A software system is presented, GIBSI, and this system was developed as a tool to assist decision makers in their management of water resources considering water quality and also quantity at watershed level. Simulations can be done with this software that is composed of a Geographical Information System (GIS), a Relational DataBase Management System (RDBMS) and simulation models. The user-friendly interface of the GIBSI is design for easy use and simulations with different management practices for agriculture, industrial and municipal applications can be made. The Chaudiere River watershed is currently represented in the GIBSI, as all spatial and attribute data have been collected and integrated in the GIS and the RDBMS.

The GIS system used is Grassland and the database system is Access TM. The model is made of submodels that represent five major processes: hydrologic cycle, the soil erosion process, the river erosion process, the transport of agricultural chemicals and the evolution of water quality. The precision of such system depends greatly on the accuracy of the data used and also the ability of the model used to well represent the reality. No information is given on this accuracy and the sensitivity of the system to different manure management or practices and the impact on the water quality.