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<br />00154~ <br /> <br />Chapter 2 - Alternatives <br /> <br />construction, and construction administration. Additional costs for constructing a fish trap would <br />be approximately $200,000, <br /> <br />Operation, Maintenance and Replacement Measures <br /> <br />These measures and costs would be the same as discussed in the "with Hydropower Plant" <br />alternative. <br /> <br />Water Supply for Fish Passage <br /> <br />As previously mentioned, about 25 cfs of Colorado River flow would be needed to operate the <br />fish ladder. Additional flows of about 75 cfs would function to attract fish to the entrance of the <br />ladder. Since river flows rarely drop below 640 cfs in this reach, no measures would be needed <br />to augment existing water supplies for fish passage. <br /> <br />Dam Removal <br /> <br />This alternative would involve partial removal of the dam to restore natural fish passage in the <br />river channel. Before Reclamation could remove the dam, four outstanding issues (discussed in <br />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 will be developed at the dam site <br />3) Obtain permission for dam removal from owners of the dam. The Mesa County <br />Irrigation District has expressed support for dam removal, but the Palisade Irrigation <br />District is currently opposed to removal. <br />4) Preliminary geologic investigations indicate landslide stability is not an issue. However, <br />if further investigation and monitoring show that dam removal would decrease landslide <br />stability, this alternative would be eliminated from consideration. <br /> <br />Design <br /> <br />The removal alternative would allow the foundation, abutments, and canal headworks to remain <br />(see conceptual drawing, Figure 3). The left abutment2 of the dam provides erosion protection <br />for the Interstate 70 highway. The right abutment protects the Union Pacific's railroad tracks <br />from erosion. The portion of the dam below the riverbed does not present a barrier to fish and <br />leaving it in place would help reduce scouring of the riverbed. The cross-section drawing in <br />Figure 4 (a "slice" view of the dam) shows the dam would be removed from the crest down to the <br />riverbed, but the entire foundation would remain. <br /> <br />2 The left abutment is on the left side of the dam, as viewed looking downstream. <br /> <br />12 <br />