On the optimization of groundwater pumpage in the Takaoka groundwater basin

摘要

The Takaoka groundwater basin of Tosa city, Kochi Prefecture, Japan, is threatened by overdraft, An optimization model is presented for optimal operation of the Takaoka groundwater system during critical periods (dry periods). Using the available data and a previously developed finite-element simulation model, a linear programming (LP) model was formulated. Based on the modeling results, optimal pumping schedules and groundwater contour maps resulting from the optimal pumpage are presented for two prospective operating scenarios, A and B. Optimal pumping schedules differed significantly under the two scenarios, and groundwater levels improved appreciably under Scenario A. The results of Scenario B indicated that in the absence of any remedial measures in the Takaoka basin, the dry period pumpage at the existing wells should not exceed the suggested optimal pumpage. On the whole, in order to ensure long-term and sustainable utilization of the Takaoka groundwater resource, the most attractive operation policy seems to be one in which the excess groundwater pumped from most productive wells is transported to meet local water demands in the less productive areas of the basin.