Tareke Kassa Abera
Department of Hydraulics and Water Resource Engineering, Kombolcha Institute of Technology, KioT, Wollo University, Ethiopia.
Heliyon. 2024 Dec 12;11(1):e41161. doi: 10.1016/j.heliyon.2024.e41161. eCollection 2025 Jan 15.
This research aims to monitor the hydrological drought trends within the geographical confines of Ethiopia, Sudan, and Egypt in the Blue Nile River Basin. Historical drought circumstances in the basin were analyzed through the utilization of the stream flow drought index (SDI). The long-term historical drought trend was investigated via the application of the Mann - Kendall Sen (MK) test. Streamflow data were collected at the border (GERD) (Ethiopia) and Khartoum and Dongola (Sudan) spanning the period from 1900 to 2001. Four distinct temporal scales were examined, including monthly (SDI1), seasonal (SDI3), bi-annual (SDI6), and annual (SDI12) frequency. Notably, SDI1, SDI3, and SDI6 exhibited a higher frequency of drought occurrences, whereas SDI12 demonstrated lower frequencies, accompanied by the longest duration of drought in all gauged stations. For the preceding 102-year period, two extreme drought events were identified across all stations: 1912/1913 and 1913/1914 in the Border and Dongola stations, and 1912/1913 and 1986/1987 in the Khartoum station. Moreover, the SDI12 results revealed that severe drought events manifested three, six, and four times, in the Border, Khartoum, and Dongola stations, respectively. Furthermore, an investigation of historical extreme and severe drought patterns led to the conclusion that extreme hydrological drought does not pose an imminent threat to downstream nations, including Egypt and Sudan. However, the trend analysis revealed that an increasing drought trend was observed in the Autumn season across all stations, while a positive trend characteristic of a wet condition was observed in the remaining seasons. Annual trend analysis did not show any statistically significant findings. Nevertheless, the study highlighted the imperative role of soil and water conservation measures in upstream countries, such as the Ethiopian highlands, in mitigating the prolonged effects of meteorological drought which gradually propagates into severe hydrological drought. Consequently, downstream nations must engage in cooperative efforts with upstream countries to address this issue collectively, rather than bestowing sole responsibility on the latter.
本研究旨在监测青尼罗河流域内埃塞俄比亚、苏丹和埃及地理范围内的水文干旱趋势。通过利用径流干旱指数（SDI）分析了该流域的历史干旱情况。通过应用曼 - 肯德尔森（MK）检验研究了长期历史干旱趋势。在1900年至2001年期间，在边界（GERD）（埃塞俄比亚）以及喀土穆和栋古拉（苏丹）收集了径流数据。研究了四个不同的时间尺度，包括月度（SDI1）、季节（SDI3）、双年度（SDI6）和年度（SDI12）频率。值得注意的是，SDI1、SDI3和SDI6出现干旱的频率较高，而SDI12的频率较低，且在所有测量站中干旱持续时间最长。在之前的102年期间，所有站点共识别出两次极端干旱事件：边界站和栋古拉站在1912/1913年和1913/1914年，喀土穆站在1912/1913年和1986/1987年。此外，SDI12的结果显示，边界站、喀土穆站和栋古拉站分别出现了三次、六次和四次严重干旱事件。此外，对历史极端和严重干旱模式的调查得出结论，极端水文干旱对包括埃及和苏丹在内的下游国家并不构成紧迫威胁。然而，趋势分析表明，所有站点在秋季均出现干旱趋势增加，而其余季节则呈现湿润状况的正趋势。年度趋势分析未显示任何具有统计学意义的结果。尽管如此，该研究强调了上游国家（如埃塞俄比亚高地）采取水土保持措施在减轻气象干旱长期影响方面的重要作用，气象干旱会逐渐演变成严重的水文干旱。因此，下游国家必须与上游国家共同合作来集体解决这个问题，而不是将责任完全归咎于上游国家。
