Opensource software for groundwater modelling
There are regular requests on how to use GIS in groundwater management or on what tools are available.
A few useful opensource software tools:
GRASS (http://grass.osgeo.org/)GIS with the r.gwflow module (http://grass.osgeo.org/grass64/manuals/r.gwflow.html)
Brief article on using GRASS for groundwaterhttp://www.hidro.ufcg.edu.br/twiki/pub/Disciplinas/GeotecnologiaAplicada/Renato.pdf
MODFLOW Groundwater modelling package from USGS (Unitd states geological services), a well used industry standard for groundwater modelling that links to a number of other software packages.http://water.usgs.gov/nrp/gwsoftware/modflow2000/MFDOC/
Google Earth , 2D structural geologic symbols, and 3D planes, cross sections, and borehole traces. Google Earth has increasing functionality added and many uses find it less intimidating to use and easier to learn. Although not a functional groundwater modelling software it has many useful features. http://www.impacttectonics.org/gcherman/downloads/GEO310/GCH_GESymbols/GCH_GE_Geology_Apps.htm?goback=%2Egde_104622_member_103403134