Storm water runoff is water from rain or snowmelt that does not immediately infiltrate into the ground, and instead flows through natural or man-made conveyance or storage systems. Stormwater runoff volume is greater in areas with high proportions of impervious surfaces (e.g., paved roads, buildings, parking lots, etc.). Runoff from areas where industrial activities are conducted can contain pollutants when facility practices allow exposure of industrial materials or activities to stormwater. To regulate the amount of pollutants entering Colorado Waters, the Colorado Water Quality Control Act mandates that certain types of industrial activities that discharge stormwater to state waters must obtain coverage under a Colorado Discharge Permit System (CDPS) permit issued by the Colorado Water Quality Control Division.