Combined Simulation-Optimization of an Excavation Site for Dewatering Purpose
By K. Demirbaş, A. B. Altan-Sakarya and H. Önder
Optimal decision of dewatering of an excavation area in an unconfined aquifer is searched by using the combined optimization-simulation approach. In combining groundwater model with the optimization model, response matrix approach, generated on the basis of linear super position, is used. MODMAN that calls MODFLOW repeatedly to generate response matrix is utilized to transform the groundwater management problem into linear integer programming problem. A hypothetical dewatering area is considered to examine the effects of nonlinearity due to pumpage. Two different iterative methods, revised unit rates and revised coefficients, are applied to account for the nonlinear response of the unconfined aquifer to pumpage. Genetic Algorithm based on selection, crossover and mutation is also used as an optimization tool to compare the results. The study has shown that modified linear optimization procedure used in conjunction with MODFLOW provides a useful and computationally efficient tool in the analysis of groundwater dewatering problems in unconfined aquifers.
Link to material: http://www.ifors.org/developing_countries/downloads/oct31_2011/2.pdf