CONTENTS 



Page 



PREFACE 1 



LIST OF TABLES 4 



LIST OF FIGURES 4 



CONVERSION FACTORS, US CUSTOMARY TO METRIC (SI) UNITS 



OF MEASUREMENT 5 



PART I : INTRODUCTION 6 



General 6 



Purpose 6 



Background 6 



Organization of Report 7 



PART II: GENERAL DISCUSSION OF SEDIMENT TRANSPORT 8 



Sediment Transport Modes 8 



Critical Conditions for Sediment Transport Under 



Unidirectional Uniform Flows 8 



Critical Conditions for Sediment Transport Under 



Oscillatory Flows 10 



Critical Depths for Incipient Sediment Motion 14 



Bed-Load Transport in Unidirectional Flows 15 



Bed-Load Transport Under Wave Action 17 



Suspended-Load Transport in Unidirectional Flows .... 19 



Suspended-Load Transport in Oscillatory Flows 20 



PART III: SCOUR PROBLEMS AT COASTAL STRUCTURES 22 



General 22 



Scour Problems at Rubble -Mound Structures 22 



Scour Problems at Piles or Other Vertical Supports ... 24 



Scour Problems at Vertical Seawalls 25 



Scour Problems at Submerged Pipelines 26 



PART IV: SCOUR PREDICTION METHODS .27 



General 27 



Scour Prediction at Rubble -Mound Structures 28 



Scour Prediction at Piles or Other Vertical Supports . . 33 



Scour Prediction at Vertical Seawalls 35 



Rule-of-Thumb Methods 36 



Semi-Empirical Methods 36 



Other Laboratory Studies to Investigate Scour at 



Seawalls 43 



Field Studies 44 



Scour Prediction at Submerged Pipelines 45 



