This new edition of the Hydrology Handbook (Manual No. 28) incorporates the many changes and advances that have occurred in the areas of planning, development, and management of water resources since the publication of the original manual in 1949. The first six chapters, Chapters 2 through 7, relate to the natural phenomena in the hydrologic cycle, while the next three chapters describe the predictions and effects of the phenomena previously described. The final chapter reviews the applications of hydrology starting with study formulation, then reviews data management, then discusses calibration and verification of hydrologic models, and concludes with accessing accuracy and reliability of results. With this new edition, academic and practicing hydrologists have a thorough and up-to-date guide to the field of hydrologic engineering.