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pits are recharging into the Wadge overburden aquifers at a rate of 118 gpm and are migrating down the dip of these strata. A salt plume from Eckman Park has migrated into the area occupied by the Foidel Creek Mine's portal. The No. 2 Mine may impact the quality of water in the underlying Twentymile sandstone aquifer. The Little Middle Creek Tract has the potential to impact the Trout Creek sandstone aquifer. The mines in the Twentymile Park basin are expected to have limited impact upon the alluvial water quality of the alluviums of Fish, Foidel, Middle and Trout Creeks. Because these mines discharge water of higher total dissolved solids it can be expected that these aquifers may be impacted. A detailed discussion of the alluvial valley system can be found in this document Section VII, Alluvial Yalley Floor. The piezometric surface in the Wadge coal-overburden aquifer will be lowered by the continued mining in the Eckman Park Mine, and will rebound once a spoils aquifer is established. Middle Creek Mine The Middle Creek underground mine is closed and reclaimed. This mine was faced up at the bottom of an Energy Mine No. 3 strip pit, and entries 65 long were driven west. During development, this mine experienced inflows 80 gpm which later decreased to 45 gpm. This mine closed in June, 1980, the status of the leases and the high inflows made further mining impractical. Following closure, discharge from the portal ranged from 5 0 feet of as 2029 gpm until the portals were backfilled in 1985. Unquantifiable seepage occurring from the top of the backfilled area. This mine is not expected to produce any significant qualitative or quantitive impacts to the adjacent drainages. Cumulative Ground Water Impacts of Coal Mining in the Twentymile Park Basin is Eight mines in the Twentymile Park Synclinal Basin are located in recharge areas of the aquifers of the Mesaverde Group. The ninth mine, the Middle Creek Mine, is located in a discharge area (Figure 3~. All of the mines, except for the Seneca II Mine, are also adjacent to alluvial aquifers within the Trout Creek drainage basin. The adjacency of these mines to the tightly folded structural basin and to the alluvial aquifer system indicates that the coal mines in the Twentymile Park Synclinal Basin will produce cumulative hydrologic impacts on ground water. The significance and extent of those impacts will be discussed below. The strata between the Lewis Shale have two p Basin, one through the other through outcrops systems of Trout Creek structural basin. Trout Creek sandstone of the Iles Formation and the pints of ground water discharge from the Twentymile Park narrow Hayden synclinal fold to the northwest, and the and subcrops of these strata to the stream/alluvial and its tributaries in the northeastern part of the -52-