Hasan Jahid, Zaman Md Alif Uz, Faridatul Mst Ilme
Department of Urban & Regional Planning, Rajshahi University of Engineering & Technology, Bangladesh.
Heliyon. 2024 Jul 26;10(15):e35274. doi: 10.1016/j.heliyon.2024.e35274. eCollection 2024 Aug 15.
River channel migration often occurs inside the floodplain areas of the river. The structural changes occurring in rivers within floodplain zones serve as a significant ecological signal of their tremendous impact on both ecological and human survival. The aim of the research is to assess the spatial and temporal fluctuations of the Meghna River's bankline from 1990 to 2020 (for 30 years), and to predict the future bankline position. The Landsat imageries from USGS were used for this study. The bankline was extracted from satellite imageries (Landsat) using Modified Normalized Difference Water Index (MNDWI) indices. The variations in bankline dynamics were assessed through the application of Net Shoreline Movement (NSM) and End Point Rate (EPR) analyses using the Digital Shoreline Analysis System (DSAS). Predictive modeling was conducted utilizing the Modified EPR Model, with validation performed via the Root Mean Square Error (RMSE) technique. Adjustment of errors was achieved by employing error coefficients tailored to each individual transect. Over the past three decades, the cumulative river erosion in Chandpur Sadar amounted to 18.03 square kilometers, with the highest Net Shoreline Movement (NSM) recorded at -1979.62 m during the study period. The forecasted maximum Net Shoreline Movement (NSM) is anticipated to be -495.79 m, signifying that the transect is associated with erosion, resulting in landward movement. Conversely, the minimum NSM is projected to be -1.01 m. The most significant movement is expected to occur in Puran Bazar, while the least movement is foreseen in Bakharpur. On average, the NSM across all transects is predicted to be -76.25 m. This study presents a cost-effective approach for evaluating the changes in river erosion over time. This technique may be valuable for policymakers in developing effective plans to reduce the negative impacts of erosion-related risks.
河道迁移通常发生在河流的洪泛区内部。洪泛区河流发生的结构变化是其对生态和人类生存产生巨大影响的一个重要生态信号。本研究的目的是评估1990年至2020年（30年）期间梅克纳河河岸线的时空波动，并预测未来河岸线的位置。本研究使用了美国地质调查局的陆地卫星图像。利用改进的归一化差异水体指数（MNDWI）从卫星图像（陆地卫星）中提取河岸线。通过使用数字海岸线分析系统（DSAS）进行净海岸线移动（NSM）和终点速率（EPR）分析，评估了河岸线动态变化。利用改进的EPR模型进行预测建模，并通过均方根误差（RMSE）技术进行验证。通过采用针对每个单独断面定制的误差系数来实现误差调整。在过去三十年中，钱德布尔萨达尔的累计河流侵蚀面积达18.03平方公里，研究期间记录到的最高净海岸线移动（NSM）为-1979.62米。预测的最大净海岸线移动（NSM）预计为-495.79米，这表明该断面与侵蚀有关，导致陆地向内移动。相反，最小NSM预计为-1.01米。预计最大移动将发生在普拉纳巴扎尔，而最小移动预计发生在巴赫尔布尔。所有断面的平均NSM预计为-76.25米。本研究提出了一种评估河流侵蚀随时间变化的经济有效方法。该技术对于政策制定者制定有效计划以减少侵蚀相关风险的负面影响可能具有重要价值。
