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<br />001072 <br /> <br />Final Environmental Assessment-Chapter 2-Alternatives <br /> <br />Water Supply for Fish Passage <br /> <br />Because of downstream senior water rights, a flow of at least 520 cfs is present in this <br />reach of the river under all but the most severe drought conditions. The Service also has <br />up to 37,650 acre-feet of storage water available from upstream reservoirs for endangered <br />fish uses in drought years. About 80 cfs of Colorado River flow would be needed to <br />operate the fish ladder. The fish passage notch would be designed to direct the fIrst 80 <br />cfs in the river to the fish passage channel. Additional flows would begin to flow through <br />the boater notch and then over the rest of the dam at higher flows until the dam is <br />completely submerged. Flows over the whitewater weirs would be directed towards the <br />fish passage entrance to attract fish. If built, the Service would require the Jacobson <br />Hydro No. 1 Project ensure delivery of attraction flow for the fish passage entrance. <br />Without the Jacobson Hydro No.1 Project, attraction flows would vary, dependant on <br />flows in the river. The Town of Palisade, W.A.T.E.R. and E.R. Jacobson have discussed <br />entering into an agreement to insure water availability for recreation on weekends and <br />holidays ifthe Jacobson Hydro No. I Project is built. <br /> <br />Dam Removal <br /> <br />This alternative would involve partial removal ofthe dam to restore natural fish passage <br />in the river channel. This alternative would not be compatible with hydropower <br />development. Before Reclamation could remove the dam, four outstanding issues <br />(discussed in Chapter 3) would have to be resolved: <br /> <br />1) Develop mitigation measures to resolve the Ute Water pump plant issue <br />2) Determine whether a hydropower plant would be developed at the dam site <br />3) Obtain permission for dam removal from owners of the dam. The Mesa <br />County Irrigation District expressed support for dam removal, but the Palisade <br />Irrigation District is currently opposed to dam removal. <br />4) Geologic investigations indicate landslide stability is an issue; however, <br />no impacts to the slide movement caused by dam removal are anticipated. If <br />the dam is removed and a landslide were to occur, potential for damage <br />liability exists. <br /> <br />Design <br /> <br />The Dam Removal Alternative would allow the foundation, abutments, and canal head <br />works to remain in place (see Figure 8). The left abutment3 of the dam may provide <br />some erosion protection for Interstate 70. The right abutment may protect the Union <br />Pacific's railroad tracks from erosion. The portion ofthe dam below the riverbed does <br />not present a barrier to fish and leaving it in place would help reduce scouring of the <br />riverbed. <br /> <br />3 The left abutment is on the left side of the dam, as viewed when looking downstream. <br /> <br />19 <br />