Sensitivity of Streamflow to Meteorological Drought in the Andit Tid watershed, Ethiopia

Abstract

• A significant correlation (P<0.05) was found between meteorological and hydrological droughts. • Streamflow Drought Index showed a stronger association with Reconnaissance Drought Index than with Standardized Precipitation Index. • Streamflow, minimum temperature, and rainfall are projected to decline while maximum temperature is to increase over the next decade. Drought is an environmental phenomenon and an integral part of climate change that can occur anywhere. Drought can take different forms, including meteorological, hydrological, agricultural, and socioeconomic droughts. The main goal of this study was to identify how meteorological droughts can cause hydrological droughts. The study confirmed that the area experienced both hydrological and meteorological droughts in 1987, 2003, and 2015. Index-based drought analysis results showed a significant (P<0.05) correlation between hydrological and meteorological droughts. Particularly, it was determined that there was a better association between the Streamflow Drought Index and Reconnaissance Drought Index than between the Standardized Precipitation Index. This demonstrates how strongly evapotranspiration influences streamflow, a factor that the Reconnaissance Drought Index considers when calculating its value. Based on projected scenarios for streamflow and climate factors, all variables in the watershed are expected to decline over the next ten years, other than maximum temperature. From the prediction process results, SARIMA catched better of the seasonality of temperature than rainfall or streamflow. Investigating index-based droughts is essential to warn the public and decision-makers about impending droughts and help them put mitigation and adaptation plans for water management into action.