This new third edition is a major revision of the earlier two editions and is based largely on the feedback the authors received from past users of the book in the classroom. Changes in this expanded and completely updated new edition include: Expanded discussion of stream channel processes, morphology, and classification; A new Part Three contains a chapter on basic water quality and a new chapter on water quality management; The topics of riparian and wetland hydrology and management have been expanded into two new chapters; A new section on Special Topics includes topics that will be of interest to managers and are intended to complement the earlier parts of the book; Chapter One Hydrologic Methods remains as a highly technical chapter that can be used to quantify some of the hydrologic relationships discussed in earlier chapters; Chapter Eighteen presents tools for analysis and research in watershed management; A new Part Six is comprised on a single, comprehensive chapter that condenses and updates material from three chapters in the previous edition that focused on socioeconomic considerations.