[A-HW18] 流域圏生態系における物質輸送と循環：源流から沿岸海域まで

[AHW18-01] Water security: Integrating Hydrological and Socio-Economic Cycles

★Invited Papers

*Ricardo Hirata¹、Reginaldo Bertolo¹、Juliana Gardenalli de Freitas²、Alexandra Suhogusoff¹、Carlos Gamba³、Shin-ichi Onodera⁴、Mitsuyo Saito⁴、Leila Goodarzi¹、Leonardo Capeleto de Andrade¹ (1.Universidade de São Paulo、2.Universidade Federal de São Paulo、3.Instituto de Pesquisas Tecnológicas、4.Hiroshima University)

キーワード：integrated water resource management, water crisis, surface and groundwater conjunctive use

According to UNICEF, four billion people experience severe water shortages for at least one month a year. Overcoming the lack of water is one of humanity's most significant challenges. It has implications for people's survival, social well-being, food security, and preserving natural and anthropic environments. For example, half of the cities in Brazil (South America) declared a water crisis between 2014-2016 due to the most severe drought in 80 years. However, water crisis is not an exclusively climatic phenomenon. It is configured when there is a lack of water in sufficient quantity and quality to serve users in a given region and at a given time, and occurs when three phenomena happen synchronously: (i) Hydrological drought or physical scarcity; (ii) lack of water supply infrastructure or economic scarcity; and (iii) lack of water resources management or poor governance. Thus, the definitive solution lies in integrating the hydrological cycles with the socioeconomic and political cycles, where environmental preservation must also be thought of as a benefit inducer to life in the long term. Specifically, within the concept of integrated water resource management, water security (as opposed to scarcity) has to consider increasing water supply (in space and time) and reducing demand, involving three strategies: (i) engineering and hydrogeology (knowing and investing) - which refers to financial investments in increasing production, storage, and distribution of water, managed aquifer recharge, water reuse technologies, controlled aquifer exploitation, surface and groundwater treatment (aquifer remediation); (ii) management (mandatory): conjunctive surface and groundwater use, water resources allocation, policies for the protection of surface and groundwater sources, anthropic pollution control, incorporation of “private water producers” in the city public water supply, planning of land use and water consumption; and (iii) social communication (induce and promote): awareness for the definition of socially inclusive practices and policies (democracy to water access). The solution to water crisis is a complex issue in any society, but it is more difficult in poor and developing countries because they move more towards short-term interests, and only traditional engineering solutions are primarily applied. Although factors such as the lack of financial investment can be one of the most significant constraints on water resources policies, it must be recognized that management mechanisms are also fundamental, as demonstrated in recent studies in Brazil, within the scope of the SACRE Project: integrated water solutions for resilient cities (Proc. FAPESP 2020/15434-0, 2022/652-7; CNPq 423950/2021-5). This project results from an international consortium involving Brazilian, Japanese, and Canadian universities and government managers, which seeks to generate technical knowledge and management solutions to subsidize and induce new water and environment policies and governance.