Development of an Integrated Drought Risk Map Using the Water Resources Approach Process Model: a Case Study of the Zayandehrud Dam Catchment, Iran

Almasinia, Mohammad; Moradi Shahgharyeh, Yousef

doi:10.22093/wwj.2026.579368.3547

Development of an Integrated Drought Risk Map Using the Water Resources Approach Process Model: a Case Study of the Zayandehrud Dam Catchment, Iran

Articles in Press

Document Type : Case study

Authors

Mohammad Almasinia ¹

Yousef Moradi Shahgharyeh ²

¹ Assist. Prof., Dept. of Geography, Faculty of Humanities, Payame Noor University, Tehran, Iran

² Retired, Dept. of Water Engineering, Isfahan University of Technology, Isfahan, Iran

10.22093/wwj.2026.579368.3547

Abstract

Drought is a recurring and destructive natural hazard in arid and semi-arid regions, where its impacts are often intensified by human-induced factors such as land degradation and groundwater overexploitation. Conventional drought assessments typically depend only on climatic indices and overlook the physical characteristics of the catchment that determine actual vulnerability. This study presents an integrated methodology for drought risk assessment through the development of a Water Resources Approach Process model. The WRAP framework combines a meteorological drought index (Standardized Precipitation Index) with key physical catchment attributes–including geology, geomorphology, land use, slope, and erosion potential–to produce comprehensive hazard and vulnerability maps. The methodology is applied to the Zayandehrud Dam Catchment in central Iran, a semi-arid region facing severe water stress. Long‑term data (1971–2014) from 15 meteorological stations and 9 streamflow gauges are analyzed. Homogeneity tests (Pettitt, SNHT, Buishand, von Neumann) are used to ensure data quality, and the Mann‑Kendall test is applied to detect trends. Drought hazard is characterized using the 12–month SPI, while vulnerability is assessed by integrating thematic layers of landform, geology, slope, groundwater depth, and erosion risk through a weighted scoring approach within a GIS environment. The final drought risk map is generated by overlaying the hazard and vulnerability layers on a 20 × 20 km grid. Results indicate that approximately 45% of the catchment area falls into high or very high drought risk categories. The western and north‑eastern sub‑catchments exhibit the highest risk due to a combination of high climatic variability, steep slopes, erosive soils, and intensive groundwater abstraction that has led to land subsidence. The central parts show moderate to low risk because of more favorable geological conditions for water retention. The WRAP model proves to be a robust tool for identifying drought‑prone areas and for supporting integrated water resources management and disaster risk reduction strategies in semi‑arid catchments.

Keywords

Drought Risk, Water Resources Approach Process Model, Standardized Precipitation Index

Vulnerability Mapping, GIS, Zayandehrud Dam Catchment

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