This publication provides introductory technical guidance for civil engineers, electrical engineers and other professional engineers, construction managers and electric power system operators interested in application of the HEC-5 computer program to power systems containing hydroelectric power plants. Here is what is discussed: 1. INTRODUCTION, 2. PROGRAM CAPABILITIES AND LIMITATIONS, 3. APPLICATION TO ANALYSIS OF A SINGLE HYDROPOWER PROJECT, 4. ANALYSIS OF HYDROPOWER SYSTEMS, 5. ANALYSIS OF PUMPED-STORAGE PROJECTS, 6. FIRM ENERGY OPTIMIZATION, 7. STRATEGIES FOR USING THE HEC-5 PROGRAM FOR POWER STUDIES, 8. PROGRAM AVAILABILITY.