HYDRO26483 - Laserfiche WebLink

Home Browse Search

COLORADO DEPARTMENT OF PUB. HEALTH AND ENVIRONMENT, Water Qe I Control Division Rationale -Page 1, Permit No. CO-0Oall61 III. RECEIVING STREAM • A. Idenriflcaion, Classiftcarion and Standards ldenrificnrion: Discharges to Fish Creek, Segment 136 of the Yampa River Sub-basin of the Upper Colorado River Basin. 2. Classification: Ibis stream segment is classed for the following uses: Reneation, Class l; Aquatic Life, Class 1 (cold); Agricubure. 3. Numeric Standards: Ike standards which have been assigned in accordanre with the abort classifltaations can be found in 3. ~ 0, Classifications and Numeric Standards for the Upper Colorado River Basin (S CCR 1002-8J, as amended September 7, 1993. The following numeric standards which have been assigned in accordanre with tbe above classifications will be used to develop eflluem limitations. Phvsicnl and Bioloeical pH =6.5-9.Os. u. FernlColiform =200/100 m1 /norennic Unionized Ammonia (NH3J, Chronic = 0. 02 mg/P Unionized Ammonia (NHtJ, Acute = 0. 43/FT/FPH/1 (mg/PJ Residual Chlorine (CltJ, Actue/Chronic = 0. 011/0.019 mg/P Morals Criteria Standard Analytica! Method Arsenic (AsJ Acute and Chronic SO ug/P Dissolved Cadmium (CdJ Acute TVS-trout TVS Cadmium (CdJ Chronic TVS TVS Chromium, her (Cr V/J Acute and Chronic TVS TVS (dissolved) Copper (Cu) Acute and Chronic TVS TVS • Iron (FeJ Chronic 1000 ug/P Total Recoverable Lead (P6J Acute and Chronic TYS TVS Manganese (MnJ Chronic 1000 ug/P Total Recoverable Mercury (HgJ Chronic 0.01 ug/P Total Nidrel (Ni) Acute and Chronic TVS TVS Selenium (SeJ Acute 10 ug/P Dissolved Silver (AgJ Acute TVS TVS Silver (AgJ Chronic TVS-trout TVS (IYS =Table Value Standards) Table Value Standards 17YS) refers to Table /!/ ojthe Basic Standards and Merhodoloeies for Surface Water. For the metals listed with TVS standards, three sets of standards may apply depending upon the rereiving stream class cation -those for protection of IJ aquatic life rcre, 2J agricultural use and 3J drinking water use. Table Value Standards for the protection of aquatic life can be divided into two categories -those that art dtpendem upon the stream hardness, and those that an not. Statdards for the protection of agricukural and water supply user arc d! hardness independent. For this stream segment, aquatic life use and agricultural use standards apply. For hardness-dependent metals standards, the numerical value of the aquatic life use based standard will depend upon the combined effluent/rcreiving stream hardness below the discharge poiru. Iht hardness values to be used art those which correspond to the lower 95th percent confldenre limit of the mean hardness value at the periodic !ow flow criteria, as detemtined from a regression analysis of site-specific data. !f data for such an analysis is not awilable, or if a regression analysis is not appropriate, other methods may be used. In this case, there is no paired flow/hardness data amilable for Fish Creek in the vicinity of the Ilventymile Coal Company discharge poim. However, hardness data alone arc available for Twentymile Coal Company station SW4, . lornted below omjall AOI. Ike mean hardness of 271 mg/P at this station, using data for the period between October, 1992, and June, 1994, will be used to calculate hardness~ependem standards.