Structurally the Chalk in Norfolk forms a relatively uniform aquifer and it is therefore possible to distinguish between aquifer inhomogeneity and anisotropy in this area. This has been achieved by comparing directional transmissivity values with the fracture pattern in the Chalk. A map of fracture directions has been constructed for the whole of the Norfolk Chalk.
Aquifer properties have been calculated as areal values, point values, and directional point values. The ability to represent aquifer anisotropy by transmissivity ellipsoids has been extended to allow prediction of properties, and, through the use of the mean radius of the ellipsoid, comparisons between point values over an area.
A family of ellipsoid curves has been developed which summarize and aid analysis of transmissive anisotropy over an area.
A comparison of fracture orientations with point and areal transmissivity ellipsoids shows not only that the anisotropic nature of the aquifer is a direct result of the fracturing but also that this behaviour can be predicted by studying the fracture pattern and vice versa.