Key Personnel:
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Arlin Grimes, Project Manager
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Kristian Gandrud, Project Supervisor
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Justin Ayer, Foreman
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Ryan Wheat, Foreman
The project goals were to restore the delta where the Clark Fork River enters Lake Pend Oreille. Two primary tasks were the focus of this restoration: 1. Protecting existing areas within the delta from further erosion using riprap, and 2. Restoring and enhancing the edge and interior areas of the delta.
The first step of the project involved gaining access to the site. The site was large, extending over 3 miles in length. Access required crossing three channels of the Clark Fork River. A 220-foot long floating bridge, capable of carrying 145,000 pounds, was installed and maintained for the duration of the project. The other two crossings were created using fill and cofferdams. The delta soil consists of 4 to 20 feet of unconsolidated, elastic silts. All access roads required geotextiles and gravel to adequately support construction equipment. Gravel borrow pits were opened by sorting and removing the silts. Access road construction required hauling over 45,000 cubic yards of material.
In order to protect the existing conditions, 118,000 tons of rock was imported to the project site. All rock was hauled over the temporary bridge and placed on the banks of the islands. During this phase, 26,000 tons were used to construct a breakwater.
The construction of new habitat features required 208,991 cubic yards of excavation. These features consisted of irregularly shaped islands designed to provide wetland island habitat within the delta. Excavated material was sorted into silts, gravels, and vegetated soils containing reed canary grass.