Publications
Urban Drainage Design Manual Fourth Edition
The Urban Drainage Design Manual, Hydraulic Engineering Circular No. 22 (HEC-22), provides a comprehensive and practical guide for the design of storm drainage systems associated with transportation facilities. Design guidance is provided for the design of storm drainage systems which collect, convey, and discharge stormwater flowing within and along the highway right-of-way.
This manual outlines methods and procedures for the hydrologic and hydraulic design of storm drainage systems. It includes evaluating rainfall and runoff magnitude, designing pavement drainage, gutter flow, inlet design, median and roadside ditch flow, drainage structure design, and storm drain piping. Additionally, it covers procedures for designing detention facilities, reviewing urban water quality practices and reviewing stormwater pump stations.
The updates in the Fourth Edition of the Urban Drainage Design Manual aim to explain the rationale behind computations and streamline storm drainage design process. Technical updates also include updating stormwater quality information with current design practices and performance data, and presenting a new curb opening inlet interception equation. An overarching goal for this manual is to support the planning, implementation, and stewardship of sustainable, resilient, and reliable transportation networks.
- FHWA Publication Number: HIF-24-006
- Publication Year: 2024