Watershed Restoration Program Success Story

Tongass National Forest – Harris River Mainstem Instream Rehabilitation

The Harris River was left vulnerable to sedimentation and stream diversion processes following the original harvest of the basin primarily in the 1960s. The overall goal of the Harris River project is to accelerate the recovery of riparian areas and restore, maintain and preserve fish habitat and fisheries. The objectives of the project are to restore and maintain large woody debris levels, reduce bank and stream channel erosion, increase and maintain pool, spawning, juvenile habitat, and restore and protect regenerating riparian vegetation while also improving trail access to the mainstem Harris River for recreational purposes.

The deterioration of large woody debris in the river is leading to increased channel erosion and accelerated lateral migration and channel avulsion frequency. Consequently, as the large woody debris and channel stability within the Harris River decrease so will the fish habitat and fisheries. Therefore, one of the primary objectives of the Harris River Rehabilitation project is to make sure that the existing habitat and fisheries do not fall apart as the existing large woody debris deteriorates.

An instream physical model, developed from field surveys, was applied to proposed treatment sites to determine suitability and feasibility of potential engineered instream large wood structures. Logistics of access and raw materials were developed and partially applied in anticipation of implementation. This included reconditioning 0.75 miles of access road and collecting large wood from three 50 year old forested strips that were designed to benefit wildlife species and achieve silviculture goals.

Large wood structure in the Harris River.
Post-reconstruction large wood structure in the Harris River.

Summer 2009 accomplishments included implementation of the instream rehabilitation work, which includes one mile of stream and two off-channel pond improvements/connections for Coho salmon overwintering.