REV06564 - Laserfiche WebLink

Home Browse Search

toward increasing TDS. Because the systems receive water from other sources, the relative amounts ofhigh-TDS spoils water and relatively "clean" water vary with other factors, so the trend of increasing salt content is not clearly defined. One exception to the non-linear trend is the water from the alluvial well GWS6-A which displays a smooth trend of increasing dissolved solids. It is possible that this well samples a zone receiving a relatively constant supply of spoil water and thus shows TDS concentration increasing linearly with time. Wells in the alluvium of the two east-draining creeks show that high-TDS water from mining activity has not yet migrated very faz beneath those creekbeds. The welisite nearest the disturbed area, S46-A on Cow Camp Creek just downstream of Pond 004, displayed a decrease in TDS concentration from 1987 to 1991 and has increased since then. The well downgradient of that, S69-A, has recently displayed a trend of decreasing TDS. Possibly the water being sampled currently at S69-A is that which passed through the upstream site several years ago. Using that hypothesis, the travel time for groundwater within the Cow Camp Creek alluvium is lower than calculated below. Water from the well in Bond Creek has not shown TDS levels elevated much beyond their historic values, near 5000 mg/l. When Seneca Coal Company can demonstrate that the reclaimed lands meet the Phase II bond release criteria, it is assumed that the majority of baseflow to Cow Camp, Bond and Grassy Creeks will be contributed by spoil aquifer discharges to the surface system. In the Grassy Creek Drainage, the quantity and quality of the flows will be similar to present conditions. All of the spoil spring dischazges issuing into the Grassy Creek drainage will pass through the Wadge Impoundment, a permanent structure. Dilution and mixing within the impoundment will diminish the concentration of dissolved solids dischazged to the alluvial system. As mining continues in this drainage, some increase in dissolved constituents is expected. Data collected at NPDES sites 002 and 003, which dischazge disturbed area drainage into Grassy Creek, indicate that there has been an increase in TDS, based on monthly average concentration (June through September) on a yearly basis for the yeazs 1982 through 2006. It should be noted, however, that the rate of increase, based on monthly average TDS concentration on a yearly basis, appeazs to have stabilized during this period. Therefore, it is not expected that the quality of the effluent will further degrade the alluvial water quality in the Grassy Creek Drainage. In the Cow Camp and Bond Creek drainages, Wadge spoils aquifer dischazges will contribute flow to these tributary creeks and eventually to Fish Creek. During the months of June and July, Cow Camp Creek and Bond Creek sustain flow their entire length to Fish Creek. During this period, each creek contributes water to the associated alluvial aquifers. The spoils spring dischazges are sufficiently diluted by snowmelt runoff to preclude degradation to the quality of the alluvial aquifers in these drainages. 28