Introductory technical guidance for civil engineers and others interested in statistical methods applied to flood analysis. Here is what is discussed:1. INTRODUCTION2. HYDROLOGIC DATA SAMPLES3. FREQUENCY DISTRIBUTIONS4. LOG-PEARSON TYPE III DISTRIBUTION5. EXAMPLE APPLICATION USING BULLETIN 17B6. LIMITATIONS ON FREQUENCY CURVE EXTRAPOLATION7. MIXED POPULATIONS8. VOLUME ANALYSIS9. PROBABILITY RELATIONSHIPS FOR UNGAUGED AREAS10. GENERAL TRENDS IN FREQUENCY RELATIONSHIPS11. FOSS DAM EXAMPLE.