Laserfiche WebLink
/°`>--^~ <br />CONE ULTIMO <br />~ '• HYDnOLOOIST <br />Charles F. Leaf, P. E. <br />..".7.41LING ADDRESS: <br />447? EAST i,tU LBERRY- 713 <br />FORT COLLINS. COLORADO 80521 <br />T ELEPNONE <br />1303,22,0050 <br />OFFICE: <br />317 SOUTH MELDRUM <br />FORT COLLINS, COLORAUO 80521 <br />DRAIIJAGE PLAN AND DESIGN AND LOCATION OF <br />PHASE I SEDIMENT :tETENTION PONDS <br />AT ORCHARD VALLEY '•1INE <br />by <br />C. ~~. Leaf, P.E. <br />PART_ A <br />• INT40DUCT1^N <br />Leaf (1977) has proposed a drainage plan for Orchard Valley '•1ine, <br />which, if implemented, will provide protection from: (a) the Probab]e <br />"'axilnum Thunderstorm should it occur upstream from the Mine, and (b) a <br />lOC-year storm should it Dcc~.tr on the mine itself. The design and <br />operation of sediment control facilities should take the proposed drain- <br />age plan into consideration. <br />Effluent limitation guidelir~es fot- coal mines require that retention <br />structures for sediment control be designed with a capacity sufficient to <br />contain a 10-year, 24-hour storm event (U.S. EP^-~ Federal Register, 1977). <br />^ccordingly, it is proposed that sediment retention ponds vJith sufficient <br />rapacity to meet These requirements be constructed dovmstream Proln Orchard <br />~~ Valley I'iine. hydrologic analyses, design specifications, and location of <br />these ponc!s are presented in this report. <br />