2000-04-20_GENERAL DOCUMENTS - C1981018

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the White River, which is less than a tenth of a percent of the base flow of the river. Therefore, the expected change in the recharge capacity of the bedrock aquifers would not be a significant impact to the alluvial aquifer. The surface recharge capacity of the alluvial material in Scullion Gulch may be reduced due to the construction of cuts and fills in the portal areas. This disturbed area is small relative to the total area of Scullion Gulch and therefore impacts are expected to be very minor. Due to the presence of Kenney Reservoir, water withdrawal from the White River lagoon will not cause measurable drawdown in the alluvium at the well field site. The quantity of water that will be pumped is less than one percent of the low flow of the river. In summary, the impact of mining on the ground water hydrologic system will be minimal, primarily because of the limited amount of ground water that is naturally found in the area. No significant cumulative hydrologic impacts are expected as a result of the mining activities at Deserado Mine. The Division finds, in accordance with C.R.S. 34-33-114(2)(c) and Rule 2.07.6(2)(c), that the operation has been designed to prevent material damage outside the permit area. III. Topsoil-Rule 4.06 Soils resource information is found in Volume 3, Section II.I, of the permit application. Removal, storage and redistribution of topsoil is addressed in Section V, of Vol. 4, with supplemental information regarding refuse area topsoil and subsoil salvage volumes presented in Appendix IV A, of Section IV, Vol. 4, of the application. Topsoil replacement thickness is presented in Table V-4. Replacement thickness will vary among different facility areas depending on quantity available for salvage. Within the refuse areas, a minimum of 1 foot of topsoil will be replaced, with a minimum non- toxic cover (topsoil plus subsoil) thickness of 30 inches. The operator has committed within Section IV.D.3 of the application, to document topsoil/cover soil material balance as future refuse area development and reclamation occurs, to ensure that sufficient quantities of suitable topsoil and subsoil are being salvaged. Vegetation cover within a significant portion of the acreage to be affected by future refuse area development is dominated by cheatgrass (Bromus tectorum), an aggressive, weedy annual brome. Cheatgrass infestation has been noted on several of the long-term topsoil stockpiles in the refuse disposal area, and has also been a problem on RP-1 permanent reclamation. Cheatgrass is notably less prevalent on subsoil stockpiles (apparently due to seedbank characteristics, or specific soil factors). In order to minimize the potential for cheatgrass establishment and dominance on future reclaimed 28