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I I I I I I I I I I I I I I I I I I I 2343 Alternatives The group participated in a discussion of each of the six storage alternati ves with respect to potential USFS issues and impacts. The following items were discussed. Lake Meredith Enlargement. USFS projects and facilities are not affected by this alternative. Turquoise Reservoir Enlargement. There will be significant and extensive impacts to USFS projects and facilities around Turquoise Reservoir. Portions of several campgrounds will be inundated, along with boat ramps. Existing water and sewer lines (all gravity lines) are just above the current high water line, and will be inundatcd by a higher pool. Other utilities including electrical and phone lines may also be impacted. Part of the perimeter trail around the lake will be inundated. Specific facilities that will bc inundated can be identified after a map of the proposed high water line is developed. There are many abandoned mines in the USFS area around the lake. USFS is in the process of completing an inventory of these mines and is working with the State and other organizations to close these sites to mitigate safety hazards. Several abandoned mines will be inundated by a higher pool level, and could allow pollutants (e.g., metals) to be leached into the reservoir water. On the other hand, inundating the mine sites will alleviate any need for further remediation. Linda Fox has a map of known mine sites. USFS staff questioned whether the 130,000 ac-ft estimate of existing Turquoise Lake volume is the original volume or is adjusted for sediment accumulation. The project staff will have to check into this. USFS staff is concerned that sediment deposition in Turquoise and Twin Lakes will decrease available reservoir volume. There may also be opportunities for recovering effective storage that has been lost in past year by sediment deposition. The cost of dredging may be less than the cost of enlarging dams. Although considerable recreation facilities would be inundated by a higher reservoir pool, none are critical and all could be replaced at a higher elevation. However, these are very popular recreation areas (all campgrounds are fully utilized every weekend from July 4 to Labor Day), and there will be lots of public interest in any changes to these resources. Wetland areas and wildlife habitat will be inundated, but it is assumed that these impacts can be mitigated. System operation changes and resulting impacts on Jake levels and streamflows are of concern to USFS staff. Rapid changes in lake levels affect boat ramps, fisheries, and other recreational amenities. Flow changes could affect fisheries. Erosion is a problem in channels upstream of Turquoise Reservoir and Twin Lakes due to transmountain deliveries. These create channel instability, adverse habitat impacts, and contribution of high sediment loads to the reservoirs. Fryingpan-Arkansas Project Re-operation. USFS has recreation facilities around Twin Lakes as well as the Turquoise facilities described above. Although this alternative will not result in 2 of 3