2012-01-05_REVISION - C1980005 (8)

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what is referred to as the Wadge Lennox interburden. These wells exhibit normal seasonal variations. Aquifer tests performed in the Wadge Coal seam indicate that the Wadge aquifer exhibits a semi - confined condition with a transmissivity value of 377.1 gallons per day per foot (gpd /ft). Wadge water levels, dependent upon well proximity to the recharge area, show some seasonal variation. Alluvium There is one alluvial aquifer system within the Seneca II permit area: the Bond Creek alluvial aquifer (drainage from below 008 pond to Fish Creek). The Fish Creek alluvial aquifer is not within the Seneca II permit area, but may be affected by water discharging from the permit area. Originally, nine wells were used to monitor alluvial water quality in the drainages. Two wells were located along Cow Camp Creek, one along Bond Creek, two along Grassy Creek and four along Little Grassy Creek. All of these wells exhibit seasonal variations. Monitoring of the alluvium is reduced to one well (GW -S68- A) in the Bond Creek alluvium, and one (008 -AU -3) in the Fish Creek alluvium. Spoils The resaturation of portions of the backfilled pits has been expressed as spoil aquifers. Water percolates through the replaced spoil material and flows down - gradient until it reaches the lower -most highwall where the infiltration rate into bedrock is much lower than flow through the spoil. When the elevation head of the spoil aquifer exceeds the ground surface elevation, the spoil water discharges in the form of springs at the topographically lowest point along the reclaimed highwall. Nine spoil springs have been identified in the original permit area, eight of which were monitored by Seneca Coal Company. In addition, Seneca Coal Company has historically monitored thirteen spoil wells in the original permit area as part of the approved monitoring plan that are no lingered a part of the monitoring plan. The current permit area will include one spoil spring that will be monitored (Spoil Spring #9). In 1977, the Water Resources Division of the United States Geological Survey (USGS) began a lysimeter study at the Seneca II Mine to determine spoil aquifer discharge quality, and how that quality changes over time. Stipulation No. 23 in the original permit required the applicant to submit the USGS report to the Division upon its completion. In 1994, the USGS published Water- Resources Investigations Report 92 -4187 titled, Hydrology and Geochemistry of a Surface Coal Mine in Northwestern Colorado. The report describes the sources of hydrologic recharge to and from reclaimed spoil, the relative contributions of recharge to the reclaimed spoil aquifer from identified source waters, and the 14