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Black Obsidian Pit—Permit M-1987-026 <br /> 112c Conversion Application <br /> Rule 6.4.7 <br /> Exhibit G <br /> Water Information <br /> The site is located in a dry upland setting. There are no aquifers, perennial streams or ditches that will <br /> be affected. The project has no water requirements. <br /> The site is on gently rolling rangeland, and includes several ephemeral drainages, which do not typically <br /> flow except after significant precipitation events. <br /> All drainage from affected land in the existing operation reports to a sediment pond below the entrance <br /> to the permit. It is unlined and percolates into the surface. Drainage from the expanded operation will <br /> report to a sediment pond to be constructed immediately below the toe of the quarry pad (in Phase 1). <br /> Due to the nature of the obsidian and the below-grade quarry floor, the quarry does impound a small <br /> amount of water. Prior to initiating activities in the quarry,the operator dewaters the limited amount of <br /> impounded water, which reports to a nearby unlined sediment pond. Effluent from this pit does not <br /> generate or carry appreciable amounts of sediment, and the existing pond therefore retains its design <br /> capacity; the new sediment pond will receive effluent from the same obsidian deposit and very little <br /> sediment is expected to be transported to that pond also. <br /> The operator has a CDPHE—WQCD stormwater management permit. Stormwater and sediment <br /> controls to be used onsite include: existing sediment pond below the Phase I quarry pad, earthen berms <br /> or silt fence to divert or direct surface flows to proper control structures, appropriate slope gradients on <br /> pit slopes and stockpiles to reduce erosion,timely revegetation on affected surfaces. <br /> Please see the stormwater and sediment controls shown on the map in Exhibit C. <br />