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COLORADO DEPARTMENT OF PUBLIC HEALTH AND THE ENVIRONMENT, Water Quality Control Division Ratiowle -Page /!, Permit No. CO-0045225 ii. The pond embankment must be constructed to withstand the peak flo}v associated with at least a 10- yr/24-hour storm event, and the downstream face of the embankment mus[ be constructed ojmateria(s lhat are no[ easily eroded. An overflow spilhvay must be provided x~hic/t wil/ protect the structural integrity of the embankment, as well as avoid excessive erosion of the downstream stream bed. iii. Because of the relatively large size of the pond in relation to the drainage area, and because of the likelihood that there will be high injihration rates, it is reasonable to expect that the ability to capture the volume of runoff resulting from a 10-year, 24-hour precipitation event will be continuously maintained without a discharge to surface waters. iv. No discharge from the lower pond is allowed except as fo!lows.• a) Overflow releases (the pond volume being exceeded) are allowed; however, the permiaee must take a[! reasonable stens to minimize the amount of overflow, and all monitoring and notification requirements of the permit must be complied with. b) Releases to regenerate the pond's capacity to comain the volume of runoff resulting from a 10- yr/24-hr precipitation event are authorized. The volume of water that may be released is limited to that amoum required to regenerate the capacity to contain the volume of runoff resulting from a 10- year, 24-hour precipitation evem, jot the area tributary to the lower pond. The release must be commenced within a time window of between 24 hours to 48 hours following the end ojthe storm evem which first resulted in the loss of a full 10-year/24-hour storm holding capacity. The release may last jot a maximum of 24 hours. c) Additional discharges are allowed to the extent that the permittee can provide evidence that such discharges were, or will be, accomplished without violation ojwater quality standards in Cripple Creek, without discharge concemrations exceeding federal ELG's, and that the discharge is accomplished wi[hin 24 hours. 2. Haul Road a. The holding capacity of ll:e settling pond below the haul road is just over the volume of runoff resulting from a !0-year, 24-hourprecipitation event. Until commencemem of reclamation of the haul road, the size of the pond in relation to the sue of [he drainage area must be maintained. b. The pond embankment must be consduued to withstand the peak flow associated with at least a 10-yr124- hourstorm event, and the downstream face of the embankment must be constructed of materials that are not easily eroded. An overflow spillway must be provided which will protect the structural integrity of the embankment, as well as avoid excessive erosion of the downstream stream bed. c. Overflow releases (the pond volume being exceeded) are allowed; however, the permirtee mast take al! reasonable steps !o minimize the amount ojovetflow, and all monitoring and notification requirements of the permit must 6e complied with. 3. Crusher Area in Arequa Gulch a. The holding capacity of this pond is over three times the volume of runoff resulting from a 10-year, 24-hour precipitation event. Until all ore is removed and crushing activities cease within the area contributing flow to the pond, the size of the pond nurst be maimained at [east 2 times the volume of runoff resulting from a IO.vear, 24-hour precipitation event.