Integrating Water Accounting and System Thinking: A Novel Framework for Human-Water Nexus Management in Water-Scarce Regions

• A hybrid systemic framework was proposed for complex human-water nexus modeling • The Rich-SD robustly captures necessary implications for coherent policy making • RICH-SD framework advances in quantitative modeling and problem conceptualization • A holistic approach is needed to capture the complexity of human-water nexus • Effective demand management to raise social awareness about water shortage Effective management of human-water (HW) systems is essential for sustainable agricultural water strategies, particularly in water-scarce agriculture. While System Dynamics (SD) models offer a holistic view of socio-hydrological interactions, their effectiveness is often limited by inadequate representation of feedback loops and insufficient integration of economic and environmental factors. To address these limitations, this study presents the Water Accounting-Archetype System Dynamics (RICH-SD) framework, which combines SEEA-Water accounting, system archetypes, and SD modeling to enhance both qualitative and quantitative assessments of HW interactions. The framework was applied to the Arak Plain, Iran, demonstrating its effectiveness in improving problem conceptualization, quantitative analysis, and scenario-based policy evaluation. Results highlight a paradox in agricultural water management: the expansion of high-efficiency irrigation, intended to conserve water, often creates a false sense of security, driving agricultural expansion, increasing water demand, and exacerbating groundwater depletion—aligning with the “Fixes that Backfire” and “Limits to Growth” system archetypes. Policy evaluation revealed that a strategy combining high-efficiency irrigation with full wastewater reuse provided the greatest overall benefits, reducing groundwater depletion by 56.97%, increasing agricultural water productivity by 15.2%, and raising per capita income by 9.67%. Meanwhile, groundwater withdrawal control with partial wastewater reuse was the most effective in reducing water stress (-14.1%) and agricultural water consumption (-49.19%), highlighting the necessity of groundwater extraction limits for long-term sustainability. This study underscores the value of integrated HW system modeling in mitigating unintended consequences and guiding more effective water management policies in water-scarce agricultural regions.