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determine at what stage or flow level the average depth of most eddies is suitable, one would need to monitor at least two transects across each of several eddies either randomly selected or thought to be representative of most eddies in the reach. Time and manpower constraints, i.e., level of funding, precluded this sort of large-scale effort. As it was, we monitored 26 transects within the Grand Valley, 13 of which were in the 15-mile reach. Of the 15-mile reach transects, four crossed primary or secondary channels within multi-channel sites, and three crossed the main channel at single-channel sites (Fig. 21 and Table 3). These sampled either riffle or run habitats. The remaining six transects sampled what later turned out to be preferred habitats: one crossed a pool, one crossed an eddy, and four crossed two portions of two backwaters. Note: At the time the transects were established (1990), we did not yet have the benefit of the data needed to determine which habitat types were preferred. The following contains a description of depths at the various transects, arranged by habitat type. Figures of each cross section with stage level superimposed is provided in Appendix No. VII. Eddy Transect (Appendix Fig. V) Transect No.5 bisected a large eddy located just outside the mouth of a large backwater within Site No.2. Maximum depth ranged from 7.3 to 12.8 ft depending on flow level; average depth ranged from 4.4 to 7.2 ft. Even at the lowest flows studied (557 cfs), suitable depth for summer (2.9-3.9 ft) and winter use (2.9-4.3 ft) was exceeded. Pool Transect (Appendix Fig. VIII) The south end of transect No. 10 bisected a pool located just outside a large backwater within site No. 3. Contours of the pool changed between fall of 1990 and fall of 1991. Moderately high spring flows in 1991 scoured bed sediments resulting in greater depth. Average depth during 1990 was less than suitable for summer use (2.2-3.3 ft) at flows less than 1,240 cfs (Table 4). Maximum depth exceeded 2.2 ft at all flows. For winter use, average depth was less than the suitable range (3.6-3.9 ft) at flows of 5,020 cfs or less. Maximum depth of the pool met or exceeded the suitability criteria at all flows higher than 810 cfs. Because the pool was deeper in 1991, suitable summer depths were met or exceeded at all flows: average pool depth was 2.3 ft at the lowest flow (557 cfs). For winter, average depths in 1991 were suitable at flows greater than 2,870 cfs. This illustrates an important point regarding maintenance of habitat quality: for some habitats, depth is a function not only of stage, or degree of inundation, but also the history of bed sedimentation or degree of scouring (discussed later under Spring Flows). Backwater Transects (Appendix Figs. V and VII) Transects No. 3 and 4 bisected a large backwater in site No. 2 (Appendix Fig. V). One (No-3) was placed towards the upstream end and the other (No.4) at about midway (Fig. 21). This backwater had a fairly uniform depth throughout its length. Average depths at the transects were never suitable for summer use (3.4-4.5 ft). Maximum depth was suitable for summer use at flows greater than 5,020 cfs at the upper site and greater than 4,426 at the midway site. Average depth was suitable for winter use at flows of 9,170 cfs or greater at the upper site and 7,620 cfs at the midway site. Maximum depth was optimum or greater for winter use (2.6-3.1 ft) at flows greater than 2,870 cfs at both upper and midway sites. In summary, most of this backwater was less than suitable in terms of depth at all flow levels typical of summer or winter conditions. Twelve squawfish locations made within this backwater during summer of 1986 and winter of 1986-1987 indicate that backwater depth was greater at that time: depth at fish locations ranged from 1.7 to 5.5 ft. One location, made one third the way up the backwater was 4.7 ft deep in August .1986 39