This new edition promises to educate those new to hydrology and challenge professionals alike with insightful solutions to classical problems as well as new approaches so important to the evolving genre. It enhances materials in the 2nd Edition and has expanded information on many topics and in particular evapotranspiration, soil erosion, two-stage ditch design and applications, and stream processes. There are new sections on rock structures in streams, hypoxia, harmful algal blooms, agricultural practices to reduce nutrient discharges into water resources, as well as new end-of-chapter problems. Also, the format has been enhanced to aid the reader in finding tables, figures, and equations.