Spatiotemporal variation of rainfall and its implications on water resources management: The case of Manyame River catchment in Zimbabwe

Abstract

AbstractRainfall is an important hydrometeorological variable that affects river flow regimes and the amount of water flowing into surface water bodies and underground aquifers. Changing rainfall patterns and magnitudes contribute to extreme events including floods, droughts, and landslides. Thus, understanding of rainfall distribution is vital to sound water resources planning and allocation to users. Owing to the shortage of evenly distributed of rainfall stations in the arid and semiarid catchments, satellite rainfall products are regarded as reliable alternatives. This study therefore analyzes the long‐term spatiotemporal variation of rainfall in Manyame River catchment in Zimbabwe. Monthly rainfall data spanning from 1982 to 2019 were retrieved from the Climate Hazards Group Infra‐Red Precipitation with Station (CHIRPS). In situ rainfall data obtained from the country's two Meteorological Services Department were used to determine the accuracy of satellite data. Rainfall trends were tested using the Mann–Kendall trend test. The results showed goodness of fit between in situ and remotely sensed rainfall data. There is no significant increasing and decreasing trends in quarterly, monthly, and wet season rainfall. Statistically significant decreasing trends were observed in the central parts of the catchment during the dry season. The changing rainfall trends highlight the need for integrated and adaptive water resource management strategies to avoid adverse effects of floods and droughts in the catchment.