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Bank erosion events and processes in the Upper Severn basin
D. M. Lawler,J. Couperthwaite,L. J. Bull,N. M. Harris
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 1997,
Abstract: This paper examines river bank retreat rates, individual erosion events, and the processes that drive them in the Upper Severn basin, mid-Wales, UK. Traditional erosion pin networks were used to deliver information on patterns of downstream change in erosion rates. In addition, the novel automatic Photo-Electronic Erosion Pin (PEEP) monitoring system was deployed to generate near-continuous data on the temporal distribution of bank erosion and accretion: this allowed focus on the magnitude and timing of individual erosional and depositional events in relation to specific flow episodes. Erosion dynamics data from throughout the Upper Severn basin are combined with detailed information on bank material properties and spatial change in channel hydraulics derived from direct field survey, to assess the relationships between flow properties and bank erosion rates. Results show that bank erosion rates generally increase downstream, but relate more strongly to discharge than to reach-mean shear stress, which peaks near the basin head. Downstream changes in erosion mechanisms and boundary materials, across the upland/lowland transition (especially the degree of development of composite bank material profiles), are especially significant. Examples of sequences of bank erosion events show how the PEEP system can (a) quantify the impact of individual, rather than aggregated, forcing events, (b) reveal the full complexity of bank response to given driving agents, including delayed erosion events, and (c) establish hypotheses of process-control in bank erosion systems. These findings have important implications for the way in which bank erosion problems are researched and managed. The complex responses demonstrated have special significance for the way in which bank processes and channel-margin sediment injections should be handled in river dynamics models.
Assessment of Pond Fishery Resources and Sustainable Development of Fisheries at Sirajganj, Bangladesh
Z. Rehena,M.N. Islam,M.A. Hossain
Journal of Fisheries International , 2012, DOI: 10.3923/jfish.2012.55.60
Abstract: An assessment was conducted in Sirajganj district of Bangladesh to determine the pond fishery resources and sustainable development of fisheries. Researchers observed 123 (56%), 59 (27%) and 37 (17%) of ponds were culture, semi-culture and non-culture ponds and on the basis of the season 192 (88%) of perennial and 27 (12%) of seasonal ponds were found out of 219 during this study period. It was observed that the highest number of ponds 175 (80%) was personal pond which occupied by the single owners and 44 (20%) was leased in pond which privately occupied by the multiple ownership. The range of cost for lease was varied from Tk. 6,000-8,000 acre-1. The average pond fish production from 219 sampling ponds in Sirajganj district was 80.51 kg decimal-1. Therefore, by using sustainable development model, pond fisheries production can be increased to a considerable level and contributes to the national economy.
Upazila Parishad in Bangladesh: Roles and Functions of Elected Representatives and Bureaucrats  [cached]
Muhammad Sayadur Rahman
Commonwealth Journal of Local Governance , 2012, DOI: 10.5130/cjlg.v0i0.3060
Abstract: This study explores whether democratic Upazila Parishads in Bangladesh have become more responsive to those who elected them and whether people's expectations about their elected representatives and their functions to their elected have changed. The study carried out in eight Upazilas from seven Divisions in Bangladesh. The study has found that Upazila Parishads in Bangladesh with democratically elected representatives have largely failed to enhance their rapport with people. The recently implemented mandatory advisory role for the members of the parliament (MPs) has complicated the role of the local government and the interference by MPs in local government affairs has weakened the independence of local government. The findings of this study reveal that awareness is low, and that only 30% of respondents were concerned about the roles and functions of the Upazila Parishad. The data reveals that though the local citizens think that they are knowledgeable about the roles and functions of elected representatives and bureaucrats in reality many remain unaware of the roles and functions.
Remote Sensing and GIS for the Spatio-Temporal Change Analysis of the East and the West River Bank Erosion and Accretion of Jamuna River (1995-2015), Bangladesh  [PDF]
Md Arafat Hassan, Suriya Jesmine Ratna, Masud Hassan, Sonia Tamanna
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.59006
Abstract: 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 (km2) during the period of 1995 to 2005 and the highest accreted area is 6.15 square kilometers (km2) 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 socio-economic problems in the proximate areas.
Bank erosion process and bank material loss potential in Manahara River, Kathmandu, Nepal  [PDF]
Pramila Shrestha,Naresh Kazi Tamrakar
Bulletin of the Department of Geology , 2007, DOI: 10.3126/bdg.v10i0.1418
Abstract: Normal 0 false false false MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-parent:"";mso-padding-alt:0cm 5.4pt 0cm 5.4pt;mso-para-margin:0cm;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:10.0pt;font-family:"Times New Roman";mso-ansi-language:#0400;mso-fareast-language:#0400;mso-bidi-language:#0400;} The Manahara River, one of the largest tributaries of the Bagmati River has been suffering from bank erosion problem and lateral shifting. Several erosional processes have been observed. Bank erosion causes loss of large amount of sediment from the watershed. The river has been assessed to find out major erosional processes to determine the relative annual sediment displaced from bank and recession rate of bank, the annual riverbank material loss was calculated using data from cross-sectional surveys of two runoff periods one is in 2005 and another is 2006, and using the factors related to bank material, bank vegetation and bank morphology. The major erosional processes identified are rill erosion, gully erosion, sheet erosion, parallel flow erosion and impinging flow erosion and slumping. Absolute bank material loss estimated from cross-sectional survey indicates that percent loss of sediment per cross-section correlates positively with downstream distance. With increase in distance from the origin, sediment gain or loss from transects also increases. The percent gain in downstream portion exceeds percent loss, therefore the river is aggrading. Contrarily, there is no correlation between distance and bank material loss. This indicates that bank material loss at the sites probably depends on local factors (riparian vegetation, bank material, bank morphology and sinuosity) other than the distance of origin of the river. Relative bank material loss assessed at 24 banks undergoing erosion results, 705 m 3 sediment depleted annually from banks and mass of displaced material (TDM) is 1243 tons. The total volume and weight of sediment displaced from the Manahara River must be much higher than this value. ? doi: 10.3126/bdg.v10i0.1418 ? Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 10, 2007, pp. 33-44
A GIS based study on bank erosion by the river Brahmaputra around Kaziranga National Park, Assam, India
J. N. Sarma,S. Acharjee
Earth System Dynamics Discussions , 2012, DOI: 10.5194/esdd-3-1085-2012
Abstract: The Kaziranga National Park is a forest-edged riverine grassland inhabited by the world's largest population of one-horned rhinoceroses, as well as a wide diversity of animals. The park is situated on the southern bank of the Brahmaputra River at the foot of the Mikir Hills. National Highway 37 forms the southern boundary and the northern boundary is the river Brahmaputra and covers an area of about 430 km2. The Brahmaputra River flows by Kaziranga National Park in a braided course for about 53 km. Sequential changes in the position of banklines of the river due to consistent bank erosion have been studied from Survey of India topographic maps of 1912–1916 and 1972, satellite IRS LISS III images from 1998 to 2008 using GIS. Study of bank line shift due to the bank erosion around Kaziranga has been carried out for the periods 1912–1916 to 1972, 1972 to 1998 and 1998 to 2008. The amounts of the bank area lost due to erosion and gained due to sediment deposition are estimated separately. The total area eroded during 1912–1916 to 1972 was more (84.87 km2) as compared to accretion due to sediment deposition (24.49 km2), the total area eroded was also more in 1972–1998 (44.769 km2) as compared to accretion (29.47 km2) and the total area eroded was again more in 1998–2008 (20.41 km2) as compared to accretion (7.89 km2). The rates of erosion during 1912–1916 to 1970, 1970 to 1998, and 1998 to 2008 were 1.46, 1.59 and 1.021 km2 per year, respectively. During the entire period (1912–1916 to 2008) of study the erosion on the whole was 150.04 km2 and overall accretion was 61.86 km2 resulting in a loss of 88.188 km2 area of the park. The maximum amounts of shift of the bankline during 1912–1916 to 1970, 1970 to 1998, and 1998 to 2008 were 4.58 km, 3.36 km, and 1.92 km, respectively, which amount to the rates of shift as 0.078, 0.12 and 0.096 km per year, respectively. A lineament and a few faults have controlled the trend of the course of the Brahmaputra around Kaziranga area. The main cause of erosion of the Brahmaputra is the loose non-cohesive sediments of the bank throughout the park. The braided channel of the river strikes the bank directly and undermines the silty bank causing overhanging blocks to be carried away easily by the river current. In future deposition is likely to be more in upstream or eastern part of Kaziranga and erosion in middle part of Kaziranga national park area due to the river Brahmaputra. Antierosion measures have been adopted only in a few places to check bank erosion at Kaziranga.
Riparian vegetation affected by bank erosion in the Lower S?o Francisco River, Northeastern Brazil
Holanda, Francisco Sandro Rodrigues;Santos, Laura Galv?o da Cunha;Santos, Cícero Marques dos;Casado, Ana Patrícia Barreto;Pedrotti, Alceu;Ribeiro, Genésio Tamara;
Revista árvore , 2005, DOI: 10.1590/S0100-67622005000200016
Abstract: changes in the hydrological regime of the lower s?o francisco river, located in northeastern brazil have brought negative environmental impacts, jeopardizing the flora and fauna of a global biodiversity hotspot, due to implementation of hydroelectric power dams and surface water withdrawal for irrigation in public and private perimeters. remnants of the riparian stratum associated to the riverbank destabilization in six fragments were studied by surveying trees, shrubs, herbs, and aquatic species. the calculation of the factor of safety (fs) was performed in order to understand the riverbank's stability related to soil texture and vegetation cover. an overall number of 51 botanic families distributed in 71 genera and 79 species were recorded, predominantly from the families mimosaceae, myrtaceae, and fabaceae. the fragmented riparian vegetation is mostly covered by secondary species under a strong anthropogenic impact such as deforestation, mining and irrigation, with an advanced erosion process in the river margins. strong species that withstand the waves present in the river flow are needed to reduce the constant landslides that are mainly responsible for the river sedimentation and loss of productive lands. a lack of preservation attitude among the local landholders was identified, and constitutes a continuing threat to the riparian ecosystem biodiversity.
Estimation of Bank Erosion Due To Reservoir Operation in Cascade (Case Study: Citarum Cascade Reservoir)
Sri Legowo,Iwan K. Hadihardaja,Azmeri
ITB Journal of Engineering Science , 2009,
Abstract: Sedimentation is such a crucial issue to be noted once the accumulated sediment begins to fill the reservoir dead storage, this will then influence the long-term reservoir operation. The sediment accumulated requires a serious attention for it may influence the storage capacity and other reservoir management of activities. The continuous inflow of sediment to the reservoir will decrease the capacity of reservoir storage, the reservoir value in use, and the useful age of reservoir. Because of that, the rate of the sediment needs to be delayed as possible. In this research, the delay of the sediment rate is considered based on the rate of flow of landslide of the reservoir slope. The rate of flow of the sliding slope can be minimized by way of each reservoir autonomous efforts. This effort can be performed through; the regulation of fluctuating rate of reservoir surface current that does not cause suddenly drawdown and upraising as well. The research model is compiled using the searching technique of Non Linear Programming (NLP).The rate of bank erosion for the reservoir variates from 0.0009 to 0.0048 MCM/year, which is no sigrificant value to threaten the life time of reservoir.Mean while the rate of watershed sediment has a significant value, i.e: 3,02 MCM/year for Saguling that causes to fullfill the storage capacity in 40 next years (from years 2008).
Management Practices on Hoar Fisheries in Itna Upazila, Kishoreganj  [PDF]
M.S.H. Bhuiyan,M.A.K.Azad,M.K. Hossain,S. Ahammed
Pakistan Journal of Biological Sciences , 2005,
Abstract: The experiment was conducted in Itna Upazila, Kishoreganj from July 2001 to June 2002. It has included survey of waterbodies, implementation of different management policies and affect of aquatic environmental issues on hoar fisheries in Itna Upazila, Kishoreganj. There are 16 hoars in Itna Upzila which were comprising of 83 jalmohals. Three management policies including revenue- based leasing system in 93% area of jalmohal, NFMP in 7% area of jalmohal with fisheries resources development project including sanctuary, have been practiced in Itna. Aquatic environmental degradation by siltation, submersible roads and flood control embankments, deforestation, conversion of water body into agricultural land, use of agro-chemicals and surface water abstraction for boro crop, social and political unwanted influence were creating a great threat to fisheries sustainability. It has been suggested that government should emphasize the sustainable haor fisheries development by implementing community-based management practices as part of an integrated holistic development plan of the haor areas.
A Survey on the Faunal Diversity of Savar Upazila, Dhaka, Bangladesh  [PDF]
Md. Eftekhar Hossain,Mohammad Mamun Chowdhury,Kazi Farhed Iqubal
Pakistan Journal of Biological Sciences , 2008,
Abstract: A survey was conducted during January to December 2006 to assess the status of faunal diversity of Savar Upazila, Dhaka, Bangladesh. A total of 30 species of birds, 24 species of winter birds, 7 species of reptiles, 3 species of amphibians, 15 species of mammalians and 32 species of fishes were recorded. Relative abundance of those species were determined. Of the birds, House Sparrow (Passer domesticus) was abundant while Blyth's Kingfisher (Alcedo hercules), Rock Eagle Owl (Bubo bengalensis), Hooded Pitta (Pitta sordida), Black-headed Oriole (Oriolus xanthornus), White-winged Duck (Cairina seululala) and Duck (Anser indicus) were rare. The relative abundance of winter bird could not be assessed because of their migratory habit. Striped keelback (Amphiesma stolata) and Common Smooth Water Snake (Enhydris enhydris) were very common while Black pond turtle (Geoclyms hamiltonii) and Pond tortoise (Melanochelys trijuga) were recorded as endangered. Common Toad (Bufo melanostictus) were abundant but Bull Frog (Rana tigrina) was rare. Asiatic Wild Dog (Cuon alpinus) and House Mouse (Mus musculus) were abundant while Common Otter, Large Indian Civet, Irrawaddy River Dolphin, Indian Hare were rare. Carpu, Silver carp, Tilapia, Nilotica were abundant while, Freshwater Garfish, One stripe spinyeel and Grey Featherback were rare. Landfilling, deforestation, poaching, industrial effluents and current jal were identified as major threats to the faunal diversity of Savar area.
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