Revised Model for Finite-Difference Modeling of Flowing Artesian Wells

It is a typical hydrogeological phenomenon for flowing artesian wells occur in aquifer-well systems. However, these wells have been seldom analyzed in the models for assessment and management of groundwater resources. The three treatment methods of flowing artesian wells that applied currently in numerical modeling of groundwater flow are unreasonable and are not verified. It proves that conventional finite-difference method can neither give accurately the water table in a pumping well, nor the flow rate of a flowing artesian well. The calculated head or flow rate of well-element must be revised. Applying analytical method, a revised model of flowing artesian wells is developed for finite-difference grid with rectangle cells, taking into account of the radial flow in the vicinity of an artesian well, and the release of storage in the confined aquifer surrounding the artesian well. Examples indicate that this revised model of flowing artesian wells gives a significantly improved numerical result of flow rate, with average relative errors less than 5% even for 1 000-m-magnitude cell size.