Laserfiche WebLink
<br />COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division <br />Rationale - Page 5 Permit No. CO-0043168 <br />A. Effluent Limitations (Continued) <br />Table VI-1 -- Effluent Limits for Outfall 001 <br />Parameter Limit Rationale <br />Flow, MGD 0.216/0.576 JJ Mass Balance <br />TSS, mg/1 30/45 J State Effluent Regulations <br />pH, s.u. 6.5 - 9.0 J Water Quality Standards <br />Oil and Grease, mg/1 10 d/ State Effluent Regulations <br />Pot. Dis. Cadmium, mg/1 0.0019/0.0083 e/ Water Quality Standards <br />Potentially Dis. Copper, mg/1 0.068 ~ Water Quality Standards <br />Total Recoverable Iron, mg/1 5.7 a/ Water Quality Standards <br />Potentially Dis. Lead, mg/1 0.0099/0.27 J Water Quality Standards <br />Total Recov. Manganese, mg/1 1.1 ~ Water Quality Standards <br />Total Mercury, mg/1 0.00001 J Water Quality Standards <br />Pot. Dis. Silver, mg,~l 0 .00023/0.0062 e/ Water Quality Standards <br />Total Zinc, mg/1 0.75/1.5 ~ BPT/BAT Federa l Regulations <br />Whole Effl. Toxicity, Acute SOX/IWG-94.3X J See Discussion, Sec. VI.B.S <br />Whole Eff~l. Toxicity, Chronic Report a/ See Discussion, Sec. VI.B.S <br />a/ 30-Da;~ Average e/ 30-Day Average/Daily Maxi mean <br />•b/ 30-Day Average/7-Day Average J 0.576 MGD limit aaplies for first 3 <br />c/ Minimum-Maximum months of discharge; 0.215 MGD limit <br />d/ Daily Maximum for flow is effective following the <br />first three month period. <br />Pot. Dis. - Potentially Dissolved :oral Recov. - Total Recoverable <br />B. Discussion of Permit Limitations and Conditions <br />1. Water Quality Standard Based Effluent Limitations: A mass balance <br />equation was used to determine the effluent concentrations for <br />those parameters which must be evaluated for this permit and which <br />have assigned water quality standards as specified in segment 13 <br />for Gregory Gulch (except in the case of pH, where the limits are <br />set directly from stream standards). The mass balance equation is: <br />Mz - MaQa - MiQi . <br />Where <br />Qz <br />Q1 - Upstream low flow from Part III.B.1 for Gregory Gulch <br />Qz - Discharge 001 flows from Part II.F <br />Q3 - Combined downstream flow (Q1 + Qy) <br />M1 - Upstream background pollutant concentration <br />Mz - Unknown; effluent pollutant concentration <br />M3 - Water Quality Standard <br />