flood plain
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Abstract Understanding the availability and distribution of wetlands is key to conservation, exploitation and better management of wetlands resources. The wetlands of Kumadugu-Yobe river basin are widely spread within the sedimentary formation beyond the famous Hadejia Nguru wetlands. This study identified and map out the spatial distribution of KYRB wetlands using field observation information, the basin base map, the topographical map and high resolution Google image and Advance very High Resolution spectroradiometer (AVHRS) NDVI (Normalized Vegetation Differncial Index) data of 2018, in mapping the wetlands spatial distribution pattern. The findings of the study classified the basin wetlands in to flood plain along the river banks, surface depressions ponds and Oasis. The basin wetlands are spread all over the sedimentary geological formation of the basin. The wetlands of the mid and downstream parts of KYRB are largely spread along river Yobe, river Kumadugu-Gana, small tributaries (Alaraba, Damaturu, Budum-Gana among others), famous Hadejia-Nguru wetlands, Oases at the northern parts of the river Yobe and isolated pockets of ponds. The study recommended for effective geo data base for the wetlands.

Erosion, transportation and deposition by running water are closely related and these works are performed in association and not in isolation. One cannot be performed without others. These works are determined on other factors like topography, geology, structure and composition of rocks, slope, amount of water availability and its characteristics, climate etc. Huge catchment area of the Gandak River is lying in the Himalayan mountainous region. This region is receiving good amount of rainfall concentrated in four months of monsoonal period June to September (JJAS). This period has also high temperatures leading to large amount of glacial ice melt. Hence, enormous water is drained off the mountain steep slope. The Himalaya is very young and has fragile rocks and ecosystem. Anthropogenic activities in those areas are primary cause, apart from natural weathering, for generation of more and more shattered materials which are brought by running water downstream much easily. Therefore, highly sediment concentrated water brings large quantity of loads. It is deposited in suitable conditions along its paths in the plain and with flood water. It results the formation of flood plain. According to the erosion and deposition, different types of major and minor features are formed. In other words, water and sediment determine the layout of the plain appearance. In this background, it is attempted to (i) study sediment concentration in discharged water and (ii) illustrate the channel planform of the Gandak River in the plain. To achieve these aims, secondary data has been collected and analyzed. It is expected that this study will help in executing an integrated development plan for the flood affected area of Lower Gandak River Plain. Keywords: sediment load, channel bars, channel planform, meandering, braiding, slope/gradient and channel cutoff.

The Ganges-Brahmaputra river system at the Bengal Basin carries large amounts of sediments on the way to finally deposit at the Bay of Bengal. Those river-transported sediments form bar deposits during dry season in many areas of Bangladesh and accumulate economic mineral depositions at suitable geological environments. Dredging is a must for most of those rivers for proper navigation, as well as protecting bank erosion, which generates millions of tons of waste sand. The dredged materials from river beds are mostly composed of silicate minerals, especially quartz and feldspar along with several dark colored heavy minerals. Like the industrial processing of heavy minerals from bulk sands, various physical separation techniques can be utilized for the beneficiation of silica from those river-born silicate minerals in dredged sands. Those silica have been successfully upgraded to near-glass sand grade in the laboratory, however, they have yet to be utilized for any kind of commercial venture. The present study attempts characterization of several river sands through physical separation and laboratory analysis. The upgraded silica was successfully compared with several quality glass sands and laboratory production of glasses. This experimental production of glass from upgraded silica could potentially be economical considering its industrial application with positive environmental consequences through minimizing the dredging cost, increasing the navigability of the river and ecological balance along the flood plain.

Introduction: Presently, there has been an emergent concern that rising numbers of the world’s population are deserted due to the undesirable impacts of natural hazards, especially floods. Geographically, Bangladesh is a low-lying flood plain country with only a few hills in the south-east and the north-east part. Undoubtedly, education is a principal factor of socio-economic development, but regrettably, Bangladesh is suffering from the uncontainable effects of floods. After considering such issues, the foremost focus of this study was to recognize both the academic challenges faced by school-going children during a flood and examine the impact of the flood on the health of the children. Methods: Interview schedule, questionnaire survey, and document analyses had been carried out for this study. The study design was carried out by applying a mixed method. Students of Biddanondokathi Government Primary School and Mangalkot Secondary School from Mirzapur village of Mangalkot union in Keshabpurupazilla were randomly selected. The well-structured questionnaires were disseminated to 80 respondents of two academic institutions of Keshabpurupazilla of Jashore district. Additionally, descriptive statistics and chi-square tests were conducted to attain research objectives. Results: The outcome of this study revealed that flood unswervingly impacts the academic routine and health status of school-going children. Almost 93.8% of students faced academic challenges and 87.5% of children were the victims of waterborne diseases like diarrhea, skin diseases, and dysentery. Almost 82% of respondents did not go to school as the roads were impassable, 28.8% of individuals faced problems due to washed away bridges, and 28.8% faced challenges as their school was surrounded by water. About 66.2% of children dropped out of school and 17.5% of students did not attend their classes at all after the flood. Conclusions: Not only school-going children but also infrastructure is the crucial victims of flood disasters, compromising the children’s rights to access to quality education, information, good sanitation, as well as their participation rights. Flood disasters have key impacts on children’s education and progress and this study suggests that strategies need to be adapted to attend to the disaster risks encountered by school-going children of Bangladesh.

This study assessed urban flood impact, flood water quality and vulnerability around Olodo area of Ibadan region, Nigeria. The study employed remote sensing and GIS techniques in creating vulnerability and risk maps. Digital terrain model (DTM) was used to get the topography of the study area. Footprints of buildings along the Egberi riverbank and flood plain in Olodo were created in the GIS environment from high resolution satellite imagery. Buffering operation was conducted to classify the buildings into risk zones based on closeness to the riverbank using ArcGIS 10.0. The study revealed that 326 buildings were within the very vulnerable and vulnerable zones because they were less than 15.2m away from the riverbank. The characteristics of water quality change during the flood and non-flood periods. TSS, DO, NOD, and COD were all higher during the flood event. Microbial analysis showed that water quality levels in the floodwater exceeded water quality standards (e.g., the coliform excess from 10 to 10,000 times), and thus this may be a health risk for local people during flood events. Concentration of Escherichia coli (E. coli) ranged from 484 to 1290 cfu/100 mL during flooding compared to 192 to 295 cfu/100 mL after flood. Salmonella was found to be high ranging from 659 to 1840 cfu/100 mL during flooding compared to 530 to 1034 cfu/100 mL after flooding.