بررسی تغییرات کاربری اراضی و ارتباط آن با سطح آب‌های زیرزمینی مطالعه موردی: شهرستان آذرشهر

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه آموزشی جغرافیای طبیعی، دانشکده علوم اجتماعی، دانشگاه محقق اردبیلی، اردبیل، ایران

2 دانش آموخته کارشناسی ارشد سنجش ‌از دور و سیستم اطلاعات جغرافیایی، دانشگاه محقق اردبیلی، اردبیل.

چکیده

هدف اصلی این تحقیق پایش سطح آب‌های زیرزمینی با استفاده از علم سنجش از دور و تصاویر ماهواره‌ای و رابطه آن با کاربری اراضی می‌باشد. به همین منظور ابتدا تصاویر مربوطه اخذ و پیش‌پردازش‌های لازم بر روی هر کدام اعمال شد. سپس نسبت به مدل‌سازی و طبقه‌بندی تصاویر اقدام شد. به منظور بررسی تغییرات کاربری اراضی، نقشه طبقه‌بندی شده کاربری ‌اراضی برای هر دو سال 2000 و 2020 با استفاده از روش طبقه‌بندی شی‌گرا استخراج شد و سپس به منظور بررسی تغییرات کاربری اراضی نقشه تغییرات کاربری ‌اراضی برای بازه زمانی 20 ساله استخراج شد. بعد از استخراج نقشه تغییرات کاربری اراضی به منظور انتخاب بهترین مدل، برای سال 2000 مدل K-Bessel و برای سال 2020 مدل Circular دارای بیشترین دقت می‌باشند. نتایج نشان داد بیشترین میزان تغییرات مربوط به باغات به منطقه مسکونی و تبدیل کاربری باغات به مرتع، تبدیل مرتع به مسکونی است. در میان کاربری‌های تغییریافته، کاربری کوهستان و نمکزار کمترین میزان تغییر را داراست. در حالی که میزان تغییر کاربری باغات به دیگر کاربری‌ها به مراتب بیشتر است و این امر نیز نشان-دهنده سرعت تخریب باغات نسبت به میزان احیای آن است. مشخصات آماری سطح آب زیرزمینی با کاربری اراضی نشان داد که بیشترین میانگین سطح آب در سال2000 برای کاربری باغات با 74/13 متر ثبت شده است و کمترین میانگین سطح آب نیز برای محدوده منطقه ساحلی 41/8 متر ثبت شده است. باملاحظه نقشه کاربری اراضی و نقشه تراز آب زیرزمینی سال 2020 نیز، بیشترین میانگین سطح آب در این سال نیز متعلق به کاربری منطقه ساحلی با 38/9 متر می‌باشد و کمترین میانگین ترازآب ثبت‌شده نیز مربوط به کاربری باغات با 65/6 متر می‌باشد، کاهش میزان سطح آب باعث تسریع در تخریب این منابع طبیعی شده و مخاطرات هولناکی در پی خواهد داشت که از مهم‌ترین آن‌ها می‌توان به بحث فرونشست زمین اشاره کرد.

کلیدواژه‌ها


عنوان مقاله [English]

Investigation of land use changes and its relationship with groundwater level Case study: Azarshahr city

نویسندگان [English]

  • Sayyad Asghari Saraskanrood 1
  • Maryam Mohamadzadeh Shishegaran 2
2 Msc Remote Sensing and GIS, University of Mohaghegh Ardabili, Ardabil, Iran.
چکیده [English]

Investigation of land use changes and its relationship with groundwater level
Case study: Azarshahr city


Background and Objective Groundwater is the most important source of fresh water in the world. Drinking water for two billion people is supplied directly from groundwater and is used to irrigate the world's largest food supply. Improper harvesting of groundwater reservoirs has led to the fact that the amount of feeder feed is not responsive to harvesting and the groundwater level has dropped. The drop in groundwater levels has led to problems such as drying up water wells, declining river and lake discharge, lowering water quality, increasing pumping costs and water extraction and land subsidence. Awareness of water level changes is necessary to understand the status of groundwater aquifers and their optimal management. By assessing groundwater level fluctuations, it can be used to manage water resources. One of the major applications of remote sensing is the detection and determination of land use changes. Using remote sensing, it is possible to study and identify various phenomena. The aim of this study was to investigate the effect of different land use on groundwater using interpolation geostatistical methods as well as object-oriented classification methods for land usemapping.
Materials and Methods
area of study
Azarshahr city is located in East Azarbaijan province, located in the northwest of Iran, with an area of 840 square kilometers, 30 kilometers southwest of Tabriz, and its altitude is 1340 meters above sea level. This city is bordered by Osko city from the north and east, Urmia Lake from the west and Ajabshir city from the south. The average annual rainfall is 329 mm.
Knowing the ratio of uses and how it changes over time is one of the most important things in planning and policy making. For this reason, in this study, in the first step, in order to classify and then examine the changes that occurred in a specific period of time in Azarshahr city. Therefore, in this research, in the first stage, in order to classify and record changes in a period of 20 years, object-oriented images were classified in eCognition software and output maps were extracted in ArcGIS10.5 software. (Figure 3). The classification accuracy in 2000 has an overall accuracy of 0.90 and a kappa coefficient of 0.87. While the classification in 2020 with overall accuracy of 92% and kappa coefficient of 0.90 has provided relatively higher accuracy.



Results and Discussion
Knowing the ratio of uses and how it changes over time is one of the most important things in planning and policy making. For this reason, in this study, in the first step, in order to classify and then examine the changes that occurred in a specific period of time in Azarshahr city. Therefore, in this research, in the first stage, in order to classify and record changes in a period of 20 years, object-oriented images were classified in eCognition software and output maps were extracted in ArcGIS10.5 software. (Figure 3). The classification accuracy in 2000 has an overall accuracy of 0.90 and a kappa coefficient of 0.87. While the classification in 2020 with overall accuracy of 92% and kappa coefficient of 0.90 has provided relatively higher accuracy.
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Conclusion
The highest rate of changes related to gardens to residential area with the amount of 2529 and conversion of use of gardens to pastures with the amount of 2126, conversion of pastures to residential with an area of 2067 hectares. Among the altered uses, the use of mountains and salt marshes has the least change, while the rate of change of use of gardens to other uses is much higher, and this also indicates the speed of destruction of gardens compared to the rate of its restoration. Also, the least changes related to the coastal area to rangeland with an area of 9, rangeland to gardens with an area of 27, coastal area to salt marshes with an area of 175 are included as the least changes of uses. In almost all land uses, the rate of conversion to residential areas has been significant, which indicates urban development as well as human interference and destruction of natural resources. According to the values of Table 5, the best model in GS + environment in order to monitor the groundwater level, the groundwater level map of the study area for both years with the method of kriging models shows the results of high accuracy. The K-Bessel method for 2000 and the circular method for 2020 were extracted, which were identified as the most accurate methods. Statistical characteristics of groundwater level with land use The highest average water level in 2000 was recorded for garden use with 13.74 meters and the lowest average water level was recorded for the coastal area of 8.41 meters. Considering the land use map and groundwater level map of 2020, the highest average water level in this year belongs to the coastal area with 9.38 meters and the lowest average recorded water level is related to the use of gardens with 6.65 meters. It can be attributed to the over-extraction of groundwater for garden crops that need more irrigation. Also, the residential area with 6.75 has the lowest recorded average. As can be seen from Tables 5 and 6, if we compare the water level of both years related to the study area, it is inferred that the average land use area of the coastal area in 2000 was 8.41, which in 2020 is 38.38. 9 It has been estimated that there has been an increase in the water level, which has increased the groundwater level and also increased the volume of water in the rivers of the region. Rangeland use also decreased significantly in 2020 compared to 2000 and decreased from 11.23 to 7.28, which indicates the critical situation of groundwater and excessive use of these resources. Water levels have been depleted, which has accelerated the destruction of these resources and will lead to horrific hazards, the most important of which is the issue of land subsidence.

کلیدواژه‌ها [English]

  • "Object-oriented classification"
  • "Groundwater"
  • "Geostatistical methods"
  • "Azarshahr"