Laserfiche WebLink
The discharge volumes from these storm events are calculated in Appendix G-1. Map G-1 <br /> summarizes the drainage basins. All runoff calculations were conducted using the TR-55 <br /> method developed by the Natural Resource Conservation Surface. Soil Hydrologic Group is <br /> taken from the soil report in Appendix 1-1. Time of concentration is calculated from site <br /> topographic data. Storm date is from NOAA. <br /> 7. Groundwater <br /> Groundwater will not be interacted with at the Hayden Gravel Pit. Groundwater is expected to <br /> be well below mining as none was encountered during exploration. If any is encountered during <br /> mining, it will be covered, and the mining depth will be adjusted to two feet above the level it is <br /> found. <br /> 8. Water Related Permits <br /> United Companies has already obtained the necessary permits regarding water for the <br /> operation. These permits are listed below. Some amendments may be required for these <br /> permits. Copies of any new permits will be provided to the Division after they have been <br /> acquired. <br /> • Stormwater Management Plan (will be modified following approval of this amendment) <br /> • Colorado Department of Public Health and Environment (CDPHE) Stormwater <br /> Discharge Permit (currently in place, will be modified to add outfalls at new pits) <br /> 8.1 . Water Rights <br /> No water rights are owned or are necessary for the operations at the Hayden Gravel Pit. Mining <br /> should not impact any existing water rights as groundwater will not be interacted with. Water will <br /> be purchased as needed to supply operations. <br /> 9. Water Consumption and Source <br /> The primary consumptive water use for the Hayden Gravel Pit is for dust control. It is also <br /> consumed in smaller quantities for processing and for concrete/asphalt production. Water for <br /> these uses will be bought from a local supplier and trucked on site. The operation has <br /> historically bought water from the Town of Hayden and Herrod Industries in Craig, CO. <br /> Table G-6 summarizes the estimated water consumption for the operation for various uses <br /> based on historic water use. The expansion should not cause any drastic changes to the typical <br /> water consumption at the operation. <br /> Table G-6 Water Consumption <br /> Hayden Gravel Pit <br /> December 2022 G-4 Lewicki&Associates <br />