نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه اموزشی مدیریت و توسعه کشاورزی، دانشکده اقتصاد و توسعه کشاورزی، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران ، کرج، ایران
2 گروه اموزشی مدیریت و توسعه کشاورزی، دانشکده اقتصاد و توسعه کشاورزی، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران ، کرج، ایران.
چکیده
کلیدواژهها
Extended Abstract
The water crisis is one of the most important issues in managing human societies and the environment, especially in arid and semiarid regions. Multiple natural and human factors, such as the amount of rainfall and the excessive withdrawal of water resources, are effective in causing and exacerbating this crisis. Iran is one of the arid and semi-arid countries in the Middle East and one of the countries facing a water crisis. Its annual rainfall is about 260-240 mm and less than one-third of the world's average annual rainfall (870 mm). Currently, about 55 percent of Iran's water needs are provided by groundwater resources, and the share of aquifers fed by atmospheric rainfall is about 35 billion cubic meters. Iran is located in arid and desert regions, which naturally results in years with below-average rainfall much longer than those with long-term annual average rainfall. Given the recent droughts in Iran, it is important to study its impact on water resources. Karkheh catchment in Kermanshah province covers about half of this province. This catchment is located in a semi-arid and Mediterranean region and its groundwater resources have declined dramatically. Therefore, the main purpose of this study was to analyze the drought process and its impact on groundwater resources of Karkheh catchment in Kermanshah province.
Methodology
In this study, in order to investigate the meteorological and groundwater drought status of Karkhe catchment in Kermanshah province, rainfall and groundwater level data of Eslamabad-e Gharb, Bistoon-Dinavar, Ravansar-Sanjabi, Kermanshah, Kangavar and Mahidasht during 30-year period (1986-2016) were used. Meteorological drought status of the region was evaluated using SPI index and its derived criteria such as number of years of exposure to drought, longest drought period and magnitude of drought period for each station. Ground water drought status of the region was also evaluated for each area using GRI index over this time period and its changes were compared with SPI changes. Mann-Kendall tests and Sen's slop were used to investigate the trend of changes in the spi index and groundwater level. Finally, using Pearson correlation coefficient the impact of drought on groundwater resource depletion in this catchment was investigated.
Results
The results of calculation of SPI index in the studied region showed that Kangavar area with 11 years had the most years of drought exposure and Mahidasht area with 7 years had the least number of years of drought exposure among the studied areas. According to this index, Kermanshah had the longest drought period, which was a 6-year period. According to Magnitude Drought index (DM), Islamabad station had the most magnitude drought period. The results of the calculation of GRI index in the region that groundwater drought has occurred continuously in all areas of the region in recent years. Results of Mann-Kendall tests and Sen's slop showed that drought in the study area was not significant but the trend of groundwater level decline was significant and decreasing, also the results of correlation coefficient between SPI index and groundwater level in the region showed that there is no significant correlation between drought and groundwater depletion.
Discussion
Based on the findings, both meteorological and groundwater droughts occurred in Karkhe catchment in Kermanshah province during the studied period, so that during this period, meteorological droughts with sinusoidal fluctuations were observed, but groundwater droughts have been less fluctuations and occurred steadily in recent years. The meteorological drought phenomenon has not had a significant impact on the groundwater resource depletion in the study area and it seems that the share of indiscriminate harvesting of groundwater resources in the aquifer's decline is far greater than drought. Drought is a climatic and recurring feature and Due to the importance of groundwater in the agricultural sector of the region, coping with drought and preserving groundwater resources for sustainable use of these resources in the region is an indispensable necessity. Development of low-water-use crops, improvement of water use efficiency in farms, development of watershed and aquifers feeding activities, providing groundwater control facilities with emphasis on groundwater wells, blocking Unauthorized wells and giving appropriate incentives to farmers by government in the region to reduce the consumption of groundwater resources were proposed as solutions in order to cope with drought and depletion of groundwater resources in the study area.
Author Contributions
This article is an extract from a postdoctoral research project, the contribution and role of the first author was as the project leader, and the second author was as the project guide and host.
Not applicable
The authors would like to thank Tarbiat Modares University and the National Elite Foundation
The study was approved by the Ethics Committee of the University of Tarbiat Modares, The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
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