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identified as a recharge azea. As such, the potential impacts of mining will be threefold: (1) Interruption of the aquifer by physically removing the coal and its overburden. Mining of the coal will interrupt the aquifer function upgradient of Twentymile Park. This will reduce the recharge potential to the down-gradient aquifer for a short period of time. (2) After discreet mining areas have been backfilled, the spoils will resaturate. A portion of the spoil water will recharge the undisturbed Wadge Coal and overburden immediately down-gradient. This recharge water will be high in TDS and other constituents. The concentrations of these constituents will be greater than that which existed in the Wadge Coal and overburden aquifer prior to mining. (3) It is thought that the Wadge overburden, through sub-crops and outcrops, may recharge creeks within Twentymile Basin. This recharge may be directly affected by the addition of the poor quality spoil discharge water during base flow conditions, or indirectly by the addition of this water to associated alluvial bodies. Rechazge to the surface system could potentially be affected by the interruption of the aquifer due to removal by mining. Furthermore, upon indirect recharge by the spoil aquifer, a plume of poor quality water could diminish the water quality of the surface water system within Twentymile Park. The alluvial aquifer system, which includes alluvial bodies in the Fish Creek Drainage (including Bond and Cow Camp Creeks) and the Grassy Creek Drainage, will be impacted by mining activities. During mining, surface runoff from the disturbed areas is contained in sediment ponds prior to discharging from the site. Historically, the sediment ponds at the Seneca II Mine discharge regularly throughout the year to the associated drainages (Grassy Creek, Bond Creek, Cow Camp Creek). These drainages, at various times ofthe yeaz, recharge the associated alluvial/colluvial aquifers with the sediment pond dischazge. These sediment pond discharges are typically higher in dissolved constituents than the naturally occurring runoff from the undisturbed site. As the alluvial/colluvial water quality closely minors the quality of the stream, a degradation (i.e. increase in TDS) is observable in alluvial monitoring wells down-gradient of the mine site. In portions of Little Grassy Creek drainage in contact with previously disturbed lands, TDS increase over baseline conditions is observable. This is due to the addition of spoils water, which has been discharged from backfilled portions of the mine site, to the alluvial system. This general trend can be seen in water quality analyses from alluvial wells in Grassy Creek and Little Grassy Creek. The water in these alluvial systems isdown-gradient of spoils and is probably receiving a contribution from spoils water containing high levels of dissolved solids. In general, water from these sites has shown an overall trend 27