GIBSI – An integrated modelling system prototype for river basin management

This paper introduces GIBSI, an integrated modelling system prototype designed to assist decision makers in their assessment of various river basin management scenarios in terms of standard water physical and chemical parameters and standards for various uses of the water. GIBSI runs on a personal computer and provides a user-friendly framework to examine the impacts of agricultural, industrial, and municipal management scenarios on water quality and yield. A database (including spatial and attribute data) and physically-based hydrological, soil erosion, agricultural-chemical transport and water quality models comprise the basic components of the system. A geographical information system and a relational database management system are also included for data management and system maintenance. This paper illustrates potential uses of GIBSI by presenting two sample applications applied to a 6680 km2 complex river basin (63.2% forest, 17.2% agricultural land, 15.3% bush, 3.1% urban development and 1.2% surface water; population: 180 000) located in Québec, Canada: (i) a timber harvest scenario and (ii) a municipal clean water program scenario. Simulation results of the timber harvest scenario showed how clear-cut activities could lead to earlier and larger spring runoff than in the investigated reference state. Results of the municipal clean water scenario revealed that substantial reduction in coliform counts and total phosphorus could be made by constructing and operating wastewater treatment plants. These applications provide a framework of how GIBSI can be used as a decision support system and ultimately as a means of incorporating sound science into political decisions involving river basin management.