scholarly journals Modelling Tidal River Salinity in Coastal Bangladesh

Author(s):  
Lucy Bricheno ◽  
Judith Wolf
1984 ◽  
Vol 16 (5-7) ◽  
pp. 139-154 ◽  
Author(s):  
Ching-Gung Wen ◽  
Jao-Fuan Kao ◽  
Lawrence K Wang ◽  
Chii Cherng Liaw

A practical method of determining reaeration coefficients would greatly aid design engineers in determining the degree of wastewater treatment required for a proposed effluent discharge. Many previous tidal river and estuary studies emphasized mainly the effects of flow conditions (such as velocity, water depth, turbulent intensity, hydraulic gradient, etc.) and temperature on stream aeration, and the effect of salts was not seriously considered. In this research a new mathematical model of reaeration coefficient considering the effect of salts has been developed for water quality analysis in tidal rivers and estuaries. The reaeration coefficient in saline water, k2s(day−1, base e) at any chloride concentration C(g/l) and at 20°C, can be expressed byin which k2f is the reaeration coefficient in fresh water at 20°C. The correlation coefficient of k2s/k2f and C is 0.88.


1993 ◽  
Vol 27 (3-4) ◽  
pp. 311-314 ◽  
Author(s):  
Aaron B. Margolin ◽  
Charles P. Gerba ◽  
Kenneth J. Richardson ◽  
Jaime E. Naranjo

Nucleic acid hybridization provides a rapid non-cell culture method for the detection of enteric viruses in water. The purpose of this work was to compare the detection of naturally occurring enteroviruses by cell culture with their detection by a poliovirus gene probe in various types of water samples. Samples of activated sludge effluent, tertiary treated wastewater (activated sludge, filtration and passage through reverse osmosis), ground water, surface water and tidal river water were processed through 1 MDS Virozorb filters to concentrate any naturally occurring virus. Viruses were eluted from the filters with pH 9.5 beef extract and reduced in volume by flocculation to 20-30 ml. These concentrates were then assayed in the BGM cell line by the cytopathogenic effects (CPE) method and by a poliovirus cDNA probe (base pairs 115-7440) labeled with 32P. A total of 233 samples were assayed in this manner. In slightly more than 93% of the samples gene probe and cell culture yielded the same results. Of these samples 36 were positive by gene probe and 28 by cell culture assay. Positive samples for gene probe were confirmed by treatment with NaOH or RNAse and then reprobed. Samples demonstrating CPE upon primary passage were confirmed positive by subsequent passage of cell lysate on a new monolayer of BGM cells. Ten samples were positive by gene probe and negative by cell culture, and 4 samples were negative by gene probe and positive by cell culture.


1998 ◽  
Vol 38 (6) ◽  
pp. 327-335
Author(s):  
Yasunori Kozuki ◽  
Yoshihiko Hosoi ◽  
Hitoshi Murakami ◽  
Katuhiro Kawamoto

In order to clarify the origin and behavior of suspended particulate matter (SPM) in a tidal river, variation of SPM in a tidal river was investigated with regard to its size and constituents. SPM was separated into three groups according to size. Change of contents of titanium and organic substances of each group of SPM was examined. SPM which was discharged by run-off was transported with decomposition and sedimentation in a tidal river. Concentration of SPM with a particle size greater than 0.45 μm increased due to resuspension in a tidal river. Origin of SPM with a size of less than 0.45 μm at upstream areas was from natural soil and most of such SPM which had been transported settled near a river mouth. It was determined from examination of the CN ratio and the ratio of the number of attached bacteria to free bacteria that SPM with a size greater than 1.0 μm at upstream areas was decomposing intensively. At the downstream areas, SPM with a size of less than 0.45 μm came from the sea. SPM with particle size greater than 1.0 μm consisted of plankton and substances which were decomposed sufficiently while flowing.


Author(s):  
Abu Reza Md. Towfiqul Islam ◽  
Mohammad Mahbub Kabir ◽  
Sharmina Faruk ◽  
Jawad Al Jahin ◽  
Md. Bodrud-Doza ◽  
...  

Climate ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 97
Author(s):  
Abdullah Al-Maruf ◽  
J. Craig Jenkins ◽  
Amelie Bernzen ◽  
Boris Braun

The main objective of this paper is to measure the level of household resilience to cyclone and storm surges in the coastal area of Bangladesh. We draw on four general disaster frameworks in terms of addressing household-level resilience to cyclones and storm surges. We use a composite indicator approach organized around four components: (1) household infrastructure (HI); (2) household economic capacity (HEC); (3) household self-organization and learning (HSoL), and; (4) social safety nets (SSN). Drawing on a household survey (N = 1188) in nine coastal union parishads in coastal Bangladesh purposively selected as among the most vulnerable places in the world, we use principal components analysis applied to a standardized form of the survey data that identifies key household resilience features. These household index scores can be used for the assessment and monitoring of household capacities, training, and other efforts to improve household cyclone resilience. Our innovative methodological approach allows us to (a) identify patterns and reveal the underlying factors that accurately describe the variation in the data; (b) reduce a large number of variables to a much smaller number of core dimensions of household resilience, and (c) to detect spatial variations in resilience among communities. Aggregated to the community level, our new index reveals significant differences in community cyclone resilience in different areas of the coastal region. In this way, we can show that shoreline and island communities, in particular, have significant deficits in terms of household resilience, which seem to be mutually reinforcing one another and making for lower resilience.


2021 ◽  
Vol 55 ◽  
pp. 102049
Author(s):  
Sanzida Murshed ◽  
David J. Paull ◽  
Amy L. Griffin ◽  
Md Ashraful Islam

Climate ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 107
Author(s):  
Sabrina Mehzabin ◽  
M. Shahjahan Mondal

This study analyzed the variability of rainfall and temperature in southwest coastal Bangladesh and assessed the impact of such variability on local livelihood in the last two decades. The variability analysis involved the use of coefficient of variation (CV), standardized precipitation anomaly (Z), and precipitation concentration index (PCI). Linear regression analysis was conducted to assess the trends, and a Mann–Kendall test was performed to detect the significance of the trends. The impact of climate variability was assessed by using a livelihood vulnerability index (LVI), which consisted of six livelihood components with several sub-components under each component. Primary data to construct the LVIs were collected through a semi-structed questionnaire survey of 132 households in a coastal polder. The survey data were triangulated and supplemented with qualitative data from focused group discussions and key informant interviews. The results showed significant rises in temperature in southwest coastal Bangladesh. Though there were no discernable trends in annual and seasonal rainfalls, the anomalies increased in the dry season. The annual PCI and Z were found to capture the climate variability better than the currently used mean monthly standard deviation. The comparison of the LVIs of the present decade with the past indicated that the livelihood vulnerability, particularly in the water component, had increased in the coastal polder due to the increases in natural hazards and climate variability. The index-based vulnerability analysis conducted in this study can be adapted for livelihood vulnerability assessment in deltaic coastal areas of Asia and Africa.


Food Security ◽  
2021 ◽  
Author(s):  
Yukyan Lam ◽  
Peter J. Winch ◽  
Fosiul Alam Nizame ◽  
Elena T. Broaddus-Shea ◽  
Md. Golam Dostogir Harun ◽  
...  

AbstractThe rising salinity of land and water is an important, but understudied, climate change-sensitive trend that can exert devastating impacts on food security. This mixed methods investigation combines salinity testing with qualitative research methods to explore these impacts in one of the most salinity-affected regions in the world—the Ganges River Delta. Data collection in 2015 and 2016 undertaken in Bangladesh’s southwest coastal region and Dhaka consisted of 83 in-depth household and stakeholder interviews, six community focus groups, and salinity testing of 27 soil and 45 surface and groundwater samples. Results show that household food production is a multifaceted cornerstone of rural livelihood in the southwest coastal region, and virtually every component of it—from rice plantation and homestead gardening to livestock cultivation and aquaculture—is being negatively affected by salinity. Although households have attempted multiple strategies for adapting food production, effective adaptation remains elusive. At the community level, improved irrigation and floodplain management, as well as restrictions on saltwater aquaculture to abate salinity, are viewed as promising interventions. However, the potential of such measures remains unrealized on a broad scale, as they require a level of external resources and regulation not yet provided by the NGO and government sectors. This study elucidates issues of accessibility, equity, and governance surrounding agricultural interventions for climate change-related salinity adaptation, and its findings can help inform the community of organizations that will increasingly need to grapple with salinity in order to guarantee food security in the context of environmental change.


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