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Student Advising M. Shah Alam Khan |
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Name of the student : Md. Gulam Kibria Program
: M .Sc (WRD)
Title: STORM SURGE PROPAGATION AND CROP DAMAGE ASSESSMENT IN A COASTAL POLDER OF BANGLADESH
Background
and Bangladesh is one of the major storm surge hotspots globally. The geographical location and climatic condition of the country are the main reasons for cyclones and other natural disasters [1]. In the recent years, Cyclone 'Sidr' caused death of 3,406 people in 2007 while 2 million people lost income and employment [2]. Severe losses were also caused by Cyclone 'Aila' in 2009 [3] and other severe cyclones [4]. In the study area (Polder No. 32), damages to the embankments have resulted in a prolonged continuation of the immediate effects that the communities faced in the aftermath of the cyclone [5]. Damages due to storm surge depend on several factors such as depth of inundation, duration of flooding, timing of occurrence [6] while sea level rise and increase in storm frequency and intensity are expected to result from climate change [7]. Vulnerability of the study area to cyclones and storm surges may increase in the future due to climate change induced sea level rise [8]. The IPCC fifth assessment report projections indicate an increase of 0.26 - 0.55 meters in sea level by 2100 under a low emissions scenario and 0.52 - 0.98 meters under a high emissions scenario [9]. This rise in sea level will increase coastal flooding and salinity intrusion into the aquifers [10]. UNFCCC (2012) estimates that the mean sea level in Bangladesh has been rising at a rate of 5.05 mm to 7.4 mm/yr [11]. IWM and CEGIS (2007) assess that 13 out of 108 coastal polders will be overtopped due to a 62-cm sea level rise in 2080 under the A2 Scenario [12]. The potential inundation zone may increase to 25.7% of coastal territory which will translate in potential inundation for additional 52 million people [13]. Ten million people of Bangladesh will one day be forced to relocate because of climate change induced sea level rise accompanied by an increase in the frequency of storm surges [14]. Halder (2011) estimates that a surge height of 6.1 m, accounted for Aila in 2009, will be 6.9 m in 2030, 7.2 m in 2050, and 7.5 m in 2100 considering the effect of sea level rise [15]. Consequently, inundated area inside the polders would increase causing a decline in agricultural production. Therefore, it is important to understand the storm surge propagation process, and the processes such as breaching and overtopping by which damages occur in a poldered area. This understanding will help assess the future impact of storm surge and assess the damages more accurately for better planning and management.
Objectives with Specific
Aims and Possible Outcome: The overall aim of the study is to assess the impact of storm surge on agriculture in a coastal polder of Bangladesh. The specific objectives of the study are: (i) to understand the process of storm surge propagation in a coastal setting, and (ii) to assess possible crop damages due to polder breaching and overtopping under different climate change scenarios. Possible outcome of the research: A better understanding of agricultural damages in the selected coastal polder caused by storm surges under different climate change (sea level rise) scenarios. This will be useful to the researchers and policy makers in better estimation of damages, and designing interventions and adaptive measures appropriately.
Outline of Methodology: Scientific literature regarding storm surge propagation characteristics, land-use and cropping pattern, land value, sea level rise, damage due to storm surge, etc., will be reviewed, particularly in the context of the southwestern coastal area of Bangladesh, to develop an in-depth knowledge. Secondary data such as water level, discharge, land elevation, land use, etc., will be collected from relevant agencies and secondary sources. Considering Cyclone Aila as the base event, storm surge propagation under different climate change scenarios will be simulated. For this purpose, an open source software 'Delft3D' (v.3.28.50.01) will be used. The study area will be represented as a sub-model of a larger model that has been calibrated and validated at IWFM under the ESPA Delta project. Output data of the larger model (WL, Q) will be the input at the boundaries of the sub-model. The simulated hydrographs at selected locations will be used to assess different situations of polder overtopping and breaching. A series of inundation maps will be prepared from a Digital Elevation Model (DEM) (Approximately 30m resolution) of the area using GIS. Damages for different depth and duration will be assessed for different land use classes. Land use classes and land value will be assessed and verified using satellite images and PRA tools. For a better understanding and assessment of the damages, a crop calendar will be prepared from the information gathered from the local farmers. Damages will be assessed from storm surge simulations in two critical windows in the calendar when cyclones and storm surges are more frequent.
References: [1] Sharbari, A., Rahman, M.M., and Faisal, M.A. (2012). Reducing cyclone impacts in the coastal areas of Bangladesh: a case study of Kalapara upazila, Journal of Bangladesh Institute of Planners, 5(December):185-197. [2] GoB (2008). Cyclone Sidr in Bangladesh, Damages, loss and Needs Assessment for Disaster Recovery and Reconstruction, International Development Community, European Commission, Government of the People's Republic of Bangladesh. [3] UNDP (2010). Cyclone Aila: Joint Multi-Sector Assessment and Response Framework, The United Nations. [4] Agarwala, S., Ota, T., Ahmed, A.U., Smith, J., and Aalst, M. (2003). Development and Climate Change in Bangladesh: Focus on the Coastal Flooding and Sundarban, OECD, France. [5] Debnath, A. (2014). Impact of cyclone Aila on paddy cultivation in Gosaba island of the Indian Sundarban region, The Indian Journal of Spatial Science, 5:7-13. [6] Hoque, M.M., Khan, M.S.A., Islam, T., Salehin, M., Mondal, M.S., and Islam, AKM.S. (2013). Development of Flood Hazard and Risk Maps with Effect of Climate Change Scenario, Final Report, Component-1, Institutional Strengthening of Climate Change Study Cell at BUET for Knowledge Generation and Human Resource Development, IWFM, BUET. [7] Murdukhayeva, A., August, P., Bradley, M., LaBash, C., and Shaw, N. (2013). Assessment of inundation risk from sea level rise and storm surge in northeastern coastal national parks, Journal of Coastal Research, 29(6a):1-16. [8] World Bank (2010). Vulnerability of Bangladesh to cyclones in a changing climate potential damages and adaptation cost, Development Research Group, Environment and Energy team, Policy Research Working Paper 5280. [9] Centre for Climate and Energy Solutions (C2ES) (2014): IPCC AR5 Highlights. http://www.c2es.org/science-impacts/ipcc-summaries/fifth-assessment-report-working-group-1. [Accessed 21.06.2014] [10] NAPA (2009). Bangladesh Climate Change Strategy and Action Plan, Ministry of Environment and Forests, Government of the People's Republic of Bangladesh. [11] UNFCCC (2012). Second National Communication of Bangladesh to the United Nations Framework Convention on Climate Change, Ministry of Environment and Forests, Government of the People's Republic of Bangladesh. [12] IWM and CEGIS (2007). Investigating the Impact of Relative Sea Level Rise on Coastal Communities and their Livelihoods in Bangladesh, Department for Environment, Food and Rural Affairs, UK. [13] Dasgupta, S., Laplante, B., Murry, S., and Wheller, D. (2009). Climate change and future impacts of storm surge disasters in developing countries, Centre for Global Development, Washington DC. [14] Glantz, M. H., and Ye, Q. (2010). Usable Thoughts: Climate, Water and Weather in the 21st century, United Nations University Press, Tokyo, 145p. [15] Halder, P.K. (2011). Future Economic and Livelihood Impact of Storm Surge Disaster Under Climate Change Context in a Selected Polder, M.Sc. Thesis, IWFM, BUET, Dhaka.
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