The Datacrossing DSS is a basin scale groundwater model to quantify the impact of point/non point source pollution. It is accessible through a user friendly web interface that relies on a distributed GRID infrastructure. msCross is a Javascript interface to the Mapserver, developed during the project. Features: * Free Software, distributed under GPL (Open Source); * Client side, works with any Mapserver CGI; * Cross-browser / cross-platform; * Simple installation and use (only one javascript file); * Easily customizable and extensible; * Sensitive Point Overlay support; * OGC WFS client support (Web Feature Service, Open Geospatial Consortium);