This document discusses the physical processes of the hydrologic cycle that are important to highway engineers. These processes include the approaches, methods and assumptions applied in design and analysis of highway drainage structures. Hydrologic methods of primary interest are frequency analysis for analyzing rainfall and ungaged data; empirical methods for peak discharge estimation; and hydrograph analysis and synthesis. The document describes the concept and several approaches for determining time of concentration. The peak discharge methods discussed include log Pearson type III,...

The Federal Highway Administration document "Highways in the River Environment - Hydraulic and Environmental Design Considerations" was first published in 1975, was revised in 1990, and is now issued as Hydraulic Design Series 6, "River Engineering for Highway Encroachments." This document has proven to be a singularly authoritative document for the design of highway associated hydraulic structures in moveable boundary waterways. This revised document incorporates many technical advances that have been made in this discipline since 1990. In addition, Hydraulic Engineering Circulars (HEC) 18,...

Hydraulic Design Series Number 5 (HDS 5) originally merged culvert design information contained in Hydraulic Engineering Circulars (HEC) 5, 10, and 13 with other related hydrologic, storage routing and special culvert design information. This third edition is the first major rewrite of HDS 5 since 1985, updating all previous information and adding new information on software solutions, aquatic organism passage, culvert assessment, and culvert repair and rehabilitation. The result is a comprehensive culvert design publication. This publication contains the equations and methodology used in...

Debris accumulation at culvert and bridge structures openings is a widespread problem. The accumulation of debris at inlets of highway culverts and bridge structures is a frequent cause of unsatisfactory performance and malfunction. This accumulation may result in erosion at culvert entrances, overtopping and failure of roadway embankments and damage to adjacent properties, increased local scour at piers and/or abutments, and the formation of pressure flow scour. Consideration of debris accumulations and the need for debris-control structures should be an essential part of the design of all...

The purpose of this publication is to provide design information for analyzing and mitigating energy dissipation problems at culvert outlets and in open channels. It provides general information on the overall design process, erosion hazards, and culvert outlet velocity and velocity modification. These provide a background and framework for anticipating dissipation problems. In addition to describing the overall design process, design examples to compare selected energy dissipators are provided. Also provided are assessment tools for considering flow transitions, scour, and hydraulic jumps.

Flexible linings provide a means of stabilizing roadside channels. Flexible linings are able to conform to changes in channel shape while maintaining overall lining integrity. Long-term flexible linings such as riprap, gravel, or vegetation (reinforced with synthetic mats or unreinforced) are suitable for a range of hydraulic conditions. Unreinforced vegetation and many transitional and temporary linings are suited to hydraulic conditions with moderate shear stresses. Design procedures are given for four major categories of flexible lining: vegetative linings; manufactured linings (RECPs);...

The most common cause of bridge failures is from floods scouring bed material from around bridge foundations. Scour is the engineering term for the erosion caused by water of the soil surrounding a bridge foundation (piers and abutments). The purpose of this document is to provide guidelines for the following: 1. Designing new and replacement bridges to resist scour, 2. Evaluating existing bridges for vulnerability to scour, 3. Inspecting bridges for scour, 4. Improving the state-of-practice of estimating scour at bridges. This document is the fifth edition of HEC-18. It presents the state of...

Approximately 500,000 bridges in the National Bridge Inventory (NBI) are built over streams. A large proportion of these bridges span alluvial streams that are continually adjusting their beds and banks. Many, especially those on more active streams, will experience problems with aggradation, degradation, bank erosion, and lateral channel shift during their useful life. The purpose of this document is to provide guidelines for identifying stream instability problems at highway stream crossings. Techniques for stream channel classification and reconnaissance, as well as rapid assessment...

The Guide to Transportation Management Center (TMC) Data Capture for Performance and Mobility Measures is a two-volume document consisting of a summary Guidebook and this Reference Manual. These documents provide technical guidance and recommended practices regarding concepts, methods, techniques, and procedures for collecting, analyzing, and archiving TMC operations data to develop measures of roadway and TMC performance, as well as documenting the benefits of TMC activities for a variety of stakeholders. This guide is designed to be used by TMC technical and management staff involved in...

This publication identifies and provides design guidelines for bridge scour and stream instability countermeasures that have been implemented by various State departments of transportation (DOTs) in the United States. Countermeasure experience, selection, and design guidance are consolidated from other FHWA publications in this document to support a comprehensive analysis of scour and stream instability problems and provide a range of solutions to those problems. Selected innovative countermeasure concepts and guidance derived from practice outside the United States are introduced. Management...