2009-05-19_REVISION - M1980055HR (28)

Home Browse Search

COLORADO DEPARTMENT OF PUBLIC HEALTH & ENVIRONMENT - Water Quality Control Division Rationale - Page 3 Permit No. COR-040000 H. BACKGROUND The federal Clean Water Act requires that industrial stormwater discharges be regulated under the National Pollutant Discharge Elimination System (NPDES) program. (Note: the Colorado Program is referred to as the Colorado Discharge Permit System, or CDPS, instead of NPI)ES.). The Water Quality Control Division (the Division) has stormwater regulations (S CCR 1002-61) in place. These regulations specifically include mining operations where stormwater has come into contact with any overburden, raw material, intermediate products, byproducts, finished products or waste products, as industrial facilities which must obtain stormwater discharge permits. Other federal regulations, specifically 40 CFR subchapter N (mining operations are covered in sections 434, 436 and 440), were developed to control the quality of discharges from mills and mine drainage. Mine drainage is water drained, pumped, or siphoned from active mining areas. This water is generally classified as 'process water" and is covered under the pre-existing Colorado Discharge Permit System (CDPS). A. General Permits The Division has determined that the use of general permits is the appropriate procedure for handling most of the thousands of industrial stormwater applications within the State. 1. Types ofGenerdl Permits: This general permit covers stormwater discharge from metal mining operations. Other stormwater general permits are available for light industry, heavy industry, auto recycling, sand and gravel mining (and other nonmetallic minerals), construction activities, and coal mines with surface discharge only. 2. Temporary General Permit Coverage: Coverage of most facilities under general permits is the fastest, most efficient means of implementing the program in the short term. However, as described elsewhere is this Rationale, general permit coverage may not be appropriate in the long term for some mining operations with a higher stormwater pollution potential. Therefore, the • Division reserves the right to temporarily cover stormwater discharge from mining activities under a general permit, even though individual permit coverage may be more appropriate. Certification of these activities under a general permit does not in any way infringe on the Division's right to revoke that coverage and issue an individual permit or amend an existing individual permit, when such specialized facility attention 'is required. B. Permit Requirements This permit does not require submission of effluent monitoring data in the permit application or in the permit itself. The narrative requirements include prohibitions against discharges of non-stormwater. They require dischargers to control and eliminate the sources of pollutants in stormwater through the development and implementation of a Stormwater Management Plan (SWMP). The plan must include Best Management Practices (BMPs), which may include treatment of stormwater discharges along with source reduction. Discharges of stormwater associated with mining operations must meet all applicable provisions of Sections 301 and 402 of the Clean Water Act. These provisions require control ofpollutant discharges to a level equivalent to Best Available Technology Economically Achievable (BAT) and Best Conventional Pollution Control Technology (BC7), and anymore stringent controls necessary to meet water quality standards. As per EPA, a fully implemented SWMP will constitute` compliance with BAT and BCT. It is believed that BMPs can be adequate to control water quality impacts. If the Division determines that additional requirements are necessary, they may be imposed as follows: 1) at the renewal of this general permit or through an industry- special general permit if the issue is categorical; 2) through direction from the Division based on the implementation of a TMDL if the issue is watershed-based; or 3) if the issue is site-specific, through guidance from the Division, based on an inspection or SWMP review or through an individual permit. t •