Abstract
The surface water in study area supports a range of uses such as water supply, irrigation and hydropower generation. Therefore, the assessment and analysis of the hydrological drought are important in the planning and management of the water resources. In this paper, hydrological drought was assessed using stream-flow drought index (SDI) based on observed mean monthly stream-flow data collected from three selected gauging stations at Greater Zab River, Lesser Zab River and Khazir River located in the North-Eastern region of Iraq. Trend analysis of the hydrological drought was investigated using Mann-Kendall non-parametric method to evaluate the significance of trends and Sen's slope method to determine the magnitude of the slope of trends for 47 years during the period 1965-2011. According to the SDI 3, 6 and 12-month time scales, the recorded drought was severe, and M-K method showed that the decreasing trends in the SDI values were statistically significant at α=0.05 mostly in the Greater Zab River and Lesser Zab River basins, increasing trend in SDI values is insignificant. This indicates that the hydrological drought is increasing over time at the study area.
Highlights
Drought is one of the world’s more costly natural disasters, which has significant impacts on human activities, economy, agriculture and environment
The stream-flow drought index (SDI) values were computed for nonoverlapping 3, 6 and 12-month time scales to assess the hydrological drought severity based on available monthly stream-flow volume data from the three selected gauging stations, and the trend of calculated SDI values was analyzed using the MK and Sen's slope methods
According to the SDI results, the severe drought in Greater Zab River and Lesser Zab River Basins was especially observed during the time scales of summer months for both 3 and 6-months due to the very low of rain
Summary
Drought is one of the world’s more costly natural disasters, which has significant impacts on human activities, economy, agriculture and environment. Drought differs from other natural disasters because its impacts are cumulative in an extended period of time over large spatial extent. It is important to analyze and assess the severity of drought. In general Palmer [1] defined drought as a moisture deficiency. Drought can be classified into: Meteorological, hydrological, agricultural and socioeconomic drought [2]. Saeed / Tikrit Journal of Engineering Sciences (2020) 27(1): 51-57
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