Gechelu Gadefa Fekadu, Shoro Keneni Elias, Baisa Sanyi Misgana, Tullu Kiyya Tesfa, Irena Buli Tefera, Urga Jabessa Boru
Faculty of Civil and Environmental Engineering, Jimma University, P O Box 378, Jimma, Ethiopia.
Department of Water Resources and Irrigation Engineering, Wollega University, PO Box 38, Shambu, Ethiopia.
Environ Monit Assess. 2025 Jun 18;197(7):765. doi: 10.1007/s10661-025-14240-x.
This study aims to investigate the impacts of climate change on future crop and irrigation water requirements in the Gojeb River catchment. Crop water requirements (CWR) and irrigation water requirements (IWR) for Shabe, Jimma, Dedo, and Bonga stations for maize, sorghum, barley, and wheat were assessed for the near future (2025-2060) and far future (2061-2096). RACMO22T, REMO2009, RCA4, and CCLM4.8 regional climate models (RCMs) were used, considering both the RCP4.5 and RCP8.5 emission scenarios. Climatic factors, such as precipitation, minimum and maximum temperatures, and potential evapotranspiration (ET), were used to evaluate future CWR and IWR. The Hargreaves-Samani equation was utilized to estimate ETo in the R programming. The results of the analysis indicate that at the base period and future projections under the RCP 4.5, maize consistently has the highest CWR and IWR at all stations, while barley requires less water. Under the RCP 4.5 scenario, the CWR for maize, sorghum, barley, and wheat is projected to increase at all stations in the near and far future. Similarly, in RCP 8.5, crop water needs increased across all stations. On the other hand, the study calculated IWR for maize, sorghum, barley, and wheat under the RCP 4.5 and RCP 8.5 scenarios, showing an increase in water needs for all crops in both the near and far future at all stations. The projected CWR and IWR values under RCP 8.5 are greater than those under RCP 4.5 at every station. The study can serve as benchmark information for future research and guide watershed managers and environmentalists in considering the impacts of climate change on surface water availability and irrigation requirements in the Gojeb River catchment.
本研究旨在调查气候变化对戈杰布河流域未来作物需水量和灌溉需水量的影响。评估了沙贝、吉马、德多和邦加站在近期（2025 - 2060年）和远期（2061 - 2096年）种植玉米、高粱、大麦和小麦的作物需水量（CWR）和灌溉需水量（IWR）。使用了RACMO22T、REMO2009、RCA4和CCLM4.8区域气候模型（RCMs），同时考虑了RCP4.5和RCP8.5排放情景。利用降水、最低和最高温度以及潜在蒸散量（ET）等气候因素来评估未来的作物需水量和灌溉需水量。在R编程中使用哈格里夫斯 - 萨马尼方程来估算参考作物蒸散量（ETo）。分析结果表明，在RCP 4.5情景下的基准期和未来预测中，玉米在所有站点的作物需水量和灌溉需水量始终最高，而大麦需水量较少。在RCP 4.5情景下，预计玉米、高粱、大麦和小麦在近期和远期所有站点的作物需水量都会增加。同样，在RCP 8.5情景下，所有站点的作物需水量也都增加。另一方面，该研究计算了RCP 4.5和RCP 8.5情景下玉米、高粱、大麦和小麦的灌溉需水量，结果表明所有作物在近期和远期所有站点的需水量都有所增加。在每个站点，RCP 8.5情景下预测的作物需水量和灌溉需水量值都大于RCP 4.5情景下的值。该研究可为未来研究提供基准信息，并指导流域管理者和环境学家考虑气候变化对戈杰布河流域地表水可利用量和灌溉需求的影响。
