Long-Term Changes of Metrological, Hydrologic and Underground Water Resources of Dasht-e-Argan Basin and Their Impacts on Argan Internationally Important Wetland

Document Type : Research Paper

Authors

1 Department of Natural Resources and Environmental Engineering, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran

2 Department of Environment, Fars Province, Shiraz, Iran

Abstract

Arjan Wetland is one of the most internationally important wetlands of Iran. This wetland has been dried in the last two decades, except for short seasons in other dry seasons. The purpose of this study was to estimate the water requirement of Arjan wetland. By examining long-term meteorological and hydrological statistics of stations located in the wetland watershed and adjacent watersheds, rainfall, evaporation, temperature changes and groundwater aquifers and runoff of the wetland basin were analyzed. Also, the water balance of the wetland was estimated based on the long-term climaticcondition and the historical hydrological regime of the basin. The data showed a decreased trend of precipatian and increased trends of temperature and underground water harvesting in studied area.Comparison of the amount of water stored in the reservoir of Arjan lake in the current situation (95.49 mm) and the report of the Atlas of Water Resources of Iran (109.40 mm) shows a significant decrease in recent years. Also, a comparison of the current runoff (13.90 mm) with the Atlas of Water Resources (15.64 mm) shows a decrease in this amount. However, the amount of underground flow entering the lake reservoir has not changed much, so that in the Atlas this value is 82.74 mm and in the current situation is 82.36 mm. Also, the results showed that the groundwater level had a decreasing trend and the last estimated year (2019) had the lowest groundwater level. years: 7.5 million cubic meters. In conclusion, the results of this study show that the drying of Arjan wetland is affected by both climatic and human factors.

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