Determination of groundwater catchment areas in two and three spatial dimensions

Abstract The protection of a water well against persistent dissolved pollutants requires the management of the total catchment area of the well. The areal distribution of the catchment for some basic configurations is analyzed in both two (horizontal) and three spatial dimensions. A criterion is derived which allows one to decide when a horizontally two-dimensional computation of flow is sufficient to delineate the catchment. It is shown under which conditions Todd's method of determining the catchment area is valid. Finally some more complex catchment areas are discussed using a numerical flow model. A distinction is made between the catchment area furnishing the recharge and the area which must be protected.