نوع مقاله : مقاله پژوهشی

نویسندگان

• شیما آزاده رنجبر ¹
• مجید خلقی ²
• افشین اشرف زاده ³

¹ کارشناسی ارشد منابع آب، گروه مهندسی آبیاری و آبادانی، دانشکدگان کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران.

² استاد منابع آب، گروه مهندسی آبیاری و آبادانی، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران.

³ دانشیار منابع آب، گروه مهندسی آبیاری و آبادانی، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران،

چکیده

منابع آب زیرزمینی در مناطق خشک و نیمه‌خشک روند کاهشی کمی و کیفی قابل‌توجهی را در سال‌های اخیر نشان داده‌اند. با توجه به رشد روز افزون جمعیت و کمبود منابع آب‎سطحی، وابستگی به منابع با کیفیت آب‎زیرزمینی برای شرب، کشاورزی و صنعت دو چندان شده است. به دلیل اهمیت کشاورزی و وابستگی شدید به آب‌های‌زیرزمینی در قزوین، این منطقه به عنوان منطقۀ مورد‌ مطالعه تعیین گردید. هدف از این پژوهش، طبقه‌بندی کیفیت آب زیرزمینی و بررسی تغییرات زمانی و مکانی کیفیت آن در دشت‎قزوین در یک دورۀ 20 ساله با تأکید بر مصارف شرب، کشاورزی و صنعت است. نتایج تحقیق نشان می­ دهد رخساره‌ها از کلسیم-بی‌کربناته به سدیم-کلره و سدیم-سولفاته تغییر یافته که بیانگر برداشت بیش از حد و نفوذ املاح است. از نظر کشاورزی، سهم آب‌های نامناسب از 75 به 90 درصد افزایش داشته است. از نظر شرب، آب‌های با کیفیت و خوب از 39 به 22 درصد کاهش یافته است و از نظر صنعتی بیش از 93 درصد آب‌ها خورنده یا رسوب‌گذار هستند. الگوی مکانی نشان داد که آب مناطق شمالی دارای بالاترین و آب مناطق جنوبی دارای پایین­ترین کیفیت است و روند تخریب از جنوب به شمال پیشروی می‌کند که نیازمند گام­های فوری مدیریتی برای جلوگیری از تخریب غیرقابل بازگشت آبخوان است.

کلیدواژه‌ها

• آبخوان قزوین
• پایپر
• پهنه‌بندی کیفیت
• شاخص لانژلیه
• شولر
• ویلکاکس

موضوعات

• منابع و مصارف آب

عنوان مقاله [English]

Classification and Spatial-Temporal Monitoring of Groundwater Quality for Drinking, Agricultural, and Industrial Uses (Case Study: Qazvin Plain)

نویسندگان [English]

• Shima Azadeh Ranjbar ¹
• Majid Kholghi ²
• Afshin َAshrafzadeh ³

¹ MSc of Water Resources, Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.

² Professor of Water Resources, Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.

³ Associate Professor of Water Resources, Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.

چکیده [English]

Extended Abstract
Introduction
In countries such as Iran, where drinking water, agriculture, and industry heavily rely on groundwater resources, management and protection are fundamental priorities. Excessive extraction has caused severe decline in groundwater levels and water quality reduction. Given increasing population and surface water shortage, dependence on quality groundwater has intensified significantly.
The Qazvin Plain, as a major agricultural and industrial hub, plays an effective role in regional food security and economic development. Agricultural and industrial activities have imposed increasing pressure on water resources. Although part of water demand is supplied through the Taleghan Dam and seasonal rivers, this plain has severe dependence on groundwater with increasing extraction, leading to level decline and serious quality challenges.
The Qazvin Plain is located within 49°10' to 50°40' East longitude and 35°20' to 36°31' North latitude. The plain area is 5059.3 square kilometers with elevation ranging between 1131 and 2902 meters. With semi-arid climate, it receives average annual precipitation of 317 millimeters. With 250,000 hectares of agricultural land, the agricultural sector accounts for more than 85 percent of water consumption. The objective is to classify groundwater quality for agricultural, drinking, and industrial uses, and investigate spatial and temporal variations over a 20-year period from 2001 to 2021.
Methodology
Groundwater quality data were obtained from Qazvin Regional Water Company. Water type and facies were determined using the Piper diagram. Qualitative classification for agricultural purposes was conducted according to Wilcox classification, for drinking according to Schoeller classification, and for industrial purposes using Langelier Saturation Index (LSI). The Wilcox method classifies water based on electrical conductivity (EC) and sodium adsorption ratio (SAR) into four classes: excellent, good, average, and unsuitable. Schoeller method classifies water into six classes based on total dissolved solids (TDS) and total hardness (TH). Langelier index categorizes water as corrosive (LSI<0), balanced (LSI=0), or scaling (LSI>0). Spatial and temporal zoning maps were prepared using Kriging interpolation in GIS at five-year intervals.
Results and Discussion
Piper diagrams analysis over five periods (2001-2021) revealed continuous aquifer degradation. In 2001, most samples showed calcium-bicarbonate facies indicating fresh water. By 2006, samples shifted toward calcium-sulfate facies. In 2011, degradation accelerated with dramatic dispersion increase and sodium-chloride facies emergence indicating serious salinization. By 2016, critical condition became evident with high facies diversity. In 2021, crisis peaked with maximum dispersion, where calcium-bicarbonate facies appeared only in limited samples, and significant portions showed saline facies dominated by sodium-chloride and sodium-sulfate.
For agricultural water quality, no sample was excellent quality. Good quality decreased from 25.25% in 2001 to 17.91% in 2021 (29% reduction). Average quality increased from 46.46% to 58.95%, and unsuitable samples fluctuated between 14.23% and 33.33%. Medium and unsuitable categories comprised 75 to 92 percent.
For drinking water quality, about 70% of samples remained in good to average categories, but good quality decreased from 29% to 22%. Completely inappropriate category increased from zero to 2.74%. In total hardness, good quality declined from 39% to 24%, while acceptable water increased to 44%.
For industrial water quality, significant changes occurred. Corrosive water decreased from 96.97% to 70.1%, while scaling water increased dramatically from 2.02% to 23.1%. Balanced water comprised only 1 to 6.7%. More than 93% falls into corrosive or scaling categories, requiring treatment before use.
Spatial-temporal analysis revealed northern areas had best quality while southern areas faced worst quality, with degradation advancing from south to north. For agriculture, medium and unsuitable water increased from 75% to over 90%. For drinking, good quality decreased from 29-39% to 22-24%. For industry, over 93% are either corrosive or scaling.
Conclusions
Groundwater resources show concerning degradation trends. Facies evolution from fresh to saline types, dramatic diversity increase, and significant reduction in suitable quality represent serious warnings.
For agriculture, unsuitable water increased from 75% to over 90%, necessitating urgent strategies including extraction control, cropping pattern modification, and drainage systems development. For drinking, good quality decreased from 29-39% to 22-24%, with southern areas requiring advanced treatment. For industry, more than 93% are corrosive or scaling, requiring treatment.
The spatial pattern indicates degradation advancing from south to north. The trend shows increasing salinity and hardness resulting from excessive extraction, reduced recharge, and likely saline water intrusion. This requires urgent actions including extraction control, artificial recharge enhancement, agricultural return flows treatment, and pollution prevention. Without fundamental measures, sustainability will be severely threatened.
Keywords: Langelier index, Piper, Qazvin aquifer, Quality zoning, Schoeller, Wilcox.
Acknowledgments
The authors wish to express their sincere gratitude to the Editor and the two anonymous reviewers for their insightful comments and constructive feedback, which significantly improved the quality of this manuscript. We also thank the Regional Water Company of Qazvin for providing the necessary data for this research.
Conflict of Interest
The authors declared no potential conflicts of interest concerning the research, authorship, and publication of this article.  Confirmation.
 Funding
The authors received no financial support for the research, authorship, and publication of this article.
Data Availability Statements
The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.
Authors’ contribution
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts. Sh. AR. handled the methodology, formal analysis, investigation, data curation, visualization, and initial draft preparation. A.A. and M. Kh. provided supervision and validation for the study. Resources were provided by M. Kh., A. A., and M. Kh. shared responsibility for the final review and editing of the manuscript. All authors have read and agreed to the published version of the manuscript.

کلیدواژه‌ها [English]

• Langelier index
• Piper
• Qazvin aquifer
• Quality zoning
• Schoeller
• Wilcox