Hydrological processes Climate variability in the recent decades in case study of Nyabarongo catchment

Abstract

Climate and land use changes affect the hydrological process in the catchment. Hydrometeorogical parameters such as rainfall, evaporation, runoff, water level , temperature and water discharge were analysed for investigating the different impacts of climate and land use changes. Water balance equation and statistical analysis was perfomed using WEAP and Origin Pro Software to determine the yearly amount of those parameters listed above. The analysis shows that the runoff water , water level and water discharge increase with increasing the rainfall. The high value of rainfall obtained is 10393mm in a single year and the lowest value is around 3218mm; In the Nyabarongo catchment the mean annual evaporation ranges approximately from 2. 25 mm to 5.25 mm where the tatal evaporation within 12 years were 6339.5mm and its corresponding runoff were 67539.5mm. The results show that in 2020 the mean temperature were high at 27.04 degree Celsius while is low in 2001 at 25.24299 degree Celsius, in 2020 the temperature increase to 1.8 degree Celsius. The calculated high value of discharge were 217mm obtained in the year 2018. The water levels in the Nyabarongo River in 5 years ago varies between 4m and 5m.