2018-10-22_REVISION - M2008078 (14)

Home Browse Search

The purpose of this Storm Water Management Plan (SWMP) is to address the potential impacts that may affect the quality of storm water being discharged from the project due to the sand and gravel mining operation activities associated with the West Farm Pit. The pit is owned by GP Aggregates, LLC (GP), and is being operated by Prowers Aggregate Operators, LLC. (PAO). The project site is located in the northeast '/4 and the northeast '/4 of the northwest %of Section 33, and the south '/z of the southeast %of Section 28, Township 22 South, Range 46 West of the Sixth Prime Meridian, in Prowers County, Colorado. The total area of the project site that will be disturbed during the sand and gravel mining is 276.42 acres. The existing vegetation includes areas consisting of various agricultural crops (wheat, barley, onions, etc.), native grasses, and sparse weed cover. The areas that are to be mined will be reclaimed as a water storage reservoir with seeding to occur on the side slopes down to the normal operating water surface when the reservoir is full and in areas that are disturbed that are not reclaimed as access roads. Stormwater runoff from the site will be discharged to the Arkansas River. The runoff will be conveyed from the site to a farm ditch that runs west to east along the north property boundary and then north into the river. All stormwater runoff will either infiltrate into the ground onsite with no offsite discharges, or be directed into the active pit area. No discharges will occur from the site during a storm event. Stormwater flows that are directed into the pit will be pumped to Discharge Point 001 after they are treated to remove pollutants. No discharge will occur at Discharge Point 002, however it will continue to be inspected. 1. SITE MAPS (SEE APPENDIX A) 2. DESCRIPTION OF POTENTIAL POLLUTANT SOURCES/MATERIAL INVENTORY The potential pollutant sources that may have an impact on the stormwater quality include sediment from the excavation of sand and gravel and runoff coming down the side slopes of the pit and disturbed areas, sediment from product wash water, fuel from refueling activities, and oil/grease from oil changes and machinery lubrication. A list of facilities and their associated potential pollutant sources is in the following table. Facility Location Pollutant Source Wash Plant West of Phase 12 Sediment/Grease Screen Plant Phase 9 Sediment/Grease Crush Plant Phase 9 Sediment/Grease Conveyor West of Phase 17 Sediment/Grease Mobile Equipment Various Fuel/Oil/Grease Fuel Tank Phase 9 Fuel Portable Sanitary Facility Adjacent to scale house Sewage Trash Dum ster Adjacent to scale house Trash Ditch Crossing Phase 11 Sediment Pea Gravel Stockpile West of Phase 12 Sediment Fines Stockpile West of Phase 12 Sediment Sand Stockpiles Phases 12, 17, South Parcel Sediment Rock Stockpiles Phases 9, 12, South Parcel Sediment Overburden Stockpiles South of Phase 17 Sediment Topsoil Stockpiles Phase 15 Sediment Haul/Pit Access Roads Various- Pit Interior Sediment 1