HEC-14 Hydraulic Design of Energy Dissipators for Culverts and Channels

Author(s): Philip L. Thompson and Roger T. Kilgore
Publisher: FHWA
Year: 2006
Links: PDF
Subjects: energy dissipator, culvert, channel, erosion, outlet velocity, hydraulic jump, internal dissipator, stilling basin, impact basin, riprap basin, riprap apron, drop structure, stilling well
HEC-14 3rd edition cover

The purpose of this circular is to provide design information for analyzing and mitigating energy dissipation problems at culvert outlets and in open channels. The first three chapters provide general information on the overall design process (Chapter 1), erosion hazards (Chapter 2), and culvert outlet velocity and velocity modification (Chapter 3). These provide a background and framework for anticipating dissipation problems. In addition to describing the overall design process, Chapter 1 provides design examples to compare selected energy dissipators. The next three chapters provide assessment tools for considering flow transitions (Chapter 4), scour (Chapter 5), and hydraulic jumps (Chapter 6).

For situations where the tools in the first six chapters are insufficient to fully mitigate a dissipation problem, the remaining chapters address the design of six types of constructed energy dissipators. Although any classification system for dissipators is limited, this circular uses the following breakdown: internal (integrated) dissipators (Chapter 7), stilling basins (Chapter 8), streambed level dissipators (Chapter 9), riprap basins and aprons (Chapter 10), drop structures (Chapter 11), and stilling wells (Chapter 12).

Much of the information presented has been taken from the literature and adapted, where necessary, to fit highway needs. Research results from the Turner Fairbank Highway Research Center and other facilities have also been incorporated. A survey of state practices and experience was also conducted to identify needs for this circular.

HDS-4 Introduction To Highway Hydraulics

Author(s): James D. Schall, Everett V. Richardson, and
Johnny L. Morris
Publisher: FHWA
Year: 2008
Links: PDF
Subjects: Hydrology, hydraulics, highway drainage, open channels, roadside ditches, pavement drainage, inlets, conduits, culverts, storm drains, energy dissipators
HDS-4 cover

Hydraulic Design Series No. 4 provides an introduction to highway hydraulics. Hydrologic techniques presented concentrate on methods suitable to small areas, since many components of highway drainage (culverts, storm drains, ditches, etc.) service primarily small areas. A brief review of fundamental hydraulic concepts is provided, including continuity, energy, momentum, hydrostatics, weir flow and orifice flow.

The document then presents open channel flow principles and design applications, followed by a parallel discussion of closed conduit principles and design applications. Open channel applications include discussion of stable channel design and pavement drainage. Closed conduit applications include culvert and storm drain design. Examples are provided to help illustrate important concepts. An overview of energy dissipators is provided and the document concludes with a brief discussion of construction, maintenance and economic issues.

As the title suggests, Hydraulic Design Series No. 4 provides only an introduction to the design of highway drainage facilities and should be particularly useful for designers and engineers without extensive drainage training or experience. More detailed information on each topic discussed is provided by other Hydraulic Design Series and Hydraulic Engineering Circulars.

This publication is an update of the third edition. Revisions were necessary to reflect new information given in the third edition of HEC-14 (Hydraulic Design of Energy Dissipators for Culverts and Channels), the third edition of HEC-15 (Design of Roadside Channels with Flexible Linings), and the third edition HEC-22 (Urban Drainage Design Manual).