COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division
<br />Rationale -Page /5, Pernut No. CO-0043648
<br />Table VI-4 Final Effluent Limits, Effective July ]. 7996. jot Discharge Points:
<br />004A Springs forming Arequa Gulch within Arequa Gulch Rock Storage Area
<br />OOSA Non-Spring Seepage from Aregrta Gulch Rack Storage Area (does not include stormwater), At
<br />Disdtarge Into Diversion Ditch Surrounding the Valley Leach Facility
<br />006A Non-Spring Seepage from Aregrra Gulch Rack Storage Area, Mired Wrth Slormwater, At Discharge
<br />From Diversion Ditch to Anqua Gulch Below the Valley Leach Facility
<br />Discharge limitations
<br />Maximum C(incentrations
<br />Effluent Parameter 30-Dny:Avg. 7:DayAvg. Datly Max. Rgionq!<.
<br />Flow, MGD Report N/A Report Discharge Assessment
<br />pH, su (minimum-maximum) N/A N/A 6.5-9.0 Water Quality Standards
<br />Total Hardness, mg/! Report N/A Report Discharge Assessment
<br />Ammonia, Total, mg/l (lbs/dayJ Not Required Until C}~anrde Removal Process Is Begun
<br />Cyanide, WAD, mg/! (!bs/day) Report (Report) N/A 0.030 (Report) Water Quality Standards
<br />Aluminum, PD, ug/! (!bs/day) Report (Report) N/A Report (Report) Water Quality Standards
<br />Arsenic, PD, ug/! (lbs/day) 50 (Report) N/A 50 (Report) Water Quality Standards
<br />Cadmium, PD, ug/! (!bs/da}~) 3.4 (Report) N/A l9 (Report) Water Quality Standards
<br />Copper, PD, ug/! (Ibs/day) 39 (Report) N/A 65 (Repon) Water Quality Standards
<br />Chromium, ill, PD, ug/l (!bs/day) 50 (Report) N/A 50 (Report) Water Quaiiry Standards
<br />Chromium, Vl, Diss, ug/1 (Ibs/day) l! (Report) N/A !6 (ReponJ Water Quality Standards
<br />/ton, TR, ug/l ([bs/day) 1,000 (Report) N/A Report (ReponJ Water Quality Standards
<br />Lead, PD, ug/l (lbs/day) 28 (Report) N/A Report (Report) Water Quality Standards
<br />Manganese, TR, ug/1 (!bs/day) 1,000 (Report) N/A Repon (ReponJ Water Quality Standards
<br />Mercury, Total, ug/l (!bs/day) 0.01 (Report) N/A Report (Report) Water Quality Standards
<br />Nickel, PD, ug/l (lbs/day) 274 (Report) N/A Report (Report) Water Quality Standards
<br />Silver, PD, ug/I ([bs/day) 0.8 (Report) N/A 22 (Report) Water Quality Standards
<br />Zinc, PD, ug/l (!bs/day) 343 (Report) N/A 379 (Report) Water Qua[iry Standards
<br /> TSS Limit Aonlies f)nfv Tn Dischar¢e Poin~ GL~SA
<br />TSS, mg11 20 N/A 30 Effluent Guidelines
<br />WAD Wenk Acid Dissocinb[e
<br />PD Potentially Di,crolved
<br />TR Total Recovernblr
<br />Diss Dissolved
<br />Note.• La'mits for discharge point OOSA apply during any period after at 24 hours have passed since the last rain event or
<br />since snowmelt in any urea tributary to this point has ceased. Limits for point 006A apply during any rain or
<br />snowmelt events which produce visible runoff in the diversion channel, up until 24 hours after such precipitation
<br />events have ceased.
<br />2. Calculation of Water Quality Based Effluent Limitations
<br />Far thr water quality based effluent limitations listed in the preceding mbles, n mass balance equation was
<br />used to dererrnine the effluent concentrations that would not violate the allowable in-stream concentrations
<br />defined by the WQ standards (except in the case of pH, where the limits are set directly from stream
<br />stnrulnrds or effluent regulations without using a mass balance approach).
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