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Sedimentation and erosion of riverbanks and canals in the Mekong Delta have been longstanding issues. However, the severity and frequency of these problems are on the rise due to multiple factors, including upstream influences, climate change, rising sea levels, and human development activities. In this study, mapping riverbank erosion potential in the Vietnamese Mekong Delta is proposed to be carried out using the MK-BEHI index, which has been modified from BEHI developed by Rosgen. The MK-BEHI assesses the potential riverbank erosion by considering various factors, including: near-bank stress, bank geology, vegetation cover, bank construction, accretion/erosion rate, and bank load. Two indicators added to the index, compared to the original BEHI index, are bank construction and bank load. The index is categorized into four levels: low, medium, high, and very high, using a semi-quantitative approach. It is calculated by summing the component hazard indexes multiplied by their respective weights. The findings reveal that segments with very high potential are concentrated in certain areas, such as the segment of the Hau River flowing National Highway 91, Vam Nao River passing through My Hoi Dong, An Giang province, and the Tien River segment flowing through Sa Dec. Furthermore, numerous high-potential erosion banks have been recorded along the Tien and Hau rivers, particularly at the beginnings of the islets, curved river sections, and the Ham Luong river area encompassing Cho Lach, Mo Cay Bac, Mo Cay Nam, Thanh Phu, and Ba Tri. The aim is to provide a foundation for disaster adaptation and sustainable management.

In Mediterranean environments, gully erosion is responsible for large soil losses. It has since long been recognized that slopes under vegetation are much more resistant to soil erosion processes compared to bare soils and improve slope stability. Planting or preserving vegetation in areas vulnerable to erosion is therefore considered to be a very effective soil erosion control measure. Re-vegetation strategies for erosion control rely in most cases on the effects of the above-ground biomass in reducing water erosion rates, whereas the role of the below-ground biomass is often neglected or underestimated. While the above-ground biomass can temporally disappear in semi-arid environments, roots may still be present underground and play an important role in protecting the topsoil from being eroded. In order to evaluate the potential of plant species growing in Mediterranean environments to prevent shallow mass movements on gully or terrace walls, the root reinforcement effect of 25 typical Mediterranean matorral species (i.e. shrubs, grasses herbs, small trees) was assessed, using the simple perpendicular model of Wu et al. (Can Geotech J 16:19-33, 1979). As little information is available on Mediterranean plant root characteristics, root distribution data were collected in SE-Spain and root tensile strength tests were conducted in the laboratory. The power root tensile strength-root diameter relationships depend on plant species. The results show that the shrubs Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. have the strongest roots, followed by the grass Brachypodium retusum (Pers.) Beauv. The shrubs Nerium oleander L. and the grass Avenula bromoides (Gouan) H. Scholz have the weakest roots in tension. Root area ratio for the 0-0.1 m topsoil ranges from 0.08% for the grass Piptatherum miliaceum (L.) Coss to 0.8% for the tree Tamarix canariensis Willd. The rush Juncus acutus L. provides the maximum soil reinforcement to the topsoil by its roots (i.e. 304 kPa). Grasses also increase soil shear strength significantly (up to 244 kPa in the 0-0.1 m topsoil for Brachypodium retusum (Pers.) Beauv.). The shrubs Retama sphaerocarpa (L.) Boiss. and Anthyllis cytisoides L. are increasing soil shear strength to a large extent as well (up to 134 and 160 kPa respectively in the 0-0.10 m topsoil). Whereas grasses and the rush Juncus acutus L. increase soil shear strength in the topsoil (0-0.10 m) to a large extent, the shrubs Anthyllis cytisoides (L.), Retama sphaerocarpa (L.) Boiss., Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. strongly reinforce the soil to a greater depth (0-0.5 m). As other studies reported that Wu's model overestimates root cohesion values, reported root cohesion values in this study are maximum values. Nevertheless, the calculated cohesion values are used to rank species according to their potential to reinforce the soil.

River bank erosion is a destructive fluvio‐hydrological hazard particularly inhabited flood plain of the dynamic Himalayan foreland basin. Every year during monsoonal months, morphology of the landscape is continuously modifying through the dynamic river system. The principal objectives of this study are (i) to identify the river bank erosion susceptibility through BESI (River Bank Susceptibility Index) model which has been modified from Rosgen's (2001) Bank Erosion Hazard Index (BEHI) model and historical reconstruction (from 1955 to 2021) of the river course of Mujnai and (ii) to examine the principal factors of river bank erosion particularly for the river Mujnai within Himalayan Foreland Basin. Sedimentary bank facies analysis has also been done to ascertain the causes of river bank instability. Hence, rate of bank migration, changes of channel width, channel sinuosity index (SI), channel length, erosion and accretion of the river bank, and so forth have been measured through geospatial techniques. Result showed that the younger Quaternary sediments are prone to erosion and BESI result illustrated that around 28% areas are under high erosion zones like Deoagaon, Dhulagaon, Hedayet Nagar, and Dalimpur villages in Alipurduar district. Average maximum width of the channel was recorded in 1980 (147.92 m). Additionally, the lateral migration in case of left bank was around 141.08 m (in the 1980) and 192.62 m in right bank (in 1980) while the shifting rate was 14.10 m/y and 17.51 m/y respectively. Quaternary bank materials, bioturbation and indistinct laminations of river bank are principal regulating factors behind bank erosion in this area. Monsoonal high‐velocity flow, bank full discharge and severe flood incidents accelerate the bank erosion vulnerability, particularly in this dynamic flood plain. Soft engineering techniques such as bioengineering, geo‐textile fabric, tree, grass and brush revetment should be implemented at high bank erosion vulnerable sites of river Mujnai.

Extreme rainfall during 15–17 of June 2013 triggered numerous landslides and caused widespread damage and loss of life in the Bhagirathi and Alaknanda river valleys, with Kedarnath town bearing the brunt of the disaster. In this paper, we present a corroboration of observations gathered from very high resolution satellite data which indicated that two events in close succession caused damage to the Kedarnath town. While the flooding on June 16, 2013 was due to the reactivation of an old landslide that resulted in breaching of the river training wall, breaching of the moraine dammed Chorabari lake on June 17, 2013 caused further flooding and damage to the Kedarnath town. We also prepared a detailed landslide inventory using multi-temporal Resourcesat-2 images (5.8 m) acquired before and after the event in order to avoid issues related to cloud and shadow. A total of 6,013 landslides were mapped, out of which 3,472 landslides with 30.4 km 2 area were classified as new ones, 1,137 landslides with 9.1 km 2 area were classified as old ones and 1,401 landslides with 11.7 km 2 area were classified as reactivated ones. The frequency-area statistics of the mapped landslides shows near completeness of this event-based landslide inventory. The debris brought down by rivers from these landslides, particularly from the glaciated deposits in upstream areas, caused severe river bank erosion in downstream areas.

This study has been carried out to analyze and report the river bank erosion hazard due to morphometric change of the Ganga River (also called Ganges in English) in the upstream of Farakka Barrage up to Rajmahal. Morphometric parameters, such as, Sinuosity, Braidedness Index, and percentage of the island area to the total river reach area were measured for the year of 1955, 1977, 1990, 2001, 2003, and 2005 from LANDSAT and IRS satellite images. The analysis shows that there is a drastic increase in all of those parameters over the period of time. This study has found that bank failure is because of certain factors like soil stratification of the river bank, presence of hard rocky area (Rajmahal), high load of sediment and difficulty of dredging and construction of Farakka Barrage as an obstruction to the natural river flow. For the increasing sinuosity, the river has been engulfing the large areas of left bank every year. The victims are mostly Manikchak and Kaliachak-II blocks of Malda district, with a loss of around 1,670 ha agricultural land since 1977. Temporal shift measurements for the river reach between Farakka and Rajmahal has been done with help of 22 cross-sections in this reach. Erosion impact area has also been estimated to emphasize the devastating nature of the hazard.

Floods and river-bank erosion are the most frequent natural hazards in India, specifically in the deltaic regions. In West Bengal, floods and river-bank erosion predominantly affect Malda district as it is located in the moribund part of the Bengal delta. This article studies the recent trend of shifting course of the River Ganga and the effects of floods and consequent river-bank erosion on livelihoods of the residents of chars [The chars (called Diara in the upper reaches of the Gangetic plains) are virgin, low-lying river islands and sand bars occurring in the plains, particularly the deltaic parts of rivers (Lahiri-Dutt and Samanta, South Asia: J South Asia Stud 30:327–350, 2007).] and river-bank areas of Manikchak block in the Malda district. Around 300 sample households were selected by random stratified sampling technique from four gram panchayats of Manikchak block. Both primary and secondary data have been used. After analysing satellite images from the year 1973 to 2018, it has been observed that the River Ganga continues to shift eastwards and is eroding villages one after another. Inhabitants face multidimensional obstacles to run their households. Large numbers of people are displaced every year due to loss of land. Failure in facilitating the required assistance in the form of alternative spaces for resettlement and other disaster-mitigating public support systems against these hazards would make it impossible for the deplorable condition of the vulnerable people to improve.

Remote sensing plays a central role in the assessment of environmental phenomena and has increasingly become a powerful tool for monitoring shorelines, river morphology, flood-wave delineation and flood assessment. Optical-based monitoring and the characterization of river evolution at long time scales is a key tool in fluvial geomorphology. However, the evolution occurring during extreme events is crucial for the understanding of the river dynamics under severe flow conditions and requires the processing of data from active sensors to overcome cloud obstructions. This work proposes a cloud-based unsupervised algorithm for the intra-event monitoring of river dynamics during extreme flow conditions based on the time series of Sentinel-1 SAR data. The method allows the extraction of multi-temporal series of spatially explicit geometric parameters at high temporal and spatial resolutions, linking them to the hydrometric levels acquired by reference gauge stations. The intra-event reconstruction of inundation dynamics has led to (1) the estimation of the relationship between hydrometric level and wet area extension and (2) the assessment of bank erosion phenomena. In the first case, the behavior exhibits a change when the hydrometric level exceeds 1 m. In the second case, the erosion rate and cumulative lateral erosion were evaluated. The maximum erosion velocity was greater than 1 m/h, while the cumulative lateral erosion reached 130 m. Time series of SAR acquisitions, provided by Sentinel-1 satellites, were analyzed to quantify changes in the wet area of a reach of the Tagliamento river under different flow conditions. The algorithm, developed within the Python-API of GEE, can support many types of analyses of river dynamics, including morphological changes, floods monitoring, and bio-physical habitat dynamics. The results encourage future advancements and applications of the algorithm, specifically exploring SAR data from ICEYE and Capella Space constellations, which offer significantly higher spatial and temporal resolutions compared to Sentinel-1 data.

River bank erosion is a serious problem in the riparian inhabitants of the alluvial plain. The study attempts to develop an integrated vulnerability index for bank erosion in the lower Ganga basin of India, employing a socio-spatial approach. The methodology for the assessment of the vulnerability index is comprised of three dimensions such as exposure, sensitivity and capacity which include 34 indicators covering social, economic, physical and environmental dimensions. A comprehensive survey encompassing 600 households across 30 villages was conducted to gather socio-economic indicators. These indicators include exposure, sensitivity, and capacity data for each village, which were aggregated to formulate an integrated vulnerability index. Subsequently, this index was exported to a geographic information system for the visualization of spatial patterns. The result shows that more than 60% of the villages are highly exposed to river bank erosion in the study area whereas 66.6% of villages have a high to very high sensitivity level and 50% have a low capacity index. The result also revealed that the east bank of the river is more vulnerable to river bank erosion in terms of vulnerability as compared to the west bank. This comprehensive methodology yields valuable insights into vulnerability to river bank erosion, providing decision-makers with essential tools for effectively managing disaster risk.

Channel bank erosion processes are controlled by numerous factors and as such are both temporally and spatially variable. The significance of channel bank erosion to the sediment budget is difficult to quantify without extensive fieldwork/data analysis. In this study, the importance of key physical factors controlling channel bank erosion, including channel slope, upstream catchment area, channel confinement, and sinuosity, was explored using regression analysis. The resulting analysis can be used in practical studies to provide a first approximation of bank erosion rates (in catchments similar to those investigated). A data set of channel bank erosion rates covering eight contrasting river catchments across England and Wales, over a time period of up to 150 years, was created using a modified GIS methodology. The best predictors were found to be upstream area, channel confinement, and sinuosity with respect to dimensionless width-averaged retreat rates (m m −1  yr −1 ). Notwithstanding these relationships, the results highlight the variability of the magnitude of sediment production by channel bank erosion both within and between catchments.

The Padma river is widely known for its dynamic and disastrous behaviour, and the river has been experiencing intense and frequent bank erosion and deposition leading to the changes and shifting of bank line. In this paper, a time series of Landsat satellite imagery MSS, TM and OLI and TIRS images and are used to detect river bank erosion-accretion and bank line shifting during the study period 1975–2015. This study exhibits a drastic increase of erosion and accretion of land along the Padma river. The results show that from 1975 to 2015, the total amount of river bank erosion is 49,951 ha of land, at a rate of 1,249 ha a and the total amount of accretion is 83,333 ha of land, at a rate of 2,083 ha a . Throughout the monitoring period, erosion-accretion was more pronounced in the right part of the river and bank line had been shifting towards the southern direction. The paper also reveals that the total area of islands had been increased significantly, in 2015 there was about 50,967 ha of island area increased from 20,533 ha of island area in 1975, and the results evidence consistency of sedimentation in the river bed.