North Canyon Stream Assessment
North Canyon Stream Assessment/Lake Tahoe Nevada State Park, Spooner Unit/Nevada-Tahoe Resource Team (NTRT)
The North Canyon Watershed Stream Assessment project was initiated by Nevada Tahoe Resource Team (NTRT). Resource Concepts, Inc. was retained by the NTRT to conduct a field-based stream assessment focused on areas of excessive erosion and sediment generation occurring along the road and stream channels in the Lake Tahoe Nevada State Park, Spooner Unit. The watershed area is approximately five square miles and the main channel is roughly 5 miles long. The North Canyon watershed ranges from 9,200 to 6,300 feet in elevation and ultimately discharges into Lake Tahoe. The objective of the project was to inventory, map, describe, and prioritize stream restoration projects within the watershed. The field reconnaissance was conducted during the fall after leaf drop for better visibility of this densely vegetated stream. The initial reconnaissance identified general Rosgen stream types and provided an overview of the geomorphology, hydrology, soils, vegetation, and previous impacts to the canyons and meadows. Areas observed during the initial reconnaissance with potential stream function problems were identified for further evaluation.
Review of historical information including archaeological reports and water rights provided critical information necessary to interpret the channel adjustments observed in the field. During the Comstock era water was diverted and significantly altered the hydrologic regime. In some areas, diversions had the effect of essentially doubling the watershed size. The subsequent increase in flow created significant erosion. Recommendations for treatment of the functional-at-risk areas and other projects suggested to restore riparian functions were developed and prioritized by RCI and the NTRT. RCI assisted the NTRT in design solutions for several of the prioritized areas.