Laserfiche WebLink
<br />COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division <br />Rationale - Page 6 Permit No. CO-0043168 <br />1. Water Ouality Standard Based Effluent Limitations: (Continued) <br />A summary of the mass balance calculations are shown and discussed <br />in Table VI.2 below. <br />For the discharge, the values for Q1, QZ and Q3 are the same in all <br />of the calculations for water quality limited parameters and are: <br />Acute Flow Values <br />Q1 0.02 cfs (or 0.013 MGD) <br />QZ 0.334 cfs (0.216 MGD) <br />Q3 0.352 cfs (0.229 MGD) <br /> Chronic Flow Values <br />Q1 0.02 cfs (or 0.013 MGD) <br />QZ 0.334 cfs (0. 216 MGD) <br />Q3 0.352 cfs (0. 229 MGD) <br />Although there are two flow limitations specified in the permit <br />(0.576 MCD for the first three months of discharge and 0.216 MGD <br />for the period following the first three months of discharge), the <br />WQS-based limits are only based upon the later flow (0.216 MGD). <br />This is because the WQS-based limits for the two flow levels are <br />considered very comparable (for example, the zinc limit is 0.76 <br />mg/1 when based upon a discharge flow of 0.576 MGD, and is 0.78 <br />mg/1 when based upon a discharge flow of 0.216 MGD). <br />Values for M1 an3 M; vary depending on the applicable water quality <br />standard (M3) and the background stream quality data (M1). The <br />water quality stzndards for the parameters limited in this permit <br />are shown in Table VI-2 as follows, along with the calculated <br />effluent limitations (M2). The individua'_ WQS calculations are <br />included ir. the permit file. <br />Table VI.2 -- Summary of Mass Ealance Calculations <br />Parameter <br />(mg/1) <br />Uostream <br />Background <br />Concentration <br />(Ml) J <br />Stream <br />Standard <br />Acute/Chronic <br />(M3) <br />WQS <br />Effluent <br />Concentration <br />(M2) <br />Total Ammonia, as N <br />Total Boron <br />Total Re:;idual Chlorine <br />Free Cyanide <br />Total Nitrite, as N <br />Total Sulfide, as H2S <br />Dissolved Arsenic <br />Dissolved Cadmium <br />Diss. Trivalent Chromium <br />Diss. Hexavalent Chromium <br />Dissolved Copper <br />Total Recoverable Iron <br />Dissolved Lead <br />Total Recov. Manganese <br />8.55 J 9.1 <br />0.75 0.79 <br />0.011/0.019 J 0.012/0.020 <br />0.005 a/ 0.0053 <br />0.050 0.053 <br />0.002 0.0021 <br />0.15/0.36 J 0.38/0.38 <br />0.0018/0.0079 J 0.0019/0.0083 <br />0.34/2.9 J 0.11 <br />0.011/0.016 J 0.012/0.017 <br />0.064 .0.067 <br />5.4 5.7 <br />0.0093/0.26 J 0.0099/0.27 <br />1.0 1.1 <br />