Sand piles are frequently used for soil-mechanical purposes in order to accelerate the consolidation of clay layers. However, when the clay layer has a significant function in the hydrological regime of an area, this regime will be permanently disturbed. Especially when the clay layer functions as a hydraulic resistance to a vertical flow of brackish or salt groundwater from lower aquifers, the resistance will decrease thus increasing the seepage. As a first approach to the problem, the grid of sand piles is replaced by a row of sand walls. In this paper, the two-dimensional flow of ground water towards the sand wall has been analysed in three ways. One of these is a rough estimate, while the other two methods are more accurate because they are based on complex variable techniques.