Water Quality Planning for Sustainability in the Pojuca River Basin (Brazil)

The work presented in this paper, supported by a bilateral Italo-Brasilian project, concerns water quality planning in view of long-term use sustainability for the Pojuca River Basin (Bahia, Brasil). Planning was performed with the aid of a Decision Support System (DSS) consisting of several submodel components. Among these, a surface-water quality model for the definition of the concentration distribution of total phosphorus, BOD, dissolved oxygen concentration and thermo-tolerant coliform bacteria pollution. Another submodel evaluates the riverine microhabitat applying autochthonous fish species habitat suitability indexes (water depth, velocity, substrate and dissolved oxygen) as evaluated 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. The 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