Douglas County, Oregon
An approximately 20-acre tract of forest land initiated movement after heavy winter rains recent timber harvest. The cause was determined to be a combination of groundwater, weak ash layering in underlying weathered siltstone, and loss of support due to an old timber haul road at the toe of the slope movement.
The selected stabilization alternative consisted of deep trench drains and a rock buttress. Groundwater intercepted by the drain and rock buttress is collected and used to maintain water levels in a stock watering pond. K & A Engineering, Inc. provided the original Geotechnical investigation, the topographic survey of the slide area, all stability analysis, and construction drawings and specifications for the repair.