WSP11446 - Laserfiche WebLink

Home Browse Search

An IFG4 habitat station was established on the Gunnison River at Whitewater in 1977 in cooperation with the Fish and Wildlife Service. This methodology is designed to predict habitat conditions in a stream at different flows. However, with the present extremely limited life history and habitat preference information available for the Colorado squawfish, data derived from the IFG4 model must be utilized only as a fair approxima- 'I tion of the amount of available habitat. The model indicated that adult squawfish habitat was optimum (5500 square feet) at approximately 1500 cfs while juvenile habitat was optimum (10,000 square feet) at approximately 600 cfs (Figure 2). However, the model predicted little or no available habitat for fry. At the established Dallas Creek project flows, the amount 'I ~ I ,I of available habitat for adult squawfish appears to be near optimum while that for juveniles appear to be adequate. Table 3 shows the pre- and post-project flows below the Redlands Diversion on the Gunnison River. This is approximately one mile above the river's con- , . > . ~' I fluence with the Colorado River. Historically, this one mile section periodically , il experiences extremely low flows during the late summer months. For instance, ~ during August and September of 1977 flows were measured at 8 cfs. During the ~ ~ ~ " I , ~ c ~ period of record (1952-1977), these extremely low flows occurred 6 times (Appendix B). The frequency of this occurrence will not increase with the p ~ t ~ ~ . ~ project. In fact with the project on line during the period of record it ~ would happen only 5 times in the 20 years. During these: extremely dry years ~ and probably most years, these fish populations undoubtedly migrate back to the Colorado River as flows are progressively reduced during the irrigation season. Indeed, it would be reasonable to assume that the present population of , I