| OCR Text |
Show E. UNAVOIDABLE ADVERSE EFFECTS Section C presented all of the known environmental impacts whether beneficial or adverse and Section D discussed measures designed to enhance, protect, and mitigate some of the adverse effects of the proposed Unit. This section is intended to list and explain the most important known adverse impacts which, under the proposed plan of development, cannot be avoided or fully mitigated. The following passages summarize the impacts of the Bonneville Unit which are presently considered would be unavoidable0 In order to fully understand the contents of this section, Sections C and D should be carefully read. The Bureau of Reclamation expects that the knowledge gained through planned environmental studies would lessen the intensity of some of the adverse impacts discussed below and allow others to be completely avoided. !• Fisheries and Aquatic Habitat a. Streams The Bonneville Unit, through inundation, reducing flows and causing excessive flows, would affect approximately 244 miles of 20 streams within the Bonneville Unit area ( refer to Table C- 19). Inundation would eliminate about 39 miles of stream. Reduced flows would occur in approximately 205 miles of stream and excessive flows would develop in 5 miles of stream. The sport fishery quality of the miles of affected streams was derived from the Utah State stream classification system'*^ and is summarized as follows: Class Bonneville 5.0 Basin Uinta Basin 0.0 Total I 5.0 II 6.7 47.9 54.6 III 26.3 65.4 91.7 IV- VT 43.6 49.3 92.9 Total 81.6 16206 244.2 The above summary does not reflect the severity of the potential adverse impacts of reduced flows upon fishery habitat. As explained in Section C, a substantial amount of water can be diverted from a stream without severely harming fish populations, Using the results of the Forest Service stream habitat study^- 09 as a basis for judgment, it has been demonstrated that stream 469 |
