Abstract
The paper presents the structure and the application of a Decision Support System (DSS) to Pojuca River watershed placed in the Northeast Region of Brazil (Bahia State). It is composed of surface-water quality models (total phosphorus, BOD, dissolved oxygen concentration and thermo-tolerant coliform bacteria pollution). A model evaluates the riverine microhabitat applying autochthonous fish species habitat suitability indexes (water depth, velocity, substrate and dissolved oxygen) valuated by local ichthyologists. Surface-water quality and microhabitat models are based on a hydrologic and hydraulic model. Models have been calibrated and validated using discharge and water quality measurements collected during a 1.5-year period of monitoring. Output data are available on a spreadsheet and ready to be spatially analyzed in a GIS software. We show how DSS can help the decision-making process to achieve the sustainable development of the basin, considering population growth, economic activities, climate change, management of sewage and wastewater treatment systems. The DSS is also applied to a challenging scenario: the building of an in series reservoir for supplying the Capital (Salvador) of drinking water. The experience has been characterized also by a large involvement of local specialists, with the aim to emphasize the existing qualifications and to consider local culture.