A Channel Type Users Guide for the Tongass National Forest, Southeast Alaska

Abstract

Revision of April 1992 version. The underlying reasons for the revision are to produce a logical demarcation of channel types within the established process groups and a descriptive label convention. The process groups are based on primary differences in hydrologic function, landform, and channel morphology. The individual channel types within a process group are determined by secondary differentia. These secondary differences are based mainly on channel width, and/or incision depth, gradient and channel pattern depending on process group. Channel width is dependent on the contributing watershed or drainage area. Stream channel width is apparent on aerial photography for the un-obscured streams and by field verification for the micro or vegetation obscured channels. Tertiary differentia is an additional characteristics designated by channel type phase. These differences may or may not be apparent from resource aerial photography but are readily observed and measured in the field. Newer remote sensing technology, such as LIDAR, is useful for classification at this level.