Along a quiet stretch of Highway 200 east of Sandpoint Idaho
, DU and partners have completed an inventive floodplain restoration project that may prove to be the model for future river delta projects in the region. The Pack River Delta Project involved utilizing a combination of traditional civil engineering and soil bioengineering techniques to restore unique wetland and upland habitats in the delta, the place where the Pack River and Lake Pend Oreille converge. This is the first known instance in Idaho where this restoration approach has been attempted and early indications suggest that it will be a success.
The Pack River is the second largest tributary to Lake Pend Oreille and drains more than 185,000 acres into what was once a large and diverse mosaic of forested islands, oxbow lakes, lush wetlands and braided river channels. The hope is that lessons learned from the Pack River project can be applied to restore the larger Clark Fork River delta. The Clark Fork River is the lake's largest tributary.
With the construction of Albeni Falls dam in 1955, much of the nearly 1,444-acre Pack River delta became submerged under several feet of water for much of the summer, dramatically changing the environment in the lower delta. In total, it is estimated that the construction of the dam resulted in the loss of 6,617 acres of wetland habitat and the inundation of 8,900 acres of deep-water marsh on the lake, impacting many resident and migrating birds, particularly waterfowl. One of the hardest hit was the wintering redhead duck population, which numbers in the tens of thousands.
The goal of the restoration project was to increase the height and stability of a portion of the summertime submerged islands to improve their ability to support high-value habitat for numerous species of waterfowl and wildlife year-round. The first step was to reconstruct the islands and other physical features that once supported a system of intertwined wetlands and riparian habitats. This required moving large quantities of soil within the delta using excavators and dump trucks in sometimes challenging conditions.
Some of the native vegetation that once occupied these sites was then replanted in the form of seeds, plugs and cuttings. Emergent aquatic vegetation such as cattail and bulrush were planted along the island shorelines, while the islands were planted with thousands of willow, cottonwood, western red cedar and red-osier dogwood. To encourage settling of river sediments in the project area, some side channels were plugged with logs and stumps to replicate this important physical process. In time, this may cause the constructed islands to expand in size and additional islands to form naturally.
A broad partnership contributed to the successful completion of this project. Major funding for the project was provided by a $1 Million NAWCA
grant awarded to DU and partners in 2007, Idaho Department of Fish and Game, Avista Corporation and a private foundation. Wood's Hauling and Crushing, the construction contractor on the project, contributed equipment and operator time to the project. A long list of other agencies, nongovernmental organizations and local community groups and schools also participated in the project. The project took place on lands owned by the U.S. Army Corps of Engineers and managed by the Idaho Department of Fish and Game.