Solving Groundwater Flow Inverse Problem Using Spreadsheet Solver

A simple spreadsheet cell-oriented methodology is proposed for solving a groundwater flow inverse problem. Initially, the numerical simulation of the groundwater flow process is carried out by using an embedded optimization approach and spreadsheet solver. The result of the simulation is compared with the result of a GMS MODFLOW simulation. The comparison shows that the result of the spreadsheet simulation is similar to the result of the GMS MODFLOW simulation. Two groundwater inverse problems are then solved using the proposed methodology. The first problem estimates the unknown pumping rates of an aquifer, and the second problem estimates the aquifer transmissivity. Using the spreadsheet method, it is easy to define boundary conditions and to initialize starting values as well as their visualization. The methodology is simple in concept and can be used for solving graduate- and undergraduate-level groundwater simulation and inverse problems. The methodology may also be used by the practicing engineer for solving small-scale groundwater problems.