This paper examines the relationship between landscape degradation and flooding in the Niger River catchment of Onitsha, Nigeria, over a 40‐year period (1992–2022), focusing on changes in land use and land cover characteristics. Satellite images were preprocessed and classified using Anderson's classification technique. Erdas Imagine GIS software was adopted to carry out change analysis for each of the classes generated. The Landsat images for all the years (1992, 2002, 2012, and 2022) were acquired for the months of July (wet season) and December (dry season) and analyzed. The trends in seasonal changes in land use and land cover characteristics were prominent in the wet season. This was significantly seen in changes for water body and vegetative area. Built‐up areas and open spaces indicated a decrease during the wet season compared to the dry season. The notable changes occurred in water bodies and vegetation across the studied years, peaking in 1992 with 1628.82 ha for water bodies and 8993.79 ha for vegetation. In 2012, these values were 2040.93 and 8977.5 ha. The largest seasonal shifts were in vegetative areas in 2012 and built‐up in 2022. After analyzing the geospatial data according to the classifications, the study uncovers a notable link between landscape degradation and increased flood susceptibility. Notably, the findings highlight that shifts in these landscape features during the wet season significantly impact flood occurrence, emphasizing the critical role of landscape degradation in exacerbating flood risks in the region.

中文翻译：

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评估尼日利亚东南部尼日尔河流域景观退化与洪水之间的联系：40 年地理空间动态（1992-2022）


本文研究了尼日利亚奥尼查尼日尔河流域 40 年（1992-2022 年）景观退化与洪水之间的关系，重点关注土地利用和土地覆盖特征的变化。卫星图像使用 Anderson 分类技术进行预处理和分类。采用 Erdas Imagine GIS 软件对生成的每个类进行变化分析。获取了 7 月（雨季）和 12 月（旱季）所有年份（1992 年、2002 年、2012 年和 2022 年）的 Landsat 影像并进行了分析。湿季土地利用和土地覆被特征的季节性变化趋势突出。这在水体和植被面积的变化中得到了显著体现。与旱季相比，雨季的建筑区和开放空间有所减少。在研究的年份中，水体和植被发生了显著变化，在 1992 年达到顶峰，水体为 1628.82 公顷，植被为 8993.79 公顷。2012 年，这些值分别为 2040.93 公顷和 8977.5 公顷。最大的季节性变化发生在 2012 年的植被区域，2022 年形成。在根据分类分析地理空间数据后，该研究揭示了景观退化与洪水易感性增加之间的显着联系。值得注意的是，研究结果强调，雨季这些景观特征的变化会显著影响洪水的发生，强调了景观退化在加剧该地区洪水风险方面的关键作用。