Spatio-temporal flood frequency dynamics in Kaziranga National Park using multi-year Sentinel-1 SAR and vegetation indices

IF 2.6 4区综合性期刊 Q3 MULTIDISCIPLINARY SCIENCES

Kuwait Journal of Science Pub Date : 2026-04-01 Epub Date: 2026-02-05 DOI:10.1016/j.kjs.2026.100552

Prasad Balasaheb Wale , Thota Sivasankar , Ratna Sanyal

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引用次数: 0

Abstract

Floods along the Brahmaputra are frequent, devastating, and dynamic, bringing severe hydrologic, ecological, and geomorphological alterations in Kaziranga National Park (KNP), a UNESCO World Heritage Site. This study presents a spatio-temporal Flood Frequency (FF) assessment and its ecological implications using multi-sensor satellite data. A total of 228 Sentinel-1 Synthetic Aperture Radar (SAR) and 8 Sentinel-2 optical images (2015–2022) were analysed to derive annual FF maps, identify hotspot regions of major FF change, and quantify vegetation response using Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Modified NDWI indices. Flood inundation maps were generated through SMILE random forest classification of pre and during-flood SAR composites in Google Earth Engine. Results show typically high FF along the Brahmaputra channel and permanent waterbodies and wetlands, whereas elevated southern highlands exhibited low FF. Extreme flood years (2017, 2020, 2022) recorded mean FF >40%. FF trend analysis revealed 81.72% of KNP remained stable, 10.04% experienced increasing FF linked to erosion and channel encroachment, and 8.24% showed decreasing FF due to deposition. Flood ridges (70% FF) digitized between 2015 and 2022 indicated average channel migration of ∼157 m upstream and ∼311 m inward, with localized shifts exceeding ∼1 km. DBSCAN clustering of FF slopes delineated 68 clusters, comprising 43 hotspots and 25 cold spots, marking zones of hydro-geomorphic instability. Vegetation analysis revealed NDVI decline in hotspots due to inundation and erosion, while cold spots showed greening from sediment deposition and grassland regeneration. The integrated SAR–optical approach underscores dynamic floodplain alterations and ecological responses, providing vital inputs for monitoring riverine ecosystems and strengthening conservation strategies in KNP.

查看原文本刊更多论文

基于多年Sentinel-1 SAR和植被指数的卡兹兰加国家公园洪水频率时空动态

雅鲁藏布江沿线的洪水频繁、破坏性强，给联合国教科文组织世界遗产卡齐兰加国家公园（KNP）带来了严重的水文、生态和地貌变化。本研究利用多传感器卫星数据进行了洪水频率（FF）的时空评估及其生态意义。利用2015-2022年共228幅Sentinel-1合成孔径雷达（SAR）和8幅Sentinel-2光学影像进行分析，得出FF年景图，识别FF主要变化热点区域，并利用归一化植被指数（NDVI）、归一化差水指数（NDWI）和修正NDWI指数量化植被响应。在谷歌Earth Engine中对洪水前和洪水期间的SAR合成物进行SMILE随机森林分类，生成洪水淹没图。结果表明，沿雅鲁藏布江河道和永久水体和湿地的FF值较高，而南部高地的FF值较低。极端洪水年份（2017年、2020年、2022年）记录的平均FF >；40%。FF趋势分析显示，81.72%的KNP保持稳定，10.04%的KNP因侵蚀和河道侵蚀而FF增加，8.24%的KNP因沉积而FF减少。2015年至2022年间数字化的洪脊（70% FF）表明，河道上游平均迁移约157米，向内迁移约311米，局部偏移超过约1公里。对FF坡面进行DBSCAN聚类，共划分出68个聚类，包括43个热点和25个冷点，标志着水文地貌不稳定区。植被分析显示，热点地区NDVI因淹没和侵蚀而下降，而寒带地区则因泥沙淤积和草地更新而变绿。综合sar光学方法强调了河漫滩的动态变化和生态响应，为监测河流生态系统和加强KNP的保护策略提供了重要的输入。

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来源期刊

Kuwait Journal of Science MULTIDISCIPLINARY SCIENCES-

CiteScore

1.60

自引率

28.60%

发文量

132

期刊介绍： Kuwait Journal of Science (KJS) is indexed and abstracted by major publishing houses such as Chemical Abstract, Science Citation Index, Current contents, Mathematics Abstract, Micribiological Abstracts etc. KJS publishes peer-review articles in various fields of Science including Mathematics, Computer Science, Physics, Statistics, Biology, Chemistry and Earth & Environmental Sciences. In addition, it also aims to bring the results of scientific research carried out under a variety of intellectual traditions and organizations to the attention of specialized scholarly readership. As such, the publisher expects the submission of original manuscripts which contain analysis and solutions about important theoretical, empirical and normative issues.