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Dewatering Evaluation Report <br />Varra Gravel Operation <br />Greeley, Colorado <br />Page 6 <br />estimated at 20 feet. However, according to the well log, the last five feet of the well was <br />completed in material described as sandy clay. The amount of water the sandy clay will <br />transmit is likely insignificant compared to the coarse grained alluvial deposits. For <br />simplicity purposes this portion of the aquifer was not considered in calculating drawdown <br />estimates. <br />The estimated drawdown at a pumping rate of 15 gallons per minute was 1.5 feet -less <br />than 10% of the static water column in the well. The drawdown estimates were based on <br />assuming a saturated thickness of 15 feet, an average hydraulic conductivity of 250 feet <br />per day and a well efficiency of 70 percent. Variations in hydraulic conductivity and well <br />efficiency will have a direct relationship to drawdown in the subject well. Details of the <br />Carbaugh well as reproduced from the Well Construction and Test Report are presented <br />in Attachment B. Hand calculations are presented in Attachment C. <br />The discussions and recommendations in this report represent our professional opinions. <br />Our conclusions, opinions and recommendations are based from information available at <br />this time and we do not guarantee that undiscovered conditions will not become evident in <br />the future. CGRS' report was prepared in accordance with currently accepted engineering <br />practices at this time and location and no other warranties, representations or certifications <br />are implied or intended. <br />This report was prepared by CGRS, INC. <br />Joby L. Adams, P.G. <br />PrincipaVHydrogeologist <br />Date ~V'e« gl oZoo `~ <br />