Document Type : Research Paper
Authors
1
Water Engineering Department , Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
2
Department of Water Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili
3
Water Engineering Department, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
10.22059/jwim.2024.371936.1141
Abstract
The occurrence of droughts that are affected by the change of climatic factors and the development of human activities have faced more serious problems in the management of limited water resources. In this research, SPI and SSI indices were used in different time scales in order to investigate meteorological and hydrological drought characteristics and extract the propagation relationship between them in the basin overlooking Samian station in Ardabil plain. To conduct the research, first, the average monthly rainfall of the study area was extracted using the IDW method. Then, by identifying the change point, the flow time series was divided into two periods before (natural) and after (disturbed) construction of Yamchi reservoir dam, and SPI and SSI indices were calculated for each period. In the natural period, hydrological drought prevailed about 30% of the time, but the share of hydrological and meteorological droughts was the same in this period. However, in the distributed period, the frequency of meteorological drought was less than 30%, but the frequency of hydrological drought was about 80%. This issue shows the effect of the construction and operation of Yamchi Dam so that in the years after the construction of the dam, the hydrological regime of the river was affected and experienced more drought. According to the correlation between SPI and SSI indices in two natural and disturbed periods, the propagation of meteorological drought to hydrological has been a third-order relationship.
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