CONTAMINANT TRANSPORT AT A WASTE RESIDUE DEPOSIT .1. INVERSE FLOW ANDNONREACTIVE TRANSPORT MODELING

An application of an inverse flow and transport model to a contaminate d aquifer is presented. The objective of the study is to identify phys ical and nonreactive flow and transport parameters through an optimiza tion approach. The approach can be classified as a statistical procedu re, where a flow and transport simulation model is combined with nonli near least squares multiple regression. The U.S. Geological Survey met hod of characteristics model is used to simulate flow and transport, a nd the optimization part is solved using a Levenberg-Marquardt algorit hm. The sensitivity of the optimization approach to steady state versu s transient flow conditions and to the amount of hydraulic and solute data used is investigated. The flow parameters, transmissivity and lea kage factor, are estimated simultaneously with the transport parameter s: source strength, porosity, and longitudinal dispersivity. This pape r is the first in a two-paper series describing contaminant transport at a waste residue site. III the second paper, reactive transport at t he site is investigated.