DESCRIPTION
The Natapoc project is a fish habitat enhancement project located on the mainstem Upper Wenatchee River at river mile 51.7. The project lies along a long stretch of a wide glide dominated river with clean sight lines and no large woody material recruitment. River left is high bank and river left is low-level floodplain inundated with large wetland complexes. Upstream has been heavily armored through human alterations and is causing the river to migrate across the floodplain in a southeasterly direction.
A total of seven bank-based engineered log structures (ELSs) were installed. Each structure incorporated a fabric encapsulated soil lift (FESL) along its face. Vertical snags were installed for added stability. No ferrous materials were used to anchor structures, but rather backfilled with native cobbles, boulders and spoils.
The Natapoc project consists of seven bank-based engineered log structures placed in areas where gaps in the riparian canopy exist. Each structure consists of a combination of rootwads, sticks and piles. Each of the rootwads extending into the mainstem Wenatchee River has a bumper log across the face to deflect any debris since this is a highly recreated part of the Wenatchee River. There are six smaller cover structures and on larger complexity structure.
Piles were driven using a vibrasonic implement to desired depth. Several piles were tested for embedment using a tensiometer and an excavator to ensure the factor of safety and depth was achieved. Along the face of each completed structure a fabric encapsulated soil lift (FESL) was installed in varying tiers. These FESLs were planted with native grasses and live willow stakes to to hold in backfilled soils. All structures were ballasted with backfill and vertical snags, no ferrous material was used.
Native vegetation was used upon project completion and planted in any disturbed areas including staging areas, access routes and structure installation.
