New method of valuation of hydrological services using water supply and demand permanence curves under climate change

Abstract

Given the current scenarios of water crisis and the occurrence of extreme hydrological phenomena, there is a need to attribute economic value to the benefits offered by the environment, also called ecosystem services, in a river basin scale.Ecosystem services can be valued through analyzes of supply and demand, as well as in the market economy, even though the said ecosystem services are not private goods and services.However, to date, there is no unified methodology for ecosystem valuation assessment that includes scientific elements of change in future scenarios and, at the same time, is easily assimilated by river basin committees.In this research, these new hypotheses with viable objectives and methodologies that are easy to apply in Brazilian basins will be assigned to value hydrological (ecosystem) services. Watershed protection services will be selected, and there will be made analysis of qualitative and quantitative permanence curves of hydrograms with and without changes. On the one hand, the methodology demonstrates how it is possible to attribute a new ecosystemic view, with its respective valuation, to the availability and to the demand for self-depuration of the river basin, based on the legal instruments for framing water bodies. Furthermore, this kind of research supports the development of strategies to mitigate the effects of these changes, such as the Ecosystems-Based Adaptations (EbA), exemplified by initiatives of Payment for Environmental Services (PES, specifically PES-Hydric), and common to the same research group. The EbAs use hydrological (ecosystem) services to help communities adapt to global changes. In the case of PES programs, valuation is essential to determine the financial incentives that will be distributed to those responsible for environmental conservation. Moreover, it is essential to execute the ecohydrological monitoring of basins under EbA to test the effectiveness of these initiatives and to see the benefits obtained from them.Then, considering vectors of climate change and soil use of future scenarios from the INCTMC2 results, the new valuation method incorporates these changes in the quali-quantitative permanence curves. Estimates of permanence curves from the RCP 4.5 and RCP 8.5 scenarios of the Eta / HadGEM and Eta / MIROC models for periods 2020-2040, 2050-2070 and 2080-2099 will be contrasted with the (historical) baseline of 1980- 2010.The application includes a total of 14 river basins, of different special scales, with different uses of the soil, located in the states of São Paulo, Minas Gerais and Paraná. This Project is linked to the Subcomponent of Water Security of the National Institute of Science and Technology on Climate Change - Phase 2 (FAPESP - Thematic Project # 2014/50848-9), in association with CEPID/CeMEAI (FAPESP # 13/07375-0).The discussion of results will be contrasted with the Hydrologic Services Index (HSI), proposed by Taffarello et al. (2018), in order to assess the advantages, limitations and uncertainties of the new valuation methodology. This scientific initiation project is linked to INCTMC2 and supports other research projects already completed, besides four in progress: a PhD, a master's degree, a scientific initiation scholarship and a postdoctoral scholarship, participating in the same research group, with EESC-USP.