Impact Of Floods Research Articles

Flood hazards and housing prices: a spatial regression analysis for Hat Yai, Songkhla, Thailand

PurposeGlobal warming exacerbates sea level rise and extreme weather events that cause severe flooding, resulting in lost productivity and property damage. To reduce the impact of flooding, residents are avoiding purchasing homes in high-risk areas. There are numerous studies on the relationship between flood hazards and housing prices in developed countries, but few in developing countries. Therefore, this study aims to investigate the relationship between flood hazards and housing prices in Hat Yai, Songkhla, Thailand.Design/methodology/approachThis study uses spatial-lag, spatial error and spatial autoregressive lag and error (SARAR) models to analyze the effect of flood risk on property prices. The main analysis examines the degree of flood risk and housing rental prices from our survey of 380 residences. To test the robustness of the results, the authors examine a different data set of the same samples by using the official property valuation from the Ministry of Finance and the flood risk estimated by the Southern Natural Disaster Research Center.FindingsThe SARAR model was chosen for this study because of the occurrence of spatial dependence in both dependent variable and the error term. The authors find that flood risk has a negative impact on property prices in Hat Yai, which is consistent with both models.Originality/valueThis study is one of the first to use spatial econometrics to analyze the impact of flood risk on property prices in Thailand. The results of this study are valuable to policymakers for benefit assessment in cost–benefit analysis of flood risk avoidance or reduction strategies and to the insurance market for pricing flood risk insurance.

Qi no tu i baba ni qwali (living down by the river): Impacts of flooding and mining on ecosystems and livelihoods

A vast ocean rich with resources to maintain a sustainable livelihood surround Pacific Island Countries and Territories. In Fiji, coastal resources are a primary source of food, medicine, income and other necessities for livelihood security. Human-induced climate change places growing pressure on the quality of coastal resources due to the increased intensity and frequency of natural disasters like coastal erosion and flooding. Anthropogenic activities like coastal mining of earth minerals further threatens livelihood security with cumulative pressure on the coastal environment and its resources. This paper discusses the compounding impacts of mining in the flood-prone community of Vanua Votua in Ba (Fiji). They currently witness the degradation of their coastal environment and its resources (iqoliqoli). The people of Vanua Votua have a cultural and spiritual attachment to their coastal ecosystem as indigenous custodians. However, they are limited in their ability to conserve and protect their iqoliqoli due to an unfair legal duality of national coastal governance structures and processes between the state and indigenous custodians. We found that a central issue of coastal mining, governance, and the people’s livelihood vulnerabilities, is Fiji’s Mining Act [Cap 146] and associated environmental legislations and policies that consolidate much of the coastal governance authority with the state. The Fiji Mining Act is currently under review. This paper provides a timely case study using the Sustainable Livelihood Approach and the Vanua Research Framework, outlining the need for current and future legislation to be nuanced and sensitive to the realities of the local context.

An Analysis of Malaysian Public Policy in Disaster Risk Reduction: An Endeavour of Mitigating the Impacts of Flood in Malaysia

An Analysis of Malaysian Public Policy in Disaster Risk Reduction: An Endeavour of Mitigating the Impacts of Flood in Malaysia

Impact of Floods on Kenyan Women: A Critical Review of Media Coverage, Institutional Response and Opportunities for Gender Responsive Mitigation

Natural disasters pose serious threat to human life and livelihoods. Kenya is perennially exposed to floods, landslides and drought due to effects of climate change. Flooding is particularly rampant in Western Kenya and women are disproportionately affected due the important roles they play in rural economies particularly in agriculture, the informal sector as well as household survival. The media is always at hand to capture the details of the catastrophe with press reports highlighting the specific experiences of individuals, and the prevailing conditions of the affected villages including: destruction of shelter, displacement and loss of livelihoods. Similarly, Government and Non–Governmental agencies move into the affected communities to provide the much-needed support. This study reviews existing institutional literature and media coverage reports to examine the specific flood related vulnerabilities among women in Western Kenya in order to identify existing gaps.Women experience specific difficulties in performing their traditional family roles, and are often unable to meet their personal hygiene and sanitation needs but are largely missing from the decision forums where Disaster Risk Reduction is discussed leading to lack of prioritization of their specific needs. The lessons drawn from this study should inform gender responsive mitigation efforts and resilience capacity building.

Rapid changes in fluvial morphology in response to the high-energy Yigong outburst flood in 2000: Integrating channel dynamics and flood hydraulics

High-energy outburst floods triggered by failure of landslide- and glacial dams have strongly impacted rivers in eastern Tibet, affecting river geomorphology, human settlements, and infrastructure. However, understanding the impact of these extreme outburst floods on river landscape evolution is hampered due to lack of event-based observations. The second-largest modern outburst flood recorded in the Yigong River in 2000 provides an opportunity to investigate changes in river morphology caused by such extreme floods. By combining remote sensing images from 1984 to 2020 and 2-D numerical flood simulations with the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) software, we show that the riverbank displacement during the Yigong outburst flood (YGOF) is an order of magnitude greater than that in other periods. Channel migration and variation in channel width in the upper reach (UR) straths are greater than those in the down reach (DR) gorges, and the curvature of the UR was greatly reduced by the YGOF while that of the DR increased. Furthermore, the channel morphology after the YGOF has become more dynamic. The relationship among the product of the dimensionless curvature (W/R), simulated flow velocity (U) and relative migration rate (M/W) in both the UR and DR follow similar distribution patterns, in which the maximum relative migration rates in the UR and DR occur where (W/R) · U ∼ 1. The results quantify the impact of the 2000 YGOF on the fluvial systems, which demonstrates that high-energy outburst floods play an extremely important role in mountainous river morphology and promotes our understanding of hydraulic process and geomorphological effects of paleofloods.

Flood disaster mitigation modeling through participation community based on the land conversion and disaster resilience

The objective of this research is to determine the relationship between non-structural flood disaster mitigation models to reduce the impact of floods. The analysis is carried out on the basis of community participation, land conversion, and community resilience. The 1398 household was conducted at 2019 is used as the sample of this research. This research is focused on the mitigation modeling by adopting three models (CLEAR model, CLUE-S model, DROP model) as variables, 15 indicators and 65 sub-indicators. Three hypotheses were formulated to effectively carry out the research. Structural equation model is used to investigate the close relationship between the three models. The relation between CLEAR and CLUE-S models have a positive correlation is about 14.806, CLEAR and DROP models have a close relation is about 4598, and CLUE-S and DROP models have a close positive relation is about 4.004. The results of these three models are very valuable to the central and local governments for formulating the policies programs in designing sustainable non-structural flood mitigation and subsequent policies with references to the three models above which are effective to reduce the flood events.

The Impact of Sea-Level Flooding on the Real Estate Development Community in Charleston SC: Results of a ULI Member Survey

Climate change is becoming an increasing concern for many communities, particularly coastal communities subject to tidal and sea-level flooding. As a result, shoreline municipalities walk a fine line between protecting their communities and allowing more development. A prime example of this dilemma is the port city of Charleston, South Carolina, USA. Despite being ground zero for sea-level flooding, the city has seen rapid real estate development growth. This paper analyzes a survey conducted with Urban Land Institute (ULI) members in the Charleston region to understand how the real estate community is coping with and combating flooding impacts. Results show that while residential real estate developers are rethinking their development patterns, commercial developers are slow to recognize the threat of climate change impacts. The paper concludes with suggestions for policies and practices to address these threats, strengthen Charleston’s commercial real estate, and better prepare the city for a safe, prosperous future.

Compound flood impact of water level and rainfall during tropical cyclone periods in a coastal city: the case of Shanghai

Abstract. Compound flooding is generated when two or more flood drivers occur simultaneously or in close succession. Multiple drivers can amplify each other and lead to greater impacts than when they occur in isolation. A better understanding of the interdependence between flood drivers would facilitate a more accurate assessment of compound flood risk in coastal regions. This study employed the D-Flow Flexible Mesh model to simulate the historical peak coastal water level, consisting of the storm surge, astronomical tide, and relative sea level rise (RSLR), in Shanghai over the period 1961–2018. It then applies a copula-based methodology to calculate the joint probability of peak water level and rainfall during historical tropical cyclones (TCs) and to calculate the marginal contribution of each driver. The results indicate that the astronomical tide is the leading driver of peak water level, followed by the contribution of the storm surge. In the longer term, the RSLR has significantly amplified the peak water level. This study investigates the dependency of compound flood events in Shanghai on multiple drivers, which helps us to better understand compound floods and provides scientific references for flood risk management and for further studies. The framework developed in this study could be applied to other coastal cities that face the same constraint of unavailable water level records.

Recovering from Financial Implications of Flood Impacts—The Role of Risk Transfer in the West African Context

In many West African river basins, households regularly experience floods and the associated impacts. In the absence of widely accessible formal risk transfer mechanisms (e.g., insurance), households often have to cope with financial impacts. Only a few studies have explored the financial effects of floods on agriculture-dependent households in the region and the role formal and informal risk transfer plays in their mitigation. This study addresses this gap, explores flood impacts with financial implications for households, and researches the existing strategies to mitigate them. Moreover, it aims to better understand how different measures influence the recovery process. The study draws on primary data from a household survey (n = 744) in the Lower Mono River basin, combined with stakeholder workshops and semi-structured interviews, and applies a generalized linear model to the survey data. The results reveal four flood impact types with financial implications: agricultural, material, health, and trade. Moreover, a shortened recovery time is significantly associated with assistance from savings groups and cooperatives—groups originally not formed to help during floods. In light of the severe and frequent flood impacts, effective and publicly accepted adaptation measures are needed to enable favorable conditions for creating sustainable and accessible risk transfer mechanisms.

Socio–Economic Impact of Urban Flooding in one of the low-lying areas of Surat in light of e-governance and Social Engineering

Flood is natural catastrophes that lead to massive damage to properties and lives. Its impact on socio-economic aspects has been highly recorded over the last two decades. Social and active learning efforts, such as flood monitoring through e-governance and Self Help Group’s (SHGs) social engineering method, effective cooperation by allowing stakeholders to talk about issues of common interest in a spirit of mutual trust and ownership, as well as breaking down information exchange obstacles. Here, we have emphasized the social impact of the low-lying area of Surat city in the context of e-governance and social engineering. In communities defined by changing climate, local economies, and demography, social and active learning through SHGs helps build an ability to manage complex socio-economic-political and environmental concerns. Using the Kadarshah Naal SHGs as a case study, we examined the SHGs framework as a catalyst for altering practices toward collaborative working and aiding the transition to more sustainable urban floods and their control. This study is collected on real-time basis data from urban flooding as a case study where the improvement in urban flood resiliency has been observed with the formation of the Kadarshah Naal SHGs. A socio-economic survey was carried out to evaluate the impact of the integration of SHGs with the urban local body (ULB) on resiliency. The study has found that the alone approach of e-governance of ULB was ineffective for faster and speedy resiliency but with the integration of SHGs, the resiliency is better. These SHGs have strengthened the peoples’ bonding and provided leverage to the ULB for handling the flood situation with disparities in viewpoints and behaviors. These SHGs have helped to reframe the tacit knowledge of handling emergency situation through social engineering approach. The Kadarshah Naal SHGs' social learning has pushed the members to move away from traditional "siloed" activities and responsibilities and provided a platform to have an integrated and inclusive approach to developing common visions and working toward urban flood resilience.

Impact of Canal Encroachment on Flood and Economic Vulnerability in Northern Bangladesh

River and canal encroachments have become a common problem in Bangladesh. The prevalence of river and canal encroachments has a direct impact on population growth. However, the impacted population appears to be unaware of its negative consequences. To this end, we aimed to investigate the past and present canal scenarios with a focus on canal encroachment as the influencing factor in Ulipur upazila (highly vulnerable) of northern Bangladesh. To examine the impact of this encroachment, the Flood Vulnerability Index (FVI), Adaptive Capacity Index (ACI) and Economic Vulnerability Index (EVI) were used. Our results showed signs of narrowing of the canal structure of Ulipur upazila in 1982 and 1992, while satellite images from 2002 and 2012 showed the presence of encroachment in the middle and lower parts of the canal. The FVI value for Hatia union was 0.703, indicating that this area was highly vulnerable to flooding. According to the ACI, the Pandul union has a high capacity to cope with flood impact, while the Hatia union has less capacity to cope with flood impact. Conversely, Hatia’s union EVI value was 72.8, denoting a high economic vulnerability. Canal encroachments will have negative consequences for these impacted unions. It is critical to reduce the flooding and economic vulnerabilities associated with canal encroachments. It is found that canal excavation is very important for controlling flood water and reducing the damage caused by flooding.

Classification of the flood severity of the Guadalquivir River in the Southwest of the Iberian Peninsula during the 13th to 19th centuries

This study estimates the flood severity between the 13th and 19th centuries on the southwestern Iberian Peninsula based on the historic records of impacts of the Guadalquivir River flooding on the city of Seville (Spain). The main documentary source was Historia crítica de las riadas o grandes avenidas del Guadalquivir en Sevilla (Critical history of the floods of the Guadalquivir in Seville) (1878), which compiles news from different observers that were contemporaries of each flood. Regarding the methodology, it was necessary to transfer the information from different documentary sources to ordinal indices, which required developing allocation criteria per flood impact. From the annual severity index assigned to the different floods, an interannual series was generated. Through interannual weighing of the flooding indices, it was possible to deduce the durations and intensities of sequences of flood periods between 1250 and 1850. Of the 10 floods classified as most destructive during the five centuries analyzed (i.e., from 1280 to 1880), five occurred during little more than a century (1598-1701). The obtained results contribute to knowledge on regional rainfall, as well as to historical climatology and hydrology, over multiple centuries.

The Impact of Flooding on Education of Children and Adolescents: Evidence from Pakistan

This study traces short- to long-term adverse effects of the colossal flood 2010 on educational outcomes of children and adolescents (age 5–16 years) in the flooded districts of Pakistan. Taking advantage of the flood — a type of quasi-natural experimental research design we utilized a difference-in-differences (DID) approach with inverse probability of treatment weights (IPTWs) to estimate the impact of the flood on educational outcomes by using a household surveys’ dataset (six waves). We compare educational outcomes out-of-school or dropout from school of — children and adolescents in the flooded households with the educational outcomes of individuals of same age groups in the non-flooded households before, during and after the flood. Our findings reveal that, on an average, 39 out of 1000 children and adolescents in the flooded districts, compared with their counterparts in the non-flooded districts, were not admitted in any educational institutions and 16 of them dropped out from schools during the flood. The effect of flood on education of children and adolescents, then, disappeared after 2–4 years after the flood. The education outcomes of children and adolescents in flooded households in rural areas compared with their peers in non-flooded districts were severely affected by the flood. Mirroring the impact of flood on education sector to the current heavy flood 2022 in Pakistan or pandemic COVID-19 is similarly compelling nations around the world for closure of their schools and educational institutions. The findings of this study may have some policy implications in terms of identifying the most vulnerable children and adolescents to mitigate the adverse impact of the natural disasters such as flood or pandemic on education outcomes and particularly significant to pinpoint shocks of disasters that have large and long-run impacts on human capital accumulation.

Floods, aridity and rivers: An environmental history of pargana Mandalghat in eighteenth-century Bengal

This essay interrogates the role of rivers and the water they provided in the context of the agricultural economy of colonial Bengal; it provides a minute analysis of the impact of excess flow or floods at the pargana or locality level and documents the destruction of crops, drowning of cattle, loss of seeds and overall devastation to habitation. Riverine water played an important role in the formation of soil in the country, and, therefore, its supply affected the agricultural economy. The augmentation of the delta through soil formation was a geologic process that was gradual and slow, while changes in river courses could be sudden and violent. This essay constructs a narrative around riverine activities including responses to flooding situations, navigability of rivers and the interventions of the early colonial state in Bengal in the second half of the eighteenth century. Focusing on the specific impact of flooding in the locality of pargana Mandalghat, this essay demonstrates that the study of floods can reveal the manner in which agricultural decline affected pockets of habitation within the Bengal delta.

Analysis of Normalized Different Wetness Index (NDWI) Using Landsat Imagery in the Ciletuh Geopark Area as Ecosystem Monitoring

Geopark is a park area that is included in a conservation area, which has elements of geodiversity, biodiversity, and cultural diversity. It has aspects in education as knowledge earth science and tourism. One of the geoparks on the Java island that concern the government is the Ciletuh Geopark. Besides the potential, the Ciletuh Geopark landscape also has threats such as floods and droughts that can disrupt its ecological function. Therefore, it is necessary to conduct a study related to the wetness status of the Ciletuh Geopark to minimize the impact of floods and droughts. One way is by using the Normalized Different Wetness Index (NDWI). This study aimed to analyze the level of wetness of the Ciletuh Geopark with the Normalized Different Wetness Index method obtained from Landsat images. The results show that compared to 2001, the area with moderate wetness and high wetness decreased almost 50% in 2015, and the non-water body increased twice. On the other hand, the wetness condition did not significantly change between 2015 and 2021. The decreasing the wetness condition suspected by drought due to global climate change.

Impact of Flash Floods On Agri-based Livelihoods In Sylhet Haor Basin

Bangladesh is most vulnerable to natural disasters and climate change. Over the past few decades, flash floods have frequently affected the livelihood of people in the Sylhet Haor Basin. This study highlights the causes of increased flash floods, their impact on farming practices and livelihoods, and possible solutions to flash flood risk in the Sylhet Haor Basin. Data were collected using a pre-tested structured questionnaire from randomly selected 298 Haor farmers in high and moderately vulnerable flash flood zones across the Haor region during November 2021 and April 2022. In moderately vulnerable areas, the lack of rivers and canal dredging was the main factor contributing to flash flood deterioration. Index scores and ranks revealed that flash floods most severely affect the primary production sector (agriculture) and threaten the lives and livelihoods of the local populace in high- and moderately flood-prone areas. After the severe flash flood, farmers were forced to turn to other occupations instead of agriculture for their livelihood. To reduce the impact of flash floods on particular features or entire wetlands, most farmers preferred the construction of embankments over sandbags, concrete or stone dams, submergible embankments, and rubber dams. For flash flood risk management, farmers in high- and moderately flash flood-vulnerable areas emphasize the construction of higher dams and embankments and the installation of more flood barriers (dams/embankments). The concerned flash flood management agencies could incorporate the key findings of this study while formulating risk mitigation strategies for the Sylhet Haor Basin. Ann. Bangladesh Agric. (2022) 26 (1) : 61-73

INFLUENCE OF THE DEGREE FLOODING AND COMPRESSION CROSS-SECTION OF A HYDRAULIC STRUCTURE WITH UNSTEADY LIQUID MOVEMENT

The article is devoted to topical issues of the influence of hydraulic structures on the behavior of channel flow. Issues related to the operation of hydraulic structures located on irrigation canals were considered: - the influence of the degree of flooding on the elements of unsteady movement in open channels; - the influence of flow compression on the elements of unsteady motion in open flows. Quantitative assessment of the impact degree of flooding and compression on the elements of the flow during steady motion was carried out taking into account the recommendations of prof. Bolshakova VO, which are based on the use of the method of prof. Vasilieva OF The question influence of hydraulic structures on the behavior of the channel flow was solved using the equations of Saint-Venan by the numerical method, namely the method of run by the implicit-difference scheme. To close the system when using this method, the following conditions were taken into account: a - initial; b - left and right boundary conditions. The initial conditions are the presence of uniform movement in the channel. The left boundary condition is determined by the schedule of water supply to the channel, which has the form of a triangular hydrograph. The right boundary condition is determined by the known formula of a spillway with a wide threshold. The initial data were obtained from field observations. Quantitative assessment of the impact of flooding and flow compression on the final flow, velocity and depth results was performed. The issue of distribution of the support along the channel bed, which was formed due to the compression of the flow, was solved using the recommendations of E.V. Eremenko. The equation of flow continuity was considered - under the condition of changing the volume of water in the elementary section of the channel. The time of increase in the volume of water due to compression was determined from the formula obtained in the calculation process. Based on the condition that the time factor is a known value, it is possible to obtain a mathematical expression that determines the length of the propagation of the compression effect. Thanks to the obtained formulas, the calculated graphs of the relative maximum depth depending on the degree of flooding were constructed. With the help of these graphs it is possible to solve the problem of water supply in irrigation canals in the presence of flooding and compression of the flow (in case of unsteady movement).

Quantifying the Impacts of the 2020 Flood on Crop Production and Food Security in the Middle Reaches of the Yangtze River, China

This study uses satellite imagery and geospatial data to examine the impact of floods over the main planting areas for double-cropping rice and grain crops in the middle reaches of the Yangtze River. During summer 2020, a long-lasting 62-day heavy rainfall caused record-breaking floods over large areas of China, especially the Yangtze basin. Through close examination of Sentinel-1/2 satellite imagery and Copernicus Global Land Cover, between July and August 2020, the inundation area reached 21,941 and 23,063 km2, and the crop-affected area reached 11,649 and 11,346 km2, respectively. We estimated that approximately 4.66 million metric tons of grain crops were seriously affected in these two months. While the PRC government denied that food security existed, the number of Grains and Feeds imported from the U.S. between January to July 2021 increased by 316%. This study shows that with modern remote sensing techniques, stakeholders can obtain critical estimates of large-scale disaster events much earlier than other indicators, such as disaster field surveys or crop price statistics. Potential use could include but is not limited to monitoring floods and land use coverage changes.

Mapping storm spatial profiles for flood impact assessments

Synthetic design storms are often used to plan new drainage systems or assess flood impacts on infrastructure. To simulate extreme rainfall events under climate change, design storms can be modified to match a different return frequency of extreme rainfall events as well as a modified temporal distribution of rainfall intensities. However, the same magnitude of change to the rainfall intensities is often applied in space. Several hydrological applications are limited by this. Climate change impacts on urban pluvial floods, for example, require the use of 2D design storms (rainfall fields) at sub-kilometer and sub-hourly scales. Recent kilometer scale climate models, also known as convection-permitting climate models (CPM), provide rainfall outputs at a high spatial resolution, although rainfall simulations are still restricted to a limited number of climate scenarios and time periods. We nevertheless explored the potential use of rainfall data obtained from these models for hydrological flood impact studies by introducing a method of spatial quantile mapping (SQM). To demonstrate the new methodology, we extracted high-resolution rainfall simulations from a CPM for four domains representing different urban areas in Switzerland. Extreme storms that are plausible under the present climate conditions were simulated with a 2D stochastic rainfall model. Based on the CPM-informed stochastically generated rainfall fields, we modified the design storms to fit the future climate scenario using three different methods: the SQM, a uniform quantile mapping, and a uniform adjustment based on a rainfall–temperature relationship. Throughout all storms, the temporal distribution of rainfall was the same. Using a flood model, we assessed the impact of different rainfall adjustment methods on urban flooding. Significant differences were found in the flood water depths and areas between the three methods. In general, the SQM method results in a higher flood impact than the storms that were modified otherwise. The results suggest that spatial storm profiles may need to be re-adjusted when assessing flood impacts.

Handling the stochastic uncertainty of flood statistics in regionalization approaches

Regional flood frequency analyses are highly affected by the number of gauged catchments and lengths of observation periods at the individual gauges. Therefore, information is unevenly distributed in the region of interest. Especially the occurrence of single extreme floods which were observed or not observed at some gauges, depending on the observation period, may have a large impact on the regionalization. We evaluated the impact of the sample length on the regionalization of a type-specific statistical mixture-model. In a case study it is shown how the regionalization error can be reduced by more than 50% if the sample sizes increase. We compare three different approaches to handle this stochastic uncertainty in regionalization. The alignment of the statistical distribution parameters to consider the impact of extreme floods proved to be most beneficial when aiming to obtain homogeneous regionalised flood quantiles for hydrologically similar regions in a region with heterogeneous observation periods.