Modelagem da cobrança pelo uso da água bruta para aplicação em escala real na bacia do rio Santa Maria

Abstract

In the last decade, significant intensification has occurred in studies on raw water charges. However, the real possibility of charge application has provoked questions and concern in society, mostly due to the few studies developed where charges were actually applied. The main objective of this research was to evaluate the applicability of raw water charges in a Brazilian basin, taking into account the limitations of existing data, other management instruments previously studied in the basin and the opinion of the water basin management committee. First, records on basin water users were improved and made consistent. Next, a raw water charge model was developed and simulated, based on actions indicating the annual values that need to be collected. Economic impact and social acceptability were analyzed. The results obtained were compared with simulations performed using raw water charge models of the CEIVAP and PCJ committees. For orientation of the values to be charged, the following principles were used: (a) PUP User-Pay Principle; and (b) PPP Polluter-Pay Principle. The Santa Maria River Basin was chosen as the case. It is located on the southernmost border of the state of Rio Grande do Sul. It has an area of 15,754 km² and its main economic activity is rice production. For the R$ 68.5 million investment financed over 20 years, the average fee was R$ 0.0085/m³, but this value could vary from R$ 0.0001/m³ to 0.0294/m³ according to the weights of the variables established in the model. The levying by sector was: Agriculture 44.85%; Urban Water Supply 41.35%; Rural Water Supply 12.36%; Industry 0.20%; and Cattle raising 1.24%; and by type of use was: Collecting 27.18%; Consumption 21.71% and Dilution 51.10%. The different simulations showed that the charging in the Santa Maria River Basin is viable, providing that the economic impact on sector users is determined. The present study also observed that the basin population is unaware of the management system for water resources. However, the general population is in favor of charges based on the objectives established in Brazilian legislation. The present study demonstrated that the principal aim of the initial raw water charge application process in Brazil will be the obtainment of financial resources to solve the problems of basin water resources. Nevertheless, the way to achieve this must be based on criteria of justice, efficiency and environmental sustainability and not based merely upon political decisions or social criteria.