# Discharge Ratings at Gaging Stations

### U.S. Geological Survey, Techniques for Water-Resources Investigations, Book 3, Chapter A10

By E.J. Kennedy

## Table of Contents

Preface

Glossary

Symbols

Abstract

Introduction

Basic concepts

Controls

Gage height of zero flow

Channel-storage effect

Data limitations

Use of computers and calculators

Plotting

Rectangular grids

Logarithmic grids

Straight-line rating curves

Adjustment of logarithmic scales

Characteristics of low-water logarithmic rating curves

Logarithmic-curve coordinates

Interpolation between logarithmic curve coordinates

Formats for ratings

Rating curve sheets

Work curve sheets

Master curve sheets

Automatically plotted curve sheets

Digital descriptors of ratings

Logarithmic interpolation

Linear interpolation

Rating equations

Rating tables

Stage-discharge ratings

Curve shaping

Slope-conveyance method

Step-backwater rating curves

Stable channel techniques

Unstable channel techniques

Shifting-control method

Low-water rating analysis for unstable channels

Complex ratings

Rate of change in stage ratings

(delta)Q/J ratings

1/(US)c, ratings

Slope ratings

Unit-fall ratings

Constant-fall ratings

Limiting-fall ratings

Normal-fall ratings

Ratings for regulating control structures

Index-velocity ratings

Vane-gage ratings

Magnetic-meter gage ratings

Acoustic-velocity meter gage ratings

Rating analysis by computer

References

International System of Units (SI) and inch-pound system equivalents

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