FHWA updates Hydraulic Engineering Circular (HEC 17)

Washington, D.C. — The Federal Highway Administration (FHWA) Office of Bridges and Structures, working with the Office of the Natural Environment and the Resource Center, recently published HEC 17 Highways in the River Environment: Extreme Events, Risk and Resilience.  The updated circular is a major and significant update that provides technical guidance and methods for assessing the nexus of riverine and transportation as it relates to floods, floodplain policies, extreme events, climate change, risks, and resilience. An important focus is quantifying exposure to extreme flood events considering climate change and other sources of nonstationarity.

Specifically, HEC-17 describes and discusses:

• FHWA and other floodplain policies and guidance
• Uncertainty associated with hydrologic models
• Nonstationarity and two drivers: climate change and land use/land cover changes
• Several tools for identifying and adjusting for trends in the historical record
• Techniques for projecting floods
• Global/regional climate models, downscaling techniques, and emissions scenarios
• Risk and resilience and the probabilistic nature of flood events

Recognizing that all plans and projects do not merit the same attention, HEC-17 also provides a five level analysis framework and specific guidance for addressing non-stationarity, including climate change. Finally, the manual provides case studies to illustrate several of the concepts.

For more information on the HEC 17 release, refer to the FHWA Transmittal Memo at www.fhwa.dot.gov/engineering/hydraulics/pubs/hec17_announcement.cfm.

Download the new HEC 17 at www.fhwa.dot.gov/engineering/hydraulics/pubs/hif16018.pdf.