Books by Ali Mohammad Rezaie
Extreme Hydroclimatic Events and Multivariate Hazards in a Changing Environment Extreme Hydroclimatic Events and Multivariate Hazards in a Changing Environment, 2019
Storm surge induced by tropical cyclones (TCs) has become a global concern due to its catastrophi... more Storm surge induced by tropical cyclones (TCs) has become a global concern due to its catastrophic and expensive impacts on many coastal and tropical areas. It is also evident that global sea level rise (SLR) is expected to amplify coastal flood risk in the future. The exposure and vulnerability to flooding due to storm surge and SLR are particularly higher in the developing countries with densely populated low-lying coastal areas. Bangladesh is known for being one of the most natural disaster prone countries in the world, where storm surge and coastal flooding have lifethreatening impacts to millions of people living in its coastal region. The country lies within an active delta with hydromorphologically dynamic coastal lands and its livelihood is highly dependent on its natural resources. High subsidence rates, increase in upstream river flows, and human interventions are also exacerbating the existing inundation regimes and drainage situations in the coastal areas of Bangladesh. Finally, an ecosystembased approach has the potential to mitigate the twin threats of SLR and TC in a difficult biophysical and socioeconomic setting like that of coastal areas of Bangladesh.
Papers by Ali Mohammad Rezaie
In the context of climate change, the term resilience was popularized by the field of ecology to ... more In the context of climate change, the term resilience was popularized by the field of ecology to describe how ecological systems respond to stress and has since been adopted and significantly adapted by various fields, including psychology, policy, urban planning, and engineering. The exact meaning of resilience has blurred over time. In the context of coastal hazards, “resilience” is a holistic idea that relates long and short-term physical hazards with societal and biological impacts and mitigation measures. However, applying this idea to community-based mitigation planning remains challenging due to: (1) the diverse meanings, perspectives, and applications of the term, (2) the tendency of the term to defer to the status quo, thereby neglecting the voices of historically marginalized populations, and (3) the non-participatory and quantitative nature of resilience studies, often depending on cost-benefit analyses. In this paper, an interdisciplinary team of researchers and practitioners develops and proposes a new conceptual model for coastal resilience that offers to help address these aforementioned challenges by focusing on meaningful community engagement. The goal of this paper is to introduce the pitfalls of existing interpretations of coastal resilience, describe the team-based approach applied to develop this framework, and provide a theoretical path forward that addresses the current challenges in describing coastal resilience. This new framework (a) integrates relevant factors of coastal resilience including hazards, exposure, vulnerability, adaptation, mitigation and preparedness to qualitatively explore a community’s perception and state of resilience which (b) transcends existing models and (c) can be interpreted through a variety of perspectives. This model can be applied to document and assess locally differential understandings of coastal resilience and to engage communities in reflections of their individual and collective sense of resilience.
Bangladesh's vulnerability to storm surge and success in reducing their impacts on the coastal co... more Bangladesh's vulnerability to storm surge and success in reducing their impacts on the coastal communities are well-known. However, global warming is expected to increase both the frequency and the intensity of tropical cyclones. Also, the country still lacks in good quality data and information that can offer enhanced services to effectively design coastal defense systems and adapt to climate changes. This study developed a storm surge inundation model and database using the available tropical cyclones' database and simulated inundation for the past 31 cyclones in the Bay of Bengal, near the coastal regions of Bangladesh. The model uses a suite of Delft3D hydrodynamic and Delft Dashboard cyclone models. The model was calibrated and validated for two major cyclones, namely Sidr and Aila, using the available data for different bed roughness, track sources, and wind drag coefficient conditions. The results suggested that spatially varying bed roughness and wind varying drag conditions provide a more reliable prediction of inundation over the coast. The results also show that historical track data from Indian Meteorological Department optimize the model performances. The inundation database indicates that depending on the intensity and location, tropical cyclones can cause the maximum inundation of 1-5 m in the coastal lands of Bangladesh. More than 70% of the storms lead to the maximum inundation of more than 2 m, and about 25 and 7% of the storms can cause the maximum inundation of more than 3 and 4 m, respectively. The study also discusses the potential applications and shares insights on the implications of the inundation database that can offer improved information for enhanced climate services in Bangladesh. The database can be advanced with information about sectoral loss and damage as well as citizen science that will not only provide necessary information to design coastal protection structures and emergency measurements but also contribute to build long-term climate adaptation plans in the data-scarce region.
Natural Hazards Review, 2021
Along the North Atlantic coasts of the United States, sea levels are rising at higher rates than ... more Along the North Atlantic coasts of the United States, sea levels are rising at higher rates than the global average. Additionally, sea level rise (SLR) can cause reduction and redistribution of wetlands across the low-lying coastal landscape. This study applied a coupled storm surge and waves model to the Chesapeake Bay regions that are prone to SLR. Two historical storms of low and high wind intensity were simulated for current and potential future sea-level and land cover conditions. The future scenarios incorporated projections of local SLR and land use due to potential reduction and changes in coastal wetlands. Simulated flood depths were used in depth–damage functions to estimate prospective property damages, and were combined with population density information to estimate potential number of people at risk. The results showed that, depending on storm intensity, the total flooded area can increase from the baseline by 1.3–2.3 times in the minimum SLR scenario, and by 2.1–4.7 times in the maximum SLR scenario. The maximum SLR was estimated to cause approximately $5.8 billion to $8.6 billion in additional damages and potentially to affect 1–1.2 million people more than the number affected in current conditions. Results also suggest that the low-intensity storm was projected to have greater impacts in the future than the high-intensity storm today, indicating that even relatively weak storms may cause considerable damage to coastal communities in a future with SLR. Finally, flooding, property damage, and the number of people affected in the future scenarios were exacerbated by wetlands reduction and change—in other words, the protective services currently provided by natural lands in coastal areas can be diminished in the future with SLR.
PlosONE, 2020
Storm surge and sea level rise (SLR) are affecting coastal communities, properties, and ecosystem... more Storm surge and sea level rise (SLR) are affecting coastal communities, properties, and ecosystems. While coastal ecosystems, such as wetlands and marshes, have the capacity to reduce the impacts of storm surge and coastal flooding, the increasing rate of SLR can induce the transformation and migration of these natural habitats. In this study, we combined coastal storm surge modeling and economic analysis to evaluate the role of natural habitats in coastal flood protection. We focused on a selected cross-section of three coastal counties in New Jersey adjacent to the Jacques Cousteau National Estuarine Research Reserve (JCNERR) that is protected by wetlands and marshes. The coupled coastal hydro-dynamic and wave models, ADCIRC+SWAN, were applied to simulate flooding from historical and synthetic storms in the Mid-Atlantic US for current and future SLR scenarios. The Sea Level Affecting Marshes Model (SLAMM) was used to project the potential migration and habitat transformation in coastal marshes due to SLR in the year 2050. Furthermore, a counterfactual land cover approach, in which marshes are converted to open water in the model, was implemented for each storm scenario in the present and the future to estimate the amount of flooding that is avoided due to the presence of natural habitats and the subsequent reduction in residential property damage. The results indicate that this salt marshes can reduce up to 14% of both the flood depth and property damage during relatively low intensity storm events, demonstrating the efficacy of natural flood protection for recurrent storm events. Monetarily, this translates to the avoidance of up to $13.1 and $32.1 million in residential property damage in the selected coastal counties during the '50-year storm' simulation and hurricane Sandy under current sea level conditions, and in the year '2050 SLR scenario', respectively. This research suggests that protecting and preserving natural habitats can contribute to enhance coastal resilience.
The project team is acknowledged for its contributions and thoughtful input throughout the projec... more The project team is acknowledged for its contributions and thoughtful input throughout the project, and in particular, during the development of this report. We kindly acknowledge the contributions of Eric Messick, Lisa Auermuller, Mike De Luca, and Celso Ferreira. Each of you made this project possible through analytic efforts, expert review, local knowledge, guidance, and meeting space. We would like to thank the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing high performance computing resources that have contributed to the research results reported within this paper. We would like to give special thanks to our reviewers: Pete Wiley, Rick Lathrop, and Ty Wamsley. Finally, we thank all of our colleagues working throughout the Jacques Cousteau NERR for the benefit of coastal communities and habitats.
The recurrent flood risks on coastal areas in the United States due to storm surge are likely to ... more The recurrent flood risks on coastal areas in the United States due to storm surge are likely to increase with warmer climate, frequent storms, and increasing coastal population. In addition, the increasing rate of sea level rise (SLR) is expected to cause submergence of wetlands and marshes across the coastal landscape. Before decision makers can develop effective floodplain management and climate adaptation plans, they need reliable scientific information about the extent of flooding and estimate of future damage due to storm surge, sea level rise and marsh migration. In this study, coastal flood vulnerability in the Chesapeake Bay regions is investigated by using a coupled storm surge and waves model (ADCIRC+SWAN) for low and high intensity historical storms. Regional rate of SLR are combined with respective marsh migration projections in the modeling approach to estimate the future change in flooding, in addition to the existing inundation. To estimate flood damage, modeling res...
The Ganges-Brahmaputra-Meghna (GBM) delta is one of the most dynamic tide dominated delta in the ... more The Ganges-Brahmaputra-Meghna (GBM) delta is one of the most dynamic tide dominated delta in the world. The flow generated in the upper catchment of the GBM basins is passing through the estuarine systems of the GBM delta. The particular feature of these estuarine systems is characterized by extreme flow concentration in one single estuary, the Lower Meghna Estuary. Due to highly dynamic nature and a huge flow volume, it is difficult to measure the discharge in the Lower Meghna estuary. Till now, there is no measuring station and no reliable estimate of total flow volume which is passing through the Lower Meghna estuary. In this study, a 1D dynamic model (HEC RAS unsteady) is applied to compute the discharge in the Lower Meghna estuary. In the schematized model network, all the major rivers of the delta are included that contribute flow to the Lower Meghna estuary. The model is validated using measured water level available at the Lower Meghna estuary. The validated model is used to...
Climate Change Solutions
Bangladesh is regarded as one of the most climate-vulnerable regions in South Asia due to its uni... more Bangladesh is regarded as one of the most climate-vulnerable regions in South Asia due to its unique geographical location and socio-economic conditions. To face these challenges, nature-based solutions (NbS) can address climate change adaptation, protection and management of natural ecosystems, and biodiversity conservation. However, effective design, implementation, and upscaling of NbS requires support from national policies and plans. This study reviews relevant Bangladeshi national policies from the past three decades to investigate NbS as as a potential framework to address climate change and societal challenges in the country.
Journal of Science Policy and Governance , 2021
This study reviews relevant Bangladeshi national policies from the past three decades to investig... more This study reviews relevant Bangladeshi national policies from the past three decades to investigate NbS as a potential framework to address climate change and societal challenges in the country. We systematically analyzed twenty policy documents across three sectors: national development; disaster management and climate change; and environment and forest. Our study found growing emphasis on preservation, protection, and management of natural ecosystems in the national policies. However, our analysis showed that among the twenty policies, nineteen of them have no direct mention of NbS terminology. Instead, the policies include various strategies and terminologies that fall under the NbS umbrella, such as ecosystem-based adaptation, ecosystem services, and green and eco-building. However, these policies are still widely missing specific implementation guidelines, robust financial support, and institutional mechanisms for monitoring and evaluating NbS initiatives in Bangladesh. We recommend several policy actions to facilitate effective and inclusive NbS interventions in Bangladesh: enhance inter-ministry cooperation; develop national funding support; develop a national promotional campaign; pursue evidence-based research and capacity-building activities; and involve youth, marginalized people, and women. These actions can optimize the benefits of NbS to enhance the country’s resilience against climate change and foster sustainable development.
Journal of Marine Science and Engineering, 2018
The increasing rate of sea level rise (SLR) poses a major threat to coastal lands and natural res... more The increasing rate of sea level rise (SLR) poses a major threat to coastal lands and natural resources, especially affecting natural preserves and protected areas along the coast. These impacts are likely to exacerbate when combined with storm surges. It is also expected that SLR will cause spatial reduction and migration of coastal wetland and marsh ecosystems, which are common in the natural preserves. This study evaluates the potential impacts of SLR and marsh migration on the hydrodynamics and waves conditions inside natural protected areas during storm surge. The study focused on four protected areas located in different areas of the Chesapeake Bay representing different hydrodynamic regimes. Historical and synthetic storms are simulated using a coupled storm surge (ADCIRC) and wave (SWAN) model for the Bay region for current condition and future scenarios. The future scenarios include different rates of local SLR projections (0.48 m, 0.97 m, 1.68 m, and 2.31 m) and potential land use changes due to SLR driven marsh migration, which is discretized in the selected preserve areas in a coarse scale. The results showed a linear increase of maximum water depth with respect to SLR inside the protected areas. However, the inundation extent, the maximum wave heights, and the current velocities inside the coastal protected areas showed a non-linear relationship with SLR, indicating that the combined impacts of storm surge, SLR, and marsh migration depend on multiple factors such as storm track, intensity, local topography, and locations of coastal protected areas. Furthermore, the impacts of SLR were significantly greater after a 1 m threshold of rise, suggesting the presence of a critical limit for conservation strategies.
The Ganges-Brahmaputra-Meghna (GBM) delta is one of the most dynamic tide dominated delta in the ... more The Ganges-Brahmaputra-Meghna (GBM) delta is one of the most dynamic tide dominated delta in the world. The flow generated in the upper catchment of the GBM basins is passing through the estuarine systems of the GBM delta. The particular feature of these estuarine systems is characterized by extreme flow concentration in one single estuary, the Lower Meghna Estuary. Due to highly dynamic nature and a huge flow volume, it is difficult to measure the discharge in the Lower Meghna estuary. Till now, there is no measuring station and no reliable estimate of total flow volume which is passing through the Lower Meghna estuary. In this study, a 1D dynamic model (HEC RAS unsteady) is applied to compute the discharge in the Lower Meghna estuary. In the schematized model network, all the major rivers of the delta are included that contribute flow to the Lower Meghna estuary. The model is validated using measured water level available at the Lower Meghna estuary. The validated model is used to generate the temporal variation of discharge and the flow volume passing through the Lower Meghna estuary for different flooding scenario.
Perennial water-logging due to the excessive riverbed sedimentation has become the most menacing ... more Perennial water-logging due to the excessive riverbed sedimentation has become the most menacing crisis to the people of South-West region of Bangladesh. Peripheral embankments, polders, made in 1960 have turned out to be curse while it had been built to save the area from natural disasters and to augment agricultural yield. Later on Bangladesh Water Development Board (BWDB) implemented Khulna-Jessore Drainage Rehabilitation Project (KJDRP) to solve this long-standing water-logging problem during 1994–2002. After that, a popular indigenous concept Tidal River Management (TRM) was adopted which allows the tidal flow during high tide where in low tide, clear water erodes the river bed and increases the depth of the river as well as deposits sediment on the low lying land. As the tidal flow is allowed to enter in low lying areas or natural depression (locally known as beel) the land remains drowned during the application of TRM for 5–6 year. So locals can do nothing with their land that they suffer and starve. Due to institutional limitations, mismanagement as well as long appliance period the process of TRM operation the area still needs further attention to solve institutional conflicts and disputes among farmers, fishermen and land owners because of shrimp firming and loss of indigenous varieties of fish and crop biodiversity. The study explains that TRM could be the best solution to menacing water-logging if it is made socially acceptable.
The estuarine systems in the Ganges-Brahmaputra-Meghna (GBM) delta have been classified in-to thr... more The estuarine systems in the Ganges-Brahmaputra-Meghna (GBM) delta have been classified in-to three different sub systems such as Eastern estuary system (EES), Central estuary system (CES) and Western estuary system (WES) on the basis of their connectivity with the upstream rivers. The EES are dominated by the Lower Meghna systems, WES are dominated by the Ganges systems and CES are dominated by the Padma Systems. To study the fluvio-tidal regime in an average hydrological condition, the Delft 3D model has been applied to the estuarine systems of the GBM delta. The preliminary results of the numerical experiment for the year of 2000 (an average year) show that 73% of the yearly total flow is carried by EES, 15% by CES and 12% by WES. Estuaries in these systems are very rich in biodiversity and flow dynamics have a direct role in generating and sustaining these ecosystem resources. In the present study, preliminary relationships have been established between the hydrodynamic parameters and fisheries resources within WES and CES.
Bangladesh is a low lying riverine country formed by a deltaic plain at the confluence of the thr... more Bangladesh is a low lying riverine country formed by a deltaic plain at the confluence of the three mighty rivers Ganges, Brahmaputra, Meghna and their tributaries. Most of the flows of these major rivers are connected to the Bay of Bengal through Meghna Esuary. The Lower Meghna River with a very dynamic estuarine system conveys the maximum flow through the estuary to the Bay of Bengal during dry and wet season . The sediment load and flow volume in Lower Meghna is respectively the highest and the third highest (after Amazon and Congo) in the world (Ahmed S. 1998). Owing to this tremendous water volume and sediment load delivered by the rivers, the estuary is an area of an active land erosion-accretion and dynamic water circulation. The main physical processes in the estuary are mainly dependent on the estuarine morpho-dynamics that causes erosion and accretion in the scale of hundred sq. kilometers per year and cause several thousands of people to become landless and homeless every year (Biswajit et al., 2013) 2000-2013. Net accretion, net erosion and the erosion trend are derived from the image processed using ILWIS 3.7.2 and ArcMAP 10. It is obvious that the erosion rate was in decreasing order from the year 1973 to 1984, 3.4km2/yr to -8.4km2/yr. Analysis also showed that in the history of the last forty years erosion rate was higher from the year 2003 to 2005, -8.4km2/yr to 15.4km2/yr. Recent year analysis predicted that the deposition is higher than the erosion. However, further research should be focused on future channel shifting pattern, erosion rate and vulnerability of different locations as well as determining effective measures to decrease erosion severity and its consequences.
Conference Presentations by Ali Mohammad Rezaie
The Ganges-Brahmaputra-Meghna (GBM) Delta is the largest and one of the most significant tide dom... more The Ganges-Brahmaputra-Meghna (GBM) Delta is the largest and one of the most significant tide dominated deltas of the world that provides rich and diverse ecosystem . The availability and diversity of the ecosystem resources depend on the spatial and temporal variations of the fluvio-tidal parameters, mainly caused by the presence of the fresh water flow and the tidal flow within the estuarine systems, of the estuaries of this delta. Recent data shows a declining trend of the fresh water flow in the major parts of these estuarine systems, which most likely affect the tidal flow and the saline intrusion into the delta, thus affecting the saline regime as well as the estuarine ecosystems that mainly depend on the availability of the fresh water flow in the upstream river system.
Bangladesh is infamous for the negative impact that flooding has on the ability of Bangladesh to ... more Bangladesh is infamous for the negative impact that flooding has on the ability of Bangladesh to grow its economy. Coastal flooding due to cyclones and storm surges brings loss of life and property, and longer term impacts such as water-logging and salinity intrusion. During the 1960s in response to tremendous floods and natural hazards the government decided to implement a program of coastal embankments (otherwise known as polders), protecting agricultural land from unpredictable and destructive coastal flooding. Although the polders were not built to protect against storm surges, almost every year they play a significant protective role which raises the issue of assessing the adequacy of the polder heights under such devastating events. Such events are likely to become more devastating due to the increased frequency of cyclones due to climate change and a projected rise in sea level in the northern Bay of Bengal of 0.1-0.3 m by 2050 and 0.3-0.6 m by 2100.
To this end, this study aims to evaluate the adequacy of the polder heights under the impacts of storm surges under current and future climate scenarios. A Delft 3D hydrodynamic model coupled with the cyclone generating tool Delft Dashboard has been applied over the coastal region of Bangladesh to generate the inundation due to recent major cyclones Sidr (2007) and Aila (2009). Additionally the strength (wind speed and pressure drop) of cyclone Sidr has been used generate the extreme inundation scenario for storm surges. To incorporate the climate scenarios the sea boundary conditions have been derived for a modelled period of 1971 to 2099 using the SRES A1B emissions scenario from the UK Met Office general circulation model HadCM3 while upstream freshwater conditions were taken for the Q0, Q8 and Q16 scenarios from a hydrological model of the river basins (Whitehead et al, 2014). Out of these scenarios the model simulation is done for the most extreme hydrodynamic and hydrological conditions which were found for the year 2047 and 2088.
The model outputs show the maximum inundation height of 5.2m occurs near Shyamnagar in Satkhira district close to the Polder 15 during a storm possessing the strength of Sidr during the year 2088 and in 2047 an inundation of 5m height is predicted to occur due to the Sidr like cyclones at the Assass union near Satkhira. Since the maximum, minimum and average polder heights in the study region are 5.75m, 4.5m and 4.79m respectively (BWDB), this study reflects the necessity of both strengthening and raising of the polders at certain locations to protect lives and livelihoods of around 35 million coastal people (BBS, 2003).
Keywords: Polders, Storm surges, Sea level rise, Delft 3D, Climate Change
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Books by Ali Mohammad Rezaie
Papers by Ali Mohammad Rezaie
Conference Presentations by Ali Mohammad Rezaie
To this end, this study aims to evaluate the adequacy of the polder heights under the impacts of storm surges under current and future climate scenarios. A Delft 3D hydrodynamic model coupled with the cyclone generating tool Delft Dashboard has been applied over the coastal region of Bangladesh to generate the inundation due to recent major cyclones Sidr (2007) and Aila (2009). Additionally the strength (wind speed and pressure drop) of cyclone Sidr has been used generate the extreme inundation scenario for storm surges. To incorporate the climate scenarios the sea boundary conditions have been derived for a modelled period of 1971 to 2099 using the SRES A1B emissions scenario from the UK Met Office general circulation model HadCM3 while upstream freshwater conditions were taken for the Q0, Q8 and Q16 scenarios from a hydrological model of the river basins (Whitehead et al, 2014). Out of these scenarios the model simulation is done for the most extreme hydrodynamic and hydrological conditions which were found for the year 2047 and 2088.
The model outputs show the maximum inundation height of 5.2m occurs near Shyamnagar in Satkhira district close to the Polder 15 during a storm possessing the strength of Sidr during the year 2088 and in 2047 an inundation of 5m height is predicted to occur due to the Sidr like cyclones at the Assass union near Satkhira. Since the maximum, minimum and average polder heights in the study region are 5.75m, 4.5m and 4.79m respectively (BWDB), this study reflects the necessity of both strengthening and raising of the polders at certain locations to protect lives and livelihoods of around 35 million coastal people (BBS, 2003).
Keywords: Polders, Storm surges, Sea level rise, Delft 3D, Climate Change
To this end, this study aims to evaluate the adequacy of the polder heights under the impacts of storm surges under current and future climate scenarios. A Delft 3D hydrodynamic model coupled with the cyclone generating tool Delft Dashboard has been applied over the coastal region of Bangladesh to generate the inundation due to recent major cyclones Sidr (2007) and Aila (2009). Additionally the strength (wind speed and pressure drop) of cyclone Sidr has been used generate the extreme inundation scenario for storm surges. To incorporate the climate scenarios the sea boundary conditions have been derived for a modelled period of 1971 to 2099 using the SRES A1B emissions scenario from the UK Met Office general circulation model HadCM3 while upstream freshwater conditions were taken for the Q0, Q8 and Q16 scenarios from a hydrological model of the river basins (Whitehead et al, 2014). Out of these scenarios the model simulation is done for the most extreme hydrodynamic and hydrological conditions which were found for the year 2047 and 2088.
The model outputs show the maximum inundation height of 5.2m occurs near Shyamnagar in Satkhira district close to the Polder 15 during a storm possessing the strength of Sidr during the year 2088 and in 2047 an inundation of 5m height is predicted to occur due to the Sidr like cyclones at the Assass union near Satkhira. Since the maximum, minimum and average polder heights in the study region are 5.75m, 4.5m and 4.79m respectively (BWDB), this study reflects the necessity of both strengthening and raising of the polders at certain locations to protect lives and livelihoods of around 35 million coastal people (BBS, 2003).
Keywords: Polders, Storm surges, Sea level rise, Delft 3D, Climate Change