In the U.S., both federal and state laws prevent wetlands from being filled in or drained unless permits are obtained by an agency of the federal government. Boundaries of a wetland must be identified and located in the field by examining three parameters: wetland plants, wetland hydrology, and hydric soils. This book is written by scientists with extensive field and academic experience. This new edition is a major revision of the 2001 book, with 11 new chapters and updates throughout.