Abstract
Anthropogenic processes have altered the natural state of the Feather River creating unsuitable habitat for spawning salmonids. These processes have restricted the natural flow of the river resulting in an armored river bed. The goal of this study is to identify areas to reduce armoring and enhance salmonid spawning habitat. This study is sponsored by the California Department of Water Resources and will be conducted for a period of 4 years starting in the Fall of 2011. Three riffle complexes on the Feather River were studied to evaluate the condition of the salmonid spawning habitat prior to restoration. The sites were analyzed for grain size utilizing Wolman pebble counts and bulk samples. Piezometers were installed throughout each riffle complex to measure hyporheic conditions such as dissolved oxygen, electrical conductivity, pH, temperature, and turbidity. Surface water depth, velocity, and direction of flow measurements were made using a Marsh/McBirney current meter affixed to a topset wading rod. Gravel permeability was tested using Barnard-McBain standpipe tests and upwelling was measured using a bubble manometer board and in-river baffle. The three restoration sites currently have poor salmonid spawning habitat. The gravels at the sites are too large for the salmonids to manipulate and low hydraulic conductivity was prevalent through the sites. Low dissolved oxygen was also present at the proposed restoration sites. The restoration sites lacked significant gravel bars or geomorphic structures. The sites need improvement with the installation of transverse bars, riffles, and the addition of smaller size grains. This will reduce armoring and increase hyporheic flow.