IDENTIFICATION AND MITIGATION OF WATERSHED DISTURBANCES IN THE KINGS RIVER PROJECT AREA, SIERRA NATIONAL FOREST, CALIFORNIA

The implementation of a Watershed Improvement Needs (WIN) inventory in portions of the Big Creek watershed in the Sierra National Forest in California has led to the identification of multiple disturbances, which contribute to increased erosion and sedimentation and are therefore detrimental to water quality. The Big Creek watershed and the adjacent Dinkey Creek watershed are within the Kings River Project area, which is the focus of an extensive ecosystem management analysis. Two subwatersheds in the Big Creek watershed and six in the Dinkey Creek watershed have been identified as highly sensitive to Cumulative Watershed Effects, indicating that land disturbing activity has had a substantial impact on the subwatershed and that an assessment is warranted. Roads and skid trails (remnants of timber harvest activities) result in soil compaction and reduced infiltration, which cause accelerated surface and gully erosion and increased sedimentation. Therefore, the areas near roads and skid trails are a focus of the WIN inventory, with particular consideration for their intersections with drainages. Multiple sets of air photos from 2001, 1970, and 1963 were used to identify disturbances. This technique is advantageous because it allows for the observation of changes in topographic features and managed areas over time. Field examination of disturbances is necessary to identify specific problems, which include blocked culverts, oversteepened cutslopes, and gullying. Possible mitigation measures include clearing culverts, reshaping slopes, stabilizing gullies, ripping roadbeds, and installing water bars.