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.., CULUlUUO DE!'n K"!'MEP!!' OF 11FALT11, Water Quality Gmtrol Diviciaa Knnnnufr - !'r{t'r' 7. /'rrrnu Nn. CO~XJ.72(7S Talde Value Standards (/VSJ rejerr !o Table 11/ of the Bacic Standnrdc rend Methodolo+eies (or Sur/nce Wruer. For the rnetnls listed with TVS standards, three sets aj standards may apply depetuling upon the recci ring stream classification -those for protection ojl) aquatic life use, 2J agricultural use and 3J drinking water «.re. Table Value Standards for the protection of aquatic life can 6t divided into two categories -those that arc dependem upon the stream hardness, and those that are not. Standards for the protection ojagricultural and water supply uses are all hardness independem. For both Oak Creek and unnamed tributaries to Trout Creek, aquatic life use, agricultural use and drinking water use standards apply. For hardnessdependem meals standards, the numerical value of the aquatic life use based standard will depend upon the combined ejjltrent/receiving stream hardness below the discharge poim, The hardness values to be used arc those which correspond to the bwtr 95th percent confidence limit of the mean hardness value at the periodic low-flow criteria, as duerntined from a regression analysis of sue-spec fu: data. If data for such an analysis is not atiailable, or if a regression analysis is not appropriate, other methods may be used. Hardness data of Oak Creek, near Oak Creek, Colorado (Station Number 09238000J, was extracted from the EPA STOREY System- The mean hardness of 120 mgR as CaCO3 will be used to ca~ulate hardness dependent standards for both the unnantrd tributaries to Trout GYeek and Oak Creek 7hc following table sunvnnrizes the muaLs standards for all uses. The mast stringem of these will be used in calculating cjfluem limitations. Table 111-1 Metals Standards Sumrturry -Oak Creek, Segment 6 and unnamed tributaries to Trout Creek, Segment 13a, of the Yampa River Sub-basin of the Upper Colorado River Basin (all cortun[ratiotu an ug/q etCr;::~';':~::i':.FSs;;:~ `'J'rr"y::..:~a:':•w:;:~::: vlvtd.Metlitid.: ':' ;.;:Tolal.Reeoveeral Chroiiir Acrue' .. ... zUse:.'.;:.:::..: Agrtcultwnl::Use bfethod . 'Chiuiric Chronic Arsenic 360 ISO SO - 100 Cadn+itun /2.13 1.31 10 10 Copper 21.06 13.82 - 1000 200 Iron 7000+ /000* - 300** - ~ad 128.66 5.00 SO - 100 Manganese - I000* - SO*'F 200 Mercury 2.4 0.0! • 2.0 - - Nickel 1059.3 109.78 - - 200 Selenium /3S 17 - 10 20 Silver 2.78 0.45 SO - - Zinc 136.57 123.7 - 5000 2000 * Aquatic Life Use standards are based upon the dissolved method ojanalysis, except for iron and manganese standards, which are based upon [he total retoverable method, and the mercury standard, w0tich is based upon the total method. ** Drinking Water Use standards are based upon the rota! recoverable method ojanalysis, euept for iron and manganese ,Sandards, which are based upon the dissolved method.