Approved by the Energy, Environment and Water Policy Committee on March 24, 2026
Approved by the Public Policy and Practice Committee on June 10, 2026
Adopted by the Board of Direction on July 21, 2026

Policy

The American Society of Civil Engineers (ASCE) urges all federal, state, and local government agencies to adopt flood mitigation and floodplain management policies that:

  • Prioritize keeping people and infrastructure out of harm’s way by restoring natural floodplains and riparian corridors through land acquisition, buyouts, and land conservation activities.
  • Reduce existing risk through the construction of conveyance and detention facilities that pose no adverse impact to other properties. 
  • Mitigate existing individual property risk through elevation and flood proofing. 
  • Mitigate new construction risk through the use of the latest building codes, drainage design requirements, and development regulations that include a minimum free-board requirement and a demonstration of no-adverse impact.
  • Account for the full range of flood probabilities and consequences, including events beyond the 1% annual chance flood, and that incorporate climate projections, sea level change, and temporal and spatial variability in rainfall.
  • Develop and regularly update high-quality flood and coastal storm hazard maps using best-available data and current modeling techniques to support flood mitigation decision making.
  • Reauthorize, fund, and enhance the National Flood Insurance Program (NFIP) with actuarially sound, risk-based rates that are fair and equitable.
  • Fund federal, state, and local programs for flood risk reduction through coordinated, sustained investment. 
  • Conduct maintenance of existing flood infrastructure.
  • Make flood risk reduction investments that support vulnerable and underserved communities.
  • Ensure that risk information, including the residual risk associated with constructed flood mitigation projects is communicated clearly to the public, elected officials, developers, and the insurance sector to support informed decision-making.

Issue

Flooding is the nation’s most frequent and costly natural hazard. Significant populations and assets have a higher than desired risk of inundation. The economic, social, and environmental costs of flooding are significant. Annual damage from flooding has been estimated to be $46 billion per year.  

Rationale

Investments in flood risk reduction infrastructure, regulations, codes, and standards are cost-effective and have been shown to cost less than response, recovery, and repair efforts. According to the National Institute of Building Sciences, every dollar spent on mitigation translates into an average savings of $13 for the American public (2025). Engineers hold paramount the health, safety, and welfare of the public and are responsible for planning, designing, constructing, and operating flood mitigation facilities and programs, so engineers support efforts to reduce flood risk and enhance floodplain management.

ASCE Policy Statement 545
First Approved in 2014