Determination of hydraulic conductivity using analytical and numerical methods applied to well and aquifer tests

Abstract

This study aims to determine the hydraulic conductivity of aquifers by analytical and numerical methods applied to water level data obtained from well and aquifer tests. Two wells 33 meters apart were drilled in an unconfined aquifer in Bursa Kucuk Sanayi region by Neojen Muhendislik. In one of the wells, a total of 18 slug tests were performed using different volumes before and after well development. Bouwer-Rice and Dagan methods were used as analytical methods and MODFLOW software, which solves groundwater flow problems using method of finite differences, was used for numerical modeling. In the other well, pumping tests were performed. Hantush-Bierschenk and Rorabaugh methods were applied to the data from step-drawdown tests and discharge-drawdown curves were obtained. In addition to these, recovery test and multirate test were performed to determine the hydraulic conductivity. In MODFLOW, simulations were made for various cases related to grid resolution and specific yield. It was observed that well development significantly contributes to well performance and the volume used in slug tests does not affect the results. In addition, different pumping tests modeled in MODFLOW yielded similar values of hydraulic conductivity.