The analysis of drought (climatic – hydrologic) by using Man- Kendal test in Zayandehrood basin (Case study: Varzaneh station)

Droughts are considered to be the most disastrous natural disasters in the face of the flood. This is while the dangers of drought are far more than those of other natural disasters such as floods, storms, volcanoes and even earthquakes. This phenomenon differs from other natural crises because it has been slowly and relatively long, and most often it lasts more than a few years. In this paper, the drought of Zayandeh Rood Basin has been studied. In order to estimate the precipitation of synoptic station Varzaneh as the nearest station to the study area, for the analysis of drought, rainfall data was used in the period of 1327-1384, monthly and yearly. The precipitation parameter process was also calculated and analyzed by a non-parametric test-Kendall test. The results show that the highest precipitation was carried out in 1329-1334-1355-1357-1377. Since 1996, the lowest rainfall has been observed in the years studied and the highest rainfall is observed in April and April and the lowest rainfall was observed in Shahrivar, August and October. Using the Man Kandal test, the rainfall parameter was measured on a scale It was yearly without trend and it is on a monthly scale in the months of June, July, October and December, and in other months it lacks trend. The other losses of this period are due to the lack of proper management and human intervention that has been exacerbated by Considering the unpredictability but its repeatability is suggested in the water resource management strategy of the catchment area The river will be revised.