TEMPORAL AND GEOMORPHIC VARIATIONS OF STREAM STABILITY AND MORPHOLOGY- MAHOGANY CREEK, NEVADA

Detailed studies of long-term management impacts on rangeland streams are few because of the cost of obtaining detailed data replicated in t ime. This study uses government agency aquatic habitat, stream morphol ogic, and ocular stability data to assess land management impacts over four years on three stream reaches of an important rangeland watershe d in northwestern Nevada. Aquatic habitat improved as riparian vegetat ion reestablished itself with decreased and better controlled livestoc k grazing. However, sediment from livestock disturbances and road cros sings and very low stream flows limited the rate of change. Stream typ e limited the change of pool variables and width/depth ratio, which ar e linked to gradient and entrenchment. Coarse woody debris removal due to previous management limited pool recovery. Various critical-elemen t ocular stability estimates represented changes with time and differe nces among reaches very well. Ocular stability variables tracked the q uantitative habitat and morphologic variables well enough to recommend that ocular surveys be used to monitor changes with time between more intensive aquatic surveys.