CONTENTS Summary 1 1 Introduction 4 Background 4 Objectives 4 Project Description 4 Report Organization 5 2 Research Approach 6 3 Data Acquisition and Analyses 8 Equilibrium Local Scour Data 8 Assessment of Data Quality 9 Local Scour Evolution Data 14 4 Equilibrium Local Scour Predictive Equations 16 Introduction 16 Initial Screening of Equilibrium Scour Predictive Equations 19 Modifications to Equilibrium Scour Predictive Methods 24 Evaluation of Equilibrium Scour Predictive Methods 26 5 Local Scour Evolution Predictive Methods 37 Introduction 37 Initial Screening of Scour Evolution Predictive Methods 40 Modifications of Scour Evolution Predictive Methods 40 Final Evaluation of Scour Evolution Predictive Methods 41 6 Scour at Piers Skewed to the Flow 45 7 Summary and Recommendations for Future Research 48 Summary 48 Recommendations for Future Research 50 References 51 List of Symbols 53 Appendices 55