Extreme Flood Research Articles

Flood vulnerability of inland bridges with foundation scour

Extreme floods can cause water level to rise above bridge superstructures. Following worldwide statistics on hydraulic bridge failure, it becomes essential to generate a comprehensive knowledge base to predict probable bridge failure scenarios under future floods and to identify appropriate countermeasures for flood risk mitigation. With this objective, the study here develops a numerical framework for systematic evaluation of forces on vulnerable bridge components during floods and to understand the global response of inland river-crossing bridges under flood hazards. Computational fluid dynamics (CFD) simulations are performed to calculate hydrodynamic forces on superstructure of a representative bridge for different inundation levels and flood velocities resulting from varied intensity flood events. Hydrodynamic forces on piers and scour depths around foundations are estimated for flood cases considered here. Knowing the forces and scour depths, finite element bridge models with and without scour are developed and analyzed to apprehend its global response and progressive failure under various combinations of water height and velocity. Further, regression relations are proposed to project component-level responses based on which damage state of the bridge under future intense flood events and fragility characteristics could be predicted. Thus, results enable identifying key factors to reduce flood vulnerability of inland bridges.

Extreme Seasonal Droughts and Floods in the Madeira River Basin, Brazil: Diagnosis, Causes, and Trends

The Madeira River, a major tributary of the Amazon River, often undergoes severe flood and drought conditions. This study seeks to investigate the climate processes associated with the opposing extreme precipitation events in the Madeira River basin and to relate them to river discharge variability based on a flood awareness dataset. Despite the uncertainty in the observational datasets, the annual precipitation cycle exhibits a rainy season from November to March. A significant result is the high correlation between the rainy season variability in the Madeira River basin and the sea surface temperature (SST) anomalies in the tropical North Atlantic Ocean and the southwestern South Atlantic Ocean. This result indicates that improving the Atlantic SST representation in climate modeling allows for capturing extreme precipitation events in the region. In addition to this impact, certain Madeira River tributaries present significant climate trends. The river discharge variability reveals an increase in hydrological extremes in recent years in the upper sector, but more significantly, in the lower basin, where it has reduced by more than 400 m3/s per decade. These findings highlight the need to improve in situ data and climate and hydrological modeling, with a focus on describing the intense climate variability and trends in river discharges.

Who is ‘stuck’ in the past? The impact of the 1998 great flood on the adoption of agricultural technology in China

ABSTRACT This study estimates the impact of the 1998 Great Flood on the adoption of agricultural technology in China and its mechanism using a cross-sectional dataset collected from the ERA5-Land, the China Labor Force Dynamic Survey, the China Rural Statistical Yearbook, and the China Population Census. The analysis reveals an inverted U-shaped correlation between farmers’ exposure to the flood event and their propensity to embrace technological advancements in agriculture. Farmers who experienced medium flood exposure tend to be risk lovers and exhibit a 4.9% higher likelihood of adopting agricultural technology compared to their counterparts who did not experience the flood. On the contrary, farmers who faced extreme flood exposure tend to be risk averse and exhibit an 11.9% diminished likelihood of adopting agricultural technology compared to those who remained unscathed by the flood.

Strategic flood risk management over time. Applying a temporal lens to see how flood risk management measures are (or are not) implemented

ABSTRACT Strategic flood risk management of river catchments involves significant increases in the complexity both of the contents (e.g. the aims and measures) of a given strategy and also its social, spatial, and temporal scales. Conceptually, flood risk management research to date has underestimated the importance of time and temporality. This paper, which is based on ‘historical Institutionalism,’ introduces a temporal lens to focus on strategic flood risk management; it highlights issues of duration and timing as well as tempo and change in tempo with respect to the implementation of measures to reduce flood risk at catchment level. The application of a temporal lens is illustrated through empirical research into strategic flood risk management for the medium-sized Aist river catchment in Austria. The paper uses a longitudinal qualitative research design to analyze the changes in strategic flood risk management in the catchment. The analysis shows that strategy efforts in reaction to an extreme flood event in the catchment in August 2002 can be differentiated into three phases. Phase 1 is characterized by the design of ambitious catchment-wide management; Phase 2 by struggles to implement the strategy due to institutional conditions and protests by citizens; and Phase 3 by redesign of the initial strategic plan to make it less ambitious and by changes to the actor constellation supporting the plan. The present paper offers a process-oriented institutional explanation for this pattern of phases, and it highlights issues of timing and tempo. It concludes with general suggestions for enhancing the temporal dimension in flood risk management.

Effects of extreme climate events and child mortality on total fertility rate in Bangladesh

Floods, storms, and temperature extremes are examples of extreme weather events that have a substantial influence on a country's demographic dynamics, including migration, fertility, and mortality. Changes in population size, composition, and distribution may result from these occurrences. This study, which spans the years 1966–2018, looks at how Bangladesh's total fertility rate (TFR) is affected by extreme weather events and child mortality, including neonatal, infant, male infant, and under-five mortality. We use data from secondary publicly accessible sources, such as the World Bank and The Emergency Events Database (EM-DAT), and we investigate the correlations using the autoregressive integrated moving average model (ARIMA), complemented by bivariate and multivariable analyses.Our findings from the univariate analysis are noteworthy. Total extreme climate events (β = −0.345, 95 % CI: 0.510, −0.180), as well as individual extreme climate events, such as extreme temperatures (β = −1.176, 95 % CI: 1.88, −0.47), floods (β = −0.644, 95 % CI: 1.0729, −0.216), and storms (β = −0.351, 95 % CI: 0.63159, −0.07154), exhibited negative associations with the TFR. Additionally, factors such as contraceptive prevalence rate (CPR) (β = −0.085, 95 % CI: 0.09072, −0.07954) and gross national income (GNI) per capita (β = −0.003, 95 % CI: 0.0041123, −0.0024234) were negatively correlated with the TFR. Conversely, various categories of child mortality, namely, infants (β = 0.041, 95 % CI: 0.040474, 0.042748), males (β = 0.038, 95 % CI:0.037719, 0.039891), and under-five (β = 0.026, 95 % CI:0.025684, 0.026979) – are positively associated with TFR. Controlling for two pivotal confounding factors, time and GNI per capita, yielded consistent results in the multivariate analysis. These findings provide insight on the dual impact of extreme weather events, which can reduce TFR while also raising it through infant mortality. This phenomena may be due to the increased vulnerability of younger children in climate-event-prone areas, prompting parents to seek additional children as both a replacement for lost offspring and an insurance mechanism against future child loss.

Channel changes during and after extreme floods in two catchments of the Northern Apennines (Italy)

The Nure and Trebbia catchments were affected by an extreme flood event on 13-14th September 2015. This study investigates the morphological responses to the flood of the Nure and Trebbia rivers and 18 tributaries with the aims to: i) quantify channel changes in width and pattern; (ii) identify the morphological and hydrological factors which might have driven channel response; (iii) quantify channel changes which have occurred after the flood event.Channel changes were characterized by field surveys and geomorphological analysis of multi-temporal orthophotos acquired before (2011), immediately after the flood (2015) and in 2020.In the tributaries, reach-scale channel widths after the flood reached up to 15 times their pre-flood values, whereas in the main channels the post/pre-flood width ratio attained a maximum value of 4. Augmented channel width in the main rivers was mostly associated with banks and islands erosion, whereas in the tributaries it was also due to deposition of coarse sediments onto the former floodplains. Islands were swept away in the main channels while both island erosion and formation occurred in the tributaries. In terms of channel pattern, pre-flood single-thread reaches displayed mainly multi-thread morphologies after the flood, mostly in response to a sudden input of coarse sediment supply. In the 5 yr following the flood, channels slightly narrowed but still remained wider than in 2011. The narrower reaches before the flood resulted to be the most sensitive to changes even some years after the flood.Statistical analyses between the channel width changes and a series of variables showed significant positive correlations with confinement index, channel slope, and the local storm rainfall depth. This study confirms how channel widening during large floods – usually neglected in flood hazard mapping and river basin management – is a very important process which must be considered in flood hazard assessment in mountain rivers.

Global experiences in flood management – perspectives through ICFM Webinar Series

Abstract. It is a major issue of concern for international organizations and governmental departments in supporting global climate governance. As floods account for 44 % of all natural disasters in recent 20 years, it is of great significance to propose countermeasures by reviewing global extreme flood events in recent years. The International Conferences on Flood Management (ICFM) and Flash Flood Program (FFP), have hosted a series of international academic webinars since 2020. Drawing upon the outcomes of the webinars and reviewing the latest flood mitigation strategies of major countries advanced in water management, this paper focuses on the global experience in response to watershed flood, flash flood, urban flood, extreme flood under climate change, and comprehensive mitigation measures. It can be learned that flood control strategies need combine both structural and non-structural measures, and draw upon nature-based solutions that integrate green, blue and gray spaces within basins or cities through multi-purpose and targeted programs, with a view to achieving flood management goals and promoting social, economic and environmental sustainability in a holistic way.

Building green and climate-resilient healthcare facilities in Uttarakhand: A step for a sustainable climate resilient healthcare

Climate change presents significant risks to human health, with healthcare facilities increasingly vulnerable to extreme weather, floods, droughts, and climate-sensitive diseases. This study examines the development of Green and Climate-Resilient Healthcare Facilities in Rudraprayag, Uttarakhand, through multi-sectoral collaboration. Key interventions include energy audits, LED lighting, solar panel installation, and rainwater harvesting, aimed at enhancing sustainability and resilience. The initiative demonstrates the importance of proactive adaptation measures and sustainable practices in healthcare infrastructure, providing a model for other regions to ensure continuous, high-quality care amid escalating climate threats. This approach underscores the critical need for innovation, collaboration, and commitment in building climate-resilient health systems.

Observed Changes in Extreme Precipitation Associated with U.S. Tropical Cyclones

Abstract Numerous recent tropical cyclones have caused extreme rainfall and flooding events in the CONUS. Climate change is contributing to heavier extreme rainfall around the world. Modeling studies have suggested that tropical cyclones may be particularly efficient engines for transferring the additional water vapor in the atmosphere into extreme rainfall. This paper develops a new indicator for climate change using the enhanced rainfall metric to evaluate how the frequency and/or intensity of extreme rainfall around tropical cyclones has changed. The enhanced rainfall metric relates the amount of rain from a storm over a given location to the 5-yr return period rainfall in that location to determine the severity of the event. The annual area exposed to tropical-cyclone-related 5-yr rainfall events is increasing, which makes it a compelling climate change indicator. Quantile regression illustrates that the distribution of tropical cyclone rainfall is also changing. For tropical storms, all quantiles are increasing. However, major hurricanes show large increases in their most extreme rainfall. This study does not attempt to make any detection claims (vs natural variability) or attribution of the observed trends to anthropogenic forcing. However, the sensitivity of the results to natural variability in tropical cyclone frequency was somewhat constrained by comparing 2 decades from the previous active era (1951–70) with two from the current era (2001–20). This comparison also shows that both the mean rainfall and the maximum rainfall associated with tropical cyclones are increasing over most areas of the eastern CONUS with the most significant increases from northern Alabama to the southern Appalachians. Significance Statement The purpose of this study is to analyze the changes in frequency and magnitude of extreme precipitation events associated with tropical cyclones with the goal of developing a new indicator for climate change. This is important because heavy rainfall and associated flooding is one of the primary causes of tropical cyclone destruction and fatalities, especially in inland locations away from where storms initially make landfall. Our results show that both the frequency and magnitude of extreme rainfall events from tropical cyclones have increased over the CONUS. The strongest storms (major hurricanes) also show more of an increase in extreme rainfall than storms of weaker intensities.

The future of the Portuguese (SW Europe) most vulnerable coastal areas under climate change – Part II: Future extreme coastal flooding from downscaled bias corrected wave climate projections

Episodic extreme coastal flooding is considered one of the most serious threats to the global coastlines, endangering infrastructure, ecosystems, and communities. The synchronized effects of extreme wave events, storm surges and astronomical tides are particularly worrying in the context of sea level rise (SLR), and a comprehensive understanding of their future dynamics remains challenging. In this study, an innovative approach for a vulnerability assessment of sandy low-lying coastal areas, based on dynamic ensemble projections is proposed. In the current Part II study, the combined effects of future projected SLR, tides, storm surges and wave action are investigated at five key-locations along the Portuguese coastline, considering projected digital terrain models, built upon the shoreline projections obtained in Part I. Future extreme total water levels are obtained through a probabilistic approach, and extreme wave events are defined considering high wave energy thresholds in a changing climate. Overall, extreme coastal flooding is projected across several urbanized sections along the Portuguese coastline, especially in areas without artificial protection infrastructures. Dune erosion is expected along the sandy stretches, reducing the natural protection against extreme coastal events up to 13.3%, and promoting widespread overtopping, leaving populations more exposed. Future projections reveal the episodic flooding of up to 1.47 km2 of land along the 14 km of analyzed coastline, threatening households and commercial hubs, besides services and communication routes. As physical and human losses may increase substantially in the future, our results call for the implementation of adequate coastal management and adaptation plans, strategically defined to withstand changes until 2100 and beyond.

River morphological behavior between two barrages on the Euphrates: A case study

The Abbassia-Shammia stream is a meandering reach in Najaf Province downstream of the Euphrates. The geomorphological traits and process-based assessment of large rivers are rarely observed globally, particularly in less developed nations. The need for such evaluation arose due to climate change, hydraulic structure construction, and the possibility of extreme droughts and floods. The hydraulic and morphological properties of the Abbassia-Shammia reach were significantly altered owing to the installation of successive barrages and climatic change. This paper aims to assess the river morphological behavior downstream of the Euphrates near the Abbassia-Shammia reach for 32 km length through the bed change investigation process, i.e. river sedimentation and erosion. The morphological performance of the Euphrates reaches between two series of barrages, namely Abbassia and Shammia, was simulated using HEC RAS2D, a tool developed by the River Analysis System program of the Hydrologic Engineering Center. The research revealed that bed change levels ranged from 5.87 meters of sedimentation to 5.720 meters of erosion. Furthermore, the results showcased how effectively the HEC RAS2D model accurately captured the features of a Euphrates section between two barrages. The results of the study provide insights into the future behavior of channels. They can help to address the issues caused by the prevailing fluvial processes such as sedimentation and erosion.

The role of regional water vapor dynamics in creating precipitation extremes

While sub-daily precipitation extremes cause flash flooding and pose risk to life, longer precipitation extremes threaten infrastructure such as water supply dams. Frequent storm or floods events replenish water supplies, ensuring the health of our ecosystems, while rarer larger storms or floods cause damage to property and life. These differing impacts depend on both storm rarity and duration and are largely dependent on coincident atmospheric water vapour. Using a novel metric that quantifies the extent of concurrency that exists between precipitation and total water vapour extremes, large regional variations are identified across the globe. Tropical regions such as Northeast Africa and South/East Asia consistently exhibit greater concurrency across all precipitation durations. In contrast, areas of the extra-tropics, such as the Mediterranean and Northwest Americas, show a rapid decline in concurrency with increasing duration. However, for rare events of long duration, non-tropical regions maintain high concurrency. With the link between climate change and increasing total water vapour well established, these results suggest that flood events will increase globally, with increases most apparent for longer and rarer events. This work underscores the need for tailored regional strategies in managing extreme precipitation and flood events in the future.

Hydrometeorological controls of and social response to the 22 October 2019 catastrophic flash flood in Catalonia, north-eastern Spain

Abstract. On 22 October 2019, the Francolí River basin in Catalonia, north-eastern Spain, experienced a heavy precipitation event that resulted in a catastrophic flash flood, causing six fatalities. Few studies comprehensively address both the physical and human dimensions and their interrelations during extreme flash flooding. This research takes a step forward towards filling this gap in knowledge by examining the alignment among all these factors. The hydrometeorological factors are investigated using the new Triangle-based Regional Atmospheric Model, radar-derived precipitation estimates, post-flood field and gauge observations, and the Kinematic Local Excess Model. The social dimension is assessed by examining the relationship between catchment dynamics and warning response times and by quantifying human behaviour during the course of the flash flood through a post-event citizen science campaign. Results reveal that a persistent south-easterly airflow brought low-level moisture and established convective instability in the region, while local orography was instrumental to triggering deep moist convection. A convective train promoted intense, copious, and prolonged precipitation over the north-western catchment headwaters. Basin response was significantly modulated by the very dry initial soil moisture conditions. After the long-lasting rainfall, an acute burst of precipitation resulted in extreme flash flooding. Fast and abrupt increases in streamflow affect small spatial scales and leave limited time for the effective implementation of protective measures. The institutional organization–protection–prevention cycle unfolded at the spatial and temporal scales typically dominated by the meteorological rather than hydrological scales. Although the citizen science campaign reveals the effectiveness of the warnings in reaching the population living in the most affected areas, a significant proportion of the respondents expressed a lack of adequate information or were unfamiliar with the intended meaning. In addition, a majority of the interviewees did not perceive any significant threat to life or property. In view of these results, this study identifies potential areas for improving social preparedness for similar natural hazards in the future.

Drought and wetness events encounter and cascade effect in the Yangtze River and Yellow River Basin

Under the background of global change, the multivariate attributes, multi-temporal and multi-watershed regional characteristics of extreme drought and flood disasters are significant. It is very important to identify the drought and wetness encounter law and spatial cascade effect in the source region-upper-middle-lower reaches of the basin. In this paper, the Yangtze River and Yellow River basins are taken as the research objects. Based on the standardized precipitation index (SPI) characterizing meteorological drought and wetness and the standardized runoff index (SRI) characterizing hydrological drought and wetness, the evolution law of extreme drought and flood events in the source region-upper-middle-lower reaches of the two basins is analyzed. On this basis, the correlation analysis and transfer function analysis are used to explore the response relationship and lag effect between the two in different partitions. A two-dimensional joint distribution model is constructed by Copula function to quantitatively analyze the joint probability of drought and wetness encounters of 9 combined events, and to deeply analyze the impact of different drought and wetness encounter scenarios. The results show that: from 1957 to 2020, the two basins showed a trend from drought to wet. The SPI-12 in the Yellow River Basin ranged from-1.57 to 1.32, and that in the Yangtze River Basin ranged from-1.24 to 1.11. The severity of drought and wetness in the Yellow River Basin was higher than that in the Yangtze River Basin; The correlation coefficients between SPI and SRI in the source-upper-middle-lower reaches of the Yellow River (Yangtze River) were 0.78 (0.76), 0.23 (0.73), 0.44 (0.55) and 0.23 (0.63), respectively. The correlation degree of meteorological-hydrological drought and wetness in the Yangtze River Basin was significantly higher than that in the Yellow River Basin. The average probability of synchronous combination events of drought and wetness in the two basins is greater than 51.43 %. The probability of drought in the Yellow River Basin is greater than that of flood, while the Yangtze River Basin is the opposite. In the same drought and wetness scenario, an average of 54.1% of the event pairs were aggravated by disasters, and more than 52 % of the events in the wetness-drought scenario had obvious drought mitigation effects. The research results can provide important support for improving the early warning and risk management of river basin disasters.

Climatic pacing of extreme Nile floods during the North African Humid Period

Understanding how large river systems will respond to an invigorated hydrological cycle as simulated under higher global temperatures is a pressing issue. Insights can be gained from studying past wetter-than-present intervals, such as the North African Humid Period during the early Holocene Epoch (~11–6 thousand years ago). Here we present a 1,500-year-long annually laminated (varved) offshore sediment record that tracks the seasonal discharge of the Nile River during the North African Humid Period. The record reveals mobilization of large amounts of sediments during strong summer floods that may have rendered the Nile valley uninhabitable. More frequent and rapid transitions between extremely strong and weak floods between 9.2 and 8.6 thousand years ago indicate highly instable fluvial dynamics. Climate simulations suggest flood variability was paced by El Niño/Southern Oscillation on interannual timescales, while multi-decadal oscillatory modes drove changes in extreme flood events. These pacemakers have also been identified in the Nile flow records from the Common Era, which implies their stationarity under contrasting hydroclimatic conditions.

Competing Influences of Land Use and Greenhouse Gas Emissions on Mississippi River Basin Hydroclimate Simulated Over the Last Millennium

AbstractThe Mississippi River is a vital economic corridor used for generating hydroelectric power, transporting agricultural products, and municipal and industrial water use. Communities, industries, and infrastructure along the Mississippi River face an uncertain future as it grows more susceptible to climate extremes. A key challenge is determining whether Mississippi river discharge will increase or decrease during the 21st century. Because the 20th century record is limited in time, paleoclimate data and model simulations provide enhanced understanding of the basin's hydroclimate response to external forcing. Here, we investigate how anthropogenic forcing in the 20th century shifts the statistics of river discharge compared to a Last Millennium (LM) baseline using simulations from the Community Earth System Model Last Millennium Ensemble. We present evidence that the 20th century exhibits wetter conditions (i.e., increased river discharge) over the basin compared to the pre‐industrial, and that land use/land cover changes have a significant control on the hydroclimatic response. Conversely, while precipitation is projected to increase in the 21st century, the basin is generally drier (i.e., decreased river discharge) compared to the 20th century. Overall, we find that changes in greenhouse gases contribute to a lower risk of extreme discharge and flooding in the basin during the 20th century, while land use changes contribute to increased risk of flooding. The additional climate information afforded by the LM simulations offers an improved understanding of what drove extreme flooding events in the past, which can help inform the development of future regional flood mitigation strategies.

Cultural and Spiritual Adaptations to Extreme Weather Events of Ethnic Farming Communities of the Three Watersheds Situated at Different Altitudinal Locations along Agno River Basin, Benguet and Pangasinan, Philippines

Ethnic farming communities in Agno River Basin face climate stressors that threaten their agricultural production. This paper investigated and assessed the cultural/spiritual adaptations to climate variabilities and extremes of ethnic farming communities in Agno River Basin, Philippines. How the presence of these cultural/spiritual practices moderate or mitigate the effects of climate variabilities and extremes were likewise investigated. The climate-related hazards considered in this study which are pronounced in the river basin are prolonged and extreme rainfall intensity, typhoons and extreme winds, drought, flood and occurrence of pests and diseases. These hazards are becoming more frequent and intense resulting to limited agricultural production. This paper considered only the sectors of agriculture/socioeconomic, water and health. The descriptive method employed in this study was based on the works of Oppenheimer et al (2014); Saroar, Routray and Leal Filho (2015) and Brooks and Adgers(undated). The data-gathering activities were household survey using pre-tested questionnaires, focused group discussions and key informant interviews. The ethnic affiliations of the farming communities were I-Karao, Ibaloi, Kankanaey and Kalanguya tribes. Secondary data on changing rainfall and erratic temperature characteristics were consistent with the general perception of the ethnic farming communities. Cultural/ spiritual traditions of Ethnic farming communities in the Agno River Basin form part of their adaptations to climate extremes and variabilities. The greatest number of rituals and activities (5) such as childless couples raising plant materials, burning of rice straws and Alay, Leppas, Maepdesan, and Ibkas or maboteng. are dedicated to ensuring a good harvest. Canyao, Libot, and Begnas are undertaken to prevent the occurrence of hazards. On the other hand, Ubob, Bayanihan, and Sakdo are adaptations to mitigate the impact of climate extremes and variabilities. Both Canyao and Leppas are also thanksgiving activities while Tagainep or dream interpretation serves as a coping mechanism.

Integrating machine learning and geospatial data analysis for comprehensive flood hazard assessment

Flooding is a major natural hazard worldwide, causing catastrophic damage to communities and infrastructure. Due to climate change exacerbating extreme weather events robust flood hazard modeling is crucial to support disaster resilience and adaptation. This study uses multi-sourced geospatial datasets to develop an advanced machine learning framework for flood hazard assessment in the Arambag region of West Bengal, India. The flood inventory was constructed through Sentinel-1 SAR analysis and global flood databases. Fifteen flood conditioning factors related to topography, land cover, soil, rainfall, proximity, and demographics were incorporated. Rigorous training and testing of diverse machine learning models, including RF, AdaBoost, rFerns, XGB, DeepBoost, GBM, SDA, BAM, monmlp, and MARS algorithms, were undertaken for categorical flood hazard mapping. Model optimization was achieved through statistical feature selection techniques. Accuracy metrics and advanced model interpretability methods like SHAP and Boruta were implemented to evaluate predictive performance. According to the area under the receiver operating characteristic curve (AUC), the prediction accuracy of the models performed was around > 80%. RF achieves an AUC of 0.847 at resampling factor 5, indicating strong discriminative performance. AdaBoost also consistently exhibits good discriminative ability, with AUC values of 0.839 at resampling factor 10. Boruta and SHAP analysis indicated precipitation and elevation as factors most significantly contributing to flood hazard assessment in the study area. Most of the machine learning models pointed out southern portions of the study area as highly susceptible areas. On average, from 17.2 to 18.6% of the study area is highly susceptible to flood hazards. In the feature selection analysis, various nature-inspired algorithms identified the selected input parameters for flood hazard assessment, i.e., elevation, precipitation, distance to rivers, TWI, geomorphology, lithology, TRI, slope, soil type, curvature, NDVI, distance to roads, and gMIS. As per the Boruta and SHAP analyses, it was found that elevation, precipitation, and distance to rivers play the most crucial roles in the decision-making process for flood hazard assessment. The results indicated that the majority of the building footprints (15.27%) are at high and very high risk, followed by those at very low risk (43.80%), low risk (24.30%), and moderate risk (16.63%). Similarly, the cropland area affected by flooding in this region is categorized into five risk classes: very high (16.85%), high (17.28%), moderate (16.07%), low (16.51%), and very low (33.29%). However, this interdisciplinary study contributes significantly towards hydraulic and hydrological modeling for flood hazard management.

Post‐Fire Sediment Yield From a Central California Watershed: Field Measurements and Validation of the WEPP Model

AbstractIn a warming climate, an intensifying fire regime and higher likelihood of extreme rain are expected to increase watershed sediment yield in many regions. Understanding regional variability in landscape response to fire and post‐fire rainfall is essential for managing water resources and infrastructure. We measured sediment yield resulting from sequential wildfire and extreme rain and flooding in the upper Carmel River watershed (116 km2), on the central California coast, USA, using changes in sediment volume mapped in a reservoir. We determined that the sediment yield after fire and post‐fire flooding was 854–1,100 t/km2/yr, a factor of 3.5–4.6 greater than the long‐term yield from this watershed and more than an order of magnitude greater than during severe drought conditions. In this first large‐scale field validation test of the WEPPcloud/wepppy framework for the Water Erosion Prediction Project (WEPP) model on a burned landscape, WEPP predicted 81%–106% of the measured sediment yield. These findings will facilitate assessing and predicting future fire effects in steep watersheds with a Mediterranean climate and indicate that the increasingly widespread use of WEPP is appropriate for evaluating post‐fire hillslope erosion even across 100‐km2 scales under conditions without debris flows.

ArchIMEDES: Computer Vision Tracking of the Inherent Changes to Structural Stability of Masonry Arch Bridges Resulting from Increased Bed Scour.

Scour-induced failure of masonry arch bridges is a common cause of bridge collapse, especially during extreme flood events. Over recent years there has been a significant increase in the numbers of documented scour induced failures of this bridge stock across Europe and the USA. The extent of the scour can erode the supporting soil or sediment around the bridge piers or abutments, leading to a loss of support for the structure. As the foundation becomes unstable, it can result in settlement or tilting of the bridge, potentially causing structural damage, while the ongoing nature of scour can result in the progressive deterioration of the bridge’s ability to safely transfer load. Traditional hydraulic adjustments, such as streamlining abutments with wing walls and using cutwaters on piers, do not significantly reduce scour depth for masonry arch bridges. This paper presents initial findings of an investigation that links the changes of response in load carrying capacity to the easement of support at the bridge foundation due to scour. Scale experiments on the FlexiArchTM under loading with realistic scour conditions is contributing to the development of an algorithm based on the relationship between the structural response of the FlexiArchTM and prevailing scour conditions. The computer vision-based monitoring package ArchIMEDES, developed as part of the research, will use this algorithm to predict current bridge scour conditions at any given time. This will allow for potential scour development to be identified and investigated before the bridge collapses, ensuring the security and safety of these vital pieces of infrastructure.