HYDRO21916 - Laserfiche WebLink

Home Browse Search

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENV/RONMENT, Wnrer Qunliry Control Division Rminnnlr - Pnye 12, Permit No. CO-0038776 The /WC for the combined flow from ourjnlls 002 and 004 is 0.63'0, which represents a wnsre+vnrer nmcemrnrion of 0.6:6 e,Qluem m 99.4% receiving srrenm. The lWCjor outfnllc 011 and 012 is 100`90, which represems n wastewnrer concenrrnrion ojl00% efj7uent l0 0% receiving srrenm. However, in addition to the IWC value jot determining whether chronic or acute WET resting regtrirenretrt.c are applicable, the clars~carion ojrhe receiving stream must be considered. According ro the Colnr•ndn Water Ounlirv Contra! Division Biomonitorine Guidance Document, dated July 1, 1993, where the receiving water is classified nquntic life, class 2 wilhout all ojrhe appropriate aguntic life numeric stnrrdnrds, acute WET testing is required, regardless of dilution. Since the receiving water for oufJal! 011, Sylvester Gulch. is classified ac Clacs 2 Aquatic Life are, but does not have all of the appropriate nquntic life numeric standards, the Division has determined that acute WET testing is applicable jot this outfit!! (also sec fo!lowirrg paragraph). 3J Acute WET Limitntians.• Because ojdemonstrnted tosiciry in several permitrees' cool mine rlrnitrnge, the Division belies~es there is reasonable potential for the discharge to interfere with nrtnirrnrerrr ojnpplicnltle water quality classifications or standards. Because of this condition, the acute toxicity limit has been itrcorpornred into the permit oral becomes effective jot outjalfs 002, 004 and Oll itrtntedintely. The pennittee is required to conduit routine monitoring, the results of which are to be reposed its nn LCso. J the LCso < I00% effluent, the permiuee is required to conduct the nurommic compliance schedule n.r identified in Pnn 1. B. of the permit. The Division considers the nquntic life clncsificmion and uses of the receiving water in determiuin,q whether ncure or chronic WET requirements are imposed. Because the receiving water jot outjnll 011 i.c r/n.csified nuumic life clots 2 with nn appropriate aguntic life numeric stardards, ncure requiremerus npplr to this discharge instead ojchronic requirements. Because ojdemonstrnted tosiciry in several pernrinee.c' cool mine drninnge, the Division believes there is rensonn6le potemrin[ jot the discharge to interfere with nrtninnrenr nJ' npplicnble Wnrer quality classifications or statulnrds. On this basis, its required under seniors 6.9.2(SJ of the Rezulntiorts for the Stare Dischnr¢e Permit System, the Division finds there is reasonable pnrerrrirrl jnr the discharge from outfall 011 ro interfere with attnirrmenr of npplicnble water qunlirv clacsificrrrintr.c nr standards. Because ojthis corulition, the acute limirnriorr has been irrcorpornterl irrro the permit. The permirree is required to corulun routine monitoring, the results of which are to be reported its nrr LCso /I the LCso < )Opg, e-(J]uent, the permirree is required ro conduct the nutomntic cornplimrce schedule nc identified irr Pnn 1. B. of the permit. The results of the testing are to be reposed nrr Division npprnverl jormc. 41 Chronic WET Limimtionc: Because ojdemorrsrrated tosiciry in several pennirrees' cool mine drninnge, the Divisimr believes there is reasonable potential for the discharge ro interfere with nnninmenr ajnpplicnble water quality clnssificmions or standards. Because ojthis condition, the chromic tosiciry limit hn.c beeu incorporated imo the permit and becomes ejjenive for outjall 012 immedinrely. The permirree is requiter! to conduit rowine monitoring. The results of the testing are to be reposed on Division approved forms. Thr• pervnirtee wiU be required to conduct n smrisrirnl derivation on the darn, looking jnr any srnristicnlh~ sign~canr difference in tosiciN between the rnntro! and the eg7uent concenrrnrions. This set of cnlrulmintr.c will look nr the full range of tosiciry (lethnliq~, growth cord reproduction). Ijn level of chronic tncicirv occurs, such that there is n smristicn/ly significnm difference in the lethnlirv (nr the 95% mrfrlence level) between the cnrurnl and any effluent concemrntion less than or equal to the hrstrennr Wn.cte Coneennzuion (IWCJ, the permirree will be required m follow the nutomntic compliance schedule idetrrifred in Pnrr l.B rf the permit, ijthe observed toxicity is due to orgmrism lethality. Only esceednnce of the liurimrinrr specifrcrl irr Pnrr LA. !. (eJ will trigger the requirement for conducting the amomnric conrplinuce schedule identified in Pmt 1. B. ojrhe pemrir. ljthe tosiciry is due to differences in the growth ojrhe fathead mimrmvs or the reproduction of the Ceriodnphnin, no immediate action on the port of the permirree will he required. However, this incident, along with aher WET dam, will he evaluated by the Division nor! nuns forur the basis jot reopening the permit and including additional WET limits or other requiremems. 5J Genera( In(nrmnrion: The permirree should rend the WET resting sections ojPnrr 1. A. cord 1. B. ojrhe permit carefully. The permit omlines the test requirements cord the required follow-up actions the perurinee nmst coke ro resolve n tosiciry incideru.