NSD + CGS collaborated with Columbia Land Trust to design and implement the restoration of floodplain processes on the 170 acre Kandoll Farm property in the tidally influenced segment of the Lower Grays River. Restoration of the property is a critical step toward salmon recovery in this historic fishing economy. A system of dikes and levees constructed along the Lower Grays River impair natural processes and isolate large areas of the valley from floodplain connectivity. Agricultural areas in the Lower Grays River include several older farms that are going fallow without a new generation of farmers and no market for land. Columbia Land Trust acquired the Kandoll Farm property in 2002 and is leading ongoing efforts to enhance off-channel habitat conditions and augment salmon recovery efforts in the Columbia River Estuary. NSD + CGS staff led design efforts and coordinated with the Expert Regional Technical Group (ERTG) to quantify project metrics for salmon recovery. Key ecological concerns included historical land subsidence and the effect of increased tidal prism on bank stability along adjacent properties that have residential or agricultural land uses. A new tidal slough network was designed to increase floodplain connectivity to the property, enhance the complexity of habitat types, address the downstream impacts to adjacent landowners, and accelerate the rate of ecological recovery for the Lower Grays River. This solution balances the needs of the local community with both fluvial and tidal processes, facilitates a more rapid recovery of subsided land to support the native Sitka spruce floodplain, and creates over 2 miles of new tidal channels for salmonid rearing within the site. The project was completed in 2013.
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