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The river in this stratum was slow-moving and meandered through low, rolling hills and some areas of alluvium. Side channels, riffles, and backwaters were relatively numerous (Figure 6). Substrate was primarily sand and gravel. Average stream gradient for t?e entire stratum was 4.4 ft/mi. Both average conductivity (micromhos/cm ) and average turbidity increased from runoff to postrunoff. Stratum 7 from RM 91.0 (km 145.6) to RM 88.7 (km 142), was very short, and confined to a 2.3 mi (3.6 km) section of steep walled Juniper Canyon. A crude man-made diversion dam at RM 90.5 (km 144.8), midway in the canyon, created a slow-moving pool habitat upstream and an area of boulders and rapids at and below the diversion structure. Average gradient in the entire stratum was 5.2 ft/mi, but gradient was much less in the upper 0.5 mi of the canyon and greater in a short section at the diversion dam. Substrate was primarily boulder/bedrock, with small areas of sand/gravel exposed at the upper end of the stratum and during low flows. Average and maximum depths during both runoff (8,3 f t; 18 ft) and postrunoff (5.0 ft; 12 ft) were the greatest of any Yampa strata. Average turbidity decreased slightly from runoff to prerunoff. Since this stratum was shorter (2.3 mi; 3.7 km) than the standardized sampling stations (2.5 mi; 4 km), no attempt was made to subdivide it. As much of the stratum as possible was sampled and this stratum was treated as_,, an index station. Stratum 6 extended from the lower end of Juniper Canyon, RM 88.7 (km 142), to the upper end of Cross Mountain Canyon, RM 58.8 (km 94). - The river in this stratum meanders through a wide alluvial plain near the town of Maybell, Colorado. Average depth of 6.2 ft during runoff decreased to 2.5 ft during postrunoff. Average stream gradient was only 3.4 ft/mi. The substrate types encountered were predominantly sand/silt with some riffle areas of rubble/cobble. Six of the eight habitat types were present in this stratum. Type 1 backwaters, eddies,.riffles, and side channels were the most common. A physical habitat simulation (PHABSIM) site was established in this reach at RM 72 (km 118) (Appen-- dix A). Stratum 5, Cross Mountain Canyon, extended from RM 58.V(km 94) to RM 55.6 (km 89). The Yampa River drops an average of 55 ft/mi and the substrate is almost entirely boulder/bedrock. Except for a large, deep pool at each end of the stratum, the river is a continuous series of swift rapids, falls, and chutes. Access to this stratum was only avail- able by foot. Since the primary responsibility for sampling was assumed by the CDOW, FWS sampling was only designed to supplement CROW data. This stratum was not sampled in rotation with other strata. Stratum 4, Lilly Park, from RM 55.6 (km 89) to the mouth of the Little Snake River at RM 51.0 (km 81.6), consisted mainly of boulder/ cobble/gravel substrate washed out from Cross Mountain Canyon. Riffles, eddies, and side channels were relatively common. At RM 53.0 (km 84.8) a large deep pool was present where Colorado squawfish were previously collected by Seethaler (1978). Average gradient in this stratum was 8.0 ft/mi and average depth was 5,9 ft during runoff and 3.2 ft during postrunoff. This stratum was generally too shallow to be consistently 24