CONTENTS. 



PART I. 

 GENERAL CHARACTERISTICS PRELIMINARIES TO IMPROVEMENT SURVEYS. 



CHAPTER I. 



INTRODUCTION. 



PAGE 



Progress of Navigation i 



Choice between Canal and River 2 



Locks 2 



Ancient Canals 2 



American Canals and Rivers 3 



Government Improvements 4 



Administration 5 



CHAPTER II. 



CHARACTERISTICS OF RIVERS. 



Physical Features 7 



Rainfall 7 



Bed 8 



Basin 9 



Slope 9 



Transportation of Sediment 9 



Formation i o 



Shoals 12 



Bars 13 



Changes in Level and Floods 13 



CHAPTER III. 



PRELIMINARY EXAMINATIONS AND SURVEYS. 



General 16 



Preliminary Examination and Report 16 



Preliminary Survey and Report 17 



Project and Estimate of Cost 17 



Preparation for the Improvement 18 



Plans and Specifications 1 8 



CHAPTER IV. 



TOPOGRAPHICAL SURVEYS AND LEVELING. 



Topographical Surveys: 



By Transit and Chain 20 



By Plane-table 21 



By Stadia 21 



By Triangulation 22 



Leveling 23 



Ordinary Levels 23 



Precise Levels 23 



CHAPTER V. 



HYDROGRAPHIC SURVEYS. 



Soundings 25 



Cross-section 25 



Methods By a Cord across the Stream .... 25 



By Range-line and Instrument 26 



By two Transits 27 



By Range-poles 28 



Discharge 29 



Over Weir 29 



Free Discharge 29 



Submerged Discharge 30 



Profiles of Overflow 31 



Velocity of Approach 32 



Free Discharge -. 32 



Submerged Discharge 33 



In Open Channels 33 



FormuUe 34 



Measurement of Velocity 35 



By Floats 35 



By Current-meters 36 



By Gauge-tubes 36 



By Hydrodynamometer 37 



Sediment 37 



Slope. 



38 



Gauges for Local Slope 38 



Observation of Daily Stages 38 



Datum for Zeros 39 



Material for Gauges 39 



