The Preliminary Diagnosis of Water Well Damage in Confined Aquifers

Abstract

The paper presents an analysis of changes in hydrogeological parameters, considering the technical efficiency of boreholes. The first part presents the preliminary assumptions and methodology for determining hydraulic and hydrogeological parameters. This is followed by a discussion of the analysis results of parameter changes for eight selected boreholes, which took place over several decades of their operation. The wells under study were drilled in porous and fractured aquifers. In all the cases discussed, there were confined hydrogeological conditions, which means that the confined aquifers were naturally isolated from the poor unconfined aquifers. In each cases, there was a situation in which contamination with coli bacteria and microorganisms was found, often combined with an increased presence of suspended solids. This caused periodic interruptions in the water supply. During the shutdown period, pumping tests were carried out in each of them to determine their hydraulic efficiency. Analysis of the test results made it possible to determine the parameters and make a preliminary assessment of the suitability of the site for further use, the need for more detailed research, or the possible abandonment of further use. The diagnostic method was based on the use of pumping equipment installed in the water wells, i.e. without the need to without the need to dismantle the submersible pump. The analysis of the results indicates the types and causes of damage and allows for a preliminary assessment of the possibility of regenerating the plant. Alternatively, it allows for the selection of more detailed, invasive diagnostic tests.