Erosion and accretion

Rivers have historically served as lifelines for civilizations, providing essential resources and opportunities for livelihood. However, they also present significant challenges, particularly when turned into disaster propelled by human interventions. The very qualities that make rivers indispensable to the dependent communities also render them vulnerable in many ways. Among the myriad challenges facing riverine communities, river bank erosion stands out as a particularly pressing issue, with far-reaching social, economic, and environmental implications. In recent time, well-being of riparian people in West Bengal, India, is seriously threatened by river bank erosion in the Ganges river basin, especially in parts of Malda and Murshidabad districts have [un]intentionally gotten worse since the Farakka Barrage was built in 1972.The article emphasises how these elements are interrelated and have consequences for the welfare of communities by looking at them through the lenses of geopolitics, feminism, and human rights.

River geomorphological investigation issues have received little attention in most countries of the world. Such processes become a pressing necessity due to climate change and anticipated events of extraordinary surges and dry seasons, which may debilitate the security of adjacent and downstream cities, particularly in locales that are exceedingly delicate and influenced by climatic changes. Al-Abbasia reach is a river that runs through the middle of the Euphrates River and is known for its numerous bends and meanders. The study of hydraulic structures such as barrages can provide important information about their influences on morphological processes in river reaches near the barrage upstream and downstream. Hydraulic analysis is made of the river behavior in u/s and d/s of hydraulic structures like barrages as a result of sediment deposition and erosion in u/s and d/s. A study, i.e., research on the impacts of the Abbassia barrage on the river system, has been conducted to address this issue using multi-temporal Landsat satellite data from 1976 to 2022 provided by the USGS. The study reach is located 5 kilometres upstream and 5 kilometres downstream of the Abbassia reach. Following the construction of the barrage, which had an impact on the sedimentation and geometry of the river, morphological variations took place in this part of the Al Abbassia reach. In this study, morphological changes throughout 49 years between 1976 and 2022 were investigated utilising remote sensing (RS) and geographic information system (GIS) approaches. Additionally, four image groups from three separate decades were used to perform change detection

A study was undertaken by the River Research Institute (RRI) to protect the Faridpur Town and its adjacent areas from the erosion of Padma river. The study area starts from Decreer Char Union under Faridpur Sadar Upazila to Zajirtek Union under Char Bhadrason Upazila in the District of Faridpur covering around 10 km long reach along the right bank of Padma river. Many permanent important installations such as High School, Primary School, Hat, Bazar, Post Office, Food Godown, Family Planning Centre, Ghat, Homesteads and Agricultural lands are affected due to the devastating bank erosion of Padma river. Every year the right bank of Padma river is shifting toward the right side at these areas. To save these areas and its agrarian economy from the devastating bank erosion of the Padma, this paper suggests retired embankment parallel to the existing banklines and also a series of spurs extending from the embankment upto this bankline. As an alternative to spur, river bank can also be pro...

This research presents a novel, comprehensive analysis of the geomorphological evolution of the Bazoft River over 30 years , combining high-resolution satellite imagery with advanced spatial analysis techniques to reveal the unprecedented interplay between extreme flood events and large-scale dam construction. It highlights, for the first time in this region, how the December 2010 flash flood and the Karun-4 Dam's impoundment revealed previously unexplored dimensions of erosion, deposition, and channel dynamics. Large bank migrations and flood-event-related asymmetric bank erosions were realized; impoundment of this dam caused ultimate variations within a radius of 21 km in geometrical status. It remarkably identifies distinct phases of instability and stabilization in the period of filling, which is important to understand sediment transport and river regulation in extreme anthropogenic intervention. The general sinuosity trends underlined the differential response of the reaches, identifying the second and third intervals as those most sensitive to hydrological and structural controls. The paper uses remote sensing to bring together temporal dynamics of extremes with spatial scales of dam-induced geomorphic modification. This would add value to the current understanding and management of river systems undergoing rapid hydrological and structural alteration and contribute to the international debate on the sustainable development of water resources and riverine ecosystem resilience.

iver meandering is an inherent characteristic of drainages in an alluvial plain. A river meandering through an alluvial plane has a series of consecutive curves of reversed order connected with short straight stretches crossing. Most rivers in the world are subject to meandering due to natural and human activities. Natural Cause of meandering is the excess of total change during floods, when excess of turbulence is developed and also because of valley slope stream load discharge, bed and side resistance. However, human activity includes Dam construction, Settlement, Agriculture farming causes meandering. Freely meandering rivers have attracted a great deal of attention from river scientists and engineers over the last century. Earlier works have demonstrated about mender platform geometry, bend flow, bend-migration dynamics, and lateral accretion sedimentlogy Knighton, 1998). A number of river in India like Ganga (Singh, 1996) Kosi (Wells and Dorr, 1987) Brahmaputra river and many other river shows special temporal shifting of their channels. Satellite images show river channels, both active and fossil, very well. Since meanders are to be recognized on their shape on satellite images, it is easy to delineate. Once they have been delineated, their metrics and spectral behaviour can be analyzed. Research on the remote sensing of river meandering has flourished since the 1972

As a major distributary of the Ganges, the Padma originates at the confluence of the Ganges and Jamuna Rivers, eventually merging with the Meghna River to flow into the Bay of Bengal. Spanning approximately 130 kilometers, the Padma is not only hydrologically significant but also politically and economically critical.

The Ganga-Padma and Brahmaputra-Jamuna river systems in Bangladesh carry 2.4 billion tons of sediments, a part of which is deposited in the flood plains each year. The comparison between deeply flooded areas in Bangladesh and the areas having more than 10 and 50 percent of the tubewells producing arsenic more than 0.05 mg/l shows that the deeply flooded areas are mainly arsenic problem areas of Bangladesh. The reducing soil environment in the deeply flooded areas produced by anaerobic conditions in fine grained sediments rich in organic matters appears to be conducive to the release of arsenic in groundwater. The reducing environment in recently deposited sediments in flood plains appears to be the main cause of arsenic dissolution from soil to groundwater in Bangladesh. The old sediments and oxidized reddish soils in Bangladesh do not release arsenic, rather they adsorb arsenic from water. In this context, presence of significant arsenic in the recent incoming upstream suspended sediments carried by river flow & flood water and sediment deposited in the river flood plain of Bangladesh 22 Fate of Arsenic in the Environment significantly influence the arsenic contamination of groundwater in Bangladesh. Arsenic content in surface water of the rivers even after flood is extremely low, almost negligible ranging from 0.11 ppb to 2.25 ppb. The arsenic content of fresh suspended sediment carried by running incoming sediment after post flood period ranges 4.067 to 5.466 mg/kg, which is not significantly higher than the usual arsenic contents of soils in Bangladesh. At every location of each rivers, arsenic in sand fraction is always lower than that in silt and clay fraction. Arsenic content in clay fractions of different type of river sediments ranges from 3.525 to 6.476 mg/kg.

The Earth's environment has experienced substantial transformations due to human activities, with a remarkable acceleration observed after 1950. The sub-Himalayan Terai Region has not been immune to such anthropogenic interventions, and the Mahananda River, in particular, faces significant threats due to these activities. To comprehend the consequences of constructing a barrage on the river's natural state, a comprehensive morphological assessment was conducted, comparing the river's condition before and after the construction of the Barrage. Furthermore, the morphological characteristics both upstream and downstream of the Barrage structure were analyzed. The research focused on various morphological aspects, such as planform configuration, channel width, braiding index, and riverbed elevation, which were affected by these human-induced changes. To investigate temporal changes, topographical maps, and satellite imagery from different years (1931, 1975, 1990, 2005, and 2022) were retrieved and processed using Arc GIS 10.2 software. This empirical study provides valuable insights into the influence of the Barrage on the fluvial landscape and stream geomorphology of the Mahananda River, shedding light on its ecological implications. The findings from this study contribute to a scholarly understanding of the significant alterations to the river's physical features and shape resulting from the presence of the Barrage. By shedding light on the human impacts on this vital river system, this research is a crucial step towards effective and sustainable river management practices in the region.

Many coastal areas and infrastructure suffered from unprecedented hazards such as storms, flooding, and erosion. Thus, it is increasing the vulnerability of urban coastal areas aggravated with the absence of coastal green infrastructure. Given the state of coastal environments, there is a genuine need to appraise the vulnerability of coastal cities on the basis of the latest projected climate scenarios and existing condition. Hence, to asses, the vulnerability level of Mataram coastal, the Coastal Vulnerability Index (CVI) accompanied by pre-assessment of readiness to climate disruption. The CVI used to map coastal into five classes of using GIS. As a case study, this approach applied to Mataram City: one of the tourism destinations in Lombok. Two of sub-districts in Mataram City, Ampenan and Sekarbela, laying in the shorelines have undergone coastal flooding and erosion. One of them, Ampenan sub-district, experienced flooding due to river-discharge and became the most severe locati...

The Prokopos Lagoon is part of the Kotychi Strofilias National Wetlands Park, which is supervised by the Ministry of Environment, Energy and Climate Change of Greece. The lagoon is situated at the northwestern coast of the Peloponnese and is protected by the Ramsar Convention. It is an important ecosystem with ecological services providing habitats for many plants and animals and essential goods and services for humans as well. No previous relevant studies for the wider wetland area are available, and given that lagoons are important ecosystems, their diachronic evolution should be under constant monitoring. Using remote sensing techniques in Geographic Information System (GIS) environment, alterations in critical parameters could be measured and applied for the protection of the area. The present study examines the spatiotemporal changes of the water extent of the Prokopos Lagoon, estimating landscape metrics and several morphometric parameters and indices related to the geomorphol...

River bank erosion is a natural process that occurs when the water flow of a river exceeds the bank's ability to withstand it. It is a common phenomenon that causes extensive land damage, displacement of people, loss of crops, and infrastructure damage. The Gorai River, situated on the right bank of the Ganges, is a significant branch of the river that flows into the Bay of Bengal via the Mathumati and Baleswar rivers. The erosion of the banks of the Gorai River in Kushtia district is not a recent occurrence. Local residents have been dealing with this issue for the past hundred years, and according to the elderly members of the community, the erosion has become more severe activities. Therefore, the main objective of this research is to quantify river bank erosion and accretion and bankline shifting from 2003 to 2022 using multi-temporal Landsat images data with GIS and remote sensing technique. Bank-line migration occurs as a result of the interplay and interconnectedness of various factors such as the degree of river-related processes such as erosion, transportation, and deposition, the amount of water in the river during the high season, the geological and soil makeup, and human intervention in the river. The results show that the highest eroded area was 4.6 square kilometers during the period of 2016 to 2019, while the highest accreted area was 7.12 square kilometers during the period of 2013 to 2016. However, the erosion and accretion values fluctuated from year to year.

River channel dynamics are natural autogenic occurrences for fluvial rivers with influences from human modifications and climatic factors. Remote sensing and geographic information system tools and techniques, aerial photographs, and satellite imagery have been used to determine epochal channel erosion, accretion, and unchanged locations along Tana River, Kenya's longest river. Six reaches within a 142-km Saka-Mnazini stretch were studied by comparing sequential changes in the position of the channel in

The Achanakmar Tiger Reserve (ATR) is an integral part of the Achanakmar Amarkantak Biosphere Reserve (AABR) with a total area of 914.017 sq. km. The Maniyari River, which flows through the reserve, is known as its life line. It originates from the core zone (Sihawal sagar) of ATR and merges in the Seonath River of the Mahanadi Basin. It flows about 105 km through Mungeli and Bilaspur districts. This river supplies its catchment area with water seasonally (6-8 months) and flows more than half of its length (about 60 km) within the protected area. Its catchment area has a rich biodiversity of tree species such as Shorea robusta, Terminalia tomentosa, Diospyros melanoxylon, Adina cordifolia, Pterocarpus marsupium, Madhuca indica, Anogeissus latifolia, Dendrocalamus strictus etc. A geospatial analysis was performed to understand the course of the Maniyari River within the ATR area over a fourteen year period between

River geomorphological investigation issues have received little attention in most countries of the world. Such processes become a pressing necessity due to climate change and anticipated events of extraordinary surges and dry seasons, which may debilitate the security of adjacent and downstream cities, particularly in locales that are exceedingly delicate and influenced by climatic changes. Al-Abbasia reach is a river that runs through the middle of the Euphrates River and is known for its numerous bends and meanders. The study of hydraulic structures such as barrages can provide important information about their influences on morphological processes in river reaches near the barrage upstream and downstream. Hydraulic analysis is made of the river behavior in u/s and d/s of hydraulic structures like barrages as a result of sediment deposition and erosion in u/s and d/s. A study, i.e., research on the impacts of the Abbassia barrage on the river system, has been conducted to address this issue using multi-temporal Landsat satellite data from 1976 to 2022 provided by the USGS. The study reach is located 5 kilometres upstream and 5 kilometres downstream of the Abbassia reach. Following the construction of the barrage, which had an impact on the sedimentation and geometry of the river, morphological variations took place in this part of the Al Abbassia reach. In this study, morphological changes throughout 49 years between 1976 and 2022 were investigated utilising remote sensing (RS) and geographic information system (GIS) approaches. Additionally, four image groups from three separate decades were used to perform change detection

The study investigated bank erosion and accretion of the lower section of the Pra River of Ghana using a topographical map of 1974 and satellite imagery of 2007, 2015, and 2018 which was augmented by field observation and key informant interviews. Bankline changes due to erosion and accretion and the total volumetric change in river channel were measured using Remote Sensing and Geographic Information System approaches. The study showed that erosion was more pronounced in both the right and left bank as compared to accretion. The study revealed that bank width area of the lower basin of Pra River increased by 50.7 m² from 16.2 m² in 1974 to 66.9 m² in 2018 eroding large portions of land along the right and left banks of the river. In general, the number of erosional spots in selected cross sections exceeded that of deposition. Erosion took place in 13 spots out of 20 spots constituting 65% with a rate ranging between 0.2 and 3.4 m/year. This research showed the value of channel morp...

The study investigated bank erosion and accretion of the lower section of the Pra River of Ghana using a topographical map of 1974 and satellite imagery of 2007, 2015, and 2018 which was augmented by field observation and key informant interviews. Bankline changes due to erosion and accretion and the total volumetric change in river channel were measured using Remote Sensing and Geographic Information System approaches. The study showed that erosion was more pronounced in both the right and left bank as compared to accretion. The study revealed that bank width area of the lower basin of Pra River increased by 50.7 m² from 16.2 m² in 1974 to 66.9 m² in 2018 eroding large portions of land along the right and left banks of the river. In general, the number of erosional spots in selected cross sections exceeded that of deposition. Erosion took place in 13 spots out of 20 spots constituting 65% with a rate ranging between 0.2 and 3.4 m/year. This research showed the value of channel morp...

Morphology is one of the most important branches of river engineering science. Examining the changes in the geometry of sections in rivers that feed large dams is of particular importance. In fact, gaining a better understanding of the river's behavior will reduce potential damages to hydraulic structures and public infrastructure. In this regard, in this research, the morphological changes of Bazoft River, one of the sub-basins of North Karun, which enters the Karun 4 Dam at the end, have been investigated. In this study, using 26 Landsat + ETM and OLI satellite images, the displacement pattern of the main river channel, along with the changes in width and sinuosity resulting from sedimentation and erosion processes in long and short-term intervals leading to the year 2015 and caused by large floods in this period of time was investigated. The results showed that the average displacement of the main channel of the river leading to erosion (sedimentation) for the right and left banks is 14 (15) and 14 (14) percent of the average width of the river, respectively. Also, the net area change rate due to the displacement of the main channel of the river for the right and left banks was obtained as -1.8 and 0.3 hectares per year, respectively. By examining the effect of floods, it was found that the amount of erosion is higher than sedimentation on both coasts, and the left coast is more dynamic than the right coast. The average width of the river in the 30-year period for the four investigated periods is 33.8, 44.7, 40.2, and 38.6 meters, respectively. Also, the width of the Bazoft River did not change much before the biggest flood in 2009 and its value did not exceed 40 meters. But after the flood, the width of the river suddenly increased and these changes seem obvious. The maximum increase in width is related to the second span of the river and its value is equal to 70 meters. Investigations related to four longitudinal intervals along the river's path showed that the sinuosity value in all years in the first interval had an almost constant trend, but in the second and third intervals, its value is higher, so these two intervals are more active than the other two intervals be in the fourth span, which leads to the Karun Dam 4, changes in sinuosity have a downward trend. Also, the results showed that the dewatering of the Karun 4 dam had a significant effect on all the morphological parameters of the Bazoft River in the fourth period. The results of this study perfectly indicated the capability of revealing the river form changes using Satellite Images Time Series (SITS). This homogeneous result indirectly shows that the erosion rate of the upstream basin and the sediment load of the river increased during this period. Therefore, while updating the status of rivers, the effects of protective and structural measures in such rivers can be evaluated in this way and corrected for improvement.

Coastal activities during the past five decades have resulted in considerable shoreline change along the northern coast of Sinai Peninsula. In the east of El Arish Harbor, the shoreline is continuously retreating. Previous activities to mitigate the erosion have not succeeded. For example, the groin field in the east of the El Arish Harbor has transferred the problem to the neighboring beaches farther downcoast. The shoreline change at El Arish Harbor was modeled using the coastal evolution model LITLINE. Having understood the coastal processes driving the shoreline change at this site, appropriate remedial measures were proposed to mitigate the problem.

This study focuses on the shoreline change detection along the North Sinai coast in Egypt using geographic information system and digital shoreline analysis system (DSAS) during the elapsed period from 1989 to 2016. The measurement of shoreline variation is mainly described for three zones: zone I, El-Tinah plain bay; zone II, El-Bardawil Lake; zone III, El-Arish valley. The rates of shoreline changes in the form of erosion and accretion patterns are automatically quantified by four statistical parameters functioned in DSAS namely endpoint rate, net shoreline movement, linear regression rate (LRR), and least median of squares. LRR results elucidate that the western seaside of El-Tinah plain bay has experienced an extremely dynamic feature with an average erosion rate of −8.17 m/year. The littoral drifts have been driven by eastward alongshore currents toward the east side of the bay to be accreted with an average rate of +4.28 m/year. Moreover, the shoreline has progressed west of El-Bardawil inlet (1), El-Bardawil inlet (2), and El-Arish harbor. Subsequently, the corresponding average beach growth rates are found to be +2.7, +8.5, and +6.5 m/year, respectively. In contrast, the shoreline on the down-drift side to the east has negatively retreated, and the corresponding beaches have regressed at rates of −4.5, −8.65, and −2.9 m/ year, respectively.

The river island is one of the important components in river ecology development because of its function as a restraining components to river flow velocity and increasing the diversification of river flow distribution. Various occurrences of river island erosion that occur in river restoration projects are thought to be due to its high resistance to river flow. Based on these problems, this study aims to identify and compare the geometric characteristics of river islands in Progo River and Solo River related to their resistance. The research will be carried out by measuring the geometry of the islands such as length (p) and relative width (l), river width (L), and the distance of the island from the riverbank (d) using satellite imagery and then continuing with the measurement of the coefficient of resistance. The hypothesis proposed in this study is that the geometric characters of the river islands of these two rivers show similarities which will be analyzed further by considering various parameters. The future benefits obtained from this research are information regarding geometry of the island and its implications to river islands development in river restoration activities.

River planimetric morphological datasets were generated from multi-temporal satellite images and were incorporated in a GIS framework to analyse the changes of the surface morphology of the rivers belong to the JBM system. The study also depicted the possible impacts of climate change on the principal rivers of the system. Landsat MSS images of the year 1972 and Landsat TM images of the years 1989 and 2010 were used for the study. The study revealed that the JBM river system was morphologically highly instable due to both erosion and accretion during the study period. The instability was higher for the larger width rivers than the smaller width rivers. Erosion was the dominant occurrence in the early decades but dominancy of morphological changing process was shifted to accretion in the later decades. The study revealed that the short term impact of climate change will primarily be seen on the foreshore of the rivers and on the Char lands.

The Dhansiri River is a highly meandering river. Its Sinuosity Index has been evaluated using satellite imageries of 1999 and 2008 which varies from 1.22 to 4.91. The river acquires a meandering course as it flows through the alluvial plains of Assam and is responsible for frequent course change and shifting of banklines due to consistent bank erosion. The progressive gradual change of the meander bends has been observed by superimposing the river layers of 1999 and 2008 in GIS platform. The length of the river course in 2008 (307.74km) became shorter by 6.20 km than that in 1999(313.94km). In the present study it has been found that the total area lost as a result of erosion is 13.13834 sq km and the total area gained as a result of sediment deposition along its bank is 15.15894 sq km.

This report aims at characterizing the area according to geology, which was investigated by the final year student of Geology and Mining, University of Barisal. This report consists of physiography, geomorphology, tectonic description, grain size, sorting and hydrogeochemical description, its interpretation, and economical significance of the study area. Different types of beach morphology such as beach, shoreline, high tide, and low tide zone, beach berm, the direction of current were identified as well as Ph and EC of seawater, grain distribution, skewness, kurtosis of beach sediments of the study area was analyzed in the laboratory. The beach sediments are

A comprehensive understanding of the dynamic characteristics of geomorphological, ecological, and human systems is essential to explaining complex charland (mid-channel island) processes and crafting and implementing policy measures. This work demonstrates that the characteristics and outcomes of riparian hazards are determined by the interactive dynamics between hydrogeology and human conditions, which constitutes a novel contribution to the literature in this research area. We further contend that such dynamic social-ecological systems demand a flexible, adaptive management and planning approach. The present research has three key interdisciplinary objectives: (i) to analyze the salient features and characteristics of the geomorphological and riparian systems of the Bengal Delta; (ii) to analyze the evolutionary discourse of the legal systems concerning eroded (diluvion) and accreted (alluvion) land in Bangladesh; and (iii) to assess the characteristics of the coping and adaptatio...

A comprehensive understanding of the dynamic characteristics of geomorphological, ecological, and human systems is essential to explaining complex charland (mid-channel island) processes and crafting and implementing policy measures. This work demonstrates that the characteristics and outcomes of riparian hazards are determined by the interactive dynamics between hydrogeology and human conditions, which constitutes a novel contribution to the literature in this research area. We further contend that such dynamic social-ecological systems demand a flexible, adaptive management and planning approach. The present research has three key interdisciplinary objectives: (i) to analyze the salient features and characteristics of the geomorphological and riparian systems of the Bengal Delta; (ii) to analyze the evolutionary discourse of the legal systems concerning eroded (diluvion) and accreted (alluvion) land in Bangladesh; and (iii) to assess the characteristics of the coping and adaptatio...

Bangladesh is a land of rivers, and the major part of the country consists of deltaic landform by three large river systems, the Ganges, the Brahmaputra, and the Meghna. The livelihood of the people and environmental settings are mainly dependent on the hydrological characteristics of the rivers and associated resources in the catchment area. However, in the riverine areas of the country, flood is a common phenomenon that causes severe impact on people and properties. The effect of flood brings enormous sufferings to the inhabitants and causes riverbank erosion and loss and devastation to the resources and constructions. The alterations in river morphology as a result of flood have been related with bank line shifting, river widening, and extensive erosion of river bank. This chapter illustrates and analyzes the hydro-geomorphological conditions of the catchment of Dharla and Dudhkumar, which are the two perennial rivers in the northwestern part of Bangladesh, and also provides a detailed understanding of inundation patterns and dynamics of floods in these catchments. This chapter further discusses and analyzes the causes and impact of floods, particularly on hydro-geomorphology, riverbank erosion, resource and live, and livelihood. Moreover, a flood vulnerability index was assessed considering the criteria for physical vulnerability, social vulnerability, and coping capacity indices. Finally, a management perspective approach and policy issues were drawn and discussed based on the findings. To fulfill the objectives, necessary data were collected and analyzed.

The Achanakmar Tiger Reserve (ATR) is an integral part of the Achanakmar Amarkantak Biosphere Reserve (AABR) with a total area of 914.017 sq. km. The Maniyari River, which flows through the reserve, is known as its life line. It originates from the core zone (Sihawal sagar) of ATR and merges in the Seonath River of the Mahanadi Basin. It flows about 105 km through Mungeli and Bilaspur districts. This river supplies its catchment area with water seasonally (6-8 months) and flows more than half of its length (about 60 km) within the protected area. Its catchment area has a rich biodiversity of tree species such as Shorea robusta, Terminalia tomentosa, Diospyros melanoxylon, Adina cordifolia, Pterocarpus marsupium, Madhuca indica, Anogeissus latifolia, Dendrocalamus strictus etc. A geospatial analysis was performed to understand the course of the Maniyari River within the ATR area over a fourteen year period between 2000 and 2013. Imagery from Indian Remote Sensing (IRS) satellite 1D a...

Bangladesh is a low-lying riverine country with the mighty Ganges–Brahmaputra–Meghna (GBM) major river system including their abundant tributaries and distributaries. Land erosion–accretion is a very common phenomenon in this riverine country. This process extensively erodes huge productive landmasses at the river confluence zones every year. The main objective of this study was to understand the confluence morpho-dynamics and identify the vulnerable areas near the Padma–Meghna Confluence (PMC) and Ganges–Jamuna confluence (GJC) due to confluence shifting and erosion–accretion phenomenon of those rivers. The present study utilized multi-temporal Landsat satellite images from 1972 to 2019 approximately ten years of interval. Results showed that the PMC indicated frequent variation in migration trend towards NW from 1972 to 1980, SE from 1980 to 2010, and then reversed towards NW direction from 2010 to 2019. On the other hand, the GJC confluence point moved NW direction (2.37 km) from...

This paper presents a hydraulic and morphological analysis of the Lower Jamuna in Bangladesh with a focus on two key bifurcations that are important for stabilization of the Lower Jamuna reach. We used ground measurements, historical data, multispectral satellite images from various sources as well as numerical models. We carried out hydraulic analyses of the changes and their peculiarities, such as flow distributions at the bifurcation and hysteresis of the stage–discharge relationships. We supplemented our analysis by using numerical models to simulate discharge distribution at the bifurcations under various flow and riverbed conditions. We developed an advanced and automated satellite image processing application for the Lower Jamuna, referred to as Morphology Monitor (MoMo), using the Google Earth Engine. MoMo was found to be an effective tool for a rapid assessment and analysis of the changes in deep-channel and sandbar areas. It is also useful for monitoring and assessing rive...

Bangladesh is a low-lying riverine country with the mighty Ganges–Brahmaputra–Meghna (GBM) major river system including their abundant tributaries and distributaries. Land erosion–accretion is a very common phenomenon in this riverine country. This process extensively erodes huge productive landmasses at the river confluence zones every year. The main objective of this study was to understand the confluence morpho-dynamics and identify the vulnerable areas near the Padma–Meghna Confluence (PMC) and Ganges–Jamuna confluence (GJC) due to confluence shifting and erosion–accretion phenomenon of those rivers. The present study utilized multi-temporal Landsat satellite images from 1972 to 2019 approximately ten years of interval. Results showed that the PMC indicated frequent variation in migration trend towards NW from 1972 to 1980, SE from 1980 to 2010, and then reversed towards NW direction from 2010 to 2019. On the other hand, the GJC confluence point moved NW direction (2.37 km) from...

Bangladesh is a low-lying riverine country with the mighty Ganges–Brahmaputra–Meghna (GBM) major river system including their abundant tributaries and distributaries. Land erosion–accretion is a very common phenomenon in this riverine country. This process extensively erodes huge productive landmasses at the river confluence zones every year. The main objective of this study was to understand the confluence morpho-dynamics and identify the vulnerable areas near the Padma–Meghna Confluence (PMC) and Ganges–Jamuna confluence (GJC) due to confluence shifting and erosion–accretion phenomenon of those rivers. The present study utilized multi-temporal Landsat satellite images from 1972 to 2019 approximately ten years of interval. Results showed that the PMC indicated frequent variation in migration trend towards NW from 1972 to 1980, SE from 1980 to 2010, and then reversed towards NW direction from 2010 to 2019. On the other hand, the GJC confluence point moved NW direction (2.37 km) from...

Bank erosion hazard is a frequent occurrence that poses threats to floodplain ecosystems. This analysis examined changes to the Jia Bharali River channel in India using the GIS-based Digital Shoreline Analysis System [DSAS]. The Jia Bharali’s future channel was predicted so as to identify the most erosion-susceptible zones. The rate of bankline movement was calculated using remotely sensed data collected over a period of 45 years (1976–2021). The results show that the river’s erosion and deposition rates were higher in the early years than towards the later part of the period under analysis. On the right and left banks of the river, the average shift rate was −9.22 and 5.8 m/y, respectively, which is comparatively high. The chosen portion of the river was evenly divided into three zones, A, B, and C. The most positively affected zone was zone A. The left bank of zone B exhibited a higher rate of erosion than the right bank, indicating that the river was moving to the left [eastward]...

Jamuna River is one of the principal rivers of Bangladesh, changing continuously due to erosion and accretion over the past decades. This analysis evaluates the East Bank and the West Bank erosion and accretion between 1996 and 2015 for Jamuna River. An unsupervised classification algorithm and post-classification change employing skills in Geographic Information System are performed to evaluate spatial and temporal dynamics of erosion and accretion for different points of Jamuna River using Bangladesh. Landsat image (1995, 2005, 2015). The correctness of the Landsat-produced map ranges from 82% to 84%. It has been evidently observed that changes in the proportion of erosion and accretion differ in different points of Jamuna River. The highest eroded area is 3.82 square kilometers (km 2) during the period of 1995 to 2005 and the highest accreted area is 6.15 square kilometers (km 2) during the period of 1995 to 2015. The erosion and accretion values fluctuated from place to place. The changing trend of Riverbank is creating many socioeconomic problems in the proximate areas.

The present work deals with meandering and bank erosion of the River Nile of Egypt and its environmental impact between Sohag and El-Minia, Egypt. The study depends on using Landsat imagery acquired on 1987-2000 and field observations. Field observations, remote sensing, and GIS analysis and sinuosity index were used in this study to investigate river meandering and the associated processes of erosion of river bank and islands, deposition of sediments and formation of new islands. The analysis of Landsat imagery revealed the migration of river course with time and space. Some islands disappear completely in the study area whereas new islands appear in other places. The lateral erosion on the river banks led to a decrease in agricultural lands bordering the river banks and decrease in the areas of the river islands which in turn reduces the agricultural production. Depositional processes create new floodplains on the convex sides of the river course and new islands and sand bars. Protection methods are recommended to protect the river bank from further movement and erosion. The present conditions of river meandering and the associated processes of erosion and deposition accelerated with human activities have its impact on the environment. The most prominent hazard problem is reduction of agricultural lands and loss of property as well as navigation problems. River control is recommended to weaken the secondary currents created by the river bends. It is recommended to regularly monitor the river banks and islands and measure the rates of erosion and deposition. Sand bars and subsurface islands should be monitored and identified with flash lights to mitigate navigation problems.

The objective of this study was to assess coastal dynamics of the Sinai Mediterranean coastline (SMC) between 1990 and 2020. In this study, remote sensing imagery and geographic information systems-based spatial computing methods were used for coastline change analysis. The study found that the SMC experienced major morphological changes during the period of study. The results show a spatial heterogeneity of coastline change rate over the study period with some periods of rapid change and other periods of stability. The overall analysis during the period of study indicated that the coastline has retreated landward approximately 555 m; the average annual erosion rate was 2.5 m/year. The percentage of the eroded section in the coastline is 60% with the remaining 40% either advancing or remaining stable. Sections of the coastline accreted as much as 542 m. The GIS-based DSAS model application used in this study is unique because it measured spatial variations of coastline dynamics over...

One of the most serious types of disasters that considers the amount of rainfall, soil structure, river morphology, topography of the river, and surrounding places is riverbank erosion. Due to this terrible calamity, hundreds of individuals are forced to relocate every year, which renders them insolvent. Due to its inherent characteristics and flows, the Kirtonkhola River in Barisal frequently sends its residents floating. Firstly , I would also want to express my sincere gratitude to our professor, Md. Abdullah Salman, Assistant Professor at the University of Barisal, for his continual supervision, wise advice, and well-articulated instructions. His presence energized us with his counsel and suggestions. Barishal is a district located in the southern part of Bangladesh, situated between the latitudes 22°47'N and 23°30'N and longitudes 89°37'E and 90°40'E. The district is bordered by the districts of Bhola to the south, Jhalokati and Pirojpur to the west, Barguna to the east, and Lakshmipur and Chandpur to the north.

The Dhansiri River is a highly meandering river. Its Sinuosity Index has been evaluated using satellite imageries of 1999 and 2008 which varies from 1.22 to 4.91. The river acquires a meandering course as it flows through the alluvial plains of Assam and is responsible for frequent course change and shifting of banklines due to consistent bank erosion. The progressive gradual change of the meander bends has been observed by superimposing the river layers of 1999 and 2008 in GIS platform. The length of the river course in 2008 (307.74km) became shorter by 6.20 km than that in 1999(313.94km). In the present study it has been found that the total area lost as a result of erosion is 13.13834 sq km and the total area gained as a result of sediment deposition along its bank is 15.15894 sq km.

Bangladesh is a riverine country. Every year it faces many natural hazards due to river. Bangladesh is mainly formed by alluvial deposits. It faces riverbank erosion frequently due to regular shifting of river channels. This research work provides an overview of the trend of riverbank erosion of Padma River of Munshiganj, Madaripur and Shariatpur district. It also shows the land cover change due to riverbank erosion. The riverbank erosion was calculated by using remote sensing and geographic information systems (GIS) techniques. Only secondary data have been used to reach the research goals. Various computer software such as Erdas Imagine, Arc GIS, Google Earth, Environment for Visualizing Images etc. have been used to process and analyze raw data. In this study, using seven selected images of Landsat TM and OLI acquired from 1988 to 2017, the riverbank migration patterns and land dynamics of Padma resulted from accretion/ erosion processes for 29 years were investigated. The migration rates are based on the differences in

Human interventions along the northwestern Egyptian Mediterranean coast recently interrupted the stability of Marina El-Alamein shoreline and resulted in spit evolution. Considering Egypt's vision 2030 for developing the northwestern Egyptian coast, continuous up-to-date monitoring programs became essential to ensure sustainability. This study, for the first time, aimed at coupling geospatial technology with Digital Shoreline Analysis System (DSAS) tool in monitoring, analyzing, and quantifying the impacts of anthropogenic activities on the spatiotemporal shoreline dynamics over the last 3 decades (1987-2017) at Marina El-Alamein resort, Egypt. In addition, the study carried out a quantitative geometrical temporal analysis for the newly formed spit from 2015 to 2020. The study used transect-and area-based approaches in estimating the shoreline changes for long-and short-term changes. The former approach computed the change in both the shoreline displacement and the rate of shoreline change, whereas the latter quantified the magnitude of spatial changes in the total land area. Results of the current study revealed that during 1987-2017, Marina El-Alamein shoreline experienced very high accretion, with an average rate of 2.8 ± 4.73 m/year (end-point rate) and 2.52 ± 4.10 m/year (linear regression rate). Quantitatively, Jetties #1 and #3 trapped sand on their western sides for a maximum distance of 706.31 m and 406.5 m, respectively. On the other hand, the eastern side of the resort experienced erosion with a maximum distance of 92.78 m. Regarding changes in the total area, Marina El-Alamein's coast gained 1.130 km 2 (0.038 km 2 / y e a r) l a n d a n d l o s t a b o u t 0. 1 1 1 5 k m 2 (0.004 km 2 /year) of its total area throughout the last 3 decades. During 2015, the continuous progressive accretion along the western side of J#1 resulted in the evolution of sand spit east of the jetty. Results of the temporal analysis showed that the spit's length was about 0.236 km during May 2015 and reached 1.44 km in April 2020 with an increment of 510.5% in length. In addition, the spit's total surface area increased by 33.606 km 2 in 5 years (6.7212 km 2 /year). Both the length and the area of the evolving spit grow annually with 102.11% and 108%, respectively. If this progressive accretion along the evolving spit continued, the lagoon's first inlet would probably suffer sedimentation that could cause its closure and deteriorate the lagoon's water quality. The study recommends carrying out an environmental impact assessment study for the newly formed spit to lessen its negative impact on the opposite tidal inlet and the lagoon's water quality.

Establishment of empirical relationships between mid-channel bar geometry and fluvial erosion intensity Explanation of the greater erosion at convex banks than concave banks Evaluation of the impact of channel changes on water levels, flood control, and waterway navigation

Due to flat terrain and dense population, the Bengal Delta is highly vulnerable to sea level rise. At present the delta building process is active in the Meghna Estuary. Information on sediment dispersal processes in the estuary and their response to different exogenic and anthropogenic forces is an important requirement for managing the sediment and developing adaptive measures to counter the potential impact of climate change. Historical maps, satellite images and tidal water level data were analysed and the response of the Meghna Estuary to extreme events, e.g. the 1950 Assam earthquake, as well as anthropogenic interventions, was assessed. The issue of sediment management was addressed, based on an understanding of the response of the estuary to the extreme natural event and anthropogenic interventions, along with an assessment of the response of the estuary to sea level rise. Among other interventions, emphasis has been directed to promoting vertical accretion by injecting sedi...

Channel dynamics is an inherent characteristic of the river in the floodplain region. The river bankline shifting and associate land use land cover (LULC) change is not only geomorphological but also an environmentally vital hazardous issue. It is a significant impact on the ecosystem and human life. GIS-based, DSAS and CA-Markov models are efficient to accurately measure historical and predictionevaluation of the relation between channel shifting and LULC change. In this study, forty-eight years (1972-2020) of earth observatory data have been used to demarcate the channel bank position and LULC change detection along the Kaljani River at the eastern Himalayan foothill. During 1998-2008, very high erosion rate on both bankline, which are about -4.48 m/y and -3.48 m/y at the left and right, respectively compared the others time frame. The overall result of the predicted bankline represents that the bulky expansion will occur along the left bank and sediment accretion will take place ...

Jamuna River is one of the principal rivers of Bangladesh, changing continuously due to erosion and accretion over the past decades. This analysis evaluates the East Bank and the West Bank erosion and accretion between 1996 and 2015 for Jamuna River. An unsupervised classification algorithm and post-classification change employing skills in Geographic Information System are performed to evaluate spatial and temporal dynamics of erosion and accretion for different points of Jamuna River using Bangladesh. Landsat image (1995, 2005, 2015). The correctness of the Landsat-produced map ranges from 82% to 84%. It has been evidently observed that changes in the proportion of erosion and accretion differ in different points of Jamuna River. The highest eroded area is 3.82 square kilometers (km 2) during the period of 1995 to 2005 and the highest accreted area is 6.15 square kilometers (km 2) during the period of 1995 to 2015. The erosion and accretion values fluctuated from place to place. The changing trend of Riverbank is creating many socioeconomic problems in the proximate areas.

Channel migration becomes the main characteristic of the Khowai River of Tripura. A study on bank erosion and channel migration of the present course of the Khowai River through the synclinal valley of Atharamura and Baramura Hill Ranges indicates that the area is under active erosion since long back. In this study, the rate of channel migration has been assessed and variation of sinuosity index and radius of curvature have also been calculated. The study of the active channel width and channel position from 1975 to 2014 indicates that a large portion of land along both the banks of the Khowai River has already been eroded away. This work also documented land use changes in its surrounding flood plain area using supervised image classification. Overall accuracy of the land use classification ranges between 88% and 93%. The whole study is being done utilising the remote sensing imagery (2014), SOI topographical map (1975) and GIS technology. The land use classification shows that there is an increase in built up area and decrease in net sown area. The channel migration directly affects the land use and land use change has direct effect on the flood plain dwellers of the study area. All the assessments of this study highlight a significant message of immense vulnerability of Khowai River and also provide news about geomorphological instabilities of the study area.

Many coastal areas and infrastructure suffered from unprecedented hazards such as storms, flooding, and erosion. Thus, it is increasing the vulnerability of urban coastal areas aggravated with the absence of coastal green infrastructure. Given the state of coastal environments, there is a genuine need to appraise the vulnerability of coastal cities on the basis of the latest projected climate scenarios and existing condition. Hence, to asses, the vulnerability level of Mataram coastal, the Coastal Vulnerability Index (CVI) accompanied by pre-assessment of readiness to climate disruption. The CVI used to map coastal into five classes of using GIS. As a case study, this approach applied to Mataram City: one of the tourism destinations in Lombok. Two of sub-districts in Mataram City, Ampenan and Sekarbela, laying in the shorelines have undergone coastal flooding and erosion. One of them, Ampenan sub-district, experienced flooding due to river-discharge and became the most severe locati...

Worldwide and especially in less developed regions, process-based evaluations and/or geomorphological information on large-scale rivers are still scarce. Such investigation become of ‎urgent ‎need due to the climate change and expected occurrence of extreme floods and drought which ‎may ‎threaten the safety of nearby and downstream cities, especially in regions that are highly sensitive and ‎affected by climatic changes. The Tigris River, in Iraq, is one such river that has undergone significant alteration to its flow and morphologic aspects due to climate change and the construction of many dams. However, morphology and its change for many reaches of this river are still uninvestigated. To this end, field and satellite-based investigations into the morphology of a reach located between Makhool District and Tikrit City have been conducted. In addition to the cross-sectional survey-based determination of the reach geometrical aspects, a sinuosity indices-based evaluation of the reach...

This paper presents the results of some of the Jamuna River erosional hazards from Bahadurabad Ghat to Bhuapur (near Jamuna Bridge). Results are also presented on the Jamuna River accretion and water discharge. Landsat images from 1977 to 2014 and water discharge data were analysed to find out a relationship between dynamics of erosion and accretion for different time intervals with average annual water discharge. It is clearly established that total amount of erosion and accretion rates varies with different times. The highest erosion rate 21.15 km 2 year-1 was observed in the period of 1989-1992 and the highest accretion rate 13.57 km 2 year-1 was observed in the period of 1980-1989. The erosion and accretion values fluctuated with increasing average annual maximum water discharge but the difference between erosion and accretion had remained low before water discharge reached to 67000 m 3 s-1 and it is estimated higher after crossing annual average maximum water discharge of 67000 m 3 s-1. This discharge value also plays an important role on bar development and active channel. It is also observed that unvegetated bar areas remained higher than active channel areas before average annual maximum water discharge reached to 67000 m 3 s-1. Finally, all the erosional hazards and accretion values are compared and evaluated to see their influence on the annual discharge.