Document Type : Research Paper
Authors
1 Associate Professor, Soil Conservation and Watershed Management Research Department, Fars Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Shiraz, Iran
2 Assistant Professor, Desert Research Department, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
3 Assistant Professor, Soil Conservation and Watershed Management Research Department, Kurdistan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Sanandaj, Iran
4 Ph.D., Natural Resources and Watershed Management Department, Bafgh County, Yazd Province, Iran
Abstract
Introduction
Currently, drought poses a significant threat to food security due to reduced rainfall and increased agricultural demand. Its impact is particularly severe in arid and semi-arid regions, where populations are more vulnerable. Drought affects groundwater systems by initially lowering water supply, followed by a decline in groundwater levels and discharge. Compared to other types of drought, characteristics such as duration, intensity, and frequency alter groundwater systems.
Materials and methods
Given the critical need for drought assessment and monitoring, this study investigated drought conditions in 12 areas within the Daranjir Watershed from 2002–2003 to 2017-2018. The watershed spans approximately 50,736.44 km² across Yazd and Kerman provinces, with elevations ranging up to 1,857.90 meters. Highlands cover 58.99% of the area, while plains cover 40.99%. Data on groundwater levels from observation wells were obtained from Iranian Water Resources Research Organization (Tamab) and regional water organizations in Yazd and Kerman provinces. Average monthly groundwater level values were then extracted from maps using inverse distance weighting interpolation in MATLAB. Groundwater drought conditions were subsequently calculated based on the Groundwater Resources Index (GRI) in MATLAB.
Results and discussion
The GRI index calculations revealed severe droughts in Daranjir, Bardsir, and Qaryeh al-Arab deserts, with deficits of 81.38, 77.75, and 75.66, respectively. Qaryeh al-Arab experienced the longest drought, spanning 121 months, indicating the area's high intensity and prolonged drought conditions compared to other study areas. Mild droughts were the most frequent after normal drought across all study areas based on GRI index class frequencies.
Conclusions
Due to insufficient and highly variable atmospheric precipitation, drought is inevitable, especially in arid and semi-arid climates. Understanding drought severity and its impact on ecosystems is crucial for effective watershed resource management and optimal resource utilization. Continuous monitoring of groundwater levels due to drought and preparation of a comprehensive atlas for other watersheds in the country are recommended. Additionally, comparing drought conditions using appropriate models is essential. Short and long-term strategies are advised to mitigate this natural phenomenon, such as expanding greenhouse crop cultivation, utilizing drought-resistant crop varieties with high water efficiency, adopting pressurized irrigation systems, and implementing infrastructure projects to enhance groundwater and surface water storage, such as cement dams, reservoirs, and floodwater spreading systems in the study area.
Keywords
J. Watershed Manage. Res. 9(17), 269-279 (in Persian).
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