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f*,1 COLORADO <br /> Department of Public <br /> Health 8 Environment Water Quality Control Division Fact Sheet, Permit No. C00048939 <br /> Data exceeding benchmarks: The renewal permit specifies Corrective Actions (required permittee actions, <br /> documentation and timelines)when the averaged monitoring values for any parameter exceeds the <br /> benchmark. After corrective action is taken, the permittee is required to continue quarterly monitoring for <br /> 4 additional quarters, and calculate average monitoring values. If the data from the additional monitoring <br /> does not exceed the benchmarks, permittees may reduce benchmark monitoring frequency to once-per- <br /> year as previously described. If this data from the additional monitoring exceeds the benchmarks, the <br /> permittees must again perform Corrective Actions and continue quarterly sampling. This monitoring <br /> framework requires continued quarterly sampling only for those facilities that continue to exceed <br /> benchmarks in stormwater samples. <br /> Visual Monitoring: The division considered requiring that the permittee conduct quarterly visual <br /> examinations of stormwater discharges for the presence of color; odor; clarity; floating solids; settled <br /> solids; suspended solids; foam; oil sheen; and other obvious indicators of stormwater pollution. These <br /> assessments of stormwater discharges are an inexpensive and valuable part of the stormwater management <br /> and planning process that may, for some discharges, provide information not provided by sampling (e.g., a <br /> sheen that some sampling would not identify). <br /> However, the benchmark sampling required at outfall 002 will provide the division with sufficient data to <br /> verify the reasonable potential conclusions identified in the fact sheet with the exception of oil and <br /> grease. Compliance with the technology-based effluent limitations (PBEIs)and other terms and conditions <br /> of this permit (such as control measure requirements, inspections, and documentation requirements)will <br /> adequately control stormwater discharges for oil and grease and other pollutants at all outfalls comprised <br /> of solely of stormwater as authorized by this permit. Therefore, the renewal permit does not contain <br /> visual monitoring requirements. <br /> B. Control Measures <br /> This permit section clarifies the divisions expectations for the control measures implemented at the facility. <br /> The division uses the term "control measure" instead of "Best Management Practices or BMP" throughout the <br /> renewal permit. This term has a broader range of meaning than BMP, as it includes both BMPs and "other <br /> methods", and as such, better describes the range of pollutant reduction practices a permittee may <br /> implement. The division does not mandate specific control measures, but leaves this decision to the permittee <br /> who is familiar with the facility characteristics and pollutant sources. <br /> The division added the requirement to retain installation and implementation specifications with the <br /> Stormwater Management Plan for each control measure used by the permittee to meet the effluent limitations <br /> contained in the permit. The division requires this in other CDPS permits and finds that it is necessary to <br /> ensure that permittees select, design, install, implement, and maintain control measures that are appropriate <br /> for specific pollutant sources. The division also added the requirement that permittees maintain control <br /> measures in effective operating condition so that they can function as intended, and correct control measure <br /> deficiencies with due diligence. <br /> The division expects that, in many cases, the control measures implemented by the permittee to meet the <br /> DRMS requirements may also be adequate to meet the terms and conditions of this renewal permit. If the <br /> division determines that this is not the case, e.g., during a division compliance inspection, it will state the <br /> reason that the existing control measure is inadequate, or additional control measures required. <br /> C. Inspections <br /> Quarterly field inspections of all drainage areas contributing runoff to the outfalls referred to in this part are <br /> required in the renewal permit. One inspection must be conducted during a run-off event, and deficiencies <br /> must be documented and corrected. Quarterly inspections and documented corrective actions are a useful <br /> means for permittees to evaluate the effectiveness of implemented control measures, and correct any <br /> deficiencies; and the run-off event inspection is a particularly useful tool for assessing control measure <br /> performance. <br /> Page 13 of 17 <br /> 4300 Cherry Creek Drive S.,Denver,CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe/wgcd * n <br /> John W.Hickenlooper, Governor I Larry Wolk.MD.MSPH, Executive Director and Chief Medical Officer CO <br /> SW/ T/:I. Sti:9t pautre3s <br />