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U.S. Floods: The Necessity of Mitigation

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Floods are the costliest natural hazard events in the United States in terms of lives and property losses. The financial costs of flood disasters are unsustainable, especially for the national government, which assumes the most costs while state and local governments have the greatest ability to avoid great losses due to their influence over land use, economic policy, and other areas that can help mitigate floods and reduce the high costs of relief and recovery. This article summarizes the types, causes, and occurrence of floods in the United States and their unsustainable economic and social costs. It explains that the growing burden to taxpayers from disaster response and recovery has resulted in increased interest by national decision makers in shifting more disaster responsibilities and costs to state and local governments. The article reviews the broad tool kit of mitigation strategies available to local governments and their residents in taking greater responsibility for the impacts of flood events.


A major responsibility of government is the protection of life and property. Among U.S. disasters stemming from natural occurrences, floods are the most costly in terms of lives and property lost and people affected (Stromberg 2007). Between 1900 and 2015, 40 percent of the 35,000 U.S. disaster events were major floods and related storms. Over the past fifty years, 85 percent of Presidential Disaster Declarations were for floods (United Nations International Strategy for Disaster Reduction Secretariat 2013). In the past five years, all U.S. states had a flood and twenty-one states had frequent flooding, although occurrences and severity vary by state. Floods are increasing in frequency and severity, especially in the Northeast and South Central United States. “Billion Dollar Disasters” occurred once everytwo years in the 1980s, but there have been about 10 per year since 2010. U.S. national government spending on extreme weather is significant—about US$400 per household in an average year. Events in bad weather years are more costly, for example, US$1,100 per household in 2011. The costs are overwhelmingly for response and recovery. Just 4 percent of federal disaster spending is for preparation. Just one in US $10 is for mitigation to prevent a disaster in the first place or reduce its impact; nine in US $10 is for response.


  1. Mitigation Works
  2. Background on Floods
  3. Challenges to Enhanced Mitigation to Reduce Flooding
  4. Structural and Non-structural Mitigation Tools and Strategies


Floods are the costliest disasters related to natural occurrences in terms of lives and property lost as well as people affected. About 1,500 people lost their lives to Hurricane Katrina in 2005; Hurricane Sandy in 2012 took 117 lives. Fortunately, there has been less loss of lives from flooding in recent years due to better warning systems, quicker and more effective response, better evacuation, and highly professional emergency management. Floods will continue to be a natural occurrence, however, and are predicted to increase in both frequency and severity. The vastly increased economic losses to residents, businesses and governments, however, harm local communities’ financial well-being.

Steps are underway to reform and modernize the nation’s major mitigation program, the NFIP. There will likely be upgrades to data systems, changes in mapping procedures, rate changes, and ways to deal with debt. The most significant transformation may be a bundle of efforts that address the “intergovernmental paradox,” resulting in more responsibility to mitigate being thrust on state and local governments, property owners, and residents of flood prone areas. Congress continues to grapple with 10 State and Local Government Review XX(X) a host of reform issues centering on insurance affordability and fairness to property owners and communities.

Successful mitigation—after risk is recognized and actions begun—relies on basic good management techniques: planning, partnerships, collaboration, capability- or capacitybuilding, and so on. Most significant is the realization that ultimately, building resilience through mitigating flood damages is both a community and a personal responsibility.