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<br />"" <br /> <br />C!': <br />c.c <br /> <br />.., <br /> <br />SOUTHERN NEVADA WATER AUTHORITY - TREATMENT AND TRANSMISSION FAClllTY <br /> <br />c.. <br /> <br />The major separate components (i.e., major facilities at separate sites) of the alternatives <br />considered in detail for the SNWA-TTF project are summarized in Table S-1. The No Action <br />Alternative, which would not meet the stated purpose and need for the Proposed Project, was <br />also evaluated. <br /> <br />THE FIVE OUT-VALLEY ALTERNATIVES <br /> <br />Alternative SI-1B: Saddle Island Intake to Foothill WTF Site <br />via Existing River Mountains Tunnel <br /> <br />Alternative SI-1 B would consist of a new intake in Lake Mead at Saddle Island, an intake <br />pumping station on Saddle Island, a WTF located at the Foothill site, water transmission <br />pipelines, a booster pumping station, two power substations, and power transmission lines. <br />The intake structure would be placed approximately 200 feet below the normal operating <br />surface of Lake Mead to ensure a readily available water supply. An intake pumping station <br />on Saddle Island would lift water from the intake structure, through a transmission pipeline, <br />to a booster pumping station in the eastern River Mountains. The booster pumping station <br />would lift water from its fore bay through the existing River Mountains tunnel to the Foothill <br />WTF. The Foothill WTF site is immediately adjacent to the west portal of the existing River <br />Mountains tunnel. Power for proposed facilities would be provided from the existing Mead and <br />Basic Substations, To supply this power, a new 230 kV power line, upgrades to existing 230 <br />kV power lines, new 69 kV power lines, and two new substations would be needed. The new <br />230 kV power line would parallel existing power line corridors from Mead Substation <br />northward to a new sNWA substation on the eastern side of the River Mountains. Power <br />would then be distributed to the intake and booster pumping stations by 69 kV power lines <br />along the pipeline alignments. Upgrades of existing 230 kV power lines from Mead to Basic <br />Substations and a portion of the line from Hoover Dam to Basic would provide system <br />reliability. A new substation and new 69 kV power lines, also along an existing power line <br />corridor, along the western side of the River Mountains would provide power to operate the <br />WTF, <br /> <br />Alternative SI-1C: Saddle Island Intake to River Mountains WTF Site <br />via Existing River Mountains Tunnel (Preferred Alternative) <br /> <br />This alternative is the agency Preferred Alternative. Alternative 51-1 C would consist of a new <br />intake in Lake Mead at Saddle Island, an intake pumping station on Saddle Island, a WTF <br />located at the River Mountains site, water <br />transmission pipelines, two booster pumping <br />stations, two power substations, and power <br />transmission lines. The intake structure would be <br />the same as for Alternative 51-1 B, A booster <br />pumping station in the eastern River Mountains <br />would lift water through the existing River <br />Mountains tunnel. A second booster pumping station would lift water from the west portal <br />of the existing tunnel through a new pipeline to the River Mountains WTF. This pumping <br />station would be located less than one mile west of the tunnel exit portal. The River <br /> <br />Alternative SI-1C is the agency <br />Preferred Alternative. <br /> <br />SUMMARY <br /> <br />S-7 <br /> <br />J <br />