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
