In triwaco the module DIGEDIT is used to define the geometry of a finite element- or finite difference grid. The model boundary, location of the watercourses, fault lines and other line elements, location of wells and density polygons (distance between nodes) can easily be defined using DIGEDIT. For convenience, existing spatial data can be loaded as a background map for onscreen digitising or existing shape files with for example water courses can be imported from a GIS (ArcView/GIS). One of the distinct advantages of triwaco is that a finite element grid as well as a finite difference grid can be created based on the same input data.

Finite element grid: TESNET

The finite element grid is genereted by the module TESNET. In addition to density polygons defined by the user it is also possible to double the amount of nodes on line elements such as watercourses and fault zones. Around wells so called 'support circles' can be defined. These 'support circles' are used to automatically create a very dense grid around wells, which dramatically improves the calculated groundwater flow around wells.

Finite difference grid: MONET

The finite element grid is genereted by the module MONET. A grid created with MONET also contains information of a finite element grid. So a grid created with Monet can be used to simulate groundwater flow using both TRIWACO-FLAIRS and MODFLOW.