CONTENTS 



CHAPTER 4 



LITTORAL PROCESSES 



Page 

 I INTRODUCTION 4-1 



1. Definitions 4-1 



2. Environmental Factors 4-1 



3. Changes in the Littoral Zone 4-6 



II LITTORAL MATERIALS 4-12 



1. Classification 4-12 



2. Sand and Gravel 4-21 



3. Cohesive Materials 4-21 



4. Consolidated Material 4-23 



5. Occurrence of Littoral Materials on U. S. Coasts 4-24 



6. Sampling Littoral Materials 4-26 



7. Size Analyses 4-27 



III LITTORAL WAVE CONDITIONS 4-29 



1. Effect of Wave Conditions on Sediment Transport 4-29 



2. Factors Determining Littoral Wave Climate 4-29 



3. Nearshore Wave Climate 4-31 



4. Office Study of Wave Climate 4-40 



5. Effect of Extreme Events 4-43 



IV NEARSHORE CURRENTS 4-46 



1. Wave-Induced Water Motion 4-46 



2. Fluid Motion in Breaking Waves 4-49 



3. Onshore-Offshore Exchange 4-49 



4. Longshore Currents 4-50 



5. Summary 4-55 



V LITTORAL TRANSPORT 4-55 



1 . Introduction 4-55 



2. Onshore-Offshore Transport 4-65 



3. Longshore Transport Rate 4-89 



VI ROLE OF FOREDUNES IN SHORE PROCESSES 4-108 



1. Background 4-108 



2. Role of Foredunes 4-108 



VII SEDIMENT BUDGET 4-1 13 



1. Introduction 4-113 



2. Sources of Littoral Materials 4-115 



3. Sinks for Littoral Materials 4-120 



4. Convection of Littoral Materials.... 4-126 



5. Relative Change in Sea Level 4-126 



6. Summary of Sediment Budget 4-126 



