بررسی کارایی شاخص کیفیت آب زیرزمینی (GQI) به منظور ارزیابی بلندمدت تاثیرات انتقال آب بین حوضه‌ای با کمک روش‌های ناپارامتری و GIS(مطالعه موردی آبخوان یزد- اردکان)

نوع مقاله : مقالات پژوهشی

نویسندگان

1 دانشجو دکترای علوم و مهندسی آبخیزداری

2 استادیار دانشکده منابع طبیعی و کویرشناسی دانشگاه یزد

10.22067/jsw.2021.71571.1073

چکیده

چکیده

بررسی روند زمانی و تغییرات مکانی کیفیت آب زیرزمینی متاثر از انتقال آب بین حوضه‌ای در مدیریت منابع آبی نقش مهمی دارد. هدف از این پژوهش، بررسی روند زمانی پارامترهای کیفی آب‌زیرزمینی با استفاده از آزمون من‌کندال و تخمین‌گر شیب سن و بررسی تغییر مکانی کیفیت آب زیرزمینی و تاثیرات انتقال آب بین‌حوضه‌ای می‌باشد. بدین‌ منظور از پارامترهای کل جامدات محلول، کلر، سولفات، سدیم، کلسیم و منیزیم مربوط به 43 چاه در دوره زمانی 1399-1379جهت بررسی روند زمانی و مکانی استفاده شد. نتایج بررسی روند زمانی نشان داد، پارامترهای سولفات، سدیم و کل جامدات محلول در بیشتر چاه‌ها روند کاهشی داشته است، اما شاخص‌های کلسیم، منیزیم و کلر دارای روند افزایشی بوده است و همه پارامترها به جز TDS، در دوره زمانی مورد بررسی بر اساس طبقه بندی سازمان بهداشت جهانی در حد مجاز قرار داشتند. نتایج رتبه‌بندی پارامترها نشان داد، TDS، کلر و منیزیم بیشترین تاثیر را بر کیفیت منابع آب زیرزمینی آبخوان داشته‌اند و همچنین پارامتر منیزیم بیشترین و TDS کمترین تغییر را در بین سال‌های 1379 تا 1399 دارا بود. کاربرد شاخص کیفیت آب زیرزمینی (GQI) در این پژوهش نشان داد که کیفیت کلی آبخوان یزد- اردکان، حتی با توجه به افت نسبتا زیاد آب‌زیرزمینی، در ابتدا و انتهای دوره زمانی مورد بررسی در رده‌ی متوسط (80-60) و قابل قبول قراردارد و کاهش کیفیت در این دوره بسیار کم و قابل چشم‌پوشی است. نتایج نهایی پژوهش حاضر نشان‌ داد،آب انتقالی با کیفیت مناسب توانسته افزایش میزان کل جامدات محلول، سولفات و سدیم را کنترل کند و موجب افزایش کلر در این مناطق شود. در انتها مشخص شد، تغییرپذیری مکانی آلاینده‌های مختلف و طیف گسترده پارامترهای اندازه‌گیری شده و به‌طورکلی توصیف کیفیت آب،امری دشوار است؛ بنابراین استفاده ازشاخص‌های کیفیت آب می‌توانند شرایط کلی کیفیت آب را به‌طورخلاصه و قابل‌درک ارائه کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of the Efficiency of Groundwater Quality Index (GQI) in order to Evaluate the Long-term Effects of Water Transfer between Basins by Non-parametric methods and GIS (Case Study of Yazd-Ardakan Aquifer)

نویسندگان [English]

  • Hossein Sarvi Sadrabad 1
  • Asghar Zare Chahouki 2
1 phD Student in Watershed Management Science and Engineering, Tarbiat Modares University
2 * Assistant Professor, Faculty of Natural Resources, Yazd University
چکیده [English]

Introduction: Inter-basin water transfer affects the environment, culture and economy of donor and recipient basin. One of the most important is the positive and negative effects on the quality of groundwater in the recipient basin. The study of temporal trends and spatial changes of groundwater quality affected inter-basin water transfer plays an important role in water resources management. The study attempts to investigate the temporal trends of groundwater quality parameters using Mann-kendall test and Sen's slope estimator. Spatial changes of groundwater quality and the effects of inter-basin water transfer were studied as well.

Materials and Methods: In this study, non-parametric methods and interpolation models were used to evaluate the temporal trend and spatial pattern of groundwater quality parameters in the Yazd-Ardakan plain. Mann-kendall nonparametric tests and Sen's slope were used to examine the temporal trend in the span of 2000 to 2020. The interpolation models and groundwater quality index (GQI) were used to study the spatial pattern and classify quality. The assessment of quality parameters of all wells including Ca2+, Mg2+, Cl-, Na+, So42- and TDS were studied in equal time periods. Groundwater quality measurements were performed twice a year using a volumetric method, one in spring and the other in autumn. The World Health Organization (WHO) standard was considered to compare the parameters amounts in the plain.

Results and Discussion: A decreasing trend was observed in the indices of So42-, Na+ and TDS in the most wells and there was an increasing trend for the parameters of Ca2+, Mg2+ and Cl-. All parameters were in the allowable ranges considering WHO classification standard except TDS. The parameter ranking showed that TDS, Cl- and Mg had the greatest impact on the quality of aquifer groundwater. The Mg and TDS parameters had the highest and the lowest changes, respectively during 2000 to 2020. Results of the GQI showed that the total quality of the Yazd-Ardakan aquifer was in the moderate class and acceptable because of the relatively large decrease in the groundwater in the span of the studied period. However, the decrease in quality is very few and negligible. Changes of the quality map showed that the most negative quality changes were related to the Yazd, Taft, Meybod, Ardakan and northern regions (Chah-Afzal desert). This indicates the high groundwater pumping in these areas and being located near the desert area. The most positive quality changes belonged to the central and southern part of the aquifer.

Conclusion: Compare between the interpolation models showed that the geostatistical methods can show better results than the definitive methods in zoning groundwater quality parameters. The Kriging and IDW models were the best models and consistent with the results of the research. The quality of groundwater was acceptable, while the reduction in quality was very low and negligible in the Yazd-Ardakan aquifer during the studied period. The temporal trends of So42-, Na+ and TDS had a negative significant trend or no trend in the Yazd area. Considering ranking maps, TDS, Cl- and Mg2+ had high impacts on determining the GQI. These trends were positive in Yazd city. Due to this, the GQI maps could not confirm the negative temporal trend and zoning maps. This showed the use of qualitative indicators could neutralize the effects of the parameters on each other and provide a better and acceptable result. In all, the transfer water with appropriate quality could control the increase of the TDS, So42-, Na and caused an increase in Cl- in these areas. There are many effective factors to study water quality so its description is difficult. Using water quality indicators can provide total water quality conditions in a concise and understandable way.

Conclusion: Compare between the interpolation models showed that the geostatistical methods can show better results than the definitive methods in zoning groundwater quality parameters. The Kriging and IDW models were the best models and consistent with the results of the research. The quality of groundwater was acceptable, while the reduction in quality was very low and negligible in the Yazd-Ardakan aquifer during the studied period. The temporal trends of So42-, Na+ and TDS had a negative significant trend or no trend in the Yazd area. Considering ranking maps, TDS, Cl- and Mg2+ had high impacts on determining the GQI. These trends were positive in Yazd city. Due to this, the GQI maps could not confirm the negative temporal trend and zoning maps. This showed the use of qualitative indicators could neutralize the effects of the parameters on each other and provide a better and acceptable result. In all, the transfer water with appropriate quality could control the increase of the TDS, So42-, Na and caused an increase in Cl- in these areas. There are many effective factors to study water quality so its description is difficult. Using water quality indicators can provide total water quality conditions in a concise and understandable way.

کلیدواژه‌ها [English]

  • Keywords: groundwater quality index, Sen'
  • s slope, Mann_Kendal, Water transfer Yazd_Ardakan

مقالات آماده انتشار، پذیرفته شده
انتشار آنلاین از تاریخ 07 آبان 1400
  • تاریخ دریافت: 28 تیر 1400
  • تاریخ بازنگری: 18 مهر 1400
  • تاریخ پذیرش: 07 آبان 1400