MODELING OF FLOW PATTERN IN A SHALLOW AQUIFER AFFECTED BY RESERVOIRS .1. EVALUATION OF THE FLOW SYSTEM BY ENVIRONMENTAL TRACERS

A process for identifying and quantifying a spatial subsurface flow pattern in a shallow semi-confined aquifer is presented. The conceptual model is aimed at describing the hydraulic effects of surface reservoirs on a shallow semi-confined conducting layer that results in salinization of the top soil. A qualitative study of the relationship between water load in reservoirs, the artesian conducting layer, and water in the top soil was based on chemical and isotopic characteristics. Results indicate limited infiltration from reservoirs into the top soil layers and probably no penetration of water into the conducting layer. Results were then used to establish the regional flow pattern emphasizing the role of surface reservoirs on the build up of artesian pressure in the shallow conducting layer. The flow system was formulated using a compartmental approach in which the unknown parameters are the various sources of recharge and the physical parameters of the aquifer. A complete mathematical setup and suggested solution for the mathematical algorithm are presented in a second paper.