scholarly journals Temporary De-Poldering for a Long Term Flood/Sediment Management in the Southwestern Bangladesh

2021 ◽  
Author(s):  
Rocky Talchabhadel ◽  
Kenji Kawaike ◽  
Hajime Nakagawa
Keyword(s):  
River System ◽  
River Management ◽  
Technical Aspect ◽  
Sediment Management ◽  
Tidal River ◽  
Tidal Basin ◽  
Gradual Process ◽  
Novel Method ◽  
Drainage Congestion

Southwestern Bangladesh has been seriously affected by perennial waterlogging over the last few decades. It is primarily due to excessive riverbed siltation outside the polders after the construction of embankments along both sides of the tidal rivers. These embankments de-linked the huge natural floodplains and restricted a gradual process of natural deposition inside the polders. An introduction of the tidal basin concept by temporary de-poldering (embankment cut) at some designated locations has substantially solved the issues. The current chapter looks at the historical practice of flood/sediment management, the evolution of embankments and their de-poldering, inclusion of Tidal River Management (TRM) in long term flood/sediment management, and discusses a technical aspect of flood/sediment dynamics across the tidal river system. The process of restoring beneficial tidal flooding by cutting embankment at certain locations, commonly known as TRM, is not a novel method. The TRM has started from age-old practice and proves technically one of the effective methods of sustainable flood/sediment management in the tide-dominated river system. It is an example of building with nature, where little human interventions are needed, and a resilient measure for waterlogging, drainage-congestion, and river-siltation.

scholarly journals Sediment management in tidal river: A case study of East Beel Khuksia, Bangladesh

2018 ◽  
Vol 40 ◽  
pp. 02050 ◽  
Author(s):  
Rocky Talchabhadel ◽  
Hajime Nakagawa ◽  
Kenji Kawaike
Keyword(s):  
Large Scale ◽  
High Tide ◽  
Sediment Management ◽  
Tidal River ◽  
Tidal Basin ◽  
River Channels ◽  
Muddy Water ◽  
Tidal Basins ◽  
Controlled Flooding ◽  
Drainage Congestion

The widespread construction of coastal embankments limited the natural deposition on the floodplain and accelerated the silt deposition in river channels. It resulted in drainage congestion and large-scale waterlogging problem. The temporary de-poldering is one of the effective methods to solve this issue. During high tide, muddy water enters the selected tidal basin depositing a major portion of sediment and at low tide, relatively clearer water erodes the riverbed. This paper presents a twodimensional numerical model to simulate the mechanism of sediment transport and deposition during the process of controlled flooding. The model was applied to three different scenarios of the embankment cuts in East beel Khuksia, Bangladesh. The study recommends operating single embankment cut at a time if the tidal equilibrium is fulfilled by the opening size of that embankment cut. The developed model can be used to assess the land heightening in sediment-starved tidal basins and ultimately plan the rotation of tidal basins for sustainable sediment management.

scholarly journals Tidal River Management (TRM) and Tidal Basin Management (TBM): A case study on Bangladesh

2016 ◽  
Vol 7 ◽  
pp. 12009 ◽  
Author(s):  
Rocky Talchabhadel ◽  
Hajime Nakagawa ◽  
Kenji Kawaike
Keyword(s):  
River Management ◽  
Tidal River ◽  
Tidal Basin ◽  
Basin Management

scholarly journals Environmental and Institutional Impacts of Tidal River Management: A Case Study on Pakhimara Tidal Basin in Southwestern Bangladesh

2021 ◽  
Vol 36 (2) ◽  
pp. 295
Author(s):  
Md. Tareq Bin Salam ◽  
Atika Ibnat Amin ◽  
Tonami Afroz ◽  
Md. Mahedi Al Masud
Keyword(s):  
Crop Production ◽  
Agricultural Land ◽  
Household Survey ◽  
River Management ◽  
Tidal River ◽  
Tidal Basin ◽  
Before And After ◽  
The Government ◽  
Social Environmental ◽  
The 1960S

<p>People in southwestern Bangladesh have been facing the waterlogging problem and protesting on the impacts for the nature for a long time. In the 1960s, the government introduced polders, embankments and cross dams to overcome the destructive scenario. Due to the failure of government initiatives, the local people of the coastal area cut into the polder so that the sediment deposited within the beel known as Tidal River Management (TRM). Then, TRM was applied several times in different catchments. The study was carried out from December 2018 to November 2019 to assess the positive and negative environmental and institutional impacts of TRM on Pakhimara beel in Tala Upazila (Sub-district), Satkhira District, by using the Sustainability Index of Tidal River Management (SITRM) framework. Sustainability Indices of TRM were designed to provide information on social, environmental and institutional gains. The environmental and institutional impacts were assessed by conducting household survey and Key Informant Interviews (KIIs). Agricultural impacts on crop, poultry, fisheries and vegetation, were also analyzed by comparing GIS map and agricultural production data (before and after TRM). This study investigated that Pakhimara beel was freed from waterlogging during the with-TRM event by 3,200 ha and the reduction of waterlogging increased agricultural land by 1,500 ha in 2018, compared to 2014. This study argued that only 54% of marginal farmers received crop compensation whereas 85% of crop production decreased due to TRM. For promoting sustainable TRM in the studied area, compensation should be guaranteed for all impacted parties, especially marginal farmers and the creation of employment opportunities, and settlement should be ensured.</p>

Basic principles for assessing the safety of fish products from the ponds exposed to the influence of nuclear fuel cycle enterprises

2019 ◽  
pp. 106-114
Author(s):  
A. V. Trapeznikov ◽  
V. N. Trapeznikova ◽  
A. V. Korzhavin ◽  
V. N. Nikolkin ◽  
A. P. Plataev
Keyword(s):  
Fuel Cycle ◽  
Specific Activity ◽  
River System ◽  
Food Product ◽  
Human Consumption ◽  
Basic Principles ◽  
Fish Products ◽  
Permissible Levels ◽  
Irtysh River

Relevance. In connection with the development of nuclear energy, many aquatic ecosystems have been exposed to radioactive substances. Fish, as an element of biota, is capable to accumulate radionuclides. However, fish is a traditional food. The control of the technogenic radionuclides accumulation level in the ichthyofauna is an important link in ensuring human security.Intention. To analyze the long-term data on the content of long-lived technogenic radionuclides 90Sr and 137Cs in the ichthyofauna of the Ob-Irtysh river system for the period from 2004 to 2016 and Beloyarsky pond for the period from 1977 to 2018.Methodology. Fish as a food product was assessed according to two criteria: a) permissible levels of specific activity of radionuclides (SanPiN 2.3.2.1078-01); b) using the indicator of conformity B and the uncertainty of its definition В (GOST 32161-2013 and GOST 32163-2013).Results and Discussion. Fish of all species that live in the river Tetcha, is not suitable for food use according to the criteria of SanPiN 2.3.2.1078-01, GOST 32161-2013 and GOST 32163-2013. The fish of the Ob-Irtysh river system, the habitat of which is located outside the Tetcha, meets the requirements for fish products. In the period from 1977 to 1989 in the Beloyarsk pond the accumulations of technogenic radionuclides in fish in quantities exceeding sanitary and hygienic standards were possible. Currently, the fish of the Beloyarsky pond fully complies with the sanitary and hygienic requirements for the radiation factor and is safe for human consumption.Conclusion. In the ponds exposed to the atomic energy enterprises, it is necessary to continuously monitor the content of long-lived technogenic radionuclides in fish and assess their amount in accordance with the requirements of SanPiN 2.3.2.1078-01 and using the conformity indicator В and the uncertainty of its determination В. 

River Quality Models for Consent Setting in England and Wales

1989 ◽  
Vol 21 (8-9) ◽  
pp. 1015-1024 ◽  
Author(s):  
C. P. Crockett ◽  
R. W. Crabtree ◽  
I. D. Cluckie
Keyword(s):  
River System ◽  
Quality Model ◽  
Catchment Scale ◽  
Quality Models ◽  
England And Wales ◽  
Future Developments ◽  
Statistical Framework ◽  
River Quality ◽  
National Approach

In England and Wales the placing of effluent discharge consents within a statistical framework has led to the development of a new hybrid type of river quality model. Such catchment scale consent models have a stochastic component for the generation of model inputs and a deterministic component to route them through the river system. This paper reviews and compares the existing approaches for consent modelling used by various Water Authorities. A number of possible future developments are suggested including the potential need for a national approach to the review and setting of long term consents.

Thermogenesis of white adipocytes: a novel method allowing long-term microcalomrimetric investigations

1991 ◽  
Vol 23 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Hartfried Böttcher ◽  
Jürgen Nittinger ◽  
Sabine Engel ◽  
Peter Fürst
Keyword(s):  
White Adipocytes ◽  
Novel Method

scholarly journals Maturity, Indebtedness, and Default Risk

2012 ◽  
Vol 102 (6) ◽  
pp. 2674-2699 ◽  
Author(s):  
Satyajit Chatterjee ◽  
Burcu Eyigungor
Keyword(s):  
Standard Deviation ◽  
Default Risk ◽  
Sovereign Debt ◽  
External Debt ◽  
Equilibrium Price ◽  
Short Term ◽  
Price Function ◽  
Output Ratio ◽  
Novel Method

We advance quantitative-theoretic models of sovereign debt by proving the existence of a downward sloping equilibrium price function for long-term debt and implementing a novel method to accurately compute it. We show that incorporating long-term debt allows the model to match Argentina's average external debt-to-output ratio, average spread on external debt, the standard deviation of spreads, and simultaneously improve upon the model's ability to account for Argentina's other cyclical facts. We also investigated the welfare properties of maturity length and showed that if the possibility of self-fulfilling rollover crises is taken into account, long-term debt is superior to short-term debt. (JEL E23, E32, F34, O11, O19)

scholarly journals Technical note: Assessing gas equilibration systems for continuous <i>p</i>CO<sub>2</sub> measurements in inland waters

2016 ◽  
Vol 13 (13) ◽  
pp. 3915-3930 ◽  
Author(s):  
Tae Kyung Yoon ◽  
Hyojin Jin ◽  
Neung-Hwan Oh ◽  
Ji-Hyung Park
Keyword(s):  
River System ◽  
Fast Response ◽  
Technical Note ◽  
Spatial Variations ◽  
Detection Range ◽  
Measurement Systems ◽  
Co2 Sensor ◽  
Continuous Measurements ◽  
Membrane Biofouling

Abstract. High-frequency continuous measurements of the partial pressure of CO2 (pCO2) are crucial for constraining the spatiotemporal dynamics of CO2 emissions from inland water systems. However, direct measurements of pCO2 are scarce, and no systematic comparisons have been conducted on the suitability of the widely used measurement systems for continuous underway or long-term deployment in various field conditions. We compared spray- and marble-type equilibrators and a membrane-enclosed CO2 sensor to assess their suitability for continuous long-term or underway pCO2 measurements in an urbanized river system in Korea. Both equilibrators had a shorter response time compared with the membrane-enclosed sensor, and could capture large spatial variations of pCO2 during a transect study along a highly urbanized river reach. The membrane-enclosed sensor based on passive equilibration provided comparable underway measurements along the river sections where pCO2 varied within the sensor detection range. When deployed in a eutrophic river site, the membrane-enclosed sensor was able to detect large diel variations in pCO2. However, biofouling on the membrane could reduce the accuracy of the measurement during long deployments exceeding several days. The overall results suggest that the fast response of the equilibrator systems facilitates capturing large spatial variations in pCO2 during short underway measurements. However, the attendant technical challenges of these systems, such as clogging and desiccant maintenance, have to be addressed carefully to enable their long-term deployment. The membrane-enclosed sensor would be suitable as an alternative tool for long-term continuous measurements if membrane biofouling could be overcome by appropriate antifouling measures such as copper mesh coverings.

The physical sustainability of the coastal zone of the Ganges-Brahmaputra-Meghna delta under climatic and anthropogenic stresses

2021 ◽  
Author(s):  
Stephen Darby ◽  
Md. Munsur Rahman ◽  
Anisul Haque ◽  
Robert Nicholls ◽  
Frances Dunn
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Average Rate ◽  
River Management ◽  
Tidal River ◽  
Natural Conditions ◽  
Fluvial Sediment ◽  
Average Value ◽  
Delta Plain ◽  
The Ganges

&lt;p&gt;The Ganges-Brahmaputra-Meghna (GBM) delta is one of the world&amp;#8217;s largest deltas, and consists of large areas of low flat lands formed by the deposition of sediment from the GBM rivers. However, recent estimates have projected between 200~1000 mm of climate-driven sea-level rise by the end of the 21st century, at an average rate of ~6 mm/yr. Eustatic sea-level rise is further compounded by&amp;#160; subsidence of the delta, which in the coastal fringes varies from 0.2 to 7.5 mm/yr, at an average value of ~2.0 mm/yr. Therefore, the combined effect of sea-level rise and subsidence (termed relative sea-level rise, RSLR) is around 8.0 mm/yr. Such high values of RSLR raise the question of whether sediment deposition on the surface of the delta is sufficient to maintain the delta surface above sea level. Moreover, as the total fluvial sediment influx to the GBM delta system is known to be decreasing, the retained portion of fluvial sediment on the delta surface is also likely decreasing, reducing the potential to offset RSLR. Within this context, the potential of various interventions geared at promoting greater retention of sediment on the delta surface is explored using numerical experiments under different flow-sediment regime and anthropogenic interventions.&amp;#160; We find that for the existing, highly managed, conditions, the retained portion of fluvial sediment on the delta surface varies between 22% and 50% during average (when about 20% of the total floodplain in the country is inundated) and extreme (&gt; 60% of the total floodplain in the country is inundated) flood years, respectively. However, the degree to which sediment has the potential to be deposited on the delta surface increases by up to 10% when existing anthropogenic interventions such as polders that act as barriers to delta-plain sedimentation are removed. While dismantling existing interventions is not a politically realistic proposition, more quasi-natural conditions can be reestablished through local- sediment management using tidal river management, cross dams, dredging, bandal-like structures and/or combinations of the above measures.&lt;/p&gt;

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