2013 Volume 69 Issue 3 Pages 297-311
In order to identify saturated hydraulic conductivity and longitudinal dispersivity, saltwater tracer tests using dual boreholes were performed for an unconfined and an underlying confined aquifer at Nagano-Wakasato campus of Shinshu University. The data of electrical conductivity monitored at injection and observation borehole were used to inversely identify the parameters by combining a three-dimensional numerical model, SIFEC3dp, for solving coupled problems of density-dependent, saturated-unsaturated flow and convective-dispersive transport of conservative tracer in an aquifer system, and Powell's optimization method. The developed method was first validated by applying to arbitrary test cases with given parameters. Furthermore, application of the inverse method to the site generated reasonable results while numerical simulations using identified parameters satisfactory reproduced measured salt concentrations.