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2020 | Book

Water, Flood Management and Water Security Under a Changing Climate

Proceedings from the 7th International Conference on Water and Flood Management

Editors: Prof. Anisul Haque, Assist. Prof. Ahmed Ishtiaque Amin Chowdhury

Publisher: Springer International Publishing


About this book

This book presents selected papers from the 7th International Conference on Water and Flood Management,with a special focus on Water Security under Climate Change, held in Dhaka, Bangladesh in March 2019. The biennial conference is organized by Institute of Water and Flood Management of Bangladesh University of Engineering and Technology.

The recent decades have experienced more frequent natural calamities and it is believed that climate change is an important driving factor for such hazards. Each part of the hydrological cycle is affected by global climate change. Moreover, increasing population and economic activities are posing a bigger threat to water sources. To ensure sustainable livelihoods, safeguard ecosystem services, and enhance socio-economic development, water security needs to be investigated widely in a global and regional context.

Table of Contents

An Overview on Isotopes in Precipitation of Bangladesh
The monthly weighted mean stable isotopic composition of rainfall in eight GNIP (Global Network of Isotopes in Precipitation) stations of Bangladesh vary in a short range i.e. δ18O = −6.998‰ to −5.58‰. The weighted δp value shows the order as HT > XB > SR > CN > DN > KH > BN > BS although modification of trend occurs when considered differently for monsoon and non-monsoon periods. Pre or post-monsoonal rain shows relatively enriched signature compared to the monsoon period. The local meteoric water lines (LMWLs) are much similar to Craig’s GMWL (Global Meteoric Water Line) except DN. The way of the effects from meteorological control vary according to seasons and locations. The spatiotemporal distribution of humidity accounts for ≈34% of isotopic variation. Temperature effect is most prominent in CN (41%, non-monsoon) and BS (19%, monsoon). Around 50% dependency on precipitation amount has been observed in coastal stations and DN during January to May, while monsoon precipitation is mostly characterized by reduced amount effect and “anti-amount effect”. Moreover, wide range of d-excess during non-monsoon precipitation bears the evidence of mixture of vapour from different sources and recycling events. However, monsoonal vapour source is rather consistent since d-excess value varies within a little margin.
Abdul Hadi Al Nafi Khan, Md. Abdul Quaiyum Bhuyian, Md. Ariful Ahsan, Farhana Islam, Md. Masud Karim, Md. Moniruzzaman
Impact of Internal Road Network on Water-Logging Inside Polders
Water logging is the most acute problem inside the polders of the south-west coastal region of Bangladesh. Though polders were constructed in order to protect the region from tidal inundation, these polders are now believed to be responsible for creating water-logging issues. It is generally believed that polders cause skewed sedimentation in the rivers, which then results in rise in bed levels of the peripheral rivers when compared to land elevation inside the polders. This phenomenon slowed down the natural gravity drainage and as a result extensive water-logging was initiated. While trying to find the causes of water-logging inside polders, impacts of the internal drainage system was largely ignored. Unplanned road construction inside polders hindered the natural drainage route which resulted in delayed and obstructed drainage. This research aims to study the impacts of road network and the dredging of peripheral river on water-logging. It is found that the appropriate drainage route along with river excavation can reduce the extent of water-logging in the area. The strategic placement of culverts plays an important role in determining maximum drainage rate. River dredging is only effective if the internal drainage system is improved.
Anika Tahsin, Sadmina Razzaque, Anisul Haque, Imran Hossain Newton, Abul Fazal M. Saleh, Rowshan Mamtaz, Md Ibnul Hasan, Md. Aminul Islam Khan, Flavia Simona Cosoveanu, Cecilia Borgia
Application of Machine Learning Algorithms for Local Level Flood Prediction: A Simplest Way of Likelihood Predictive Model of Monsoon River Flood
Floods account for substantial economic losses to a country by causing damage to agriculture, households, livelihoods, infrastructures and so on. Development of an accurate predictive model with locally observable factors for indicating early warning of a monsoon river flood could help to minimize losses. Such a model should be readily available and accessible by people and local agencies. In this study, six well-known machine learning algorithms and regression models, including Decision Tree, Naïve Bayes, Support Vector Machine (SVM), Artificial Neural Networks (ANN), Logistic Regression, and LASSO have been compared in terms of accuracy of flood prediction. Hydro-meteorological observed data of associated station of Manikganj in Bangladesh, have been fed into this model to learn how to predict monsoon flooding as instructed by the algorithm on which the respective model has been built upon. Each model has been trained with one set of water level time series data of associated station, but models for all the stations share the same set of spatio-temporal rainfall data, observed from a common station. ANN and SVM have a reputation for delivering good performance for many applications and LASSO was found to be appropriate according to a previous study. However, the results of this study indicate that the model based on Naïve Bayes is best suited for monsoon river flood prediction.
Arif Hasan Khan, Md. Abdulla Hel Kafi, Shah Mostafa Khaled, Mollah Md. Awlad Hossain
Developing a Composite Map of Vulnerability to Rainfall Extremes in Sri Lanka
Climate change is emerging as a global phenomenon and associated changes in climatic variability are likely to incur adverse consequences for Sri Lanka. Recent studies have shown changes in rainfall characteristics across the country. This study was undertaken to develop a composite map of extreme rainfall events in Sri Lanka for a thirty year period (1986–2015). Daily rainfall data for this period was obtained in 103 locations representing dry, wet and intermediate zones of the country. Six different indicative parameters of rainfall were developed to understand the changes in rainfall patterns over time. Subsequently, a composite map of extreme positive rainfall events for the thirty year period was developed to reflect the extreme conditions and the vulnerability to rainfall extremes using Inverse Distance Weighted (IDW) interpolation method in GIS. According to spatial variability of rainfall extremes, the wet zone of the country is experiencing increased incidence of wet extremes while the dry zone is experiencing increased incidence of dry extremes. According to the temporal variability of rainfall, most of the rainfall extremes have occurred during the period of 2006–2015. The developed maps under the study can be used for a wide range of applications such as agricultural planning and management, urban planning, analysis of climatic variability and extremes, environmental conservation, etc.
E. M. G. P. Hemachandra, N. D. K. Dayawansa, R. P. De Silva
Deciphering of Groundwater Recharge Potential Zones in Dhaka City, Bangladesh by RS and GIS Techniques
Groundwater resources in Dhaka city have reached critical limits due to over-exploitation. Over-pumping of groundwater accompanied by lack of replenishment via infiltration have resulted in substantial declination of water-levels over the last two decades. Replenishment of groundwater using artificial recharge is therefore essential for proper management of groundwater resources in the city. This study employed various remote sensing (RS) data and geographical information system (GIS) techniques to explore favorable artificial recharge sites for Dhaka city. Different influential thematic layers such as drainage density, lineament density, land use/land cover (LULC), slope, and lithology were integrated by weighted overlay method to form a new integrated layer. The integrated map reveals favorable artificial recharge zones in Dhaka city. The results of the study reveal that about 11% of the study area can be considered to possess excellent potential for artificial recharge, while 25%, 23%, 22%, and 19% of the study area demonstrate good, moderate, low, and poor potential, respectively. The outputs of the study could contribute to effective planning for future projects on artificial recharge in Dhaka city.
Imran Hossain Newton, Rashed Uz Zaman, Sara Nowreen, A. K. M. Saiful Islam, Sadmina Razzaque, G. M. Tarekul Islam
Impact of Climate Change on Water Balance in Lakes of Shchuchinsk-Borovsk Resort Zone of Kazakhstan
This paper computes water balance in the lakes of Shchuchinsk-Borovsk resort zone of Kazakhstan in the context of climate change. Long-term measured data on precipitation, air temperature and water level are analyzed. Methodology is developed to calculate evaporation from the surface of lakes during the warm and cold periods. Applying the newly developed methodology, evaporation and water balance for the three lakes in the study area is calculated. The results show that from the middle of twentieth century to the beginning of twenty-first century, inflow of water in the lakes of the study area decrease due to increased evaporation which is triggered by the increase of air temperature.
Marzhan Saduokasova
Assessment of Cyclone Aila Recovery Progress in Bangladesh: A Comparison Between Rice and Shrimp Farming Villages in Koyra
Land use planning is one of the basic principles of Build Back Better (BBB) and it shapes the risk reduction aspects. In the south-western region of Bangladesh, the conflict between shrimp and rice farming is the most critical obstacle to implement any land use plan. There are several studies which tried to compare shrimp and rice farming from the context of economy, livelihood, environment, and gender, to aid the land use planning process. This research aims to compare shrimp and rice farming from the context of disaster management. The study investigated the recovery process in Koyra Upazila after it was hit by cyclone Aila, and attempted to assess the recovery progress in the shrimp and rice dominated villages of Uttarbedkashi, Koyra. This study thereby brings another dimension i.e. “performance in post-disaster recovery” to consider when land use planning. It helps to understand whether to prioritize shrimp or rice cultivation in the area. To measure recovery progress, the research adopted a people’s perception generated synthetic data based method. FGDs were conducted with the local people to acquire time series data on the recovery progress. This perception-generated time series data helped to construct synthetic recovery curves which illustrate the progress of recovery. The results evidently show that resuming rice cultivation and switching shrimp to rice contributed to better community recovery.
Md. Shibly Sadik, Hajime Nakagawa, Md. Rezaur Rahman, Rajib Shaw, Kenji Kawaike, Gulsan Ara Parvin
Salinity Intrusion in Southwest Coastal Bangladesh: An Insight from Land Use Change
Coastal areas are considered as one of the important hubs of natural properties and people, where different forms of natural and man-made calamities alter the standard of resources. Salinity is an emerging issue in coastal areas for which land use changes appear to have impacts on livelihood in coastal areas of Bangladesh. Following the statement, this research was conducted to understand the relationship between salinity intrusion and land use changes in the perspective of different forms of land use pattern. This study was done in Bagerhat district through image classification from 1980 to 2018 and 27 Key Informant Interviews (KIIs) were done to understand the land use dynamic. This research stated that agricultural land was decreased around 303 km2 (7.97 km2/year) from 1980 to 2018 in Bagerhat district while aquaculture is increasing dramatically at the rate of 486 km2 (12.78 km2/year). Along with natural event induced salinity intrusion, people’s perception identified poor water management and upstream intervention as reasons behind the consequence of saline water intrusion induced land use change. This study will help the government, non-government authorities and local representatives to initiate necessary steps regarding sustainable land use management in coastal areas of Bangladesh.
Md. Hasibul Hasan, Mohammad Jobayer Hossain, Md. Arif Chowdhury, Maruf Billah
Groundwater Vulnerability Mapping to Salinity Intrusion Using GALDIT Method: A Case Study of the South-Western Coastal Region of Bangladesh
The south-western region of Bangladesh is part of the Ganges floodplain with numerous rivers and channels linked with the Bay of Bengal. The areas which are closer to the sea face heavy risk of being affected by the increase in salinity of groundwater. Assessment of groundwater vulnerability owing to salinity is crucial for effective groundwater management. To address this issue, GALDIT approach was taken in eight Upazilas (sub-districts) of three districts in South-Western Bangladesh, where 161 tube wells were considered for groundwater sampling. Parameters including salinity, as well as other parameters, were measured using a field test-kit. Besides, qualitative survey in relation to groundwater salinity was further verified with the kit. The field values obtained were modified according to relations derived from the laboratory test results. The GALDIT index was estimated by multiplying each of the six parameters weight by its rating, corresponding to its study area and summing the total value. Finally, a map was prepared, where about 17.0% of the study area was marked as high vulnerability risk, 62.4% is moderately vulnerability risk and 20.6% low vulnerability risk classes. The moderate vulnerability risk class is situated in the north, the east and central part of the area, which should be taken care of the contamination of groundwater.
Md. Rezaul Hasan, Md. Esraz-Ul Zannat, A. F. M. Afzal Hossain, S. M. Shah-Newaz, M. Monowar Hossain
On the Importance of Typhoon Size in Storm Surge Forecasting
Over the past several decades, operational forecasts of typhoon tracks have improved steadily. However, storm surge forecast skills have experienced rather modest improvements as it has been assumed to be primarily a function of maximum typhoon wind speed. In this study, numerical sensitivity experiments have been conducted for the semi-enclosed Tokyo Bay to investigate the existence of any connection between typhoon size and peak storm surge height. The radius of the maximum wind (Rmax) derived based on the 50-kt wind radius (R50) is used to define the size of a typhoon. The results show that peak storm surge height tends to increase as the size of typhoon becomes larger, which may also be supported by historical observations. Storm size plays a significant role in surge generation, particularly for very large typhoons making landfall in the upper bay. Analyses show that for a given hypothetical typhoon, the water level in the inner bay is increased by 1 m, changing Rmax from 13 to 89 km. The findings of this study will be beneficial for the storm surge modeling community as it gives insight into the role of typhoon size, which is essential to forecast peak surge height precisely.
Md. Rezuanul Islam, Hiroshi Takagi
Investigation of Flash Flood Producing Rainstorm in Northeast Bangladesh Using WRF Model
Flash flood events occur in the northeastern region of Bangladesh when convective cells assemble into a mesoscale convective system (MCS) over the steep edge of the plateau. On 17 and 18 April 2010, a flash flood, caused by rainstorm over Meghalaya plateau, inundated the low-lying regions (locally known as Haors) of northeastern Bangladesh. Prediction of this sudden incident is challenging when it happened on the high terrain of Meghalaya plateau and adjoining Bangladesh. This study investigated the synoptic flow patterns and numerical features of the flash flood-producing storm and its associated tropospheric conditions in northeast Bangladesh using the Weather Research and Forecasting (WRF) model. The study revealed that the 48-h simulated rainfall was about 152 mm for outer domain-1, 195 mm for inner domain-2 and 209 mm for the innermost domain-3 whereas actual rainfall was 223 mm as recorded by BMD. For instance, in convection resolving resolution at 9 km and 3 km domain, the model error was 12.3% and 5.9% respectively.
Mohan K. Das, A. K. M. Saiful Islam, Samarendra Karmakar, Jamal Uddin Khan, Khaled Mohammed, G. M. Tarekul Islam, Sujit Kumar Bala
Assessment of Rainwater Quality from Harvested Rainwater in the Coastal Region of Bangladesh
The remote coastal regions of Bangladesh have been identified as climate induced hazard-prone areas. The traditional drinking water sources (e.g. rivers, groundwater) in the coastal area have become contaminated due to saltwater intrusion from the rising sea levels and frequent natural disasters. The main objective of this study is to assess the quality of harvested rainwater (HRW). The rainwater quality assessment programme comprised of fifteen households with rainwater harvesting (RWH) systems, and an analysis was conducted on the physical, chemical and microbiological parameters. Additionally, a sanitary inspection survey was conducted for the RWH systems, which was used to compare the microbiological data obtained from HRW. The physical and chemical parameters of HRW were within the Bangladesh and World Health Organization (WHO) standards for drinking water quality, however the assessment for the microbial quality did not pass the requirements. All samples were contaminated by total coliforms (TC) and 60% samples were contaminated by faecal coliforms (FC). A positive correlation was found between FC and sanitary risk score (R2=0.6861). Additional treatment is recommended for the HRW due to frequent detection of microbial contamination and to achieve the new SDG target of ‘safely managed water’.
Al Imran Mostafa, Zaman Samina, Chakraborty Tapos Kumar, Ghosh Gopal Chandra
Assessment of Water Availability for Agriculture and Other Uses – Development of Indices for Deduru Oya River Basin in Sri Lanka
Water availability is a critical factor in deciding the performance of water use sectors. Spatial and temporal availability of water in a location is determined by a combination of parameters. The objective of this study was to assess the spatial and temporal availability of water in Deduru Oya river basin in Sri Lanka by developing Water Availability Indices (WAI). In this study, the Divisional Secretariat Division (DS) (an administrative division) was considered as the basic spatial unit for data collection and mapping. Spatial data such as rainfall, drainage density, surface water resources, agro well density, pipe borne water coverage, water quality, land use (paddy) and population density were considered as the parameters that affect water availability. Analytical Hierarchical Process (AHP) was used in assigning weightages to each parameter. Individual DS was given a score between 0 and 20 scale for each parameter based on actual parameter values. Finally, these parameters were compiled into two WAIs which are based on general water availability (WAIg) and consumption related water availability (WAIc). Results revealed a considerable spatial variation of WAIs within this basin. Temporal variability in indices was also seen between two major cultivation seasons namely Yala and Maha, indicating impacts on water related activities in the basin.
D. L. K. Gunawardena, N. D. K. Dayawansa
Flash Flood Forecasting of Jadukata River Basin at Laurergarh, Sunamganj from Real Time Satellite Precipitation Product by Using HEC-HMS
Over the last few decades, the north-eastern zone of Bangladesh has been subjected to recurrent flash floods. Jadukata is a trans-boundary river that contributes to exacerbating flash floods in Sunamganj district of Bangladesh. Since hydrologic modeling is a basic requirement of flash flood forecasting, in this study, a hydrologic model of Jadukata river basin with drainage area of 2480 km2 was generated using HEC-HMS 3.5.0. The terrain pre-processing was performed by HEC-Geo HMS using Laurergargh as the outlet of the basin. Precipitation data used here was a satellite product and was collected from CHRS data portal. Following necessary calibration and validation, the model was checked if it can successfully determine the flash flood of March 2017. Observed precipitation data was collected from CHRS Data portal for 26 March to 10 April. The model successfully showed that there was a flash flood during that time. Along with flash flood forecasting, this hydrological model can be utilized for further study of climate change, flood inundation mapping, morphological studies, tracing effects of changes in land-use etc.
Nusrat Khan, Md. Mostafa Ali
Awareness and Attitudes of Sri Lankans About the Value of Potable Water and Water Security
Water is a vital resource for human beings. However, it is recognised that the general Sri Lankan public is not sufficiently aware of water security issues including the importance of safe drinking water and the cost involved in producing potable water from raw water sources. A questionnaire survey was conducted among 100 households in Kegalle District to understand citizens’ attitude and practices regarding water use. Results found that 34% obtain drinking water from National Water Supply and Drainage Board (NWS&DB), 52% from wells, 14% from community-based organizations (CBOs) and 4% from nearby rivers. For the NWS&DB consumers, 72% are charged between Rs.100 and 1000. When it comes to domestic water use, 100% used potable water for bathing, 89% used it for washing, 61% watered the gardens with it and 11% bathed their pets with it. 97% of the people who get water from rivers, streams and wells have not subjected it to any laboratory testing, leading to consumption of potentially unsafe water. Around 55% were found to not store water for emergency and crisis situations. Majority of the respondents were found to exhibit practices and habits which lead to wastage of potable water. The media has also been relatively unsuccessful in improving awareness on water issues among the citizens. Overall, the awareness and attitudes of public about issues pertaining to water security were found to be highly dissatisfactory. In the context of rapid development and climate change contexts, it is essential that sustainable water conservation practices are promoted and fostered among the population.
Pavithra Abhayawardana
Distribution, Access and Gendered Roles of Common Property Water Resources in Bhotechaur, Nepal
Water is an essential requirement for human sustenance on earth; its uneven distribution creates disputes with respect to access and consumption. These may be further intensified by the physical and socio-economic conditions of the area. This study has intensely observed distribution and access induced issues amongst the people living in the mountains of Nepal, who rely on springs. The study has further examined the issues from a gendered perspective, within the socio-economic context of Bhotechaur area in Nepal. The research methodology adopted include key person interviews, time line surveys, resource mapping and time use survey. The gender based contribution to the System of National Account (SNA) and the Non System of National Account (Non-SNA) were analyzed. Apart from the temporal depletion of Common Property Resources (spring water), water quantity in the area is not much of an issue. It can be apparently seen that, disparity exists between upper and lower belt areas in terms of access. The victims of these circumstances are usually women and people belonging to the lower caste living in the lower belt of the study area. Though women contribute to SNA and Non-SNA work, their actual presence, despite their representation in the committee, in the Water User Committee is dormant due to male dominancy.
Poonam Pandey, Mafruha Akter, M. M. G. S. Dilini, K. Deepika Laxme, Carolin Arul, Robert Dongol, Sunil Tiwari
Gender Vulnerability Assessment due to Flood in Northern Part of Bangladesh (A Case Study on 2017 Flood)
Bangladesh is a tropical delta-shaped country with complex geo-physical characteristics and many rivers which make flood the most common natural disaster in the country. This paper assesses flood induced vulnerabilities faced by gender in the 2017 flood, one of the most devastating floods in recent years. Gender here refers the most vulnerable groups of people including women, children, adolescent girls, elderly, disabled and other disadvantaged people. Two districts from north-west, Kurigram and Nilphamari and one district from north-east, Netrokona were selected as study area. Primary data were collected using Participatory Rural Appraisal (PRA) tools; 12 Focus Group Discussions (FGDs) and a number of Key Informant Interviews (KIIs) were accomplished focusing on affected gender. Flood affects daily life, damages infrastructure, valuable assets, crops and crop lands, but is particularly devastating for gender groups. . Gender groups need to fight for food, drinking water, safe shelter and sanitation more than other affected people. The Capacities and Vulnerabilities (CVA) framework has been used to assess the vulnerabilities faced by gender in the event of a disaster. The ability of a society to cope with and recover from disasters depends largely on the social, economic and cultural capacities, which vary among different groups of people. This paper concluded with few suggestions to develop gender focused disaster risk reduction, planning and management.
Rabeya Sultana Leya, Debanjali Saha, Sujit Kumar Bala, Hamidul Huq
Groundwater Fluctuation in Response to Annual Rainfall in North-West Region of Bangladesh
Bangladesh is dependent upon groundwater to satisfy the enormous demand for domestic and agricultural water supplies. As reliable surface water resources have reduced significantly and the demand for water continues to rise there is an increase in groundwater reliance. In order to ensure future sustainability of groundwater supplies it is essential to make better utilization of such an important resource. A simplistic statistical approach (i.e., correlation) is done with the assumption that a strong relationship exists between these two variables particularly in case of a shallow unconfined aquifers. However, only 35% of the groundwater monitoring wells show high positive correlation with the corresponding rainfall observations. Poor statistics are found in cases where natural recharge condition might be absent due to the strong influence of irrigation withdrawal of GW or the closer proximity of the influent river(s) or the unfavorable impermeable topsoil condition. Some evidence shows that groundwater level is discharging to surface water level during the dry season while reversing behavior is observed during the wet season. Additionally, the study compares the GW level position during the dry (April–May) and wet (July–October) seasons for 1993–2017. Increasing dependency on groundwater over surface water shows a significant drop in groundwater position, especially during the dry season.
Rashed Uz Zzaman, Sara Nowreen, Imran Hossain Newton
Analysis on Flow and Water Balance Parameters of Teesta River Basin due to Climate Change and Upstream Intervention
Teesta, one of the prominent trans-boundary rivers of Bangladesh, possessed significant annual runoff during pre-barrage period (1967–1990) ranging between 3674 cusecs to 139 cusecs during high flood season (HFS) to mean monthly minimum flow (MMN). But the availability of water has significantly reduced due to a number of developments upstream in India, making dry season scarcity of water in Bangladesh a vulnerable issue. Also, flow in this river varies greatly due to the high variation in the intensity of rainfall, an issue which is expected to be worsen as a result of climate change. To understand the impacts of climate change on the river basin, this study employs a semi-distributed hydrological model of the Teesta river basin, developed using the Soil Water Assessment Tool (SWAT). The whole study area including India and Bangladesh is divided into 83 sub-basins for addressing the impact of land use and soil type pattern better. The developed hydrologic model has been calibrated by using SWAT-CUP for 2001 to 2007 and validated for 2008 to 2016 using the available stream flow at a location named Dalia, upstream of Teesta barrage within Bangladesh. The validated hydrologic model has been used to evaluate the change of flow and water balance parameters for the 2020s, 2050s, and 2080s using RCP 2.6 and 8.5 scenarios for two specific selected model named as MIROC-ESM-CHEM and HADGEM2-ES. Comparative analysis of future flow scenarios at Dalia shows that the change in discharge was 187% for the model MIROC-ESM-CHEM for RCP 8.5 depicting the maximum increase. On the other hand, the least percentage change in discharge was found to be 4.83% around 2020s for model HADGEM2-ES of RCP 2.6. Overall analysis on flow depicted increased availability of flow in future with drier dry seasons and wetter monsoon seasons. Conclusions have been drawn on the comparative analysis of water balance parameters.
Reazul Zannah, Khaled Mohammed, Afeefa Rahman, Anika Yunus
Selection of Appropriate Shifting of Tidal River Management
A perennial waterlogging situation has emerged in the polders of the southwest (SW) coastal part of Bangladesh over the last few decades. The earthen embankments delinked the huge natural floodplains and restricted the gradual process of natural deposition inside the polders. At the same time, they accelerated riverbed siltation outside the polders and even closed the exits of the sluiced gates. As a result, tidal rivers are unable to drain the nearby lands and polders anymore. Temporary de-poldering in order to allow tidal movement in a selected tidal basin, popularly known as tidal river management (TRM), is one of the most effective measures to address this issue. To solve the problem in the long-run, such operations are to be shifted effectively in different beels (large depressions). This study attempts to investigate the shifting of TRMs considering two virtual cases in a small stretch of Hari river: (1) from downstream (d/s) to upstream (u/s) and (2) from u/s to d/s. From the perspective of the indicator taken in the study as total sediment deposition, it is found that shifting the TRMs from d/s to u/s produced a slightly better result. The effective shifting of TRMs is thus necessary for sustainable operation of TRMs.
Rocky Talchabhadel, Hajime Nakagawa, Kenji Kawaike
Vulnerability Assessment of Bangladesh Coastline Using Gornitz Method
The coastal area of Bangladesh is frequently threatened by storm surges, coastal floods, shoreline erosion, and sea level rise etc. This study analyzed the coastal vulnerability using the widely adopted Gornitz method considering coastal characteristics and coastal forcing parameters of the Bangladesh coastline. Six parameters namely: Sea level rise, cyclone track density, significant wave height (SWH), rate of shoreline change, mean tidal range and coastal slope were analyzed from historical records. The quantification of those parameters was carried out using remotely sensed and model derived data. A 2-km strip along the shoreline was considered for representation of the coastline in Arc-GIS v10.3 environment. The parameters were ranked in a vulnerability scale 0–1 and classified in five categories i.e., very low, low, medium, high, and very high. Chittagong coast was found to be very high in vulnerability due to high tide range and cyclonic activity. Cox’s Bazar coast showed high vulnerability due to SWH. The Feni estuary and Passur river entrance was under moderate vulnerability class due to shore line erosion. The rate of SLR was 8–35 mm/year along the coastline. The study revealed that about 55 km of shoreline is very highly vulnerable and 90 km is highly vulnerable. The developed vulnerability map will certainly help in the coastal management of Bangladesh under climatic risk.
S M Samiul Islam, Ahad Hasan Tanim, Md. Reaz Akter Mullick
Government and NGO Provided Water Interventions and Its Effectiveness on Urban Poor: A Study in Gazipur Sadar Area
This study focuses on present water-based interventions provided by the Government and NGOs for establishing a feasible source to fulfill the long-term basic water needs of the urban water insecure in Gazipur Sadar areas (Baimail Nadir Parr, Koroitola and Machimpur). The data were collected through permutation of qualitative and quantitative approaches: 210 semi-structured household surveys, 4 FGDs, 6 KIIs, 9 IDIs, 3 Case Studies and field observation. It has been identified that both interventions (submersible, motorized water pumps with water tanks) have been effective to secure water for the urban poor as 80% respondents’ were satisfied with changes brought by the interventions; opined by around 72% of respondents that water collection has become less time consuming, as well as intervened source has made water more accessible and available, and confirmed no negative changes were brought on by the interventions; while 67% agreed that water-borne diseases have been reduced. However, people trust Government supplied water to be safer (92%), compared to that provided by NGOs (81.6%). Forthcoming studies focusing on water security issues might be able to use this study as a baseline for the Government and NGO interventions scenario in Gazipur Sadar and the perception of people concerning those interventions.
Saadmaan Jubayer Khan, Shamima Prodhan
Virtual Water Information for Water and Food Security in Peri-Urban Khulna: Present Status and Future Requirement
This research was conducted through analysing existing agricultural information services through ICT and traditional platforms and their usefulness in farming practices, and to explore farmers’ needs of a virtual platform (using ICT) for weather and climate information for sustainable agricultural in peri-urban Khulna. The result shows that local farmers cannot use available weather information for agricultural decision-making as it lacks location and time specific information service. Besides, majority of the farmers do not know about availability of the existing information services. In total 44% of farmers strongly agreed for an ICT based information service. Besides, 43% of farmers were agreed, and 10% of farmers were undecided for ICT based information service for agricultural decision-making. Very few farmers (only 3%) were disagreed for ICT based platform. For crop related decision-making, 27% of farmers were interested in rainfall forecast, 21% of farmers were interested in cyclone and storm surge forecast, 18% of farmers were interested in hailstorm forecast, 16% of farmers interested in temperature forecast, 14% of farmers were interested in fog forecast and 4% of farmers were interested in humidity forecast. Among 200 interviewed farmers, 34% of them told that one-week lead-time forecast is enough to prepare, while 32% of them claimed a minimum one-month led-time forecast is necessary for extra preparation according to the weather situation. This study shows that farmers preferred ICT tools are mobile apps, where 60% of them demanded information service with text, audio, and video format. This study concludes that at present situation an information service tool may have potential for sustainable agricultural practices by local farmers in the study area. In addition, to enhancing uptake and use of the existing weather information, farmers’ capacity building would bring the maximum output for informed agricultural decision-making.
Sadia Ashraf, Uthpal Kumar, Sharmistha Roy, Dilip Kumar Datta
Assessment of the Impact of Agriculture on Livelihood of the Farmers in a Polder: A Case Study in the South-West Coastal Area of Bangladesh
A comparative study was carried out to understand and evaluate the agriculture-based livelihoods in polder and non-polder areas in Khulna district, situated in the south-west coastal zone of Bangladesh. Three common Rabi crop (i.e., Boro rice, sesame, and mungbean), as well as Aman rice-growing farmers, were purposively selected for the study. Farmers’ Livelihood Security Index (FLSI) was used to establish linkages between crop production and livelihood. Several focus group discussions (FGDs) were conducted with selected farmers to assess different indicators for FLSI under five livelihood assets. Collection and scaling of indicator values were done using a multi-criteria analysis. The result of this index yielded the livelihood security level for each crop in percentages. The highest level of livelihood security was estimated for mungbean in both polder (64%) and non-polder areas (55%), whereas the lowest level of security was estimated for Boro rice (24%) in the polder area due to less availability of fresh water for irrigation, and sesame (41%) in the non-polder area due to seed damage during rainfall events late in the season. The livelihood security for Aman rice in the polder area (61%) was found to be much higher than that in the non-polder area (47%) due to the flood protection and water management provided by the polder.
Swarnali Mahmood, Abul Fazal M. Saleh
Climate Smart Agriculture and Intelligent Irrigation System for Management of Water Resources in Arid and Semi-Arid Regions – A Review
Most of the impacts of climate change on agriculture are expected to result from changes in the water cycle. Because of this, the design of climate-smart agriculture (CSA) strategies will need to be viewed through a ‘water lens’. Climate change will affect both rainfed and irrigated agriculture through increased crop evapotranspiration, changes in the amount of rainfall, and variations in river runoff and groundwater recharge. The impact of climate change on water use in agriculture must be considered within a wider context in which a number of issues are taken into account including: increased water demand from all sectors; the degradation of water quality and heightened competition for water at various levels (community, river basin and aquifer). Climate change adaptation in the water sector includes a range of response options related to policies, investments, water management, institutional and technical factors. These options will need to be applied at different scales: on fields and farms; in irrigation schemes in watersheds or aquifers in river basins and at the national level. Therefore, it can be concluded that addressing the problem of water scarcity in across the globe would require the adjustment of irrigation practices. The aim of this scientific paper is to shed light on the new irrigation systems, how they can be applied, and what their benefits are.
Zakaria Fouad Fawzy, Shaymaa I. Shedeed
Water, Flood Management and Water Security Under a Changing Climate
Prof. Anisul Haque
Assist. Prof. Ahmed Ishtiaque Amin Chowdhury
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