The Use of Urban Wetlands as an Integrating Element for Wastewater and Stormwater Solutions in an Ecosystem-Based Disaster Risk Reduction Approach: A Case Study in Rio de Janeiro, Brazil

This study addresses significant flaws in the separate sanitary sewer system of major Brazilian cities, where sanitary and storm sewers often face operational difficulties due to undersized systems or irregular connections. Such flaws result in the overloading of networks and environmental degradation of water bodies, particularly during dry periods due to untreated stormwater contamination. Additionally, climate change poses further risks with potential precipitation increases that exceed these systems’ hydraulic capacity. To mitigate these challenges, the study proposes the Ecosystem-Based Disaster Risk Reduction Approach, which leverages ecosystems to support urban resilience. A key solution highlighted is constructing wetlands, which mimic natural wetlands, to restore water storage and improve environmental quality. The study applies a Multilayer Hydrodynamic Unified Simulation (MODCEL-MHUS) integrating urban stormwater, sanitary sewer, and surface flow systems. This method, coupled with an environmental quality model, was applied in a pilot basin to evaluate its effectiveness. The findings suggest that constructed urban wetlands play a crucial role in flood mitigation and enhancing wastewater treatment, contributing to biodiversity preservation, and offering ecosystem services within urban areas.