Economic valuation of the contribution of a protected area to water quality in the mountainous region of Santa Catarina, Brazil

Protected areas play a crucial role in preserving natural resources and providing essential ecosystem services. Therefore, the present study aimed to estimate the economic value of the contribution of the protected area denominated the Farofa Mountain Range Complex to the preservation of springs in the mountainous region of the state of Santa Catarina, Brazil. The area preserves 4987.16 ha with native forests and has springs that form the Caveiras River, which supplies water for human consumption in the city of Lages. The novelty of this paper resides in the determination of valuation using two methods combined with physicochemical water quality variables. The contingent valuation method considered a sample of 374 interviewees who expressed their “willingness to pay” for preserving and conserving the area. The reduction in water treatment costs for the human supply in the city of Lages was also estimated using the “avoided costs“ method, considering the reduction in chemical products resulting from the improvement in the physicochemical variables of the water from the protected area. The results showed that 37.4 % of respondents were willing to contribute an average pay amount of $1.27 per family/month, corresponding to a total economic value of 6.46 to 28.21 million dollars, depending on the opportunity cost of capital adopted in Brazil. The reduction in water treatment costs due to the better quality produced by the protected area corresponded to a potential average avoided cost of 11.0% and 3.6% in the polynomial and logarithmic models, respectively, compared to expenses with conventional treatment. The results demonstrate the importance and relevance of the protected area as an important provider of ecosystem services and water resources. The combination of two valuation methods and water quality data proved to be complementary in this study, expanding the scope of the assessment.