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• 111 Illllllllllll III 999 i Colorado State University Department of Earth Resources Fort Collins, Colorado 80523 Tel: 970 491-5430 Fax: 970-491-6307 28 May 2001 John Eastman Routt County Planning Dept. 136 6w Street Steamboat Springs CO, 80477 Dear John, I have reviewed the report by "Sowce water consulting" on the Camilletti/Milner gravel pit. I have numerous comments, and have limited time in this letter to do any more than highlight some of the issues that need further analysis and consideration. ~ This report needs considerable work before it can be considered a complete analysis of the issues. In the first pazagraph the author states "Riparian settings aze protected habitats as per Section 404 of the Clean Water Act", which is not true. The Ciean Water Act regulated discharges into waters of the U.S.... it does not and never was intended to protect habitats. The main question to be addressed by this study is stated in the report "would the normal health and vigor of the cottonwoods and associated vegetation surrounding the proposed site be maintained in the presence of the mine dewatering, given the mitigation measures proposed". However, the question was not really addressed. I'm unclear about the three cross sections, eg. what is the difference between the "greatest groundwater impact zone" and the "worst-case scenario zone". Two seepage face elevations, 4 and 7 m above the pit bottom were analyzed in the modeling. Why wasn't a seepage face at the pit bottom analyzed? Other ground water models for similar gravel pits consider that a cone of depression is developed in gravel , pits, with the pit bottom as the 0 point from which ground water contows are extended. I'm also unconvinced that the model utilized is the correct one. Why was the Dupuit- Forchheimer equation used? In scientific analyses when more than one approach is