A new hydrogeological map of Guelderland and Flevoland

Abstract

A new mapping technique is proposed to represent on one sheet the hydrogeological data of a region. The main features represented are: - the structure of the alternation of aquifers and resisting layers. The map gives the transmissivity of aquifers and the ranges in hydraulic resistance of less pervious layers. The symbols used are coloured beams (thickness indicating transmissivity values and colour the geological origin). - Ground-water heads in the form of contour lines and the relevant surface water pattern. - The location and the extent of ground-water extraction, indicated by circles of squares of a variable size. - Ground-water quality by means of the distribution of fresh and brackish ground-water. The map has been composed for the situation of the Netehrlands, but can most likely be used for any area, where the aquifer systems consist of unconsolidated sediment. Another requirement is that the available data allow a quantitive representation.