Document Type : Research Article
Authors
1 Irrigation and Reclamation Engineering Department, University of Tehran, Karaj, IRAN.
2 Department of Environmental Sciences and Technologies, Faculty of Energy and Sustainable Resources Engineering, University of Tehran, Tehran, IRAN.
3 Department of Environmental Sciences and Technologies, Faculty of Energy and Sustainable Resources Engineering, University of Tehran, Tehran, IRAN
Abstract
Drought is one of the detrimental climatic phenomena that, in addition to affecting surface water, must also be monitored and identified regarding its impact on groundwater resources. A significant part of the country's water consumption is provided by underground water sources. The occurrence of intermittent and long-term droughts and high weather fluctuations aggravates the lack of water, especially surface water sources; The lack of these resources has reduced the groundwater feeding process and in such a situation, the volume of underground water gradually decreases and this can cause the aggravation of water shortage in urban and rural areas. Given the significant importance of the country's groundwater resources, the main objective of this article is to study and examine the effects of drought on the behavior of groundwater tables in the Qazvin Plain using the Groundwater Resources Index (GRI). To achieve this, the groundwater level was investigated as the main criterion in wells with the minimum, maximum, and average levels of decline, using data from the years 1966-2011, and necessary calculations, zoning, and assessments were conducted. The results indicated a decreasing trend in GRI values during the years 1996-2001, and on the other hand, high-degree droughts occurred in the studied groundwater table during the same time frame. Furthermore, the results showed a significant correlation at the 99 percent level between the hydrogeological drought index GRI and the meteorological drought index SPI over a 48-month scale with a three-month time lag. The assessment of a large number of wells in the region using the GRI index indicated their optimal suitability for the Qazvin Plain. Therefore, it can be confidently suggested that without the need for any specific adjustment factor or modification, the groundwater drought index can be used as a suitable and applicable indicator for the Qazvin Plain and similar plains. Drought, 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. The 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 was used to investigate the drought of groundwater resources in the Qazvin plain. Additionally, to examine the relationship between the two indices GRI and SPI at different time scales, the correlation coefficient between these two indices was calculated. Following this, the GRI index was localized in this plain by analyzing GRI in various wells. The 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. The study of the localization of the GRI index in Qazvin plain region, it was concluded that the GRI index had a good responsiveness for assessing and evaluating groundwater drought in this region. It effectively indicated wet and dry years and showed a reasonable 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.
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