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The regraded spoils are partially saturated and provide some additional source of local recharge to
<br />the natural groundwater system. Groundwater from the spoils aquifer enters the Wadge coal,
<br />is overburden and Little Grassy Creek alluvium within the permit area, in part through direct lateral
<br />flow from the spoil into the undisturbed bedrock adjacent to the reclaimed spoils aquifer and in part
<br />from re- infiltration of the flow of spoil- aquifer springs adjacent to the alluvium.
<br />Water -level monitoring data, summarized in Table 2.04.7 -T1, and provided in Exhibit 2.04.7 -E1,
<br />Hydrologic Information, indicate that groundwater in the potentially affected bedrock units is
<br />present under confined conditions; that is, water levels measured in monitoring wells screened
<br />across those units rise to elevations above the tops of the units. Potentiometric surface elevations in
<br />monitoring wells (Exhibit 2.04.7 -E1, Hydrologic Information) are generally below the ground
<br />surface, ranging from about 102 to 770 feet below ground surface (bgs), except at the location of
<br />wells COV23, CW23, and CWU23 in the west - central part of the Permit Area, where the
<br />potentiometric surface in all three wells is approximately 108 to 120 feet above the ground surface,
<br />and at wells SW19 and SWU11 along Little Grassy Creek near the center of the permit area, where
<br />the potentiometric surface was approximately 26 to 48 feet above the ground surface. This situation
<br />is created by factors that include recharge in areas that are high both structurally and
<br />topographically, which results in a high - elevation potentiometric surface in the recharge areas, and a
<br />hydraulic gradient that slopes more gently than the land surface. At some point downgradient from
<br />the recharge area, the elevations of the land surface and the potentiometric surface intersect.
<br />Upgradient of the intersection, the potentiometric surface is below the land surface, and
<br />downgradient of that area, the potentiometric surface is above the land surface.
<br />Hydrographs for monitoring wells in the overburden unit, Wadge Coal, underburden unit, and
<br />• alluvium and spoils are presented in Figures 2.04.7 -F1, 2.04.7 -F2, 2.04.7 -F3 and 2.04.7 -F4,
<br />respectively. Baseline monitoring measurements at these bedrock monitoring wells began in June
<br />or November 2008, depending on the completion dates for the five new bedrock wells. Water
<br />levels in wells COV23, COV2633 and COV2702, in the overburden unit (Figure 2.04.7 -F1),
<br />showed small fluctuations through the period of record with some wells exhibiting falling water
<br />levels from November to December 2008 (COV2633) or January to August 2009 (COV23),
<br />followed by rising or nearly standing water levels. Water levels in wells CW23, CW2632, and
<br />CW2701, in the Wadge coal (Figure 2.04.7 -F2), generally declined slightly through the period of
<br />record. Water levels in underburden wells CWU13, CWU14, and CWU23 (Figure 2.04.7 -F3)
<br />fluctuated two to 15 feet during the period of record. Water levels in CWU13 and CWU14
<br />appeared to undergo a downward adjustment to equilibrium conditions following the first
<br />measurements, which typically occurred shortly after well construction and initial water quality
<br />sampling efforts. Water levels in the alluvium and spoil wells (Figure 2.04.7 -F4) rose during the
<br />spring, and declined to a minimum in the late summer, as would be expected given their hydrologic
<br />connection with surface water and dependence on seasonally - variable recharge.
<br />Although the period of record for the baseline monitoring program is long for wells previously
<br />monitored at the Seneca and Yoast mines, at least 12 months of monitoring data have been collected
<br />at the five new bedrock wells installed in 2008, and should be adequate to define seasonal changes.
<br />Hydrographs for the entire period of record for all wells are included in Exhibit 2.04.7 -E1,
<br />Hydrologic Information. Water levels in overburden well YOV28 are typically high during summer
<br />and low during winter, with annual fluctuation of two to five feet. Water levels in Wadge Coal
<br />• wells follow different seasonal patterns, depending on location. Well YW28, near the Yoast mine
<br />and structurally high, exhibits high water levels in spring and summer months, low water levels in
<br />winter months, and annual fluctuations of two to five feet, like the overburden well at that location.
<br />PSCM Permit App. 2.04 -37 Revision 12/17/09
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