Analysis of temporal and spatial relationship between meteorological and hydrological drought in Zohreh-Jarahi basin

The water crisis is one of the concerns in countries with arid and semi-arid climates in recent years. This study aimed to investigate the trend of temporal and spatial changes of meteorological and hydrological drought in the Zohreh-Jarahi watershed over five decades. For this purpose, hydrological (SDI) and meteorological (SPEI) drought were used. According to the results, climate change in the region had a direct effect on river flows. The calculation of basin drought indices over 50 years showed the matches of temporal and spatial changes of hydrological and climate drought of Zohreh, Jarahi, and Kupal rivers. The index of hydrological and climatic drought in the first four decades of the study period (1966-1975 to 1996-2005) was humid, normal, and mild. However, climatic and hydrological drought indicated a severe drought in the last decade (2006-2016). Drought changes intensified from east to west and downstream of the basin due to spatial changes trend in meteorological and hydrological drought. Therefore, over a period of 50 years, an intensification of the climate drought from the past until now is indicated in the results, the effects of which has manifested itself as hydrological drought.