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I I I I I I I I I I I I I I I I I I I 2.0 PROJECT DESCRIPTION The NGWSP is proposed to deliver treated municipal water to selected Navajo communities, a portion of the Jicarilla Apache Nation and the city of Gallup, New Mexico. The project is planned with adequate capacity to serve approximately 203,000 people in 43 Chapters in the Navajo Nation, 1,300 people in the Jicarilla Apache Nation, and approximately 47,000 people in Gallup, the projected populations as of year 2040. The service area includes most of the New Mexico portion of the Navajo Nation, the Navajo Nation in the Window Rock area within Arizona, the Jicarilla Apache Nation and the City of Gallup, New Mexico, as shown in Figure 2.1. The water supply will be from the San Juan River with surface return flow in the San Juan basin and groundwater recharge to the San Juan, Rio San Jose and Rio Puerco Basins. For water balance considerations, the groundwater recharge is not assumed to return to surface flow in any of the basins due to the distance from the surface water bodies and existing pumping within the basins that will keep the water surface elevation in the aquifers from rising to levels that would allow discharge. The proposed action is called the San Juan River Public Service Company of New Mexico (PNM) 2040 Alternative, consisting of the Cutter Lateral and the San Juan Lateral. The Cutter Lateral diverts water from the NIIP main canal at Cutter Reservoir. The San Juan Lateral diverts water from the San Juan River at the PNM diversion dam. A treatment plant would be located at each diversion location, along with main pumping plants supplying water to a total of 267 miles of pipeline. The system would include 19 forebay tanks, 24 pumping plants, 5 regulating tanks and approximately 25 community storage tanks. The general project layout and service area are shown in Figure 2.1. Pumping and treatment plant capacity could be staged, with initial capacity adequate for 2020 demands. Additional capacity would be added as needed. Only 2040 capacities are discussed here. The effect of construction, operation and maintenance of the project, along with potential contracts to deliver water from the San Juan River and Navajo Reservoir through the Department of the Interior, are covered in this biological assessment. 2.1 Water Requirement The project is designed to divert a total of 37,764 acre-feet of water per year from the San Juan River with a resulting depletion of 35,893 acre-feet, based on 2040 projected population with a demand rate of 160 gallons per capita per day. The Cutter Lateral would require 4,645 acre-feet per year with no return flow to the San Juan River. The San Juan Lateral would take the remaining 33,119 acre-feet of diversion, with an average return flow of 1,871 acre-feet. The planned diversion and depletion by location is shown in Table 2.1. It is assumed that the only return flow from the project to the San Juan River would enter the river at the Shiprock wastewater treatment plant. There may be some water delivery to users with individual septic systems in the Shiprock area, but the delivery is expected to be a small percentage of the total. Assuming return flow through the treatment plant is the highest impact case, and is therefore a conservative assumption. The return flow rate is assumed to be 50% of delivery for the Shiprock deliveries. All other deliveries would have similar losses, but the resulting return flow would be lost to evaporation, or recharge local groundwater aquifers. For BIOLOGICAL ASSESSMENT NAVAJO GAllUP WATER SUPPLY PROJECT September 3, 2004 Page 2