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measurements, physical habitat assessment, description of adjacent riparian habitats, and assessment of aquatic macroinvertebrate populations upstream and downstream from the point of discharge. Censuring of fish populations was not included in the study, although this report summarizes what is known about the fishery in the area. Description of the Study Area: The study azea lies on the eastern edge of the Colorado Plateau, about 15 miles southeast of Grand Mesa in Gunnison County. A ] 600 m stretch of the river was studied between the town of Somerset and the West Elk Mine, located approximately I mile east of Somerset (Figure 1). Adjacent to, and upstream of, the study area, the North Fork and its tributaries drain a region that is mostly underlain by geologic formations of the Mesa Verde Group of Cretaceous age, and the Wasach Formation of Tertiary age. The cliffs and upper slopes above the study azea consist of exposures and materials derived from the Mesa Verde Group. These formations consist mostly of sandstones and shales. Much of the watershed above the study azea is covered by loosely consolidated and unconsolidated surficial deposits of glacial origin or of mass wasting that has produced numerous landslides and slumps. Valley bottoms aze covered by extensive deposits of alluvium. As a result of the poorly competent bedrock and loose surlicial deposits in the region, lazge sediment loads aze carried down the river during spring runoff. Much of the sediment is trapped by the Paonia Reservoir, located about 5 miles upstream of the study azea, however, the river quickly turns brown from fine sediment loads during regional runoff events. Immediately upstream of the town of Somerset, the river has been impacted by various underground coal mining activities, recent highway construction, and hydrologic changes due to the construction and operation of Paonia Reservov. The offices, shops, and coal storage and loadout facilities of the Bear Mine are located adjacent to the lower portion of the study azea on the south side of the river. The offices and loadout facilities of the lazge West Elk mine aze located a few hundred meters upstream of the study area, and a holding pond for the West Ell: mine is situated adjacent to the river and the upstream portion of the study area on the south side. Colorado Highway 133 runs through the valley and is located adjacent to the study azea along the north side. Railroad tracks to the West Elk loadout facility parallel the north side of the highway. The Sanborn Creek Mine is located to the north of the railroad tracks. Drainage from the mine is pumped into a holding pond, and the outlet from the pond flows into Sanborn Creek. From there, the creek passes through a culvert under the railroad tracks and highway to the North Fork River. The Mine's NPDES discharge monitoring point is located on Sanborn Creek, approximately 2 m upstream of its confluence with the North Fork. Sanbom Creek is a small, appazently intermittent stream. Flows were estimated to be less than 200 gpm during the times CSM investigators visited the site. About five yeazs ago, the Colorado Department of Transportation completed extensive reconstruction of Highway 133 east of Somerset. During the reconstruction project, the highway was widened, straightened, and the riverbank adjacent to the highway was stabilized with