The Oregon Department of Geology and Mineral Industries (DOGAMI) maps historic stream channels to determine future channel migration hazards.
Channel migration is the natural process by which streams move laterally over time. It is typically a gradual phenomenon that works over many years to effect significant migration. In some cases, usually associated with flood events, significant migration can happen rapidly.
Channel Migration Zones
Following methods developed by Washington Department of Ecology, we bring together historic photos, lidar, and field data to create channel migration zone mapping. These maps can be used to understand a type of hazard that is not typically accounted for in traditional FEMA flood maps. Channel migration hazards can exist outside the 1%-annual-chance flood zone.
Schematic of channel migration zone and its components.
Statewide Channel Migration Assessment
To prioritize future channel migration zone mapping efforts we produced a statewide screening of channel migration susceptibility. We evaluated the major rivers of Oregon and classified their segments as having high, moderate, or low susceptibility. Download the publication.
Lidar reveals historic channel patterns in ways never before possible. We have created a series of landscape maps to highlight the evolution of channel configurations in the Willamette Valley and beyond.
Portion of poster showing historic channels of the central Willamette Valley.
- Detailed channel migration zone mapping of Sandy River
- Detailed channel migration zone mapping of Hood River
- Detailed channel migration zone mapping of Coos and Coquille rivers
- Willamette River historic channels poster
- Northern Willamette Valley historic channels
- Tualatin Valley and Lower Willamette Valley historic channels
- Central Willamette Valley historic channels