Abstract

For the last ten years, the Association quebecoise des techniques de l’environnement (AQTE) and Ministère de l’environnement et de la faune (MEF) have been involved in the definition and development of an integrated water resource management plan at the watershed level (AQTE, 1993). An integrated water management plan is currently being implemented in the semi-rural watershed of the Chaudière River by the Comite regional du bassin de la Rivière Chaudière (COBARIC), (COBARIC, 1996). Similar plans for managing other watersheds (the Saint Charles and the Assomption River basins) are also being considered. In collaboration with the MEF and the Quebec Urban Community (QUC), the Institut national de la recherche scientifique (INRS-Eau) is develop-ing a framework for the integrated water management of Quebec's urban areas (Vescovi and Villeneuve, 1996a). The main objectives of an integrated water management approach in the Quebec City region are to develop support among community planners and water managers for an ecosystem-based approach to land use (see Figure 6. 1); water planning and management criteria; and, tools to assess the health of critical streams within the Saint Charles River basin and the QUC.

The first step in a successful urban water management program is to maximize the knowledge of the dynamics between the rural and urbanized portions of a river basin and the principal sources of surface water contaminants (see Figure 6.2). Several diagnostic tools are available to accomplish this.

Probably, the most flexible means of water resources management are rapidly emerging software systems that integrate simulation models, geographical information systems and database management systems. An example of one such system is GIBSI (Gestion Intégrée des Bassins a l’aide d'unSystème Informatisé), which is being developed at INRS-Eau. Work on establishing the needs of the system was carried out in 1995 and the first applications were carried out in 1996 (Villeneuve et al., 1996). These initial applications raised some questions as to the suitability of the model for diagnosing the water quality status of moderately urbanized river basins.

This chapter proposes an integrated watershed modeling approach to develop water management programs in urbanized river basins. This approach provides a means of delineating and incorporating urban areas as subwatershed units of a river basin, as well as a unique way of improving water management by initiating partnerships between users of water resources.

To determine their suitability, two operational simulation models (a hydro-logical model and a water quality model) were applied to the moderately urbanized 550-kM2 Saint Charles River basin. Because the main objective of this study was to use simulation models for diagnosing a past event, CEQUEAU (Morin et al., 1995) was calibrated against data available for a specific period and no further model validation was performed. Simulations with QUAL2E (Brown and Barnwell, 1987) were performed without calibration. The models were chosen because of their high robustness and user-friendliness. The proposed catchment modeling process makes the most effective use of the available data in the watershed.

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