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I I I I I I I I I I I I I I I I I I I Storage tank locations typically would include the storage tank (size varies depending on location), chlorination building, pumping plant, air chamber, electrical control and ancillary equipment in an enclosed yard. The typical footprint is about one acre. 2.3 San Juan Lateral The San Juan lateral would have its diversion point at the existing PNM diversion dam, located as shown on Figure 2.1. The pumping plant intake would be located just upstream of the PNM: intake on the nonh bank of the San Juan River as shown on Figure 2.4. It will supply the main pipeline located as shown on Figure 2.3, delivering up to 33,119 acre-feet per year to the 36 ::\avajo Kation Chapters and the City of Gallup, NM. \Vater would be diverted through a self-cleaning screen with 3/32" openings and a through- screen velocity of less than 0.5 feet per second to a sump where low-head pumps would lift the raw water into senling ponds for removal of suspended sediment. The remaining treatment and pumping plant facilities would be as described for the Cuner Lateral, except that the capacity is 2reater at 38.25 m2d (59.19 cfs). There would be seven ultrafiltration units. seven L"V - - I I disinfection units, and a 797,000 gallon clear well. There would be two senling ponds and two sediment drying beds at this site that are required to handle the elevated suspended sediment concentration. The associated buildings and ancillary equipment listed for the Cuner Lateral \,,'ould also be requirerl at this site, although of a larger size. The total footprint at this site is expected to be about 18 acres, much of which is previously disturberl, sparsely inhabited trailer park. The pumping plant would feed approximately 145 miles of buried pipeline ranging in diameter from 12-inch to 48-inch located as shown in Figure 2.3. The buried pipeline would cross the San Juan River just upstream of the treatment plant and ascend to the mesa on the south side of the river. From there it would proceed west following Navajo Highway 64 to U.S. Highway 491, following the highway route through the city of Gallup to connect to five Navajo chapters on the southern border of the city. The project facilities serving the Gallup area is called the Gallup Regional System and consists of one new pumping plant and upgrades to three additional pumping plants, five storage tanks, and 32 miles of pipeline. There would be seven re-lift "lations alone the main line. with three on the Dalton Pass branch and two on the Window Rock - - - branch. Along the route there would be 17 storage tanks (plus five community storage tanks in the Gallup Regional System), three regulating tanks, with additional junctions to Shiprock, Burnham and Gallup water supply systems and a turnout to NIIP. A new electrical transmission line, paralleling the pipeline over much of its route, is shown on Figure 2.3. The method of construction at the San Juan River crossing has not been determined. The pipe will be placed under the river, either by open cut with construction of coffer dams in one half of the river width at anyone time, or by underground directional boring. The riparian disturbance is about the same with either method and impacts from both methods have been considered and are reported in Section 2.4. BIOLOGICAL ASSESSMENT NAVAJO GALLUP WATER SUPPLY PROJECT September 3, 2004 Page 8