Analyzing water ecosystem services in green urban areas and efficiency of Nature-based Solutions (NbS) for removing nutrients from surface and groundwater

Abstract

"Nature-based Solutions" (NbS) employ or mimic natural processes performed by soils, plants, and the hydrological cycle, to increase water resources availability and to recover (rehabilitate) water quality. Their economic efficiency and effectiveness in securing water supply are studied increasingly as less costly and more ecologically sustainable water supply approaches than traditional engineering-based methods. The use of vegetation cover, for example, can restore ecosystem services associated with the protection of water resources. However, only a few studies related to aquifers, and such studies are virtually nonexistent in Brazil. Phytoremediation is one of the NbS that use plants and trees and their interactions with microorganisms to treat polluted soils and water. Although phytoremediation has been used to nitrate removal from water by exotic tree species and by eucalyptus, no experiments have tested the performance of vegetation cover with species-specific to São Paulo, nor have analyzed the geochemical environment under the vegetation, or how this can assist in the groundwater treatment process and the induction of denitrification. The scientific challenge is to evaluate green urban areas' efficiency in improving groundwater quality and increasing water availability through induced changes in the hydrological cycle components, such as runoff/infiltration, recharge/evapotranspiration/interception, and irrigation with water from other sources (MAR, Managed Aquifer Recharge). This project aims to develop a pilot-scale system to remediate urban aquifers and rivers contaminated by dispersed and multiple sources based on phytoremediation with native forest (NbS) and MAR technique. Methodology: A pilot-scale project will be developed at the "Horto Florestal" in Bauru city to assess the capacity of using phytoremediation coupled with managed aquifer recharge to remove nutrients and emerging contaminants from the surface and groundwater. An area with adult native trees will be irrigated with contaminated water from a small tributary of the Bauru River to test the NbS based on phytoremediation. This area will be selected considering the trees' type, age, and groundwater depth. Monitoring multilevel wells will be constructed to evaluate the system efficiency with periodic and continuous parameters analysis. (AU)