Environmental Hydrology is presented in four sections: Hydrologic Processes, Hydrologic Analysis, Hydrologic Design, and Hydroloic Model Applications. Hydrologic processes describe the scientific principles governing hydrologic phenomena. Hydrologic analysis emphasize computational methods in hydrology for specific tasks such as rainfall runoff modeling and analysis of extream events. Hydrologic design focuses on risk analysis and decision support system in the selection of design storms. On the basis of the three sections, the hydrologic models are applied to environmental problems such as flood disaster mitigation, water resources management, and hydrologic cycle monitering.