USGS

Measurement of Peak Discharge at Width Contractions by Indirect Methods

U.S. Geological Survey, Techniques of Water-Resources Investigations, Book 3, Chapter A4

By Howard F. Matthai


Table of Contents

Preface

Symbols and units

Abstract

Introduction

The discharge formula

Approach section

Contracted section

Water-surface levels

Velocity head

Friction loss

Froude number

Classification of contractions

Single-opening contractions

Type 1

Type 2

Type 3

Type 4

Modified standard types

Spur dikes

Dual bridges

Abutments parallel to flow

Nonstandard types

Combination sites

Multiple-opening contractions

Field procedures

Selection of a site

High-water marks

Cross sections

Bridge geometry

Channel conditions

Discharge coefficient

Channel-contraction ratio

Determination of the discharge coefficient

Base coefficient

Adjustment factors

Eccentricity

Piers or piles

Submergence

Abutments parallel to flow

Other factors and conditions

Angularity

Intermediate embankment slopes

Different abutments

Nonstandard geometry and flow conditions

Maximum coefficient

Special conditions

Other embankment slopes

Timber-and-pile bridges

Spur dikes

Arch bridges

Computations

Outline

Example

Combination sites

Multiple-opening contractions

Division into single-opening units

Determination of h1 and h3

Computation of discharge

Selected references

 


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