Analyzing the Impact of Climate Change on Crop Water Demand in the Semi‐Arid Bilate Watershed, Ethiopia

The aim of this study was to look at the potential effects of climate change on the Bilate watershed’s crop water requirements (CWRs). Under two climate scenarios (RCP4.5 and RCP8.5), the CWR was anticipated for 2021–2050 and 2071–2100. The power transformation (PT) and variance scaling (VARI) methods were employed to correct biases in the rainfall and temperature climate variables, respectively. The CROPWAT 8.0 model was used to simulate CWRs and crop irrigation requirements (CIRs) for both the current and future periods. The estimated results for 2071–2100 reveal a drop in effective rainfall ( Pe ) of 29.6%–38% under RCP 4.5 and 24.7%–43.3% under RCP 8.5. CWRs would increase by 12.3–51 mm under RCP 4.5 and 16.3–62 mm under RCP 8.5 per growing season, but the rates of decrease/increase would vary by crop. Similarly, the anticipated irrigation requirements for the following crops increased when compared to the baseline period: wheat (from 68.1 to 81.6 mm), tomato (from 163 to 193 mm), sorghum (from 80 to 102 mm), maize (from 121 to 134 mm), cotton (from 163 to 192 mm), cabbage (from 193 to 221 mm), soybean (from 104 to 120 mm), and banana (from 95 to 135 mm). The study’s findings are important in demonstrating how climate change has a detrimental impact on crop water availability in the Bilate watershed, as well as in improving water resource management planning.