Hybrid nature-based solutions for water management under climate stress: performance, sustainability, and scalability in the Global South

ABSTRACT

The hybrid nature-based solutions (NbS) are a potential solution to water management in the Global South as climate changes pose increasing challenges. This review reports on the performance, sustainability, and scalability of hybrid NbS in wastewater treatment, stormwater treatment, and flood protection. These results confirm that hybrid systems have 80–95% removal rate for BOD/COD, 60–85% removal rate for TN/TP, and 2–4 log reduction in pathogens in comparison with standalone NbS. Further, these systems provide carbon sequestration rate of 1.5–5.0 t CO2-eq ha−1 yr−1 for a single system, energy use save of 30–60%, and reduce operating costs by 20–50% over traditional grey infrastructure. They enable biodiversity conservation and resource reusing, but their mainstream adoption is constrained by fragmented governance, access to financing, and inadequate monitoring and evaluation. Based on experiences and lessons from successful and documented failures in countries like India, China, Brazil, and South Africa, the current review explores design, operation, and institutional factors that impact performance and the role of hybrid NbS in resource-constrained contexts. This review also addresses the implications for scaling hybrid NbS in resource-constrained settings and the need for integrated planning, stakeholder engagement, and adaptive management for climate resilient water systems.