2010-08-02_REVISION - M1977300 (25)

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Environmental Protection Plan, Schwartzwalder Mine 11-3 • • Table 11-2. Proposed New Discharge Permit Effluent Limitations Effluent Limitations Maximum Concentrations Monitoring Requirements Effluent Parameter 30-Day Average 7-Day Average Daily Maximum 2-Year Average Frequency Sample Type Effluent Flow (MGD 0.288 Report Continuous Recorder pH su 6.5-9 5 Days / Week Grab COD (mg/1 100 200 Weekly Composite TSS, effluent (mg/1) 20 30 3 Days /Week Composite Oil and Grease (mg/1) 10 5 Da s/Week Visual TDS (m l) Report Report Quarterly Composite As, TR I 0.02 2 Days / Month Composite Cd, PD 1 Report Report 2 Days / Month Composite Cr+3, TR (µg/1 50 0.75 2 Days / Month Composite Cr+6, Dis ( Report Report 2 Days / Month Composite Cu, PD ( g/1) 12 18 1.8 2 Days / Month Composite CN, WAD 1 5 0.85 2 Days / Month Composite Fe, Dis 1 300 45 2 Days / Month Composite Fe, TR (µg/1 Report Report 2 Days / Month Composite Mn, Dis (µg/1 50 7.5 2 Days / Month Composite Hg, Tot ( 1) Report 2 Days / Month Composite Ni, PD ( g/1 Report Report Report 2 Days / Month Composite Se, PD l Report Report Report 2 Days / Month Composite A g, PD 1 0.13 3.5 0.02 2 Days / Month Composite U, TR ( g/1) 30 22 2 Days / Month Composite Zn, PD ( ) Report Report Report 2 Days / Month Composite B, Tot (m 1) 0.75 2 Days /Month Composite Chloride (mg/1 250 54 2 Days / Month Composite Fluoride (mg/1) 2 2 Days / Month Composite Sulfate (mg/1) 250 131 2 Days / Month Composite Sulfide (mg/1 Report Report 2 Days / Month Composite Radium 226+228 Ci/I 5 2 Days / Month Com osite Radium 226, dis 3 10 2 Days / Month Com osite Radium 226, total 10 30 2 Days / Month Composite Thallium 1 0.24 2 Days / Month Composite Antimony I 5.6 2 Days / Month Composite WET. chronic Pime hales Lethality Stat Diff & Quarterly 3 Composites / Test Cerioda hnia Lethality IC25 J IWC Quarterly 3 Composites / Test Pime hales Toxicity Report Stat Quarterly 3 Composites / Test Cerioda hnia Toxicity Diff & IC25 Quarterly 3 Composites / Test (ii) Stream Standards The Colorado Department of Public Health and Environment (CDPHE) Water Quality Control Commission (WQCC) has published in-stream water quality standards for this reach of Ralston Creek. Located in the Clear Creek Basin, Reach 17b includes the "mainstem of Ralston Creek from the source to the outlet of Arvada Reservoir, including Ralston Reservoir and Upper Long Lake" (5CCR 1002-38). Regulation Number 38 (5CCR 1002-38) lists the specific numeric standards for Stream Segment 17b, while Regulation Number 31 (5CCR 1002-31) gives the basic stream standards and methodologies applicable to all state waters. The applicable water quality standards for cold water biota in Ralston Creek Stream Segment 17b are listed in Table 11-4. Acute and chronic standards for metals are based on dissolved concentrations, except where noted otherwise in Table 11-4. The numeric criteria for cadmium, chromium III, copper, lead, manganese, • nickel, silver, uranium, and zinc are hardness dependent, and are calculated according to the following equations: 4109C.100731 Whetstone Associates 6