Hydrogeochemical evolution in aquifer of Iranshahr plain

Articles in Press

Document Type : Original Article

Authors

• Masoomeh Navardi ¹
• Reza Jahanshahi ²
• Naser Asadi ¹
• Mohammad Reza Mirbalouchzehi ³

¹ Geology Department, Faculty of Sciences, University of Sistan and Baluchestan, Zahedan, Iran.

² School of Geology, College of Science, University of Tehran

³ Sistan and Baluchestan Water and Wastwater Co., Iran.

10.22067/jfcei.2024.89496.1318

Abstract

This research investigated the hydrochemistry and quality of the groundwater resources in the Iranshahr plain, Sistan and Baluchestan Province, South East of Iran. Major ions, electrical conductivity and pH of groundwater have been studied in 27 points of deep, semi-deep wells and qanats in the study area. According to the results, the topographic height of the plain decreased from east to west and the direction of ground water flow was from east to west too (almost parallel to direction of the seasonal river in the study area). The lag time between rainfall and water table showed that around of Iranshahr and Bampur cities and observation wells far from river were increased. In the of plain groundwater extraction amount in the downstream of plain was more than upstream. There were three types of Na-Cl, Na-HCO3, and Na-SO4 in the groundwater of study area. The amount of EC increased from about 649 to 7047 µS/cm from east to west of plain, while the pH decreases in this direction. Simultaneously with the decrease in the level of ground water due to extraction from the aquifer, the process of increasing the electrical conductivity and decreasing the quality of the groundwater had happened. Most of the groundwater samples in the study area were supersaturated with respect to calcite and dolomite (tend to precipitate), while they were undersaturated with respect to anhydrite, gypsum, and halite (tend to dissolution). Generally, geology setting and groundwater are factors effecting the quality groundwater.

Keywords

• Groundwater
• Hydrochemistry
• Lag time
• Mineral saturation index

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