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[)lYtilOh OF ,ti11,tiERAlS Atrp GFO~O~.Y 15' . Slreimo~r it , Rp,~m 21 i7rnver, f_;:Icr~:'o yO:.U ,, ~,;~;~ ei_~y:or, To: Minerals Progrzm Teams / From: 6ruce Humphries ~ i /J/._L- Date: 0223.'99 J /// Re: Ground ~^later Protectton Pnl cy m • 14a9 -c~a r_.,._ . _; T~-'~T~ ~ F C~~LUI~I`~~ ~ i - •.i , \tl`.Ll,.Af GEOIi~I~ •~ H ;ri `I G•5 ~~' .a,.,rr iirq f. tvn ~,. Use of the policy issues addressc-d in ;his memo and aitachrnent assumes a thorough tamlliaripy vnth f~1LR8 Rul= 3.1.7 and with Regulation No. 41, the Basic Standards for Ground bVater of the Water QuaSty Ccntrol Commission iVdOCC), including the Statements cf Basis and Purpose for these regulations. Enclosed with this memo are three pages from a recent adequacy revievr that highlight some of the precepts for implementation of the ground water regulations. Ncte, in particular. / For a statistical analysis of ambient ground water data using DMG software (DumpStat) a minimum of eight data points are required. Mors data points may be required depending on the variance of the data. Operators should design their ambient characterization sample collection plan such that the timing of sample collection will coincide vrith anticipated seasonal fluctuations of the water table elevation. In shallow ground watedrapid recharge regimes, operators should consider collecting samples following storm events as well as collecting samples during extended dry periods. Chmakc cnndrtions leading up to the sample collection event should be documented by the samples Theso measures will serve to better assure that that the Lull spectrum o1 ground water conditions are analyzed. / Numeric protection levels are established in unclassified areas in accordance with the Interim Narrative Standard of the WQCC. In areas where the lNOCC has established standards, those standards are applied. Ii the DMG establishes numeric protection levels at an unclassified location, and the location is subsequently classified, the WQCC standards will supersede the numenc protection levels. / Ambient ground water quality may be established through the use of down grad~eni wells prior to the introduction of a contaminant source, by using upgradient wells following the introduction of a source, or, for site with extant contaminant sources, using best profess.onal judgement as to what consitutes adequate Information to determine or estimate the ground water quality that existed nn January 31,1993. / If the leading edge of an expanding zone of ground water contamination can be delineated at existing sites, the Interim Narrative Standard does not allow for expansion. cf the zone unless the contaminant levels are below applicable standards, except that the GMG is provided with some flex.bddy to estaLlsh the location nl poiras of compliance as descrifred in Rule 3.1 7(6; / In accordance with Rule 3.1.7(5), permit conditions relative to ground water such as paints of compliance and numenc protection levees maybe established or modified via the technical revision process. The ground water compliance protocol included in the attarhment was develcped by Dr, Jim Stevens; other elements of the policy were developed with Input from Dr. S•,evens, Dr Ha.,rry Posey and Allen Sorenson, EnClCSUre(5) _ ,.r. ujow,'.e .craryroi.ntl w3;?r prF_eC45 dOr: