2011-01-13_REVISION - C1981038 (8)

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Valley Floors. Slope outwash deposits and alluvial deposits located upslope (northwest) of the Fire Mountain Canal did not meet the geologic and water availability criteria, and were given no further consideration. The Alluvial Valley Floor along the North Fork continues downstream, as shown on Map 5-2. The operator will be affecting 11.4 percent of the Terror Creek watershed. This area and the adjacent Terror Creek were not considered in the Division's original Alluvial Valley Floor determination August 20, 1981, but were considered during the review of the permit revision of June 20, 1985. The operator did not identify any areas along Terror Creek that contain significant bodies of alluvium. Most of the deposits are colluvial in nature and confined to the immediate stream channel. The Morrell Camp area contains primarily colluvial deposits and as such does not meet the definition of Alluvial Valley Floors. East and West Roatcap Creek were also not determined to be Alluvial Valley Floors. The sediments are predominately colluvial in nature and are too limited to support agricultural activities. In reviewing the original application, some concerns were raised over whether the applicant proposed to use augmentation water that would normally supply an AVF. The applicant responded by showing that Terror Ditch and West Reservoir waters supply Garvin Mesa and an irrigated area known as "The Basin," both of which are out of the valley floor complex and are not Alluvial Valley Floors. Therefore, the Bowie No. 1 Mine will not be affecting an AVF because of augmentation mitigation. Alluvial Valley Floors - Findings The applicant is eligible for exemption from the requirements of Section 34-3 3 -114(2)(e)(11) of C.R.S. 1973 by virtue of having a permit issued before August 3,1977. This permit was a License to Mine, issued by the Colorado Division of Mines on December 14,1976. This was the primary permit required at the time by Colorado law to operate an underground coal mine. The extent of this exemption must be based upon a demonstration of financial or regulatory commitment to mine before August 3,1977. In this case, mine maps submitted to the Division of Mines and information in the permit application (see "Ground Water Investigation of Steven's Gulch" in Volume 4) provide the appropriate financial or regulatory demonstration. Therefore, the area identified as an Alluvial Valley Floor along the North Fork of the Gunnison River is exempt from the requirements of Section 34-33-114(2)(e)(I). The permit revision areas and the potential Alluvial Valley Floor in adjacent Terror Creek are not covered by the grandfather provision, and will be discussed separately. Although exempted from Section 34-33-114(2)(e)(I), the applicant must still comply with Section 34-33-120(2)0)(VI) for all activities that involve surface operations or surface impacts incident to the underground portions of the mine. To demonstrate compliance, the applicant must identify the essential hydrologic functions of an Alluvial Valley Floor and submit a plan demonstrating that the essential hydrologic functions can be preserved throughout mining or restored after mining. The essential hydrologic functions of the AVF along the North Fork of the Gunnison are both flood irrigation and subirrigation. The lower levels of this AVF are subirrigated naturally. Yet, the upper portions, between the Farmers Ditch and the river, which exhibit some subirrigation, may be attributed to recharge from adjacent irrigation ditches and canals. In these areas flood irrigation is the essential function. 43