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ownpetent non-erodible bedrock. If no ang~etent bedrock is encaintered, <br />the trapezoidal channel will be riprapped (see Adderdinn 7-6f-C). Please <br />refer to Edribit 7-7 for the general location of Diversion No. 1. <br />Pond 008 <br />7.his Sedi.IIlPSit Pond 008 modification redesigns the principal dI1d emergency <br />spillways. ~1re elevation of the principal spillway orifice is at <br />elevation 7011.5 and the orifice is 4.7 inches. 'rile top of the 24-inch <br />perforated riser pipe is at elevation 7015.0. A trapezoid channel, at <br />elevation 7015.8, replaced the emergency spillway function of the ciurent <br />riser pipe. No modifications were done to the embankment. Please refer <br />to Dthibit 7-17C for the redesign of Pond 008 spillways. <br />DESIGN ANALYSIS <br />General <br />Rhe diversion ditch was designed to meet Colorado Mined Lard <br />• Reclamation Division regulations. 'IIze diversion aryl existing Porr1 008 <br />were designed with the following in mird: <br />1. ~e diversion ditch was desicyred to safely convey the runoff <br />from the 10-year, 24-hour storm event. <br />2. Pond 008 had to continue to meet design r~ ~i rements aril all <br />applicable CM[RD regulations as originally designed. <br />3. Pond 008 m~.~-t have a separate principal and emergency spillway. <br />Hydrology <br />'ihe hydrology of the watershed was analyzed utilizing the SIDCAD+ ocanputer <br />program. SID(AD+ is an enhanced PC version of the SIDIMC7r II c:rnyxrter <br />program. Adderdiun 7-6f-A contains a listing aryl description of the <br />SIDCAD+ input variables. in performing this analysis, the characteristics <br />of the minesite aryl reclamation procedures, along with on-site sediment <br />wntrol procedures were considered. A complete listing of the SEDCAD+ <br />inputs aryl outputs for the 10-year aryl the 25-year design storms are <br />provided. <br />• <br />7-6f-2 Revised 08/24/92 <br />