding in highly-populated coastal areas, with cities like New York, NY and Norfolk, VA experiencing multiple floods per year. Residential properties in the U.S. face an annualized expected loss of $20.3 billion across the country from flooding in 2021, with the costs projected to increase to $34 billion across the U.S. over thirty years.
Hurricane Sandy’s storm surge in 2012 resulted in New York City’s transportation infrastructure being flooded. The 111-year-old tunnels used by New York commuter rails and Amtrak have continued to deteriorate, and large amounts of rainfall from more recent storms like Hurricane Ida have pushed city officials to widen drainage pipes and separate the combined sewage system that serves 60 percent of the city into two systems that will deal with household water and runoff water separately.
Cities throughout the U.S. face challenges in trying to make streets, railways, and other critical infrastructure collect, absorb, and slow down water so that it does not accumulate and damage infrastructure. Different types of more porous concrete and bioswales (landscaped curbside areas that water-loving plants can be planted in) have been utilized to allow water to drain into sewer systems and avoid pooling in large amounts on the surface. Additional flood gates and walls can reroute rainwater to areas where it can be absorbed or disposed of and can also be activated during storms to protect specific low-lying areas.
Vulnerable areas like Norfolk Naval Station also occupy crucial national interests that are under threat from continually rising sea levels. Multiple flood gates surrounding the base, home to the U.S. Atlantic fleet, have been only temporary fixes. Officials face the choice of closing the gates and letting the creeks swell or leaving the gates open and allowing the ocean to flood the base.
Department of Defense officials have used artificial oyster reefs to reclaim land lost to sea-level rise and also to further protect against erosion at the base, but a lack of funding has resulted in no new piers or other key naval infrastructure being constructed. The city of Norfolk has erected major flood walls and begun street-raising projects to protect key transportation infrastructure, but even a sea-level rise of three feet or less would mean large portions of Portsmouth Naval Hospital, the Chesapeake Deepwater Terminal, and the Norfolk Naval Shipyard could be submerged.
Inland communities have also faced flooding risks from rivers and dam collapses, as a combination of severe weather and aged dams mean that communities downstream of these facilities are increasingly at risk. The Association of State Dam Safety Officials identified 15,600 dams nationwide that would cause death or widespread property damage if they failed. The U.S. has roughly 91,000 dams, of which a majority are more than 50 years old.
Most of the dams throughout the U.S. are privately owned, which makes regulators unable to hold owners to state or federal standards if they do not have the funds to repair their dams. Estimates of the cost of repairing the most high-hazard dams could cost more than $20 billion. FEMA’s Rehabilitation of High Hazard Potential Dams Grant Program stands to receive an influx of funds from the infrastructure bill that will go to participating states.
The Infrastructure and Jobs Act has rightly marked $3 billion in federal funds to go towards dam updates, repairs, and maintenance. However, more flood mitigation infrastructure like levees and privately-owned dams need to be monitored to ensure that these structures continue to meet quality and safety standards.
The privately-owned dam owners also should continue to be transparent about the resources they need, and states should work to share information with these key stakeholders. As for coastal flood mitigation, innovative approaches like land reclamation and more porous construction materials for roads and other transportation methods can ensure that water can be absorbed, controlled, or diverted away from crucial infrastructure. Ultimately, this is a space where policymakers and private actors must work together. Whether that is information sharing, collaboration, funding partnerships, or encouraging innovation in infrastructure resilience, lives and livelihoods depend on it.
Written by Roy Mathews, Public Policy Associate
The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.