Member Login Menu

Policy Statement 545- Flood Risk Management


Approved by the Energy, Environment and Water Policy Committee on February 13, 2017
Approved by the Public Policy Committee on June 5, 2017
Adopted by the Board of Direction on July 29, 2017


The American Society of Civil Engineers (ASCE) urges all federal, state and local government agencies, in collaboration with the private sector, to adopt flood-risk management policies that provide for:

  • A consistent definition of flood risk and an accepted framework for how risk should be estimated; 
  • Effective and sustainable management of risks posed by floods to life safety, human health, economic activity, cultural heritage and the environment; 
  • Collaborative risk sharing and risk management at all levels of government and by all stakeholders;
  • Risk informed communication, policies and funding priorities; and
  • The use of natural processes to mitigate the consequences of flooding.


Flood risk is defined as the potential of a loss from flooding, and is measured by both the consequences and their probability of occurrence. There is no common vision of how the nation should organize and coordinate to reduce its flood risk. Proposals to deal with this challenge have languished in multiple congressional committees of Congress. The Unified National Program for Floodplain Management, called for by Congress, was last revised in 1994 and has not yet been implemented. We do not have a sound analysis of the potential risk to the nation from flooding.

Collaborative risk management requires continued operation and maintenance of our flood infrastructure. Currently our flood infrastructure remains in marginal condition and there is no realistic plan in place to deal with or improve these conditions. Federal funding is minimal, and local communities lack the resources with which to address the problem. 

Federal, state and local governments share the responsibility for continued non-sustainable development within flood prone areas. Unintended consequences of flood insurance, rebuilding funds, tax incentives and political pressures provide a mixed message to the citizens and local governments that are responsible for land-use regulation. Unless more is done to reduce risk, we are creating a potentially insurmountable challenge for future generations.

An effective national risk assessment and risk management initiative will require a consistent definition of flood risk and an accepted framework for how risk should be estimated for different scales and purposes. It needs to incorporate sensitivity to the economic activity and the history of place. While risk is a relatively simple concept, it is far from simple to apply given the dearth of relevant input information and the variety of methods available for its estimate. In reality, there exists a broad spectrum of risk estimation options, some very general and even qualitative and others highly sophisticated.

Climate change and population growth will further stress this already difficult situation. The Federal Emergency Management Agency reported in 2013 that as a result of this change and growth, the 100-year floodplain in the contiguous states could expand by 45 percent by the end of the 21st century.


Among the great challenges the U.S. faces today is recognizing the magnitude of risk posed by flooding and motivating the public and decision-makers to make the investments required to reduce flood risk. This includes making emergency preparations, strengthening our flood protection systems, land use planning, and finding new ways to reduce our vulnerability to flooding.

Ignoring the challenges is not an option. Brought to focus by Hurricane Katrina, the nation has slowly begun to shift from a mind-set of controlling floods to one of recognizing that absolute protection against these natural hazards is not possible. It is clear that when such action is justified and feasible our efforts must be focused on identifying our risks and developing and implementing a portfolio of approaches to deal with these risks-a portfolio referred to collectively as flood risk management (FRM). Despite the continuing tension between development and FRM, limited steps have been taken and progress has been made in some communities to reduce and more effectively deal with flood risk. Awareness on the part of the public has also increased, especially in light of the continuing occurrence of catastrophic flooding events.

Risk management is a powerful tool in the decision-making process where the conclusions of risk assessment and comparative risk analysis are weighed among other considerations such as statutory requirements, costs, public values and politics, expectations, and exposure to hazards. For engineers, risk assessment is a guide that directs proper land use and engineering planning, design, construction and operation, and maintenance practices. While it is important to plan for possible failure (including provisions for insurance, emergency evacuation, flood proofing, etc.), it is equally important to adequately address risk in the planning, design, and maintenance of systems and how consequences are managed.

ASCE Policy Statement 542
First Approved in 2014