The national economy and food security of many sub-Saharan countries relies on rain-fed agriculture, hence the impact of rainfall variability is highly significant. The intent of this study is to characterize rainfall variability and trend in Awash River Basin for agricultural water management using standard rainfall statistical descriptors. Long-term climate data of 12 stations were analyzed. Onset and cessation dates, length of growing period (LGP) and probability of dry spell occurrences were analysed using INSTAT Plus software. The Mann–Kendall test and the Sen's slope method were used to assess the statistical significance of the trend. The results show high variability of rainfall (38–73%), LGP (30–38 days) and high probability of dry spell occurrence (up to 100%) during the Belg season (the short rainy season from March to May) compared with the Kiremt season (the main rainy season from June to September) in all stations. Belg season showed a non-significant decline trend in most of the stations, whereas the Kiremt season indicated the contrary. The finding also revealed that supplementary irrigation is vital, especially in the Belg season to cover up to 40% of the crop water requirement deficit.

No abstract

No abstract

Natural resource degradation resulting from inappropriate land use and subsequent hydrological change is one of the key problems threatening environmental welfare and sustainable development. This study investigates the changes in the hydrological process in response to the land use and land cover (LULC) dynamics of the Keleta watershed, Awash River basin, Ethiopia using the Soil and Water Assessment Tool (SWAT) model. The model was calibrated and validated using monthly observed stream flow data for the baseline year (1985) and performed well (NSE ≥ 0.74, RMS ≤ 0.51, and PBIAS ≤ 15.3). An overall increase in the amount of surface runoff and base flow (10.4%) and (0.6%) and a decline in groundwater flow (3.5%) were observed in 2010 compared with the baseline year (1985). The trend of increasing surface runoff and declining groundwater flow due to LULC changes has wider implications for environmental and water resource development. This is expected to exert a substantial adverse impact on ecosystems, hydraulic structures such as dams, reservoirs, and irrigation canals, and rural livelihoods unless appropriate integrated landscape management is implemented.

No abstract