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<br /> <br />DEPARTMENT OF NATURAL RESOURCES <br />David M. GeKhe4 F~eoutlve DlrettOr <br />MINED LAND RECLAMATION DIVISION <br />DAVID C. SNELTON, Dlnetor <br />Richard D. Lamm <br />Governor <br />October 11, 1984 <br />Mr. Larry Reschke <br />Grand Mesa Coal Company <br />P.O. Box 226 <br />Delta, CO 81416 <br />I I II 1111111 _/,~j <br />Re: Permit Stipulations No. 1 and No.~ <br />File: C-034-81 <br />Dear Mr. Reschke: <br />With respect to Stipulation No. 1, the responses dated October 9, 1984, are <br />acceptable, and pond expansion should be initiated as soon as possible. <br />With respect to Stipulation No. (drainage channel reconstruction), we have <br />the following concerns: <br />A) The Drainage System Map and Final Contour Map submitted do not show the <br />entire drainage contributing to the headwater of the reconstructed <br />channel. From the "Drainage System Map", the permittee states that <br />areas 5 and 6 contribute to the upper stream. Why don't areas 4 and 7 <br />also contribute? <br />B) A point midway down the channel was considered to receive 1/2 of the <br />peak discharge of the lower reclaimed area. From the configuration of <br />the basin, it appears that this point would receiver greater than 1/2 <br />of the drainage. Intermediate points from the upper to lower <br />reconstructions should be evaluated to determine the minimum cross- <br />sectional area required to contain the flow. These points should <br />coincide with the intersection of major sub-basins into the <br />reconstructed stream channel. <br />C) Using equation: <br />N = 0395 d 50 1/6 <br />a rip=rap d50 sizing of 4.85 inches does not coincide with an n value <br />of .04. The n value should be justified. <br />\ 423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. (30R) 866-3567 <br />