Sensitivity analysis of a multi-cell groundwater model

Abstract

The mechanics of groundwater movement and storage is a complex phenomena where a number of natural and artificial processes interact. For the planning and development of groundwater resources a comprehensive orientation of the ongoing processes are necessary. With the advantage of huge computational facilities in the field of mOdeling: a four layer multi-cell groundwater balance model has been reconstructed to investigate the ongoing hydrological and hydrogeological processes at the soil surface and underlying strata. Considering the general aquifer and topographic characteristics of Bangladesh: the different horizontal layers as represented in the model are soil surface: root zone: semiconfining layer and aquifer. To study the relative influences of the hydrological processes and hydrogeological characteristics of water bearing formations on the groundwater movement and storage: the model has been structured mainly into two parts. The computations of flow balance components in the upper two layers are performed directly and the computations related to the lower two layers are done with successive iterations. The model is a finite difference model and the iterations are done to satisfy the flow balance equation at semi-confining layer and aquifer. Out of the numerous influencing parameters: only the rainfall and flooding characteristics and potential rate of surface infiltration and deep percolation have been selected as varied parameters of the sensiti vity study. The other parameters are kept at their base values throughout the model runs.