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COLORADO DEPARTMENT OF PUBLlC HEALTH AND ENVIRONMENT, Water Quality Control Division
<br />Rationale -Page 7, Permit No. CO-0027!54
<br />pH, s. u. (Minimum-Maxinturrt) N/A 6.5-9.0 Water Quality Standards
<br />Electrical Conductivity, umho/crn Report Report CO Salinity Regulations
<br />Cadrniurn (PD), mg/0
<br />through December 31, 2002 Report
<br />02
<br />0 Report
<br />0
<br />2 Interim Monitoring
<br />W
<br />beginning January !, 2003 .0 .01 ater Quality Standards
<br />Copper (PD), m /P
<br />through Decem~er 31, 2002
<br />Report
<br />27
<br />0
<br />Report
<br />0
<br />Interim Monitoring
<br />beginning January 1, 2003 .0 .044 Water Quality Standards
<br />/tort (I7t), mg/C
<br />tltrougit December 31, 2002 Report Report Interim Monitoring
<br />beginning Jnnuarv 1, 2003 1.0 Report Water Quality Standards
<br />Manganese (PD), mgg/!'
<br />through December 31, 2002
<br />Report
<br />Report
<br />/nrerint Monitoring
<br />beginning Jnnuarv 1, 2003 2.467 6.524 Water Quality Standards
<br />Silver (PD), mg/E'
<br />through December 31, 2002 Repot! Report /nterim Mortitorirtg
<br />beRirtninR January 1, 2003 0.0004 0.0/1 Water Quality Standards
<br />' Tltese parameters are primary tiruirations and may be exempted under certain condkions. See Part LA.4. of the perrrr
<br />of Proof Requirements.
<br />Table V-3 -- Effluent Limitations for Outfalls 002, 004, 006, and 008
<br />Discharge Limitations
<br />Maximum Concentrations
<br />Parameter 30-Day Avg. Daify Max. Rationale
<br />Flow, MGD Report Report Monitor Flow
<br />Total Suspended Solids, mg/F* 35 70 Federal Effluent Guidelines
<br />Settleable Solids, mf/!* NA
<br />Oil and Grease, ntg/2 N/A
<br />pH, s. u. (Minimum-Maximum) N/A
<br />Electrical Conductivity, umho/cm Report
<br />Iron (Torn!), mg/?* 3.5
<br />These parmneters are prinmry limimtions and may be
<br />of Proof Requirerrrents.
<br />2. Discussion of Effluent Limitations
<br />0.5 Federal Effluent Guidelines
<br />/0 State Effluent Regulations
<br />6.5-9.0 Water Quality Standards
<br />Report CO Salinlry Regulations
<br />70 Federal Effluent Guidelines
<br />a) Water Qua/iN Standards (WOSI Based Effluent Limitations Analysis: /n order to calculate water quality
<br />stmrdnrd based /in:its for this facility, nn analysis was performed by the Division. /n most situations, a mass
<br />balance equation is used to determine the effluent concentrations that would not violate the allowable in-
<br />strenm concentrations defined by the WQ standards (except in the case of pH, where the limitations are set
<br />directly from stream standards or effluent regulations without using a mass balance approach).
<br />These water quality bused limitations have been developed jar outfalls 001, 003, 005, 007, 009, and 020
<br />because these sir outfalls contain mine water and/or spoils spring water and have continuous discharge or the
<br />potential for continuous discharge (as opposed to surface runoff-only outfalls that normally discharge during
<br />high stream flow), thrts they nary impact the classified uses of the receiving waters. Appendix A to this
<br />ratiorra[e describes the process used to develop these limits. As shown in Table A-11 of Appendix A,
<br />cad»tiurrt, copper, iron, manganese, and silver are limited for t/tese outfalls.
<br />None ojthese five parameters except iron have previously been applied to outfalls 003 and 009, and the
<br />previous iron limitations were 3.5/7.0 mg/~ based on federal effluent guidelines. However, recent years'
<br />monitoring data have shown that routine discharge has occurred from these nvo discharges; outja(1 003
<br />discharged every quarter and outfall 009 discharged 9 of t/te 24 quarters. Further, these outfalls are
<br />described as discharging surface runoff and spoils spring water. Spoils spring water lras been found to be
<br />similar in nature to mine water. Since surface ntnoff is not routine, it can be inferred that spoils spring
<br />water is the reason for the routine discharge. Thus, t/:e parameters limited for these outfalls needs to
<br />regulate the potential pollutants being discharged. As s/town In Appendix A, nl! Jive outfalls that disc/rarge to
<br />Foidel Creek have the same [imitations while outfal1009, which discharges to Middle Creek has different
<br />limitations.
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