Spatial Analysis of Hydrogeological Subsystems

Regionalization based on multivariate statistical analyses of hydrochemical data proved successful in differentiating distinct groups of groundwater types and hence of varying hydrogeological origins within the Sasso Lungo dolomitic mountain stock, Northern Italy, and the Luz de Tavira area, Portugal.

Further studies have now indicated that universal kriging, cokriging and block kriging are not always suited for delineation and classification of groundwater systems, since the basic assumption that subsystems are internally homogeneous does not comply with reality. The shallow groundwater level which is mainly controlled by gravity drainage in Luz de Tavira area yielded satisfactory results using universal kriging technique. But the kriged maps of EC of either the Sasso Lungo (because of multi-layer aquifer system) or the Luz de Tavira (because of more than one controlling factor) were not error free. Therefore, for interpolation to unknown localities one cannot rely on kriging; additional information concerning the groundwater subsystems under study is needed.