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Stormwater Management Plan <br /> STORM WATER MANAGEMENT PLAN <br /> CERTIFICATION OF THE <br /> STORM WATER MANAGEMENT PLAN <br /> CDPS GENERAL PERMITS <br /> FOR <br /> INTRODUCTION AND PROJECT DESCRIPTION <br /> The CJK SPECIALITY AGGREGATES Stormwater Management Plan(SWMP) is prepared in <br /> accordance with the Colorado Department of Health and the Environment(CDPHE)and the Colorado <br /> Division of Reclamation Mining and Safety(CDRMS)processing and Safety criteria. The SWMP is <br /> intended to satisfy the requirements of both the CDPS General Permit for Stormwater Discharges <br /> Associated with Construction Activity (CGP) and the CDPS General Permit for Stormwater Discharges <br /> Associated with Metal Ore processing Operations (MMGP). The constructed Engineering Control <br /> Measures(ECMs)outlined in the SWMP includes,but is not limited to this narrative SWMP Drainage <br /> Plan,The operator will file a Notice of Intent for coverage under the CGP for its initial aggregate <br /> processing corrective action and construction activities, including but not limited to the construction <br /> activities identified in its Construction Plans,and will file a Notice of Intent for Coverage under the <br /> MMGP for the aggregate processing operations set forth in CJK SPECIALITY AGGREGATES <br /> processing Permit Application.) Thereafter,the operator will continue to implement its SWMP to comply <br /> with the MMGP. <br /> The SWMP identifies potential sources that could contribute pollutants to waters of the State, and Best <br /> Management Practices(BMP aka ECM)) that, when implemented,will reduce,or eliminate possible <br /> surface water quality impacts. The plan is designed to be implemented after the permit to ore processing <br /> has been granted by the Colorado Department of Reclamation Mining and Safety(DRMS)The <br /> stormwater management plan for the site summarizes plan assumptions, approach to the design, ECMs, <br /> maps,drawings,drainage basin characteristics,culverts, and ditch design flow calculations for the site- <br /> specific structures. <br /> Site surface water flow is estimated using methods developed by Wilkes, S.G and E.C. King, 1975 <br /> "Procedures for Determining Peak Flows in Colorado",published Soil Conservation Service,U.S. <br /> Department of Agriculture. Input parameters included NOAA 2-, 10-, 25-and 100-year 24-hour Type II <br /> storm rainfall estimates(U.S. Department of Commerce, 1961); curve number(s)(a runoff coefficients <br /> which considers slopes,vegetation types,and densities), management factors(Wilkes et at, 1975); and <br /> drainage area. The rainfall for the rainfall return rates for CJK Aggregates for the 100-year 24-hour <br /> 2 4 inches, and a 10 ear-24-hour return is 1.58 inches. The National Resource <br /> return period is 8 y <br /> Conservation Service(MRCS)runoff Run off Curve Numbers(RCN). The drainage areas points of <br /> interest and associated acreages are describe in Appendix I -Site Drainage Report. <br /> CJK SPECIALITY AGGREGATES <br /> CIK Milling Company,LLC <br /> Leadville,Colorado <br /> Page 4 of 32 <br />