Interpreting a pumping test influenced by another well in an anisotropic aquifer

Estimating aquifer properties is central to groundwater studies. Yet, when multiple wells operate in close proximity, their interactions can skew pumping test interpretations. While traditional methods often ignore these interactions, they may lead to inaccurate transmissivity and storativity estimates. Prior research has shown that neglecting nearby wells can introduce systematic errors. However, the specific impact of interference in anisotropic settings remains unclear. This gap motivated the development of new methods to account for interfering wells. The need for precise hydraulic parameter estimation is especially high in confined aquifers. Existing techniques typically assume isolated pumping conditions, which may not reflect real-world scenarios. This paper addresses the challenge of interference in anisotropic confined aquifers.

The goal of this work is to develop and evaluate methods for estimating aquifer properties in the presence of interfering wells. The study aims to improve the accuracy of transmissivity and storativity calculations in anisotropic confined aquifers. Traditional approaches often overlook the influence of nearby wells, potentially leading to flawed interpretations. This study introduces two distinct methods depending on which well starts pumping first. The methods aim to reduce errors caused by unaccounted interference. The study also tests these methods against numerical models to validate their effectiveness. The ultimate objective is to provide a more reliable framework for pumping test analysis. By addressing interference effects, the study contributes to more precise aquifer characterization.

The study proposes two distinct approaches for analyzing pumping tests with interfering wells. One method is used when the tested well is the first to operate, while the other applies when the interfering well starts first. Both methods rely on the pumping rate of the interfering well and the elapsed time since pumping began. The tested method does not require initial piezometric level data if the interfering well starts first. The methods use data from at least three monitoring wells to estimate hydraulic parameters. The position of these wells affects the accuracy of the results. The study compares these methods with an analytical approach that ignores interference. The numerical models help assess the performance of the new methods.

The new methods produced more accurate transmissivity and storativity estimates than traditional approaches. When the interfering well starts first, the method requires only pumping rate and elapsed time. The tested method does not need initial piezometric data in this case. The accuracy of parameter estimates depends on the placement of monitoring wells. The study found that three monitoring wells are sufficient for reliable results. The numerical models confirmed the superiority of the new methods. The results suggest that ignoring interference leads to significant errors. The study also provides guidelines for optimal monitoring well placement.

The authors conclude that the new methods improve the accuracy of pumping test interpretations in anisotropic aquifers. The study shows that ignoring interfering wells can lead to erroneous results. The methods require knowledge of pumping rates and elapsed times but not initial piezometric levels in some cases. The placement of monitoring wells significantly affects the accuracy of parameter estimates. The study recommends specific positions for monitoring wells to enhance results. The numerical models support the effectiveness of the new methods. The findings suggest that these methods should be used when interference is present. The authors propose that these methods can be applied in real-world pumping tests.