Drought Indication in Lake Hawassa Watershed, Southern Ethiopia

Abstract

Trend analysis was conducted by using nonparametric trend tests (Mann-Kendall and Sen’s slope). Lake Hawassa watershed station showed statistically significant downward trend from January to April, October, and December, and upward trend from May up to September and November. For the metrological drought severity and occurrence analysis, SPI at 3 month time scales was applied by dividing the whole period in to seven equal time periods. By analyzing the drought severity, it was observed that drought severity is increasing with time for near normal except for 2070s and 2080s, increasing with time for moderate drought, and constant for extreme droughts 2020s and 2030s and vice versa for severe drought. The drought occurrence in the study area experience mostly near normal drought that account at least 43% for all time periods, severe that account at least 27%, moderate that account at least 11% and null except for 2020s and 2030s for extreme drought. The observed inter-annual variability in the study area mostly experienced near normal inter-annual variability (about 73.33%). Keywords: drought, Climate change, SPI and Lake Hawassa watershed DOI: 10.7176/JETP/12-4-01 Publication date: October 31 st 2022