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• , • III III IIIIIIIIII III <br />°` `~ STATE OF COLO[ZADO <br />Roy Romer, Governor <br />DEPARTMENT OF NATURAL RESOURCES <br />MINED LAND RECLAMATION DIVISION <br />FRED R. BANTA, Director <br />DATE: December 5, 1989 <br />T0: Dan Hernandez <br />FROM: John T. Doerfer <br />RE: Review of Response to Adequacy Concerns, <br />Corrective Action Plan, Snyder Quarry Access Road, <br />Castle Concrete Company, NOY M-89-015, File No. M-77-210 <br />As you requested, I have reviewed the responses provided by Castle Concrete <br />Company on November 29, 1989 on the above-referenced subject. I restricted <br />rRy review to those items you identified concerning hydrologic aspects of the <br />plan. My comments following review are provided below. <br />Culvert Designs. The operator has made a commitment to <br />lnstaTT die six (6) culvert crossings according to the <br />designs provided in the Appendix. The Appendix includes <br />individual drawings of each culvert crossing and discusses <br />entrance and exit conditions, freeboard requirements, erosion <br />control and channel conditions downstream. Also, a commitment <br />to provide as-built drawings has been included but no time <br />frame was specified. <br />The designs indicate riprap will be provided down to the <br />existing natural channel. I would recommend that the Division <br />require as-built drawings be submitted 60-days after completion <br />of construction. With this commitment by the operator, the <br />Division's concerns will be satisfied. <br />8. Freeboard Requirements. The Appendix provided in the response <br />sped 1es e~eadwa~er depth needed at each culvert entrance <br />under design conditions. These headwater values (noted as "HW" <br />in the appendix) should be considered minimum valves. These <br />specifications can be approved as submitted are sufficient and <br />can be checked upon inspection after construction. <br />215 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. (30:3) 866-3567 <br />