بررسی میزان انطباق شاخص gri در خشکسالی منابع آب زیرزمینی دشت قزوین

خشکسالی یکی از پدیده های زیان‌ بار آب‌ و هوایی است که علاوه‌ بر آب‌های سطحی تاثیر آن بر منابع آب زیرزمینی نیز بایستی پایش و شناسایی شود. هدف اصلی مقاله حاضر، مطالعه و بررسی اثرات خشکسالی بر رفتار سفره آب زیرزمینی دشت قزوین با استفاده از شاخص خشکسالی منبع آب زیرزمینی (gri) بوده است. برای این منظور تراز آب زیرزمینی به‌‌عنوان معیار اصلی مطالعه در چاه هایی با کمترین، بیشترین و مقادیر متوسط افت، مورد بررسی قرار گرفت. از آمار سال های 1390-1345 به دلیل کامل بودن اطلاعات استفاده و محاسبات و ارزیابی‌های لازم انجام شد. نتایج نشان داد که یک روند کاهشی در مقادیر شاخص gri طی سال های 1380-1375 وجود داشته و از طرف دیگر در همین محدوده زمانی، خشکسالی‌های با درجات بالا در سفره ‌آب زیرزمینی مورد مطالعه رخ داده است. همچنین نتایج بیانگر وجود همبستگی معنی‌داری در سطح 99 درصد شاخص خشکسالی هیدروژئولوژیکی gri با شاخص خشکسالی هواشناسی spi در مقیاس 48 ماهه و تاخیر زمانی سه ماهه می‌باشد. ارزیابی تعداد زیادی از چاه های منطقه با شاخص gri نشان داد که این شاخص عملکرد خوبی در دشت قزوین دارد. لذا با قاطعیت می توان اظهار نمود که بدون نیاز به هیچ ضریب تعدیل و یا اصلاح خاصی، شاخص خشکسالی منبع آب زیرزمینی gri برای آبخوان دشت قزوین به‌عنوان یک شاخص منطبق قابل استفاده است.

assessment of the gri index compliance in groundwater drought in the qazvin plain, iran

introductiondrought, as an environmental crisis, not only impacts ecosystems but also poses risks to human activities and has significant negative effects. the occurrence of intermittent and prolonged droughts, along with significant fluctuations in climate, exacerbates water scarcity, particularly in surface water resources; thus, groundwater resources play a key role as a vital source for supplying water for various consumption needs.groundwater drought is one of the serious and increasing challenges that has been acutely felt in recent years. climate change and increasing water demand in agricultural and industrial sectors has led to increase dextraction from groundwater sources, significantly affecting many plains and groundwater resources in the country, resulting in severe depletion. this has consequently led to water crises and recurrent droughts. therefore, understanding the relationship between drought and the status of groundwater resources is crucial. this issue not only impacts agriculture and food security but also has negative effects on public health, the economy, and the environment. for this reason, proper and sustainable management of these resources in the face of drought challenges is essential. materials and methodsthe examination of hydrogeological droughts and the monitoring of groundwater levels is essential for providing appropriate solutions for the protection and management of water resources.in the present study, the groundwater resource index (gri) was used to assess groundwater drought in the qazvin plain. additionally, to explore the relationship between the gri and the standardized precipitation index (spi) across different time scales, the correlation coefficient between the two indices was calculated. subsequently, the gri was localized within the plain by analyzing its values across various monitoring wells. results and discussionthe high correlation between the gri index and the spi drought index over a 48-month timeframe indicated that groundwater resources in the qazvin plain were influenced by both wet and dry weather phenomena, with a time lag of approximately three to six months before meteorological drought translated into groundwater drought. eslamian et al. (2009) also reported a three-month time lag for the effects of drought on the groundwater resources of the qazvin, buin zahra, and hamadan plains in their research. conclusionthe localization study of the gri index in the qazvin plain region concluded that the index is highly responsive for assessing and evaluating groundwater drought. it effectively identified wet and dry years and showed a strong alignment with the behavior of the groundwater table. the analysis of drought during the years from 1996-2001 also illustrated that the impacts of drought continued into subsequent years on groundwater resources, and according to the gri index, the decline in groundwater levels persisted in later years. this was evident even with increased precipitation in 2002 and thereafter, where we continued to witness declines and the ongoing trend of groundwater drought. acknowledgmentswe would like to thank the university of tehran and the water resources management company of iran for providing the necessary facilities to conduct this research study and prepare relevant papers.