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West Elk Mine As noted above, if a party intends to dredge and/orf 11 in a regulatory wetland, a 404 permit must be acquired in advance of the activity. Note that the regulatory "trigger" is dredging and/orflling. No such activities aze proposed in the Apache Rocks or Box Canyon permit revision area. To ascertain whether potential wetlands impacts caused by mining-induced subsidence would be regulated under Section 404, MCC representatives met with staff from the U.S. Army Corps of Engineers (USAGE), Grand Junction office in September 1994. In this meeting, USAGE staff indicated that, at the West Elk Mine, wetlands impacts as a consequence of subsidence would not be regulated. In addition, due to the many reasons presented above regarding the general lack of impacts to streams, spring/seeps and groundwater, it is unlikely that the wetlands in the Apache Rocks and Box Canyon permit revision area will be significantly affected by the mining. The wetlands in question derive their water from surface drainages and spring/seeps. WWE's calculations indicate that the maximum potential spring and streamflow loss in the current permit and Box Canyon permit revision azeas is less than 3 acre-feet per year. A loss of this magnitude, especially when distributed over the full permit revision area, is of no consequence relative to the wetlands. If the total annual surface water and spring "losses" of 3 acre-feet were to reemerge downgradient, slope stability is not likely to change significantly. The introduction of 3 acre-feet of additional groundwater discharge is smaller than the natural, year-to-yeaz fluctuations in groundwater dischazges. This finding, coupled with the small wetlands acreage in the Apache Rocks and Box .Canyon pemut azeas, leads to the conclusion that the probable hydrologic consequences from the perspective of wetlands aze not significant. • Water Rights R.,~kg n~,.~d -This section discusses the potential effects on vested water rights that may be caused by MCC's longwall mining operation, and the associated subsidence in the permit azea. The location of Apache Rocks and Box Canyon permit revision areas aze shown on Map lA. Related impacts include inflows from faults and storing water in underground sumps. All of these topics are addressed herein. The water rights analysis has been prepared by WWE with 35 years of experience in this subject. W WE recommends that readers review the next major section of this report Mine Water System for background to facilitate an understanding of water management at the mine, and associated water rights implications. The proposed longwall mining operation within the current permit and Box Canyon pernut revision areas could potentially affect water supplies and water rights in the Dry Fork and North Fork drainages. Each drainage and its accompanying water rights that could potentially be affected by subsidence is discussed below. Following this discussion is an evaluation of the water rights aspects of the sealed panels sumps, fault inflows, and MCC's North Fork diversions. In the following analysis, the term "depletion" is calculated as diversions minus return flows. DrJ, Fork 1)rn;nn~ _ MCC has a comprehensive decreed water augmentation plan (86CW38) in • place to mitigate the possible mining related depletions to Minnesota Creek and its tributaries. Approximately 60 percent of the Apache Rocks pemut revision azea mining is planned in the Dry 2.05-/69 November 100 PRIT