Extended Abstract
Introduction: Evaluating the water resources adequacy in watersheds to meet local community needs is critically important—particularly in arid and semi-arid regions where water scarcity and environmental stress are significant. In the context of ongoing climate change and unsustainable water management practices, a comprehensive and multidimensional evaluation of water adequacy—encompassing quantitative, qualitative, institutional, and social dimensions—is essential. In Iran, as a country with a large proportion of arid and semi-arid regions, the necessity of addressing this issue is increasingly apparent. Accordingly, a systematic review of indicators and models for assessing water adequacy, accompanied by critical analysis and identification of research gaps, can provide a reliable foundation for developing evaluation frameworks that are suited to national conditions. Previous studies—largely based on approaches involving quantitative indicators, qualitative measures, institutional-social metrics, and simulation or decision-making models—have made significant contributions. However, they also exhibit several limitations, including a narrow focus on one or two dimensions (e.g., solely quantitative or qualitative), lack of context-specific indicators for dry regions with variable precipitation and limited resources, insufficient attention to social components such as local community resilience, distributive justice, and indigenous knowledge, and the absence of integrated conceptual frameworks that combine indicators with modeling tools and the actual needs of watershed inhabitants. Only a limited number of studies have succeeded in integrating productivity indicators, simulation models, and institutional measures to offer a comprehensive picture of water adequacy. Moreover, most existing research has not adequately addressed the specific needs of watershed communities in arid regions in terms of livelihoods, resilience, and participation. This review article comprehensively analyzes the most critical indicators, models, and challenges related to the evaluation of water resource adequacy in watershed areas, with a particular emphasis on the applicability and adaptability of these approaches to watersheds in arid and semi-arid environments.
Materials and methods: This critical analytical review study was conducted through a comprehensive search of international databases (Scopus, ScienceDirect), academic search engines (Google Scholar), and nationally credible databases (SID, Magiran), with source selection based on scientific credibility and thematic relevance. Through an analytical framework, the identified indices and models were categorized into six distinct groups: (1) quantitative indicators, (2) qualitative indicators, (3) institutional-social indicators, (4) productivity and indirect consumption measures, (5) risk and resilience metrics, and (6) simulation and decision-making models for water adequacy assessment. Each category was examined to identify its advantages, implementation challenges, and limitations, with particular emphasis on arid and semi-arid regions. The final synthesis focused on analyzing studies employing integrated approaches.
Results and Discussion: The review of 130 selected scientific studies reveals that, foremost, quantitative indicators are among the primary tools used to assess water resource adequacy in watersheds. At more advanced levels of analysis, qualitative indicators—particularly in studies concerned with environmental aspects—have received increasing attention. Additionally, indicators of indirect water use, such as water footprint, virtual water, and economic–physical productivity, have enabled recent studies to explore the water–livelihood nexus at both micro and macro scales. Institutional and resilience-related indicators—such as stakeholder participation, institutional flexibility, and the adaptive capacity of local systems—have opened new perspectives for understanding socio-structural sustainability in the context of water adequacy evaluations. Given the complexity introduced by limitations such as the lack of reliable data, institutional fragmentation, and environmental challenges, integrating various indicators and models—while considering the specific characteristics of arid and semi-arid regions, including those in Iran—is essential for delivering more accurate and practical assessments of water adequacy. Moreover, greater emphasis on institutional-social dimensions, as well as on risk and resilience, contributes to a deeper and more comprehensive understanding of the issue, and lays the foundation for the development of sustainable water resource management policies and strategies.
Conclusion: To enhance the effectiveness of evaluations, there is a need for up-to-date field data, coherent conceptual frameworks tailored to the specific region under study, and cross-sectoral collaboration. Future research must develop dynamic indicators and integrated, empirically-grounded models that address the evolving needs of watershed communities in arid and semi-arid regions and to support the achievement of sustainable water security. This study can provide valuable insights for water resource managers and policymakers to improve decision-making and promote sustainable resource management.