River bank erosion

Over thirty years (1994-2024), the braided Brahmaputra River has driven dramatic erosion and accretion in Bangladesh's Rangpur Division in northern Bangladesh, reshaping landforms and livelihoods. Our Normalized Difference Water Index (NDWI)-based satellite analysis identifies three phases: from 1994 to 2004, intense bank collapse and channel migration caused a net loss of 62.69 km 2 ; from 2004 to 2014, sediment deposition-bolstered by embankments and land-management practices-produced a net gain of 101.81 km 2 ; and from 2014 to 2024, renewed fluvial forces and diminished sediment retention led to a further net loss of 32.83 km 2. Fulchhari emerged as a hotspot of decline, while Ulipur and Chilmari showed alternating erosion-accretion patterns, highlighting localized sediment dynamics. These morphological changes have severe socioeconomic impacts: agricultural lands have been swallowed by shifting channels, communities face repeated displacement, and infrastructure, including roads, schools, and flood defenses, remains at risk. By integrating multi-temporal NDWI metrics with Geographic Information System (GIS) mapping, this study moves beyond prior short-term or localized research to offer a comprehensive, longitudinal assessment of the Brahmaputra's geomorphological evolution. Addressing a key research gap, our findings elucidate the interplay of natural hydrodynamics and human interventions over decadal scales and provide essential guidance for sustainable riverbank management, infrastructure planning, and community resilience in one of South Asia's most dynamic fluvial landscapes.

The stream power is one of the important river variables which is used in morphological analysis. Therefore, the stream power determines both erosion and deposition. This research examines the stream power, instability and morphometric changes of the channel using the annual geomorphic energy (AGE) in Haji Arab River in Buin Zahra (Qazvin Province). The AGE is calculated by integrating the relationship between the excess specific stream power and discharge using a flow duration curve. The AGE values for each reach should be either positive or negative. Therefore, according to the differentials in AGE values, depositional and erosional reach are determined. In this paper, the results of the AGE method were compared with the rapid geomorphic assessments (RGA), including the channel stability indicators (CSI) model and OSEPI index. Also, the RHS method based on the field works was used to identify depositional and erosional geomorphic landforms. Comparing the results of the AGE with rapid RGA indices, shows that results of the OSEPI are more consistent with the erosional and depositional status of the reaches, based on the AGE. Spatial variations in lithology and structure, when combined with the course of the Haji Arab River indicate that channel morphometry locally reflects geological factors that have caused slope differences in different reaches. The calculated AGE values at different cross-sections have significant variability, reflecting characteristic local variation in bed slope, cross-section geometry and bed-sediment composition.

The Haor region is characterised by annual flooding, with over 90% of the land submerged for half of the year. The compact rural settlements characterized by indigenous architecture and planning techniques enable the village to cope with the challenging hydro-meteorologic conditions while fostering social cohesion. However, recent developments using non-local materials potentially can disrupt social coherence, thereby creating adverse effects on community wellbeing. Since the rural settlements have gone through organic growth, maintaining vernacular patterns and formal documentation of the planning concepts are essential. This research identifies the settlement pattern from empirical study, on-site observation, and analysis of the pattern with an understanding of local norms and architectural knowledge. It is evident from the study that the rural houses are built aligned with the cardinal directions even when the site orientation is different. The settlement clusters are linearly aligned to the monsoon flood flow direction. Though the linear courtyards are subdivided in terms of ownership, practically, they are maintained as barrier-free connectivity among houses within the same housing cluster. This research will provide valuable guidelines for future planning in the challenging topography of the Haor Basin.

Flood and riverbank erosion management in the Brahmaputra River basin (BRB) has traditionally relied on structural engineering interventions. However, there is growing evidence of their ineffectiveness and the social-ecological concerns they raise, including emergent systemic risks. This paper presents a social-ecological systems approach, offering a model that acts as a boundary object to integrate knowledge, foster stakeholder collaboration to tackle community vulnerability, and facilitate policy experimentation—key elements for advancing adaptive management. Employing systems thinking and system dynamics-based modelling can bridge the divide between science and policy, especially in areas characterized by data limitations and uncertainties like the BRB. This study adopts a nested approach encompassing three scales: macro (basin-level hydro-geomorphology), meso (flood control policies and infrastructure at administrative levels), and micro (village-level socio-economic conditions). The constructed boundary object promotes cross-scale learning and policy experimentation. Model scenarios of policy alternatives demonstrate that an integrated strategy—leveraging land covered with coarse sediment, innovating land use, and redesigning floodplains—significantly enhances effective land use and minimizes embankment failures. The findings emphasize the reinforcing dynamics between embankment degradation and community protests, highlight the limitations of compensation mechanisms, and reveal the erosion of adaptive capacity under the current control-based policy regime. A crucial insight from this study is that flood management strategies must evolve continually, reflecting scientific advancements, assessing policy impacts, and addressing local adaptation needs. Furthermore, a greater focus on riparian land use within development strategies is essential. The model scenarios advocate transitioning from traditional flood control to a landscape design harmonizing cropping practices and floodplain development with river morphology dynamics. While rooted in the Indian BRB context, the modelling framework provides a basis for adaptive water governance in other sediment-rich, politically sensitive, and hydrologically dynamic transboundary basins.

Bangladesh is a riverine country. About 800 rivers including tributaries flow through the country constituting a waterway of total length around 24,140 km. Most of the country's land is formed through silt brought by the rivers. The North West Region of Bangladesh is bounded by the Jamuna River to the East, the Ganges to the south, and the international border to the north and west. Dharla River is one of the trans-boundary Rivers of Bangladesh. It enters the country at Lalmonirhat through Changra Bandha of Patgram. In its upper course, it is known as the Jaldhaka or Singimari. Before it falls to Brahmaputra the river passes through six upazills like Patgram, Lalmonirhat sadar, Rajarhat, kurigram, Fulbari and Ulipur. Dharla becomes wide and turbulent during the rainy season, severe erosion problem occurs in the near vicinity. For being a meandering river, there is formation of secondary current, that accelerates the bank erosion rate which causing severe erosion. This study concentrates on the assessment of the hydrological characteristics of the Dharla River. Data including discharge, water level and elevation have been analyzed to determine design parameters for working site. Design considerations of the bank protection works implemented by BWDB are followed to do so. Available up-to-date data (from 1996 to 2011) of two stations in Dharla River have been collected from surface hydrology section of BWDB and used in the present analysis. After determining maximum discharge for different years, flood frequency analysis is done. Finally, a revetment is designed as a bank protection work , based on the design data.

Bangladesh is a riverine country. About 800 rivers including tributaries flow through the country constituting a waterway of total length around 24,140 km. Most of the country's land is formed through silt brought by the rivers. Rivers especially large rivers of Bangladesh are unique in behavior because of its dimension, discharge, sediment characteristics and morpho-dynamic activities. There is active bank erosion almost in all major rivers in the country causing damage to valuable lands, settlements and infrastructures from year to year. Because of high density of population along the river bank a great number of people are also displaced due to this continuous bank erosion process. Bangladesh is a poor country. We have not sufficient amount of money to carry out river training work in major rivers to protect our valuable land as well as asset from river erosion. Same type of protective work is not suitable for all types of river in Bangladesh. Before taking any decision to implement bank protective work, we have to consider sustainable and economical design criteria. The intention is to help the designer and engineers to a reliable design with correct choice within the available resources and environment of the country. In this study, different types of river bank protective works, sustainability of these protective works with the consideration of their working principle, hydrological effects, design & expected lifetime are done. Comparison of costs for different works & identifying their socioeconomic return are also evaluated. Bank developed by sand filled Geo-textile bags through Areal Coverage method is cheaper than any other bank protection work. Revetment serves better as bank protection measures while Groynes / Spurs are problematic as bank protection measures in large rivers as experienced in Bangladesh. Cost effective riverbank protection commonly relies on the falling or launching principle. Considering the cost and sustainability of revetment, the falling apron. From experience, we have observed that spurs and groynes are not suitable for our country because the morphology of our rivers is changed rapidly. Considering other types of protective works, revetment work is more cost effective solution in context of Bangladesh as it doesn't hamper the direction of flow on the channel & regular maintenance works need to be ensured.

Bangladesh is frequently flooded because of its position, which has an impact on livelihoods and housing structures. The Brahmaputra River runs through the Jamalpur District, making it extremely susceptible to periodic flooding. Heavy monsoon rains, coupled with riverbank erosion, further exacerbate the problem, leading to displacement and significant property damage. The rising threat of climate change is expected to intensify these challenges, necessitating innovative flood-resilient housing solutions. The purpose of this study is to create a sustainable and flood-resistant home concept that is appropriate for the area. To suggest a novel flood-resilient dwelling design, a variety of building methods, eco-friendly materials, and climate adaptation tactics are examined. The study explores traditional stilt houses, amphibious architecture, and floating home technologies to determine the most viable approach for flood-prone communities. Additionally, locally sourced, low-cost materials such as bamboo, compressed earth blocks, and recycled plastic are considered to enhance affordability and sustainability.To identify the ideal elevation and structural reinforcements needed for resilience, the analysis incorporates historical flood data. This includes assessing past flood levels, frequency, and duration to establish reliable flood-proofing benchmarks. Advanced GIS mapping and remote sensing techniques are utilized to identify high-risk zones and plan strategic housing layouts. A thorough approach is used, which includes cost-effective material assessment, structural modelling, and hydrological data analysis. To ensure practical implementation, stakeholder engagement with local communities, policymakers, and engineers is conducted, allowing for inclusive decision-making. Furthermore, energy-efficient features such as passive cooling, rainwater harvesting, and solar power integration are explored to enhance long-term sustainability.In line with sustainable development objectives, the results provide a workable and expandable solution for areas vulnerable to flooding. By integrating resilience, affordability, and sustainability, this study presents a scalable housing model that can be replicated across flood-prone regions in Bangladesh and beyond.

Channel morphology refers to different fluvial aspect like relief, surface, discharge of water, volume of water, cross section, hydrological regime etc. Ecotourism means sustainable tourism maintaining proper guidelines of the environmental ethics. Channel shifting is a common phenomenon mainly in plain land. It helps to develop or modification of various form of channel and their characteristics. Present paper is mainly discussed, with the passage of time the change of morphological characteristics of river Hooghly and formation of an ecotourism environment between Sajiara to Mayapur region, bank of this river. The landsat imagery data with GIS processing, field survey, questionnaire survey and various primary and secondary data has given a proper idea about this changing riverine phenomenon. This wetland has developed due to effect of some Geo-morphological phenomenon but based on these morphological features, local people of this region are depends on different types of economy, ...

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This paper presents the influence of geotechnical properties of bank material, hydraulic parameters representing flow characteristics and geomorphology of a river for planning and designing of river bank protection methodology for the rivers and sea coasts. In this paper a brief discussion on the type of protection techniques and their design guidelines have been made. After detail understanding of mechanism and cause of failure of river bank, its protection techniques should be designed. Stability of river banks is expressed by its maximum shear strength which it can withstand against different driving forces. To ascertain the dominating cause of river bank failure, analysis has to be carried out considering both geotechnical and fluvial aspects. This paper provides guidelines for planning and designing of bank protection measures for river bank. Existing design methodologies for different types of revetments are also briefly discussed in this paper. In West Bengal the characterist...

The bed of the main channel system represents an important store of fine sediment in lowland groundwater-fed catchments, in the UK, on account of the deposition promoted by their naturally subdued hydrological regimes, low channel gradients and the reduction of flows caused by water abstraction. Although a number of recent investigations have contributed to an improved understanding of the magnitude and spatio-temporal variability of fine sediment storage, much less is known about the role of remobilization of fine sediment from the channel bed in the suspended sediment fluxes from lowland permeable catchments. To address this shortcoming, the authors report the use of a composite fingerprinting technique, incorporating uncertainty analysis, to investigate the magnitude and timing of the remobilization of fine sediment sequestered on the channel bed of three lowland permeable catchments in the UK. The findings are used to assess the relative contributions of three principal potential sediment sources to the sediment loads sampled at the catchment outlets, namely: fine sediment remobilized from the channel bed of the main stem; suspended sediment inputs from tributary sub-catchments; and sediment originating from channel banks along the main channel.

The densely populated Bangladesh is located in the south Asian sub-continent and is prone to flooding as being situated on the deltaic floodplain of the Ganges–Brahmaputra–Meghna (GBM) River basin. Bangladesh has experienced periodic floods of severe magnitudes in 1974, 1984, 1987, 1988, 1998, 2000, 2004, 2007 and 2010. Dharla River, among one of the 57 trans-boundary rivers originated in the Himalayas, along with Brahmaputra River has a great influence on the recurring floods and erosion in north-western Bangladesh. Almost every year, excessive flooding caused by Dharla render thousands of people homeless with massive loss of crops and poultries. In this study, to identify the low lying areas prone to inundation and to reduce the uncertainty in flood mitigation measures, HEC-RAS based 1D/2D Coupled hydrodynamic model has been carried out for Dharla River. Boundary conditions for upstream and downstream have been defined by discharge of Taluk-Simulbari station and water level of Kur...

The intricate and interdependent relationship between rural communities and rivers has long been recognized as a crucial aspect of rural livelihoods, providing essential water, food, transportation, and recreation sources. However, with its annual course changes, the mighty Padma River poses a formidable challenge to these communities, transforming landforms that can create new land (Char) or disintegrate existing land. Inevitably, these changes can have a profound impact on farmers, fishermen, and migrant communities, leading to significant shifts in their livelihoods and occupational patterns. The GIS and RS-based method provides visual information about the land use change in Yusufpur along with river course change and PRA (Participatory Rural Appraisal) helps in understanding the community, and promotes active community participation, resulting in more relevant and impactful research outcomes. In light of these challenges, this study aims to investigate the course changes of the Padma River over time and explore the effects of these changes on the socioeconomic landscape of the Yusufpur union. The study area encompasses a range of communities, including Kakra Mari hat, Yusufpur Bazar, Yusufpur Primary School, one high school, a fishermen community, migrant communities, and an agricultural community, with a significant portion of land dedicated to agricultural use along with identifying and analyzing the causal mechanisms underpinning the socioeconomic changes in the study area. Ultimately, this analysis provides valuable insights and strategies for fostering socioeconomic development and resilience in these rural communities facing river course alterations.

The Dhansiri River is the main river of the Golaghat District of Assam. However, unpredictable shifts of the river, serve erosion and frequent flooding have major adverse effect on the economy and ecology, affecting and threatening key villages, agricultural lands, school, and natural heritage sites. Erosion displaces a large number of the population often rendering them poor and landless. This study is aimed to investigate the flood erosion and bed aggradations scenarios of the Dhansiri River in the Golaghat district, Assam. Most of the villages in Golaghat district have been submerged by flood water and people and animal are taking shelter on the roadside and on the highlands. Golaghat in upper Assam has been most flood affected, where over 1, 19,179 people of 109 villages under Khumtai, Dergaon, Golaghat and Bokakhat revenue circle in Golaghat district have been affected by floods due to rise water of Brahmaputra and Dhansiri rivers. There are many problems being faced by this flood affected are due to river bank erosion: social, economic, health, education and political. The major impact of erosion is social, i.e., homelessness due to land erosion which compels people to migrate. After forced migration they suffer economic crisis, namely loss of occupation and loss of property.

A new equation is proposed for the design of armor units on protected river banks under the combined action of ship-induced waves and river flow. Existing observed field and experimental data in the literature have been examined and a valuable database has been developed. Different conditions, including the river water depth, flow velocity, river bank slope, Froude number, wave height, wave period, and wave obliquity have been considered. Results from an empirical equation (Bhowmik, 1978) that only considers the maximum wave height and river bank slope have been compared with the results calculated by the newly developed equation. Calculated results have also been verified against field data. Results show that not only the maximum wave height and river bank slope but also the water depth, flow velocity, wave length, wave obliquity, and wave period are important parameters for predicting the mean diameter of the armor units, highlighting the multivariate behavior of protecting the river bank in the presence of ship-induced waves and river flow velocity.

Riverbank protection in alluvial rivers of great mobility often faces unpredictable and suddenly changing conditions. Designers need to know possible rates of scour development, in order to protect their work against undermining and sudden failure. Because various types of scour and combinations thereof can occur, systematic analysis of measurements is necessary before design depths and rates of scour formulas can be established for particular environments.

This study focuses on the sediment transport by ship-generated waves in restricted waterways. Two data sets from Göta River in Sweden, an important shipping lane on the Swedish west coast, were analyzed in detail to determine the impact of ship waves, namely (1) continuous recordings of turbidity at seven stations along the river with 1-min resolution; and (2) dedicated field campaigns to measure water level and turbidity during ship passages. Measured turbidity was related to the suspended sediment concentration (SSC) and used as a proxy for the sediment transport. Several existing formulas were tested to evaluate their capability to predict both the primary and secondary waves, and the PIANC formula yielded the overall best agreement for the secondary (divergent) waves and a relationship based on the vessel sinkage for the primary (drawdown) waves. The turbidity (SSC) was found to depend primarily on the drawdown wave properties and empirical equations were derived to estimate the...

Over a thirty-year period (1990-2020), the spatiotemporal changes in riverbank erosion and accretion along the Jamuna River in Shariakandi Upazila, Bogura District, Bangladesh, were investigated using Landsat satellite imagery processed through ArcGIS 10.8 and Erdas Imagine 2015. The analysis delineated significant alterations in the riverbank, quantifying a decrease in the river area from 108 km 2 to 79.99 km 2 , with a net erosion of 50.02 km 2 and an accretion of 78.03 km 2. Among the nine unions affected, Karnibari, Kazla, and Chaulabari were most impacted, with erosion accounting for 14.79%, 25.98%, and 28.42% of the total, respectively. This study established a direct correlation between riverbank erosion and increased vulnerability for local populations, characterized by loss of homesteads and agricultural lands, displacement, income reduction, and a cycle of poverty. Environmental repercussions included deteriorated water quality and an increased prevalence of diseases. The effectiveness of various local adaptation strategies, such as financial reliance on external sources, migration, and occupational shifts, was also assessed, revealing a spectrum of success and underscoring the necessity for more sustainable, holistic approaches. This research emphasizes the imperative for integrated riverbank management strategies that concurrently address the geological and socioeconomic ramifications of riverbank erosion.

Bank protection structure is applied generally as a countermeasure of the bank erosion problem. The structures, such as groynes, revetments and so on, will success to protect the riverbank locally. However, usually the structures will change the cross-sectional geometry, which lead to change the flow pattern or others hydraulics parameters. Furthermore, the structure will produce another bank erosion problem in another place, especially in case that the flow is a dominant factor in riverbank erosion problem. The horizontal two dimensional bed deformation analysis of the Sesayap River is performed. The advantage of the dredging method is discussed. The dredging of bars is the appropriate choice for the countermeasures of bank erosion of the Sesayap River at Malinau, when we considered the financial efficiency and bed degradation along both banks.

Stability of river banks almost 10 m or more in their heights and movement of their failed soil mass are analyzed by a simplified Junbu method and the Newtonian law of motion. In analysis the bed near the bank slope was degraded drastically to make relative bank heights increase and water level was supposed in two cases: during and after flooding time. Then, calculation was carried out in cases of several river bank heights of 12-19 m. The outputs of analysis are values of the safety factor for bank slope, while acceleration, velocity, and movement distance for failed soil mass. Results show that bed degradation increases in relative banks height which have strong influence on the stability of river bank and the higher the river bank is, the farther the failed soil mass moves.

In hydrodynamic models, vegetation is commonly approximated as an array of vertical cylinders to represent its impacts on flow and sediment transport. However, this simple approximation may not be valid in the case of Rhizophora mangroves that have complicated three-dimensional root structures. Here, we present a new model to represent the impacts of Rhizophora mangroves on flow and sediment transport in hydrodynamic models. The model explicitly accounts for the effects of the three-dimensional root structures on flow and turbulence, as well as the effects of two different length scales of vegetation-generated turbulence characterized by stem diameter and root diameter. The model employs an empirical model for the Rhizophora root structures that can be applied using basic vegetation parameters (mean stem diameter and tree density), without rigorous measurements of the root structures. We showed that compared to the conventional approximation using an array of cylinders, the new model significantly improves the predictability of velocity, turbulent kinetic energy, and bed shear stress measured in a model and a real Rhizophora mangrove forest. The model further suggested the high efficiency of the three-dimensional root structures of Rhizophora mangroves on sedimentation, which allows a relatively high sediment supply to the forest but effectively regulates sediment erosion through reduced bed shear stress, compared to cylinder arrays that exhibit equivalent sediment supply or sediment retention. The presented model could be a fundamental tool to advance our understanding of the sedimentary processes in Rhizophora mangrove forests which are linked to mangroves' vulnerability and ecosystem service.

Fine sediments were saturated with phosphorus throughout the Fox River Basin and have potential to release phosphorus when water column concentrations are low  Current land use had no detectable effect on sediment phosphorus concentration and small potential effect on sediment phosphorus retention  Best agricultural land management practices had a small positive effect on sediment phosphorus retention capacity

This study focuses on the sediment transport by ship-generated waves in restricted waterways. Two data sets from Göta River in Sweden, an important shipping lane on the Swedish west coast, were analyzed in detail to determine the impact of ship waves, namely (1) continuous recordings of turbidity at seven stations along the river with 1-min resolution; and (2) dedicated field campaigns to measure water level and turbidity during ship passages. Measured turbidity was related to the suspended sediment concentration (SSC) and used as a proxy for the sediment transport. Several existing formulas were tested to evaluate their capability to predict both the primary and secondary waves, and the PIANC formula yielded the overall best agreement for the secondary (divergent) waves and a relationship based on the vessel sinkage for the primary (drawdown) waves. The turbidity (SSC) was found to depend primarily on the drawdown wave properties and empirical equations were derived to estimate the...

This paper presents an overview of RIVERINE project (RIver-VEgetation interactions and Reproduction of Island Nuclei formation and Evolution) preliminary results. We show some exemplary statistics of the both eroded and non-eroded material as resulting from a competitive dynamics between vegetation growth time scale and interarrival time of disturbances with constant magnitude. Two experiments, that is within channels with either regular geometry (parallel walls) or converging walls are discussed. Results show coherency of the results between the two geometries as far as the selective erosion mechanism of riparian vegetation is concerned. The experiment with convergent walls also conjectures that island formation is limited by the stream power associated to the local specific discharge.

Riverbank erosion coupled with recurrent flooding has been a persistent problem in large parts of the Eastern India. Published data on bank erosion of the Ganga River in West Bengal suggests an annual average of 8 sq. km. land-loss during 1969-1999 and that potentially affected lives of nearly a million people and destroyed various human establishments. In this study, we aim to constrain the spatiotemporal change in the path of the Ganga River and its impact of on sediment reworking in the plains area. For this, we used LANDSAT imagery from the year 1987 to 2019. Our analysis is based on a MATLAB-based toolbox called RivMAP. We show that the mean reach-averaged migration rates of the Ganga River vary from 200-600m/yr. Over the last three decades, the Malda district suffered a land-loss of ~140 km2, yielding an average annual loss of 4.5 km2. First order mass estimate suggests ~30 Mt/yr sediment yield from the Ganga riverbank in Malda, which is ~815% of the total annual sediment loa...

The atmospherically-derived cosmogenic (7 Be), anthropogenic (137 Cs), and airborne radionuclides (210 Pb xs) were used to investigate the origin and travel time of the mobile soil particles discharged from the tile drain in a heavy clay soil. These radionuclides were accumulated mainly in the surface layer of the soil profile; nevertheless, they were detected with high activities in all the mobile soil particle samples collected from the tile drainage water in a rainfall event. This indicates that the major origin of the mobile soil particles discharged from the tile drain is the mobile soil particles in the uppermost surface soil. The average travel time of the mobile soil particles moving from the uppermost surface soil to the tile drain is estimated as about 35 d based on the difference in the activity ratio (7 Be/ 210 Pb xs) of the mobile soil particles between in the surface runoff and in the tile drainage waters.

Excessive delivery of fine-grained sediment and sediment-bound nutrients to surface waters results in water quality impairment. Information on the relative contribution of different sources contributing sediment to river systems is a prerequisite to target management practices. Sediment fingerprinting technique can help to estimate sediment contributions from various sediment sources to fluvial sediment load. The overall goal of this study was to determine the sources of in-stream sediment (stream bed and suspended) at a subwatershed scale using sediment fingerprinting approach in an urbanized, 31 km 2 Moore's Mill Creek watershed in Southern Piedmont region in Alabama. The relative source contribution from construction sites and stream banks to in-stream sediment was quantified for two different particle size fractions, 63-212µm (fine sand) and <63µm (silt and clay). Results of this study showed that both construction sites and stream banks were important sources of stream bed sediment. The stream bed sediment in the upstream reaches originated largely from channel bank sources, and in the lower reach (watershed outlet), construction sites were the dominant sources of stream bed sediment. Also, this study showed that the construction sites were the dominant sources of suspended sediment in the watershed with contribution ranging from 0 to 100%, varying temporally. The relative source contribution from different sources is dependent on the particle size of the sediment, time and location of sampling within a watershed, riparian buffers, and areas of construction activities in proximity to the sampling sites. Also, it was observed that different source contributions could be obtained with different fingerprinting procedures as apportionments are sensitive to the statistical iii procedures employed. Soil and Water Assessment Tool (SWAT) was used in parallel to assess valuable information of watershed-level hydrological processes that affect sediment erosion and transport within a watershed. SWAT identified areas that generate high surface runoff and water yield and have the potential to contribute disproportionately high amount of sediment to streams. Targeting best management practices (BMPs) in these areas can significantly reduce the sediment loadings to the streams. Overall, this study underscores the importance of considering the spatial and temporal variability of sediment sources as a function of sediment particle size for targeting BMPs. The combined use of sediment fingerprinting technique and watershed-level modeling can provide valuable information of sediment transport processes and dynamics within a watershed. iv ACKNOWLEDGMENTS I express my sincere gratitude to my Major Professor Dr. Jasmeet Lamba for providing me a wonderful opportunity to work under his able guidance. The encouragement by Dr. Lamba has been the greatest asset to my pursuit of an interesting project. I thank him for nurturing my interest, guiding me, motivating me, and showing faith in me throughout my study. The constructive comments and critical suggestions provided by members of my advisory committee helped to improve the manuscripts. My sincere thanks are due to my committee members for their time and effort. I am grateful to people who helped me during field and lab work at various stages of my research. I am also thankful to my colleagues and friends, Palki Arora,

Excessive delivery of fine-grained sediment and sediment-bound nutrients to surface waters results in water quality impairment. Information on the relative contribution of different sources contributing sediment to river systems is a prerequisite to target management practices. The overall goal of this study was to determine the sources of stream bed sediment at a subwatershed scale using sediment fingerprinting approach in an urbanized, 31 km 2 Moore's Mill Creek watershed in Southern Piedmont region in Alabama, USA. The relative source contribution from construction sites and stream banks was quantified for two different particle size fractions, 63-212 μm (fine sand) and < 63 μm (silt and clay). Results of this study showed that both construction sites and stream banks were important sources of stream bed sediment. The stream bed sediment in the upstream reaches originated largely from channel bank sources, and in the lower reach (watershed outlet), construction sites were the dominant sources of stream bed sediment. The results of this study showed that the relative source contribution from different sources is dependent on the particle size of the sediment, time and location of sampling within a watershed, riparian buffers, and areas of construction activities in proximity to the sampling sites. Conservation practices in this watershed should be targeted to stream banks or construction sites depending upon the dominant source of stream bed sediment within a subwatershed. Overall, this study underscores the importance of considering the spatial and temporal variability of sediment sources as a function of sediment particle size for targeted implementation of best management practices.

Predicting the erosion of cohesive materials has long been a challenging task owing to the difficulty in determining the controlling forces that resist entrainment by hydraulic stress, and in characterizing the inherent variability of a cohesive deposit. Whereas entrainment of non-cohesive materials is a function of factors such as particle size, shape, weight and degree of hiding or exposure, the resistance of cohesive materials is controlled by the nature and strength of the inter-particle bonds. Still, accurately quantifying entrainment thresholds (critical shear stress) and erosion rates (erodibility coefficient) are crucial for predicting the stability of earthen structures as well as rates of channel adjustment. In recent years, three field instruments have been developed to indirectly measure the critical shear stress (c) of cohesive deposits in situ; two jet-test devices and the cohesive strength meter (CSM). The jet devices also provide an indirect measurement of the erodi...

Numerical research was performed on the attenuation mechanisms of both low-and highfrequency (HF) waves through forestation. Additionally, under severe conditions approaching the sea dike, the impact of mangrove width on this attenuation process was investigated. When the mangrove forest's width is insufficient, it appears that the mangrove squeezing on the beach, which is connected to wave transformation over the dike, cannot be reduced. Additionally, it demonstrates that inside the mangrove forest, high-frequency waves (HF) dampen more quickly than LF waves. A minimal width of this vegetation that can successfully attenuate under extreme circumstances will be investigated. However, over that proposed width of 800 m mangrove, the LF waves inside the mangrove still propagate the dike although their energy is significantly mitigated.

Local people in the Central Dry Zone (CDZ) of Myanmar have been facing climatic variability for several decades. They are among the first communities to observe climate and environmental changes first-hand, and are applying traditional knowledge and skills in order to adapt to these changes. We used participatory action research in which a series of group discussions and debates were conducted in community workshops at the village level. Using this input, we analysed the perceptions of the local people about climate variability, impacts, and adaptation practices. The majority of the local people perceived climate change patterns in the CDZ with the increase of temperature and erratic rainfall patterns perceived as the most critical changes. The majority of the people also perceived that the impacts of climate change have already been affecting agriculture and its related sectors, including land and water resources and their livelihood strategies. Most of the local people also perceived that migration of young people away from the communities has gradually increased due to the consequences of climate change impacts. Farmers have already been attempting to cope with those climate change impacts by using locally relevant adaptation measures such as mixed and multiple cropping systems, changing to drought-resistant plant varieties, and using soil conservation measures to cope with water scarcity. In addition, most of the local people perceived that getting information from traditional weather prediction was helpful to cope with drought and erratic rainfall patterns. However, the results suggest the adaptive capacity of the local people in responding to the impacts of climate change can be improved. In this regard, effective adaptation planning relies on the best available knowledge base, and the urgent need to respond to the pressures of climate change has put a premium on the generation, interpretation and use of information to improve adaptive capacity, including improved access to scaling up the traditional best practices of local people.

Sources of fine-grained suspended sediment in the Pocomoke River watershed draining above Willards, Maryland, were identified using a 'sediment-fingerprinting' approach. Potential sediment sources in the watershed were cropland, forest, channel and ditch banks, and ditch beds. Samples of fine-grained suspended sediment were obtained for seven storms between July 2001 and November 2002 and showed that the channel corridor (channel and ditch banks, and ditch beds) were significant sources averaging 76.5 % of the total sediment sources for the seven storms. Results indicate that sediment sources vary between events, and may be affected by seasonality and runoff conditions. Cropland was an important source of sediment for the two storms with the highest peak flow which occurred in the late summer and fall when harvesting began and vegetative cover was low. Ditch beds, which contributed an average of 46.1 % of sediment for the seven storms, were important sources of sediment over a range of peak flows (0.2 m 3 /s to 15.7 m 3 /s) and may also be important when crop areas have mature leaf cover.

The early agrarian community was established in the northern part of Bangladesh because of its unique Barind tract formation. Rural homesteads were the core building block of these settlements. Though 70% of Bangladeshi still live in rural areas, the rural homesteads are being transformed rapidly. Many socio-economic indicators such as population density, limited expansion opportunity, access to modern technology and diverse types of materials and many more are working as a core driving force behind these changes. This article investigates the transformation pattern of the rural homesteads in Kakon Hut Paurashava of Godagari Upazilla in Rajshahi District, in terms of both spatial pattern and construction materials, to develop an in-depth understanding of the impact of adaptation of modern techniques, technologies, and materials in the urban fringe areas. This research is based on an empirical research strategy and consequently progressed through qualitative data collection, observat...

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In the present study, a numerical model, based on one-dimensional de Saint-Venant equations along with sediment continuity equation, is developed for prediction of bed levels in non-cohesive sediments in aggrading alluvial channels. One-dimensional, unsteady flow equations and sediment continuity equations are solved using 'shock-capturing', second order accurate, explicit MacCormack finite difference scheme while considering upstream and downstream boundary conditions in the channel. Series of experimental investigations have been undertaken for measurements of bed and water levels in an aggrading channel due to overloading of nonuniform sediments, extracted from the bed of Tapi River at Surat City, in a flume installed in Advanced Hydraulics Laboratory of SVNIT, Surat, India. A satisfactory coupling between the water flow and sediment flow has been achieved. The sediment continuity equation is used for the each size class to compute the volume of each size class after each time step at any computational node in the computational grid. The fractional bed and suspended load transport capacities for different size fractions have been computed using fractional transport laws for nonuniform sediments. The active bed layer concept has been implemented in finite difference scheme to consider the interaction and exchange of sediment and water flow near the mixing layer. The performance of developed numerical model has been satisfactorily verified with independent experimental data of nonuniform sediment bed. Also, consideration of sediment nonuniformity in computation of bed level variation has been demonstrated by comparing the results based on sediment transport functions of uniform and nonuniform sediments.

Sources of fine-grained suspended sediment in the Pocomoke River watershed draining above Willards, Maryland, were identified using a 'sediment-fingerprinting' approach. Potential sediment sources in the watershed were cropland, forest, channel and ditch banks, and ditch beds. Samples of fine-grained suspended sediment were obtained for seven storms between July 2001 and November 2002 and showed that the channel corridor (channel and ditch banks, and ditch beds) were significant sources averaging 76.5 % of the total sediment sources for the seven storms. Results indicate that sediment sources vary between events, and may be affected by seasonality and runoff conditions. Cropland was an important source of sediment for the two storms with the highest peak flow which occurred in the late summer and fall when harvesting began and vegetative cover was low. Ditch beds, which contributed an average of 46.1 % of sediment for the seven storms, were important sources of sediment over a range of peak flows (0.2 m 3 /s to 15.7 m 3 /s) and may also be important when crop areas have mature leaf cover.

Currently the Ministry of Construction is responsible for planning and construction of bridges across the country but remote sensing and satellite data are not widely used in the Ministry's routine process. Although the inspection and monitoring are carried out by the conventional methods, the remote sensing and GIS techniques are available as an alternative way with time and cost saving. From this study, the channel migration in the locations of Ayeyarwady bridges will be analyzed and mapped by identifying temporal changes of channels. Google Earth Engine is used as the primary application in this study and surface water extraction from historical Landsat satellite imagery is done by GEE. River centerline processing and erosion-deposition area identifications are carried out by GIS technique. Study period of each bridge is between 1987 and 2017. Bo Myat Tun Bridge and Ayeyarwady Bridge (Pakokku) are toped in the list with highest migration and erosiondeposition rate according to the study. The goal of this study is to assist the bridge inspections and channel monitoring works by means of remote sensing and GIS techniques which are currently undertaking by Ministry of Construction with conventional techniques.

According to the conditions of any river, different methods are used to protect of erodible rivers bank. One of these methods is the use of banks protection structures such as submerged vanes. The main problem of these structures is to local scour of around the nose structure. One of the effective methods of flow pattern improvement around the structures is creating slot in structure. In this study, has been created rectangular slot (with fixed dimensions) in three different positions in bank attached triangular vane, this means that the slot is parallel to the chord in first vane, parallel to the base in second vane and parallel to the vertical side of triangular vane in third vane. The research aim is to determine the slot optimal location, with defined dimensions. Experiments were conducted in the single-vane posture and under different hydraulic conditions (clear water condition). Results showed that the first vane (slot is parallel to the chord) had the best performance to reduction of volume, Length and width of scouring. Also, the maximum scour depth in this vane was 35% and 13% less than two other vanes that slot is parallel to the base and parallel to the vertical side, respectively.

Bank erosion is the most common problem faced in river engineering practices in many countries, especially in Bangladesh and this has been recognized as an awful threat to the society. So control of erosion is very much important to save agricultural land, property and infrastructures like bridges, culverts, buildings etc. located alongside the rivers. Treatment of bank erosion is usually expensive and is not particularly susceptible to engineering analysis. Because diagnosis and prediction of bank erosion is often difficult as it may be caused by a number of factors operating separately or together. Engineers play a dominant role to design the optimum bank protection works, which sounds justified both technically and economically. In this paper the probable causes, mechanisms and methods of predictions of bank erosion and sustainable strategies of different bank protection measures with special attention to economic analysis are briefly discussed.

The fluvial process is characterized by an intense meandering riverbed. The aim of this study was to perform a reconstruction of the lateral migration of a 15 km length of an active meandering river during the period 1930-2016. River morphological changes were analyzed and quantified from cadastral maps and aerial photographs as well as by geodetic survey and GIS. Hydrological characteristics and extreme hydrological events were evaluated in relation to bank erosion rate. The rate of bank erosion was markedly different from the long-term studied meanders, just like in the short-term period. During the 87 years of observation (from 1930 to 2016), the length of the Kolubara River was enlarged by 3.44 km. The average migration rate of the Kolubara River for monitored meanders in the period 1930-2010 was 1.9 m•year -1 , while in the period 2010-2016, the average migration rate was 3.3 m•year -1 . The rate of bank erosion was more intensive across the entire short-term period than during the longer period, and the maximum annual rate of bank erosion during the period 2010-2016 varied between 0.3 and 11.5 m. It is very likely that in the period from 2010, frequent discharge variations and rapid change of its extreme values caused more intensive bank erosion. These research results will be valuable for river channel management, engineering (soft and hard engineering), and planning purposes (predicting changes in river channel form) in the Kolubara River Basin.

Samenvatting xi Curriculum Vitae List of Publications in de mangroven en hoe langzamer de dempings-processen. Ondanks de toegenomen kennis en besef van het belang van de processen beschreven in de verschillende hoofdstukken, bestaan er nog steeds lacunes. Dit proefschrift concludeert dat de grootste uitdaging de verdieping van ons begrip ligt in de validaties op werkelijke schaal en in de simulaties van bedding en zwevend sedimentprocessen. SIWRR (2010). Tien Estuary Investigation Report [ in Vietnamese].

It is often difficult to assess stream bank erosion. Bank Assessment for Non-point source Consequences of Sediment (BANCS) model is a renowned procedure for evaluating Stream Bank Erosion Hazard Potential (SBEHP). In the present article inventory of stream bank condition have been assessed from field surveys on 24 sample segment over a consecutive 5 year period for 86.36 km stretched river Bakreshwar of Eastern India. Bank Erosion Hazard Index (BEHI), Near Bank Stress (NBS) and field based data have been considered for this appraisal. The results show that (1) BEHI is high in the upstream and near the confluence segments. (2) Compare to BEHI, NBS is less for most of the sites. (3) Fragile lateritic soil, sparse vegetation, etc., in the upstream and steep slope and barren bank, sinuous channel, loosely compact alluvial sediments, etc., in the downstream can be accountable for high SBEHP in those counterparts. (4) On the annual basis, a total of about 173595.75 metric tons of sediment entrains into the river from banks. (5) Banks have experienced varied rate of erosion from similar BEHI-NBS combinations. Therefore, we concluded that BEHI and NBS is potentially not a sound bank erosion hazard predictive model for our present study. Keywords Bank assessment for non-point source consequences of sediment (BANCS) Á Bank erosion hazard index (BEHI) Á Stream bank erosion hazard potential (SBEHP) Á Near bank stress (NBS) Á BEHI-NBS matrix calibration Á Bank erosion & Krishna Gopal Ghosh

Tobacco is being dealt as one of the major cash crops which are largely grown in Kushtia, Chittagong Hill, and northern regions of Bangladesh. Actually it is a non-food plant used as a basic raw material for products that is proved to be harmful for health, environment and society. Tobacco is both dangerous and addictive. Its production thus raises ethical questions. The study is aimed to estimate the factors affecting tobacco yield and investigate whether any ethical issues influence the production behavior of tobacco farmer in Lalmonirhat district. Both primary and secondary data are used in this paper. Primary data is collected from 100 farmers using simple random sampling method from Aditmari upazila of Lalmonirhat district. are used .To estimate the influencing factors including ethics on the tobacco yield, both multiple linear and double log regression model are used. Tabular method is followed to describe the socioeconomic profile and explore ethical consideration of tobacco farmers regarding its cultivation. The result shows that actually major farmers have no ethical concerns about tobacco farming. It also reveals that the majorities of tobacco farmers are reluctant to leave its production though they claim that tobacco production is unethical. The linear regression result of tobacco yield shows that the variables fertilizer, pesticides, seed, labors, support from the company, and land quality are positively significant to affect the tobacco yield. From the normative point of view, ethical concern of the farmers would be negatively related with their tobacco yield. But the paper finds an insignificant relation between ethics and tobacco yield.