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<br />' <br /> be explained. However, it is difficult to conceive of <br />' how this sealing could occur since the drilling was done <br />with hollow stem augers. Because no fluid was used <br /> during drilling, it is also difficult to imagine how <br /> water could have gotten into the wells. These <br /> considerations along with the fact that the water levels <br />' generally fluctuate both up and down indicate that the <br /> wells are not sealed. <br />' 3.) The most apparent, cause of different water levels in <br /> companion wells is the possible existence of distinct <br /> aquifer zones in the pile. This has been discussed in <br />' previous paragraphs and seems to provide the only <br /> realistic explanation. <br />' 4.) In addition to the aquifer zoning mentioned above, there <br />also appears to be an additional effect in the vicinity <br />of well P-1 which results in higher than expected water <br />' levels. Three possible causes for 'this condition have <br />been considered: <br />a) It seems more than coincidental that, in the area of <br />' well P-1, seepage water is found daylighting on the <br />surface above the bench at elevation 4880 and that such <br />seepage water collects and runs in a ditch on that bench. <br />' Because the piezometric surface in the vicinity of PZ P-1 <br />has remained constant over the years; the ground surface <br />above and around PZs P-1T1, P-1 and P-1T2 shows signs of <br />' continuous seepage; and PZ P-1T1 measurements seem to <br />verify PZ P-1 measurements it is believed that moisture <br />surfaces above the first slope bench, at or near PZ-P1, <br />flows on or just below the slope surface and collects on <br />' the inside of the first bench. It would appear that <br />moisture which concentrates on the surface of the first <br />slope bench south of PZ P-1 flows off (on the surface) <br /> towards the south, eventually finding the perimeter toe <br />' ditch. While, moisture which concentrates on the bench <br /> in the vicinity of P-1, and possibly extending to the <br /> north, filters vertically into the pile. This theory <br />' assumes that there is some type of well established <br /> aquifer or perched zone within the pile that feeds <br /> directl y and constantly into the area above PZ P-1 via a <br />' pervious conduit or pervious zone that is not intercepted <br />or measured by the higher tier piezometers. In general, <br />it seems plausible that daylighting seepage water is <br /> collected by the ditch and is reintroduced into the pile <br />' through a pervious zone in the area of we ll P-1. This <br /> would mean that the collection ditch is acting as a <br /> source for seepage water in this vicinity. However, such <br />' a condition is not adequate to explain all unusual <br /> conditions found in the P-1 area. <br />1 <br />14 <br />1 <br />