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were blo cked with fine mesh seines to allow the complete removal offish from a small area. A maximum of three sections were blocked out in each backwater using large (12.2m x 1.8m x 1.6mm) seines. Sections were 4-5 m wide and; where possible, stretched across the backwater. Each section was initially seined once using the standard Interagency Standardized Monitoring Program (ISMP) protocol, and all fish were identified and counted. Then successive passes were made until no more fish were caught. Sampling efficiency, or capture probability C(p), was expressed as a percentage, approximately represented by the total number offish collected in the first seine haul divided by the total fish present in the section. The data were analyzed using CAPTURE, a statistical program that produces population estimates based on capture probabilities, generated from capture/removal studies (White et al. 1982). Capture probabilities were generated for each fish species collected, and for each sub-section. In addition to susceptibility to sampling gear, sampling efficiency is affected by several factors including: mud depth and consistency, large cobble/boulder substrates, debris, water depth and turbidity, and size of the backwater. Seining difficulty in each section was rated from 1 (easy) to 6 (hard), and capture probabilities were compared between each rating. A paired means test was used to compare the difference in species' relative abundance between the first seine haul and the total present in the section. A diversity index modified by Keefe and Bergersen (1977) was used to further test the difference in ~ species composition and relative abundance between the first haul and the total. RESULTS AND DISCUSSION Geomorphology: Ouray Nursery habitats occur in the lee of emergent bed- and barforms at base flows. Bank- attached compound bars were the predominate barform and most consistent contributor to available nursery habitat, and the most stable channel features. Within the 10 km study reach, the location of the study and point bars was fixed, but the location of midchannel bars and the thalweg was transient. Fourteen sites were consistently occupied bybank-attached compound bars or point bars during the study period. The low-flow morphology of these deposits varied greatly from year to year, but the location of these deposits changed little during this study. J. Mayers (LTSU, pers. comm., 1995), determined that location of these deposits has changed little since 1966. In addition to these spatially stable bars, there were many transitory mid-channel bars. The magnitude and duration of flood flows have yearly effects on total habitat availability. The 1993 peak was moderately high (570 m3/s [20130 cfs]), and the 1994 peak was low (330 m3/s [ 11650 cfs]). The total habitat availability in the 10 km reach after peak flow was estimated from the video at comparable base flows of 45 m3/s (1590 cfs) for 1992, 1993 and 1994. In 1992, the total habitat area was 21700 m2, compared to 12361 m2 in 1963. In 1993, the total habitat area had decreased from 19921evels to 19517 m2, but the area of deep habitat had increased from 13220 to 17460 m2. In 1994, the total habitat area increased to 23624 mZ, but the area of deep habitat decreased from 17460 to 3080 m2. The response of individual geomorphic features and habitats to various flow regimes was assessed on the study bar. Bank-attached compound bars with secondary channels which viii