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Stormwater Manae<ment Plan 1228/97 • 3.0 INDIVIDUAL SWMP SITE PLANS The Focus of each site plan is to temporarily stabilize each of the sites during mining and plant operations. Various Best Management Practices (BMP's) are summarized in the individual site plan narratives. Details of the BMP's aze contained in an attached Appendix. The records obtained from the U.S. Weather Service via their Internet site at the National Oceanic and Atmospheric Administration (NOAA) File Transfer Protocol (FTP) site in the file "datasel.html" identified the daily precipitation for the last 43 years. The highest value observed in Pueblo was slightly over 3.0". Additional NOAA data sources west of Pueblo near Parkdale indicate that 2.3" is a maximum 24 hour storm event. Storm water events up to 100 year events were evaluated by Agile's contract engineering firm when considering water shed impacts and crossing designs, storm water berm/pond designs. The plan assumes a maximum rainfall of 3.5" of precipitation in one day. Each of the gravel pit areas will be sloped within a surrounding 100' wide buffer. The plant area elevation will be reduced about 7' within this buffer. Since mining will produce an obvious depth much greater than 3.5", all stormwater precipitated directly into each facility will be retained within the disturbed areas. Percolation tests were conducted at 2 • areas on the gravel bar indicating that water will be absorbed and transmitted at rates in excess of 1.5"/minute. These test results probably explain why no surface erosion features can be found on the gravel baz. The quarries will contain a storm water diversion and retention berm. The diversion berm will limit waters entering mining and plant areas while the retention aspect of the berm will retain the waters at elevations below mining and plant operations to settle any sediment carried by any water from the mining and plant areas. Massive water shed studies were conducted by Verkaik and Associates to determine appropriately sized pemlanent storm water ponds and berms whose plans are enclosed. A similar percolation test was performed in the granite plant area with the same results. Detailed long-term stabilization objectives for the Parkdale Project site are contained in the project's Mining and Reclamation Plans. Long-term stabilization of the sites are shown on the Reclamation Plan Maps. Material, equipment, and technique specifications for ripping, seedbed material sampling, seedbed preparation, seeding, and mulching are presented in the Reclamation Plan prepared by Azurite [nc., Cedar Creek Associates, Inc., Environmental Management Services Company, and Verkaik Associates Engineers. • Page 6