Channel migration zone
From Salish Sea Wiki
- Rapp & Abbe 2003 describes a framework for delineation funded by WDOE.
- CMZ delineation is a prediction of future processes based on historical and current observations.
- A CMZ determination must specify a design life.
- Channel migration zone includes the historical migration zone (largely based on historical maps and photography), an avulsion hazard area (based on observation of topography and vegetation), and an erosion hazard area, which combines an erosion setback (predicted rate of erosion over the time of interest), and where appropriate, a geo-technical setback (a distance beyond the erosion zone necessary to establish a stable slope). Portions of the historical channel migration zone may be disconnected by berms, levees, or causeways.
- CMZ mapping, can with county approval, affect FEMA National Flood Insurance Program and thereby affects the definition of "floodway" and implementation of the NFIP Biological Opinion.
- EPA has provided funding through WDOE for migration zone mapping, the project appears to be led by Ms. Patricia Olson, of the Shorelands and Environmental Assistance Program.
- WDOE offers a page on channel migration assessment.
- Channel migraiton zone mapping is (required?) under Shoreline Master Program updates mandated by the Shoreline Management Act
- A large number of studies are apparent as PDFs through a google search, but it is difficult to find a map based description of existing data.