Reframing Valuation Paradigms for Levee-Setback Projects: A Critical Synthesis of CBA, ESV, and MCDA in Floodplain NbS Evaluation
Ruoxuan Wang, MLWS 2025
Nature-based solutions (NbS) are now widespread attention in the field of flood management due to their synergistic ecological, social and economic benefits. However, the current mainstream assessment methodology is still centered on traditional cost-benefit analysis (CBA), which overemphasizes the monetizable benefits of flood control and systematically ignores non-market benefits such as biodiversity, recreational experiences and cultural values. This “misalignment” has led to a serious underestimation of the true value of NbS. This study systematically reviewed the evaluation literature of 59 NbS flood management projects between 2015 and 2025, and identified three new dominant valuation paradigms: Enhanced CBA (incorporating ecosystem service value estimation), Multi-Criteria Decision Analysis (MCDA), and Foundational Assessments. The study found that from 2023 onwards, more than 80% of the literature has shifted to convergent or non-monetized valuation approaches, marking the gradual disintegration of the single-indicator valuation paradigm. The study found that from 2023 onwards, more than 80% of the literature has shifted to convergent or non-monetized valuation approaches, marking the gradual disintegration of the single-indicator valuation paradigm.
