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The following finding is required in order to allow Powderhom Coal Company to conduct <br />surface coal mining operations within 100 feet of the Colorado River: <br />The Division approved surface or underground mining activities within 100 feet of a <br />perennial stream or stream with a biological community. This decision was based on a <br />finding that the original stream channel will be restored, water quality and quantity shall <br />not be adversely affected, and appropriate riparian vegetation will be reestablished. The <br />buffer zone variance is granted for the area located under the conveyor system and located <br />neaz the loadout (4.05.18(1)). <br />Probable Hydrologic Consequences <br />The protection of the hydrologic balance is outlined in Volume 5, Tab 19 of the permit <br />application. This permit section addresses possible impacts due to mine subsidence, possible <br />impacts due to mine water discharge, and effects related to surface disturbance. Possible <br />hydrologic impacts due to construction of coal refuse piles are also discussed in this document. <br />The permittee's statement of hydrologic effects has been reviewed by the Division for <br />compliance with Rule 4.05.1 and 2.05.6(3). <br />Surface Water <br />Surface Water Ouantity <br />Possible hydrologic impacts on quantities of surface water due to the Roadside and Cameo <br />Mines include impacts to: <br />1. Quantity of flow in the Colorado River, <br />2. Quantities of flow in Rapid and Cottonwood Creeks, <br />3. Surface seeps and springs above the Roadside Mine, <br />4. Dams and reservoirs above the Roadside Mine, and <br />5. Impacts due to water consumption by mine operations. <br />The permittee states that approximately 0.47 cfs of mine discharge water is added to the <br />Colorado River, increasing the flow by an average of 0.01 percent. Most of the water <br />pumped from the Roadside North Portal ultimately comes from the Colorado River by way <br />of aquifers which subcrop below the alluvium of the river. In addition, the water pumped <br />from the Roadside Mine would naturally contribute to base flows in the Colorado River <br />through aquifer dischazges to the river. Therefore, the mining operation should have an <br />insignificant effect on the quantity of water in the surface and groundwater systems of the <br />Colorado River. <br />2. Monitoring of both Cottonwood and Rapid Creek since 1985 has shown minimal <br />disturbance due to subsidence. Both creeks have infrequent flow patterns. Cottonwood <br />Creek, although a major tributary to Rapid Creek, is dry by late summer. Rapid Creek is <br />intermittent in nature. Where surface cracking was observed, within a yeaz the crack was <br />refilled with sediment from the creek channel. Minor ponding has also been observed to <br />have taken place in the subsided azeas. This ponding was for a relatively short period and <br />30 <br />