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<br />Construction of new facilities will disturb 56.3 acres, which includes some areas that <br />may have been disturbed in the past but do not currently have a concrete pad, road, or <br />other such specific development. <br />There will also be four ponds at the Parachute Site, which are described in Section D.2.4. <br />D.2.4 Ponds <br />There will be a total of five ponds constructed for the Yankee Gulch Project. One will be <br />located at the Piceance Site, and four will be located at the Parachute Site. 'The ponds <br />will be used for process water, surface water runoff, and make-up water. 'The ponds to <br />be developed are: <br />• Piceance Evaporation Pond <br />• Parachute Evaporation Pond <br />• Parachute MVR Purge Pond <br />• Parachute Stormwater Retention Pond <br />• Parachute Water Storage Pond. <br />In the final design process, American Soda is working to reduce or eliminate much of <br />the pond requirements. <br />D.2.4.1 Piceance Site Pond <br />The Piceance Site evaporation pond will be located near the processing plant area and <br />its location is depicted in Figure D-2. It will have a surface area of 13 acres and a total <br />disturbed area of approximately 23 acres. The pond will be constructed with a double <br />liner and leak detection system in accordance with the CDMG requirements. The liner <br />system will consist of two geomembrane liners and a leak detection and collection <br />system. The top liner will be 60-mil high density polyethylene (HOPE), and the bottom <br />liner will be 40-mil HOPE. A geonet material would be installed between the two liners <br />to collect any water that may leak through the upper liner, and a sump pump would <br />transport any leakage back to the pond. <br />The berms for the pond will be designed in accordance with Bureau of Reclamation <br />Design of Small Dams criteria. Adequate freeboard would be provided to 1) <br />accommodate the normal maximum operating level plus the 100-year (24-hour) <br />precipitation event; 2) accommodate wave action on the pond level described in (1) <br />without overtopping; and 3) provide at least 1 foot of freeboard above the level <br />determined in (2). <br />D-6 <br />