[A-HW22] Material transportation and cycling in watershed ecosystems; from headwaters to coastal areas

[AHW22-01] Integrating traditional and new water solutions to increase cities' resilience in tackling global climate change problems

★Invited Papers

*Ricardo Hirata¹, Shin-ichi Onodera², Mitsuyo Saito³, Yuta Shimizu⁴, Reginaldo Bertolo¹, Edson Wendland¹, Luciana Rodrigues Ferreira⁵ (1.USP University of Sao Paulo, 2.Hiroshima University, 3.Okayama University, 4.National Agriculture and Food Research Organization, 5.Institute of Geological Institute of the State of São Paulo)

Keywords:conjunctive surface and groundwater, integrated water resource management, aquifer remediation, managed aquifer recharge

Between 2013 and 2017, periods of drought generated a water supply crisis that affected 48% of Brazilian municipalities, causing severe public health and economic problems at a national scale. Traditional solutions, based on centralized single-source water systems, have been ineffective in Brazil and developing countries. The main objective of this project is to create new hydro-economic hybrid solutions to reduce the water vulnerability of urban and rural areas, integrating into unprecedented fashion classic and innovative engineering, management, and nature-based techniques solutions (NE&MS). The development of methods for the remediation of aquifers contaminated by diffuse or multipoint sources, based on NE&MS, will increase the not potable water availability. The proposal is based on groundwater flow and reactive transport model (coupled with a surface water model); concepts of water resources allocation and conjunctive surface-groundwater use; low-cost groundwater treatment solutions (phytoremediation and reactive barriers, focusing on nitrate and emerging contaminants); managed aquifer recharge (MAR); and riverbank filtration systems. These solutions are being evaluated within an original administrative arrangement for water resource management, considering economic aspects, social habits of private and public water users, and land-use policies. A range of solutions and institutional involvement is being tested in a pioneering fashion based on deepening the relationships between city-countryside and ground-surface water in the Bauru-Batalha watersheds, where the municipalities of Bauru, Piratininga, and Agudos (São Paulo State in Brazil) are partially located. All the cutting-edge interdisciplinary scientific experience in the areas of hydrogeology, hydrology, water resource engineering, socioeconomics, and water governance, based on the development and adaptation of intersectoral NE&MS, allows the creation of a multiple-solutions hydro-economic digital platform that assists in the water resource management, tailored to the biophysical and socio-economic conditions of the study area. This is an ongoing project, and the text presents the basic conceptual model and strategy for its development, looking for the synergies of different methods for optimizing strategies for tackling global climate change problems.