Laserfiche WebLink
Ralston Quarry Seepage Analysis <br /> Page 2 of 2 <br /> July 24, 2019 <br /> x10E-5 cm/sec was used in the model which resulted in a calculated inflow of 143 gpm. Using <br /> the State Engineer's design standard the allowable inflow was determined to be 167 gpm <br /> (based on a perimeter of the pit of 10,178 feet, a depth of the pit from ground surface of 94 <br /> feet, and the area of the bottom of the pit of 2,312,997 square-feet). The results of the <br /> model indicates that groundwater seepage at the site is below the design standard referenced <br /> in the 1999 SEO Guidelines. Therefore, Brierley concluded that there is no ground water <br /> source known to exist within or outside the quarry mine that could be exposed at the site or <br /> in excess of the design standard referenced in the 1999 SEO Guidelines. <br /> Based on the seepage analysis provided, we found that the Applicant satisfied the DRMS <br /> requirement of technical revision AM4 and therefore a SWSP or well permit is not required for <br /> the site. However, in order to ensure the seepage into the quarry mine remains below the <br /> design standard referenced in the 1999 SEO Guidelines, all water inflow and outflow from the <br /> boundaries of the pond and change in storage must be accounted for on a monthly basis and <br /> provided to the division engineer upon request. If stormwater runoff is intercepted by this <br /> mining operation and is not diverted or captured in priority, the quarry mine must meet the <br /> requirements of a storm water detention and infiltration facility as defined in section 37-92- <br /> 602(8), C.R.S. Otherwise, the operator will need to replace depletions resulting from all out- <br /> of-priority storage through either a court approved augmentation plan or SWSP approved by <br /> the State Engineer. Note that releases to the stream may require a discharge permit from <br /> CDPHE-WQCD. <br /> Water shall not be impounded in the quarry mine except pursuant to lawful diversions <br /> allowed by statute or decree. At all other times, all inflow of water into the reservoir from <br /> any source, including precipitation and groundwater inflows shall be removed to prevent <br /> illegal storage of water. <br /> Please contact me at 303-866-3581 ext. 8246 if you have any questions. <br /> Sincerely, <br /> 4 acu'G <br /> loana Comaniciu, P.E. <br /> Water Resource Engineer <br /> Ec: Corey Deangelis, Division Engineer, Water Division 1 (Corey.DeanQelisCstate.co.us) <br /> Jason Smith, District 7 Water Commissioner (Jason.Smith2Cstate.co.us) <br /> Eric Scott, DRMS (Eric.Scott@state.co.us) <br />