Green Island Floodplain Connectivity Enhancements (FIP Phase III)

This project improved hydrologic connectivity and winter refugia for juvenile salmonids and other native species at Green Island. The lowering of road profiles and grading of swales created secondary channel habitat to achieve floodplain interconnectedness. Logs were used for bank and in-channel woody debris, which created a diversity of habita and improved channel complexityt. The proposed project had reported spawning gravel placement, however, this was not a necessary project activity as there is now gravel in some channel areas as a result of channel regrading.

The resulting project would benefit salmon, steelhead, and other native species in multiple ways. The proposed project would increase channel complexity / off-channel habitat. The dynamic nature of this section of the Willamette overall ensures that the side channel and habitat forming processes will continue to generate significant habitat resources for species that are dependent on native floodplain forest. It is likely that during a flood events, such as that in 1996 and 2019, the side channel(s) will breach the banks and scour across the swale, enhancing high-water refugia for fish and other species. The National Marine Fishery Service (NMFS) reported to the U.S. Congress that decreased juvenile salmonid access to rearing habitats was one of five limiting factors to the recovery of salmon in the region. The Northwest Power Planning Council (NWPPC) has singled out the lower McKenzie River and confluence area as a focus for restoration and protection of just such rearing. The McKenzie Watershed Council’s biological assessment of the McKenzie-Willamette confluence area highlighted the specific conservation and restoration opportunities at the site. NMFS most recently reported that the Upper Willamette River Chinook is currently at a high risk of extinction. The reduced access to off-channel habitat and reduced floodplain function and connectivity were again identified as limiting factors to the recovery of Upper Willamette River Chinook. The resulting restoration project would provide off-channel refugia, it would restore floodplain connectivity, and it could lead to future avulsion, which is lacking in the current Willamette River Basin and it a key floodplain habitat process.