Description: This study provides Oregon communities with new information about the natural hazards from channel migration. During 2023 and 2024, the Oregon Department of Geology and Mineral Industries (DOGAMI) produced channel migration zone maps for the Zigzag River in Clackamas County. This polygon represents the channel migration zone (CMZ). It identifies the area within which a given stream is most likely to move laterally and change its channel course during the next 30- and 100-years. The CMZ is comprised of the combined active channel; historical migration area; low, medium, and high erosion hazard areas; and avulsion hazard area.
Copyright Text: This project was funded by a U.S. Federal Emergency Management Agency Cooperating Technical Partnership grant.
Description: This layer represents the Channel Migration Zone along the Sandy River based on analysis designed by Rapp and Abbe, 2003. The Channel Migration Zone (CMZ) represents the cumulative product of historical analysis and morphological interpretations characterized by the following equation: CMZ = HMZ + AHZ + EHA - DMA.
Copyright Text: John T. English, Daniel E. Coe, and Robert D. Chappell