10.2190/DD37-EG9W-PFFD-WJM7 DD37EG9WPFFDWJM7 4 Comparison of Two Approaches to Modeling Moisture Movement Through Municipal Solid Waste 41 63 20020509 20020509 20020509 20020509 DD37EG9WPFFDWJM7.pdf http://baywood.metapress.com/link.asp?target=contribution&id=DD37EG9WPFFDWJM7 1 Mark Uguccioni Chris Zeiss Stanley Associates, Edmonton University of Alberta, Edmonton Channeled flow through municipal solid waste layers affects the time, rate, and amount of leachate generation. Leachate flow through the waste layers can be predicted either as a one-dimensional uniform Darcian flow through a homogeneous matrix layer or as a two-domain flow regime of channeled and matrix flows. This research project tests the performance of one-dimensional water balance models (HELP) and two-domain fractured-porous media flow models (PREFLO) by comparing calibrated predictions with experimental results for pilot-scale landfill leachate cells. the measured breakthrough time was much shorter than predicted by HELP. the measured cumulative leachate discharge volumes vary between 104 and 300 L. HELP and PREFLO models with default values predicted discharges to be zero and therefore significantly underestimated the actual discharges. When calibrated, both models provided much improved results. HELP approximated the time to effective storage and the leachate discharge with less than 30 percent difference. In the short term, modified parameter values can be used to improve leachate predictions. In the long term, a new model needs to be developed to predict the leachate flow through the waste layer. G. P. Korfiatis, A. C. Demetracopoulos, E. L. Bourodimos, and E. G. 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