Document Type : Original Article

Authors

• Zahra Baazm ¹
• Abolfazl Akbarpour ²
• Mostafa Yaghoubzadeh ³
• Seyed Saeed Eslamian ⁴
• Hossein Khozeymehnezhad ⁵

¹ PhD Student, Water Science and Engineering, Faculty of Agriculture, University of Birjand, Birjand, Iran.

² Professor, Department of Civil Engineering, Faculty of Engineering, University of Birjand, Birjand, Iran.

³ 3. Associate Professor, Department of Water Science and Engineering, Faculty of Agriculture, University of Birjand, Birjand, Iran

⁴ Seyed Saeid Eslamian, Department of Water Science and Engineering, College of Agriculture, Isfahan Univetsity of Technology, Isfahan, Iran

⁵ Associate Professor, Department of Water Science and Engineering, Faculty of Agriculture, University of Birjand, Birjand

Abstract

. Seawater intrusion poses an increasing threat to groundwater resources in coastal regions. Cutoff walls are widely applied to prevent the advancement of seawater wedges. The use of cutoff walls represents an effective engineering strategy for managing and mitigating nitrate contamination in coastal aquifers. The dispersion and transport of contaminants in groundwater resources can render them unusable and exacerbate drought crises in arid and semi-arid regions. Therefore, protecting groundwater resources from the intrusion and accumulation of specific pollutants is essential and necessary. In this study, the effect of a cutoff wall on controlling seawater intrusion and nitrate contamination in coastal aquifers was investigated using the Meshless Local Petrov–Galerkin (MLPG) simulation method. Five scenarios were analyzed, including a case without a cutoff wall and cutoff walls with heights of 15, 30, 45, and 60 meters, in order to evaluate their impact on seawater intrusion and nitrate transport. The results indicated that the reduction ratio of seawater increased continuously and significantly with wall height, rising from about 53.9% at 15 m to more than 82.26% at 60 m. . Cutoff walls can help maintain favorable conditions for nitrate removal by preventing seawater wedge advancement. Hence, considering the effectiveness demonstrated in this study, cutoff walls can be regarded as an efficient and practical engineering approach for reducing seawater intrusion and groundwater contamination.

Keywords

• Shape function
• Simulation
• Water quality
• Optimal management
• Governing flow equations

Main Subjects

• ًQanat and aquifer