3D input structural data for 3D groundwater flow model

The study is focused on unconfined aquifer of Milan area, in the Po Plain; its vertical extension is about 80- 100 m depth..Using a water well data base TANGRAM, developed in the IDPA-CNR Milano, about 2200 data are stored, georeferenced and their stratigraphic logs are translated into alphanumeric codes. Textural well data have been translated and imported into GOCAD (Geological Object Computer Aided Design), where a 3-D grid of the aquifer volume (SGrid) is reconstructed with 3-D cells (Voxel). This grid is formed by 2.116.030 cells, 185 rows, 266 columns and 43 layers; each cell is a 250 m square, with a no constant thickness: it is between –1.8 m and 2-2 m. To each layers a permeability and porosity spatial value have been assigned and In MODFLOW the same dimensional stratigraphic grid have been created and the hydrogeological properties of each 43 layers imported: a value of top elevation, of bottom elevation, of permeability and of porosity define each cell. The model produces a piezometric distribution considering all input data used for the 3D reconstruction of real hydrogeological system and it reproduce correctly the aquifer gradient and flow. This is the first basically model our future research progress modelling in this area.