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1 1 1 1 1 1 1 1 1 1 that wells which extend into the foundation exhibit consistently lower water levels than companion wells which terminate in the refuse material indicates that a low permeable boundary either initially existed in the original ground surface or was created as part of the early construction activities. The anomaly in the vicinity of well P-1 which was previously described for well P-1T2 which extends into the foundation was also found in the wells which terminate in the pile itself, wells P-1 and P-1T1. These wells show water levels which are higher than would be expected based on the measurements of other wells which end in the pile material (P-2 and P-3). c) As has been previously discussed, it is likely that roughly horizontal layers of lower permeability material exist in the refuse material which separate the pile into distinct aquifers. It is not known how many of these zones exist. One such zone appears to occur above a permeability boundary just above the first slope bench at elevation 4880 as evidenced by the seepage which daylights at that elevation. An interesting condition is found in the southern portion of the pile in the vicinity of wells B2-4, P-la, BO-1, B2-1 and B1-l. As was discussed in previous paragraphs, the water levels in these wells seem to show a pattern of a uniformly sloping piezometric surface following the underlying ground surface. This is somewhat odd for two reasons. First, if the pile is divided by low permeability layers into a number of approximately horizontal aquifers, as is suspected, it is difficult to explain how a uniformly sloping phreatic surface could occur. It would seem likely that water level readings would be more erratic with patterns similar to those found in other parts of the pile. Second, since drain No. 1 is located beneath this part of the pile, it would be expected that some indications of phreatic surface drawdown towards the drain would be apparent similar to that seen in the vicinity of drains 2 and 3. No such effect can be identified. Since underdrain No. 1 does appear to intercept moisture and is flowing 1 to 2 GPM the most likely explanation for not seeing any drawdown effect would be that multiple aquifers are present. Because there are only four wells in this area, in which water levels in the pile are measured, and the depth at which the primary pore pressure influence exists cannot be determined, it is possible that the readings do reflect multiple aquifer zones. If multiple aquifer zones exist, the actual conditions are masked by the lack of multiple-depth wells in the same locations and therefore, the measurements only coincidentally show a uniformly sloping pattern. 12 1