USGS

Levels at Streamflow Gaging Stations

U.S. Geological Survey, Techniques of Water-Resources Investigations, Book 3, Chapter A19

By E.J. Kennedy


Table of Contents

Preface

Abstract

Introduction

Leveling method and concepts

Curvature and refraction

Precision

Accuracy

Leveling classifications

Gaging-station levels

Ordinary levels

Adjustment of elevations

Engineer’s level

Automatic level

Tilting level

Dumpy level

Level accessories

Leveling rod

Checking the rod

Holding the rod

Operating the engineer’s level

Transporting the level

Checking the tripod

Setting up the level

Leveling the instrument

Focusing the level’s telescope

Establishing a reading routine

Adjusting the engineer’s level

Reticle

Circular level vial

Collimation

Fixed-scale test

Peg test

Gaging-station datum control

Determining frequency of levels

Establishing gage datum

Installing reference marks

Installing reference points

Running levels

Checking gages

Electric tape

Float tape

Wire weight

Vertical staff

Inclined staff

Bubble gage

Other gages

Maintaining level summary sheets

National Geodetic Vertical Datum

Bench mark level tie

Checklist of equipment for gaging-station levels

Selected references

Appendix: Master copies for duplicating notekeeping and level-summary forms

 


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