A tale of two cities: public preferences for nature-based solutions and the effect of drought-related experiences on willingness to improve water security

• Autor(a) principal: Sone, Jullian Souza
• Data de Publicação: 2023
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/18/18138/tde-10012024-154025/
• topic: adaptação à escassez hídrica; drought adaptation; economic valuation; falta d\'água; gerenciamento de recursos hídricos; valoração econômica; water management; water shortage

Societal behavior and perceptions of water scarcity is expected to play a critical role in ensuring water security. Nonetheless, these drivers need to be better understood mainly because water scarcity-related experiences seem to influence public attitudes differently across countries. Thus, this thesis addresses: (i) how different experiences with water restrictions and rationing trigger people to invest in conversation measures and (ii) how public perception of nature-based solutions (NbS) affects preferences for this kind of measures to improve water watershed services. To explore these questions, water security is assessed in Campo Grande (CG) and the São Paulo Metropolitan Region (SPRM) by contrasting water demand with probabilistic levels of water availability under climate change and water demand scenarios. Then, a discrete choice experiment was used to investigate public preferences for measures to reduce the frequency and duration of future water shortages. These two sites and their respective supplying basins were chosen since their population has faced different restrictions and rationing efforts. In the first chapter, the foundation is laid for the problem statement and research questions. The results and methods are then divided into two parts: (i) water security under climate change and (ii) willingness to pay (WTP) to improve water security. This thesis\' general conclusion is also presented in the third and last part. Part I starts with the respective methods adopted to assess future water security in the two basins feeding CG and the SPMR. The physically-based model SWAT+ was used to simulate the basins\' hydrological response to three different Shared Socioeconomic Pathways (SSP): (i) SSP2-4.5 (medium forcing), (ii) SSP3-7.0 (medium-high forcing), and (iii) SSP5-8.5 (high forcing). An imbalance between availability and demand is the main driver of water insecurity in the Guariroba basin, which supplies CG. Due to a decrease in precipitation, water scarcity risk considerably increases in the future in the Jaguari basin, which supplies the SPMR. Even a reduction of 20% by 2070 in water demand is not enough to improve water security in both basins. This finding highlights the need of non-strutuctural measures such as NbS to safeguard future water supply. In part II, the material and methods adopted to design and implement the choice experiment in CG and the SPMR are described in detail, as well as the econometric models estimated to investigate public preferences and WTP for NbS to improve drinking water reliability. Water rationing experiences significantly influence public decision-making and WTP for NbS in both cities. Agroforestry is the most preferred solution in both cities although a considerable share is uncertain about the effectiveness of NbS. Protest motives are also explored in this part, and the main reason for nonparticipation is the lack of trust that the public authorities would invest the money in the measures. Part III provides an overview of the thesis outlining key findings and a general conclusion putting together all evidence contributing to answering this thesis\' research questions. The findings indicate that there is public understanding for the need of environmental protection in watersheds feeding cities to achieve water security and support for NbS. The findings of this study provide important insights into relevant feedback between droughts and societal vulnerability and response inserted into the present-day Brazilian cultural, socioeconomic, and political context.