Numerical modeling of groundwater flow into a radial collector well with horizontal arms

Abstract

In this study, we present a new numerical model for evaluating drawdowns in the horizontal arms of a radial collector well. This model accounts for internal friction losses, which depend on the Reynolds number, and pipe roughness in the arms of the collector well. It also accounts for diverse flow regimes (laminar, transitional, and turbulent) in the arms; thus, the drawdown in the well and the groundwater influx into the well can be evaluated. This model also evaluates the effect of the roughness coefficient on the drawdown and influx distributions along the well in the case of a turbulent flow. The results obtained by using the proposed model are in good agreement with the analytical and numerical solutions presented by Hunt (2005) and Mohamed and Rushton (2006) for the flow into a horizontal well. This proves the effectiveness of the model. We also present examples of applications of the model in order to illustrate the effects of the friction factor and roughness coefficients on the drawdown and groundwater influx into the horizontal arms. The simulation results indicate that the combined effect of variations in pumping rate, friction factor, and pipe roughness leads to varying drawdown and groundwater influx distributions along the horizontal arms of the collector well. The proposed numerical model can be used for predicting well yield, identifying the origin of water pumped by a well, and designing collector well systems in a various hydrogeologic setting.