scholarly journals A Multi-Data Geospatial Approach for Understanding Flood Risk in the Coastal Plains of Tamil Nadu, India

2021 ◽  
Author(s):  
Rasme Allat V ◽  
Leo George Sekar ◽  
Arun Prasad Kumar ◽  
Balasubramani Karuppusamy
Keyword(s):  
Flood Risk ◽  
Tamil Nadu ◽  
Flood Hazard ◽  
Secondary Data ◽  
Data Sources ◽  
Flood Hazards ◽  
Coastal Plains ◽  
Synthetic Aperture Radar Data ◽  
Flood Risks ◽  
Administrative Units

Abstract The coastal plains of Tamil Nadu (India) are highly vulnerable zone for coastal floods, the most common disaster, experienced every year. In the study, the coastal plain is delineated through a watershed approach with 5020 micro-administrative units covering an area of about 3,000 sq.km. A comprehensive flood risk assessment was carried out by preparation of hazards, vulnerability, and exposure layers using multiple data sources including from field surveys, satellite data and secondary data sources. The flood prone regions are delineated initially from Sentinel-1 Synthetic Aperture Radar data coupled with SRTM-DEM on a probability scale (0–1) and validated with the District Disaster Management Plans of 13 coastal districts. In addition, National Resources Conservation Service – Curve Number (NRCS-CN) method was adopted to estimate surface runoff potential for flood risks. The vulnerability and exposure of the population to the flood hazards was determined using census and household data based indicators. A focused group interview was conducted at 514 locations targeting deprived communities of all major settlements of the study area. The public perceptions were used to understand the flood risks and to validate the hazard and vulnerability layers. To estimate location-specific flood risks within the micro-administrative units, built-up areas with different categories were delineated and intersected with the flood hazard. The amalgamation of results shows that very high flood risk prevails in the northern parts of coastal Tamil Nadu, especially the stretch between Chennai and Cuddalore. In addition to provide a baseline datasets for the first time at micro-administrative units for entire coastal plains of Tamil Nadu, the study offers a pragmatic methodology for sustainable development measures in general and flood risk management in particular.

scholarly journals Revealing the socio-economic vulnerability and multi-hazard risks at micro-administrative units in the coastal plains of Tamil Nadu, India

2021 ◽  
Vol 12 (1) ◽  
pp. 605-630
Author(s):  
Balasubramani Karuppusamy ◽  
Sekar Leo George ◽  
Kanagarajan Anusuya ◽  
Ravichandran Venkatesh ◽  
Periasamy Thilagaraj ◽  
...  
Keyword(s):  
Tamil Nadu ◽  
Coastal Plains ◽  
Economic Vulnerability ◽  
Administrative Units

scholarly journals Taking the heterogeneity of citizens into account: flood risk communication in coastal cities – a case study of Bremen

2009 ◽  
Vol 9 (6) ◽  
pp. 1931-1940 ◽  
Author(s):  
T. Martens ◽  
H. Garrelts ◽  
H. Grunenberg ◽  
H. Lange
Keyword(s):  
Risk Communication ◽  
Flood Risk ◽  
Media Analysis ◽  
Specific Information ◽  
Flood Hazards ◽  
Meso Level ◽  
Flood Risks ◽  
Protective Actions ◽  
Distribution Of Resources

Abstract. The likely manifestations of climate change like flood hazards are prominent topics in public communication. This can be shown by media analysis and questionnaire data. However, in the case of flood risks an information gap remains resulting in misinformed citizens who probably will not perform the necessary protective actions when an emergency occurs. This paper examines more closely a newly developed approach to flood risk communication that takes the heterogeneity of citizens into account and aims to close this gap. The heterogeneity is analysed on the meso level regarding differences in residential situation as well as on the micro level with respect to risk perception and protective actions. Using the city of Bremen as a case study, empirical data from n=831 respondents were used to identify Action Types representing different states of readiness for protective actions in view of flood risks. These subpopulations can be provided with specific information to meet their heterogeneous needs for risk communication. A prototype of a computer-based information system is described that can produce and pass on such tailored information. However, such an approach to risk communication has to be complemented by meso level analysis which takes the social diversity of subpopulations into account. Social vulnerability is the crucial concept for understanding the distribution of resources and capacities among different social groups. We therefore recommend putting forums and organisations into place that can mediate between the state and its citizens.

scholarly journals Distribution of Flood Risk Area in Bodri Watershed of Kendal Regency

2021 ◽  
Vol 6 (2) ◽  
pp. 59-69
Author(s):  
Husna Fauzia ◽  
◽  
Eka Cahyaningsih ◽  
Hery Hariyanto ◽  
Satya Nugraha ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Modeling ◽  
Flood Risk ◽  
Flood Hazard ◽  
Risk Level ◽  
Flood Hazards ◽  
Risk Area ◽  
Flood Peak ◽  
Risk Levels ◽  
Central Java

Flooding is a catastrophic phenomenon that can occur due to various factors, such as uncontrolled landuse changes, climate change, and weather anomalies, and drainage infrastructure damage. The Bodri watershed in Kendal Regency is one of the watersheds in Central Java, which is categorized as critical based on Decree No.328/Menhut-II/2009. Some of the problems in the Bodri watershed include land use that is not suitable for its designation, flooding, erosion, and landslides. This study aims to conduct spatial modeling to create flood hazard maps and flood risk level maps in the Bodri watershed. The method used is hydrograph analysis, flood modeling, potential flood hazards, and flood risk levels. Analysis of the potential for flood hazards from the spatial modeling inundation map with the input of the flood peak return period of 2 years (Q2), 5 years (Q5), and 50 years (Q50). Vulnerability analysis based on land use maps of flood hazard areas. The distribution of flood-prone areas in the Bodri watershed is in Pidodo Kulon Village, Pidodo Wetan Village, and Bangunsari Village.

scholarly journals Assessment of Flood Hazard and Agriculture Damage Under Climate Change in the Bagmati River Basin of Nepal

2019 ◽  
Vol 8 (2) ◽  
pp. 55-69 ◽  
Author(s):  
Badri Bhakta Shrestha
Keyword(s):  
River Basin ◽  
Flood Risk ◽  
Damage Assessment ◽  
Growth Stage ◽  
Flood Hazard ◽  
Flood Damage ◽  
Flood Risk Management ◽  
Flood Inundation ◽  
Flood Hazards ◽  
Bagmati River

Assessment of flood hazard and damage is a prerequisite for flood risk management in the river basins. The mitigation plans for flood risk management are mostly evaluated in quantified terms as it is important in decision making process. Therefore, analysis of flood hazards and quantitative assessment of potential flood damage is very essential for mitigating and managing flood risk. This study focused on assessment of flood hazard and quantitative agricultural damage in the Bagmati River basin including Lal Bakaiya River basin of Nepal under climate change conditions. Flood hazards were simulated using Rainfall Runoff Inundation (RRI) model. MRI-AGCM3.2S precipitation outputs of present and future climate scenarios were used to simulate flood hazards, flood inundation depth, and duration. Flood damage was assessed in the agricultural sector, focusing on flood damage to rice crops. The flood damage assessment was conducted by defining flood damage to rice crops as a function of flood depth, duration, and growth stage of rice plants and using depth-duration-damage function curves for each growth stage of rice plants. The hazard simulation and damage assessment were conducted for 50- and 100-year return period cases. The results show that flood inundation area and agricultural damage area may increase in the future by 41.09 % and 39.05 % in the case of 50-year flood, while 44.98 % and 40.76 % in the case of 100-year flood. The sensitivity to changes in flood extent area and damage with the intensity of return period was also analyzed.

scholarly journals Assessing the susceptibility of schools to flood events in Iran

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Saleh Yousefi ◽  
Hamid Reza Pourghasemi ◽  
Sayed Naeim Emami ◽  
Omid Rahmati ◽  
Shahla Tavangar ◽  
...  
Keyword(s):  
Flood Risk ◽  
Flood Hazard ◽  
Rural Students ◽  
Flood Hazards ◽  
Analytic Hierarchy ◽  
Flood Susceptibility ◽  
Susceptibility Maps ◽  
High Flood ◽  
Analytic Hierarchy Process Method ◽  
Very High

Abstract Catastrophic floods cause deaths, injuries, and property damages in communities around the world. The losses can be worse among those who are more vulnerable to exposure and this can be enhanced by communities’ vulnerabilities. People in undeveloped and developing countries, like Iran, are more vulnerable and may be more exposed to flood hazards. In this study we investigate the vulnerabilities of 1622 schools to flood hazard in Chaharmahal and Bakhtiari Province, Iran. We used four machine learning models to produce flood susceptibility maps. The analytic hierarchy process method was enhanced with distance from schools to create a school-focused flood-risk map. The results indicate that 492 rural schools and 147 urban schools are in very high-risk locations. Furthermore, 54% of rural students and 8% of urban students study schools in locations of very high flood risk. The situation should be examined very closely and mitigating actions are urgently needed.

scholarly journals Environmental Inequalities in Flood Exposure: A Matter of Scale

2021 ◽  
Vol 3 ◽  
Author(s):  
Clémence Poussard ◽  
Benjamin Dewals ◽  
Pierre Archambeau ◽  
Jacques Teller
Keyword(s):  
Flood Risk ◽  
Flood Hazard ◽  
Economic Status ◽  
Flood Hazards ◽  
Socio Economic Status ◽  
Flood Exposure ◽  
Class 1 ◽  
Riverine Floods ◽  
Peripheral Areas ◽  
Hazard Level

Studies on inequalities in exposure to flood risk have explored whether population of a lower socio-economic status are more exposed to flood hazard. While evidence exist for coastal flooding, little is known on inequalities for riverine floods. This paper addresses two issues: (1) is the weakest population, in socio-economic terms, more exposed to flood hazard, considering different levels of exposure to hazard? (2) Is the exposure to flood risk homogeneous across the territory, considering different scales of analysis? An analysis of the exposure of inhabitants of Liège province to flood risk was conducted at different scales (province, districts, and municipalities), considering three levels of exposure to flood hazard (level 1- low hazard, level 3- high hazard), and five socio-economic classes (class 1-poorest, class 5-wealthiest households). Our analysis confirms that weaker populations (classes 2 and 3) are usually more exposed to flood hazards than the wealthiest (classes 4 and 5). Still it should be stressed that the most precarious households (class 1) are less exposed than low to medium-range ones (classes 2 and 3). Further on the relation between socio-economic status and exposure to flood hazard varies along the spatial scale considered. At the district level, it appears that classes 4 and 5 are most exposed to flood risk in some peripheral areas. In municipalities located around the center of the city, differences of exposure to risk are not significant.

scholarly journals Assessing tropical cyclone compound flood risk using hydrodynamic modelling: a case study in Haikou City, China

2021 ◽  
Author(s):  
Qing Liu ◽  
Hanqing Xu ◽  
Jun Wang
Keyword(s):  
Flood Risk ◽  
Flood Hazard ◽  
Copula Function ◽  
Coastal Flooding ◽  
Future Research ◽  
Flood Hazards ◽  
Storm Tide ◽  
Inundation Area ◽  
Joint Occurrence

Abstract. The co-occurrence of storm tide and rainstorm during tropical cyclones (TCs) can lead to compound flooding in low-lying coastal regions. The assessment of TC compound flood risk can provide vital insight for research on coastal flooding prevention. This study investigates TC compound flooding by constructing a storm surge model and overland flooding model using Delft3D Flexible Mesh (DFM), illustrating the serious consequences from the perspective of storm tide. Based on the probability distribution of storm tide, this study regards TC1415 as the 100-year event, TC6311 as the 50-year event, TC8616 as the 25-year event, TC8007 as the 10-year event, and TC7109 as the 5-year event. The results indicate that the coastal area is a major floodplain, primarily due to storm tide, with the inundation severity positively correlated with the height of the storm tide. For 100-year TC event, the inundation area with a depth above 1.0 m increases by approximately 2.5 times when compared with 5-year TC event. The comparison of single-driven flood (storm tide flooding and rainstorm inundation) and compound flood hazards shows that simply accumulating every single-driven flood hazard to define the compound flood hazard may cause underestimation. For future research on compound flooding, copula function can be adopted to investigate the joint occurrence of storm tide and rainstorm to reveal the severity of extreme TC flood hazards.

scholarly journals The Analysis of the Degree of Flood Risk in the Middle Bobr Valley

2018 ◽  
Vol 28 (2) ◽  
pp. 68-75
Author(s):  
Magda Hudak ◽  
Urszula Kołodziejczyk ◽  
Jakub Kostecki ◽  
Ireneusz Nowogoński ◽  
Marta Żebrowska
Keyword(s):  
River Basin ◽  
Flood Risk ◽  
Land Development ◽  
Anthropogenic Factors ◽  
Flood Hazards ◽  
Flood Risks ◽  
The Impact ◽  
The Town ◽  
Geographical Characteristics ◽  
Rainfall Level

Abstract This paper presents the impact of rainfall on the degree of flood risk in the basin of the middle Bobr River in western Poland. When the average rainfall level reaches 15 to 20 mm, this apparently calm river may dramatically change its character within just one week. The most important flood risks are flood waves in the headwaters. Because of the mountain character of the river basin, during intensive rainfall there is a huge surface runoff and the water level rises rapidly in the river. This phenomenon was observed in June 2017 in the town of Zagan (Lubuskie Voivodeship). It has been shown that the course and dynamics of hydrological processes occurring in the Bobr River basin depend on its physical and geographical characteristics and the influence of anthropogenic factors. The location is one of the main cause of numerous floods for Zagan, on the other hand changes in land development plays significant meaning in flood hazards. Continuous monitoring of the river is the basis for a comprehensive forecast of flood risks.

Urban Flood Risk Assessment and Development of Urban Flood Resilient Spatial Plan for Bhubaneswar

2021 ◽  
Vol 12 (2) ◽  
pp. 269-291
Author(s):  
Alisa Sahu ◽  
Tushar Bose ◽  
Dipak R. Samal
Keyword(s):  
Risk Assessment ◽  
Land Use ◽  
Land Use Planning ◽  
Flood Risk ◽  
Flood Hazard ◽  
Geographic Area ◽  
Spatial Modelling ◽  
Disaster Risk ◽  
Flood Hazards ◽  
Urban Flood

Urban flooding is growing as a serious development challenge for cities. Urbanization demands the conversion of pervious land to impervious land by pushing the transformation of water bodies, flood plains, wetlands and green spaces into built-up spaces. This affects the hydrological setting of the city’s geographic area. Bhubaneswar, one of the first planned cities of independent India, has expanded rapidly with an increase in the settlement land use cover from 41 km2 to 81 km2 in the last two decades. Non-consideration of disaster risk assessment in the land use plan has placed the city at high disaster risk. Hence, this article explores various avenues for making a flood resilient city through spatial planning. To understand the flood and its consequences, a flood hazard and vulnerability map was prepared by overlaying the existing social and infrastructure networks, and flood risk zones were generated through analytical spatial modelling in GIS. This accounts for the areas in which flood hazards are expected to occur, as well as the area whose socio-economic and infrastructure susceptibility to the disaster is more. The key outcome is to ensure urban development that can work concurrently with nature by integrating disaster risk reduction strategies into land use planning.

Place-Based Assessment of Intersection of Biophysical and Social Vulnerability to Flooding in Accra, Ghana

2020 ◽  
Vol 11 (1) ◽  
pp. 55-68
Author(s):  
Dacosta Aboagye ◽  
Elvis Attakora-Amaniampong ◽  
Ebenezer Owusu-Sekyere
Keyword(s):  
Flood Risk ◽  
Social Vulnerability ◽  
Flood Hazard ◽  
Vulnerability Index ◽  
Flood Hazards ◽  
Social Vulnerability Index ◽  
Community Members ◽  
Resilient Communities ◽  
Index Mapping ◽  
Hazards Of Place

The relationship between flood hazards and social vulnerability is firmly on the intellectual agenda of geographers in Ghana. In an attempt to theorize and empirically examine this relationship, scholars have commonly followed a one-sided methodological strand. In this article, a triple-helix approach that relies on the application of social vulnerability index; mapping potential flood hazard zones; and examining degree of coincidence between flood hazards and social vulnerability, is used. Situating the analysis within Hazards-of-Place Model of Vulnerability, the study identifies spatial disparities in biophysical and social vulnerability within the City. It emerged that communities in the Ashiedu Keteke sub-metro were the most vulnerable based on the hazards-of-place model. Significantly, while flood risk awareness was very high among community members, the perception of flood risk management was poor. The study argues that understanding place-based vulnerability is crucial in mitigating the effect of hazards and building resilient communities.

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