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will there be moisture in the pile sufficient to result in deep <br />percolation. <br />The complete refuse pile will occupy essentially all of the small <br />watershed in which it is located. Direct runoff from the refuse will be <br />routed through a sediment pond before discharge. The quantity of direct <br />runoff from the refuse will probably not be identical to that from the <br />same area before placement of refuse, but the small area involved insures <br />that any such change will be inconsequential relative to the total runoff <br />on the Pullgatoire watershed. <br />Materials to be placed in the refuse pile were not available in <br />quantities sufficient for leach testing. Therefore, the results of the <br />leach tests on existing refuse were utilized to estimate potential <br />impacts on water quality. It is expected that direct runoff from the <br />completed, reclaimed pile will exhibit water quality that is essentially <br />the same as that from undisturbed lands. The quality of direct runoff <br />from the refuse during construction will probably be degraded as the <br />result of contact with the refuse. <br />The quality of direct runoff contacting a surface with soluble <br />chemical species is always much better than might be expected from the <br />chemistry of the solids contacted. Only a thin surface layer of the <br />solids are contacted by the overland flow. The volume of water <br />contacting the solids in this thin layer is very large relative to the <br />pore volume of the later and their resident soluble materials are very <br />rapidly leached. Furthermore, most of the leaching occurs by waters that <br />infiltrate the surface at the beginning of the precipitation event before <br />overland runoff is initiated. By the time overland flow is established, <br />most of the readily soluble materials present in the near surface have <br />been dissolved and carried below the surface by infiltrating waters. <br />Regardless of the chemistry of the refuse to be placed in the <br />proposed disposal pile, the above described mechanism is expected to <br />protect surface runoff from serious degradation. The chemical <br />composition of runoff will likely be dominated by the common ions, <br />sodium, sulfate and bicarbonate with a total dissolved solids <br />(Revised 05/11194) • <br />2.05-79 <br />