Tides Return to Kerry Island
After being being diked, ditched, and drained for decades, Kerry Island is once again part of Westport Slough's natural floodplain. With luck, it will provide vital habitat to rearing juvenile salmon and steelhead.
Kerry Island, acquired by Columbia Land Trust in 2013, is a 100-acre island located along Westport Slough, two miles upstream from the confluence with the Columbia River. Kerry Island has been significantly altered by past and present human disturbance including local impacts including diking, ditching, culvert installation, grazing, and vegetation clearing. What was once a tidal wetland in Columbia County, Oregon was converted to a drier landscape that offered little benefit for area wildlife.
In early October 2016, Westport Slough was reunited with its historic tidal floodplain at Kerry Island for the first time in more than a century when construction crews breached the surrounding levee. This was one of the final steps in a summer-long construction project that also involved filling existing drainage ditches, developing inland tidal channels, and placing wood along the channels.
These efforts, along with revegetation, will restore wetland ecosystem conditions and functions at Kerry Island, including the restoration of processes that provide food sources and rearing habitat for Endangered Species Act-listed juvenile salmon and steelhead species. The photo below shows the drastic difference when a seven-foot tide (with precipitation influences making it more like 10 feet) inundates the previously dry and disconnected landscape:
Photos from throughout the levee breaching process show a radical landscape transformation taking place over the course of a single day:
To learn about how our Kerry Island restoration work fits into a broader strategy to restore tidal floodplain habitat across the Columbia River Estuary, be sure to read our fall issue of Fieldbook, due out later this month.
Columbia Land Trust, including Kerry Island project manager and Natural Area Manager Jeff Malone, would like to thank Inter-Fluve and PC Trask for their design services, Henderson Construction (along with subcontractors Alfonse Excavation out of Astoria and O’Malley Brothers Corporation) for implementing the construction phase, and Bonneville Power Administration for their funding support.