Environmental Erosion Research

fa تحلیل آسیب‌پذیری آبخوان دشت خویش با استفاده از روش در استیک در محیط GIS Investigating the vulnerability of Khovayes Plain Aquifer Using the DRASTIC Method in a GIS Environment روشهای نوین و دقیق در تهیّه نقشه فرسایش (سنجش از دور و سیستم‌های اطلاعات جغرافیایی) مستخرج از پایان‌نامه / رساله / طرح پژوهشی شناسایی و تهیه نقشه پهنه بندی مناطق آسیب‌پذیر آبخوان، یک ابزار مدیریتی مناسب جهت جلوگیری از آلودگی منابع آب زیرزمینی می‌باشد. با توجه به اهمیت دشت خویش در استان خوزستان تأمین آب کشاورزی، شرب و صنعت منطقه، از مدل DRASTIC جهت ارزیابی آسیب‌پذیری آبخوان استفاده‌شده است. در مدل دراستیک از مشخصه‌های مؤثر در ارزیابی آسیب‌پذیری آبخوان آب زیرزمینی شامل عمق سطح ایستایی، شبکه تغذیه، جنس آبخوان، نوع خاک، شیب توپوگرافی، مواد تشکیل‌دهنده منطقه غیراشباع و هدایت هیدرولیکی استفاده‌شده است؛ که به صورت هفت لایه در نرم‌افزار ArcGIS تهیه شدند و با وزن دهی و رتبه‌بندی و تلفیق هفت لایه فوق، نقشه نهایی آسیب‌پذیری آبخوان نسبت به آلودگی تهیه گردید. در این نقشه منطقه موردمطالعه به پنج محدوده آسیب‌پذیری خیلی کم، کم، متوسط، زیاد، خیلی زیاد تقسیم‌شده است. در مرحله بعدی از غلظت نیترات 23 نمونه چاه جهت واسنجی مدل دراستیک استفاده گردید. نقشه پهنه بندی نهایی تهیه‌شده از غلظت نیترات و همپوشانی این لایه با نقشه نهایی تهیه‌شده آسیب‌پذیری نشان داد که کلیه نقاطی که دارای نیترات بالا هستند، در محدوده‌ای قرارگرفته‌اند که دارای آلودگی بالایی می‌باشند. این نتیجه بیانگر دقت و صحت مدل اجراشده در منطقه است.   1- Introduction Groundwater is the main source of water and one of the most important sources of fresh water on Earth. The quantity and quality of groundwater are deteriorating due to increasing urbanization and its side effects (Amanpour et al., 2021). Recently, with rapid population growth, urbanization and industrialization, groundwater resources have been at risk and have created a serious environmental problem (Afsaw et al., 1, 2020). Therefore, human activities in some cases damage the balances of capacity in nature. One of the most important water resources vulnerable to pollution is aquifers. These resources are exposed to pollution in various ways, which makes detecting and controlling pollution in them more difficult and costly than surface waters. Also, due to the persistence of pollution in these resources, the best way to prevent their pollution is to identify polluting sources and vulnerable areas, prepare vulnerability zoning maps, and adopt appropriate management policies (Aghdam et al., 2017). Identification and preparing zoning maps of vulnerable areas of the aquifer is an appropriate management tool to prevent pollution of underground water resources. Considering the importance of Khovayes Plain in agriculture water supply, drinking and industrial conditions, the drastic model is used to assess the aquifer vulnerability. In the drastic model, some significant indices in the assessment of underground water aquifer vulnerability including water table depth, water supply network, aquifer type, soil type, topographic dip, components of  the unsaturated zone , and hydraulic conductivity were used and prepared as seven layers in ArcGIS software; after weighting, ranking and integrating the seven mentioned layers, considering the pollutions, the final map of vulnerability aquifer was prepared. After matching the Nitrate Ion on the final drastic map, it was found out that all points with a high amount of Nitrate, are located in a highly polluted realm which confirms the accuracy and validity of the used model. 3- Results The vulnerability zoning of the Dasht-e Khosh aquifer, which was obtained by combining the seven raster maps of the parameters of the DRAS-1 model by considering the weight of each parameter in the Geographic Information System (GIS) environment, shows that in the Dasht-e Khosh region, the parameters of groundwater depth and unsaturated environment have the greatest effect and the parameters of land slope have the least impact in determining the level of vulnerability of the aquifer. Nitrate ion a natural pollutant in the region) was used to verify the final vulnerability map. By matching nitrate ions on the final DRAS-1 map, it was determined that all points with high nitrate ions are located in an area with high pollution force, which can confirm the accuracy and precision of the model. In terms of area, it can be said that about 17.16% of the study area is in the very low vulnerability range, 23.55% is low vulnerability, 19.21% is medium vulnerability, 28.72% is high vulnerability, and 11.36% is in the very high vulnerability range. The northern and southern parts of the plain aquifer are highly vulnerable. Therefore, controlling this area against pollution should be considered. Nitrate pollution in this area is also high, so this area requires more care and the imposition of certain restrictions. The central areas of the plain have a medium vulnerability potential, and the northwestern and southeastern areas of the plain have a lower vulnerability potential. 4- Discussion & Conclusions In this research, in the first part, effective characteristics in assessing the vulnerability of groundwater aquifers, including water table depth, recharge network, aquifer type, soil type, topographic slope, unsaturated zone constituents, and hydraulic conductivity, were used to implement the model. These were prepared as seven layers in ArcGIS software, and by weighting, ranking, and combining the above seven layers, the final map of aquifer vulnerability to pollution was prepared. Then, nitrate ion adaptation was performed on the final map of Drastic. Therefore, control of this area against pollution should be considered. Nitrate pollution in this area is also high, so this area needs more care and also the application of certain restrictions. The central areas of the plain have a medium vulnerability potential and the northwestern and southeastern areas of the plain have a lower vulnerability potential. Because the removal of pollution from groundwater resources is costly, the vulnerability zoning of the plain aquifer can be provided as a valuable tool to officials and trustees so that they can make the necessary decisions for land use and management of the plain aquifer. These decisions can include the management of agricultural fertilizers and urban wastewater to safer points and land use changes.   آسیب‌پذیری, آب‌های زیرزمینی, دشت خویش, Drastic Vulnerability, Drastic model, Underground Water, Khovayes plain. 22 43 http://magazine.hormozgan.ac.ir/browse.php?a_code=A-10-1028-1&slc_lang=fa&sid=1 morteza pourzare مرتضی پورزارع pourzare@iamu.ac.ir 10031947532846009926 0009-0009-3965-3555 Yes Department og Geogrphy,Faculty of Geography,University of imam ali military , Tehrn, Iran گروه جغرافیا، دانشکده علوم پایه، دانشگاه افسری امام علی (ع)، تهران، ایران shahnaz Joudaki شهناز جودکی shila.joodaki@yahoo.com 10031947532846009927 10031947532846009927 No Department og Geogrphy,Faculty of Geographical Sciences, University of Isfahan, Isfahan, Iran گروه جغرافیای طبیعی، دانشکده علوم جغرافیایی و برنامه ریزی، دانشگاه اصفهان، اصفهان، ایران Mojtaba Yamani مجتبی یمانی myamani@ut.ac.ir 10031947532846009928 10031947532846009928 No Department of Geogrphy, Faculty of Geography, University of Tehran, Tehran, Iran گروه جغرافیای طبیعی، دانشکده جغرافیا، دانشگاه تهران، ایران