Upper Blue River geology clipped to the Andrews Experimental Forest, 1991

Rock units of parts of the Blue River basin (including the Lookout Creek watershed and upper Blue River above the junction with Lookout Creek), were described by several investigators who covered different portions of the basin at different scales. A unit correlation table was developed (see below) and units were manuscripted using Priest et al. (1988) for Lookout Creek and Walker and Duncan (1989) for upper Blue River. Units were digitized and attributed using the investigators' descriptions. The upper Blue River geology layer was clipped by the H.J. Andrews boundary to create this layer. Rock unit strength was added as an attribute when the geology layer was used in a landslide hazard analysis. Rock strength was determined by Swanson based on rock type and age.