Flood Events Research Articles

Enhanced Flood Monitoring in the Pearl River Basin via GAIN-Reconstructed GRACE Terrestrial Water Storage Anomalies

Floods are a significant and pervasive threat globally, exacerbated by climate change and increasing extreme weather events. The Gravity Recovery and Climate Experiment (GRACE) and its follow-on mission (GRACE-FO) provide crucial insights into terrestrial water storage anomalies (TWSA), which are vital for understanding flood dynamics. However, the observational gap between these missions presents challenges for flood monitoring, affecting the estimation of long-term trends and limiting the analysis of interannual variability, thereby impacting overall analysis accuracy. Reconstructing the missing data between GRACE and GRACE-FO is essential for systematically understanding the spatiotemporal distribution characteristics and driving mechanisms of interannual changes in regional water reserves. In this study, the Generative Adversarial Imputation Network (GAIN) is applied to improve the monitoring capability for flood events in the Pearl River Basin (PRB). First, the GRACE/GRACE-FO TWSA data gap is imputed with GAIN and compared with long short-term memory (LSTM) and k-Nearest Neighbors (KNN) methods. Using the reconstructed data, we develop the Flood Potential Index (FPI) by integrating GRACE-based TWSA with precipitation data and analyze key characteristics of FPI variability against actual flood events. The results indicate that GAIN effectively predicts the GRACE/GRACE-FO TWSA gap, with an average improvement of approximately 50.94% over LSTM and 68.27% over KNN. The reconstructed FPI proves effective in monitoring flood events in the PRB, validating the reliability of the reconstructed TWSA. Additionally, the FPI achieves a predictive accuracy of 79.7% for real flood events, indicating that short-term flood characteristics are better captured using TWSA. This study demonstrates the effectiveness of GAIN in enhancing data continuity, providing a reliable framework for large-scale flood risk assessment and offering valuable insights for flood management in vulnerable regions.

The impact of dam management and rainfall patterns on flooding in the Niger Delta: using Sentinel-1 SAR data

This study explored how dam operation and rainfall patterns interact to influence flooding in the Niger Delta, Nigeria. This study utilizes Sentinel-1 Synthetic Aperture Radar (SAR) data to analyze the flood events from 2018 to 2022, focusing on key locations such as Obiafu (downstream), Kainji/Jebba, and Lagdo dams (upstream). Analyzed Sentinel-1 satellite data [European Space Agency (ESA), 2018–2022], shuttle Radar Topography Mission, alongside rainfall data [Center for Hydrometeorology and Remote Sensing (CHRS), 2018–2022] and surface water level to assess flood variations between 2018 and 2022. The flood extent was differentiated from that of permanent water bodies using Sentinel-1 images with an RGB band (Snap 7.0), and the rainfall patterns were examined via inverse distance weighting (IDW) interpolation (ArcGIS 10.5). The findings reveal that the intensity and timing of flooding vary significantly across these regions. Obiafu experienced high flooding in October 2020 and 2022, while Kainji/Jebba and Lagdo dams had contrasting flood severities during these periods. Additionally, a comparative analysis of hydrograph data from these locations shows a delayed downstream response, highlighting the need for coordinated water release strategies to mitigate flood risks. The results also indicate that upstream dam operations, particularly water releases, contribute to downstream flooding, although local rainfall patterns remain a crucial factor. By aligning SAR data with real-time water levels, this study emphasizes the importance of integrating satellite-based monitoring with hydrological models to improve flood prediction accuracy and minimize socio-economic impacts in the Niger Delta. The study concludes that enhanced flood management strategies, incorporating both rainfall forecasting and dam operation schedules, are critical for reducing flood-related vulnerabilities in the region.

Analysis of natural and technological factors of changes in exogeodynamic conditions of mine No. 2 of the Stebnytsky potassium deposit as a consequence of self-rehabilitation flooding

The Stebnytsy deposit of potash salts is located in the foothills of the Ukrainian Carpathians. The engineering-geological and hydrogeological conditions of the field’s operation due to the development of a thick layers of loose and water-soluble rocks are difficult of loose and water-soluble rocks are complex and therefore sensitive to mining-technological influences, extraction of rocks, deformation of the surface, hydrographic network, activation of the interaction of surface and groundwater. The most threatening situation was at mine No. 2, where in 1978, due to too intensive blasting, violation of waterproof layers, loosening and increase of water permeability, reduction of rock strength, an emergency breakthrough of super-saline waters occurred in the spent chambers of the first horizon. The total inflow of brines during the years of existence of the flow here constantly increased and reached up to 1700 m³/day, in 2002, the outflow of suprasaline waters developed in 22 points and acquired an irreversibly negative character, suffusion-diffusion processes began to develop actively. During the operation of the mine, ore extraction was carried out for a long time without laying out spent cavities, as a result of which more than 15 million m³ of unlined cavities were formed at the mine, the deformations of which disturbed the geodynamic regime of the salt-bearing massif with the subsequent development of sedimentary and karst-failure processes. In 2004, a comprehensive project for the conservation of mine No. 2 and the reclamation of disturbed lands was approved in order to restore the ecological balance in this area. Mine conservation works were carried out behind the design schedule, which led to the failure of the main provisions of the project and increased the danger due to the expansion of existing karst cavities and the formation of new ones. It can be argued that the works on the conservation of mine No. 2, including: preparation of brines, feeding them to underground mine workings, laying of chambers, etc., were carried out in a timely and incomplete manner, which does not ensure the cessation of negative consequences for the natural environment and ecological safety. The results of our research can be used in the future in the development of projects for the conservation or liquidation of salt mines.

Sediment transport characteristics at the flood-event scale in the Minjiang River Basin, China

ABSTRACT In recent years, the significant change in the runoff–sediment distribution in the upper Yangtze River has led to an increased sediment contribution from the Minjiang River Basin (MRB) to the Three Gorges Reservoir. However, previous studies on sediment load changes in the MRB have focused mainly on annual-scale characteristics, thereby neglecting features driven by floods. Therefore, this study focused on examining the changes in flood-event sediment loads in the MRB based on mathematical statistics and comprehensive measurement data. The results indicated that human activities, climate change, and seismic events have caused an increasing trend in the flood-scale sediment load in the upper MRB and a decreasing trend in the lower MRB. The changes in the flood-scale sediment modulus at low runoff erosion power levels were greater than those at high runoff erosion power levels at different abrupt-change stages. During extreme flood events, the actual sediment concentration in the MRB remained below the sediment-carrying capacity. This study provides novel insights into water resource management during the flood season in the MRB and similar basins.

Landslide Prediction Validation in Western North Carolina After Hurricane Helene

Hurricane Helene triggered 1792 landslides across western North Carolina and has caused damage to 79 bridges to date. Helene hit western North Carolina days after a low-pressure system dropped up to 254 mm of rain in some locations of western North Carolina (e.g., Asheville Regional Airport). The already waterlogged region experienced devastation as significant additional rainfall occurred during Helene, where some areas, like Asheville, North Carolina received an additional 356 mm of rain (National Weather Service, 2024). In this study, machine learning (ML)-generated multi-hazard landslide susceptibility maps are compared to the documented landslides from Helene. The landslide models use the North Carolina landslide database, soil survey, rainfall, USGS digital elevation model (DEM), and distance to rivers to create the landslide variables. From the DEM, aspect factors and slope are computed. Because recent research in western North Carolina suggests fault movement is destabilizing slopes, distance to fault was also incorporated as a predictor variable. Finally, soil types were used as a wildfire predictor variable. In total, 4794 landslides were used for model training. Random Forest and logistic regression machine learning algorithms were used to develop the landslide susceptibility map. Furthermore, landslide susceptibility was also examined with and without consideration of wildfires. Ultimately, this study indicates heavy rainfall and debris-laden floodwaters were critical in triggering both landslides and scour, posing a dual threat to bridge stability. Field investigations from Hurricane Helene revealed that bridge damage was concentrated at bridge abutments, with scour and sediment deposition exacerbating structural vulnerability. We evaluated the assumed flooding potential (AFP) of damaged bridges in the study area, finding that bridges with lower AFP values were particularly vulnerable to scour and submersion during flood events. Differentiating between landslide-induced and scour-induced damage is essential for accurately assessing risks to infrastructure. The findings emphasize the importance of comprehensive hazard mapping to guide infrastructure resilience planning in mountainous regions.

The Impact of Floods on the Mobility of Automobile Commuters in Shanghai Under Climate Change

AbstractAs sea level rises, low-lying coastal cites face increasing threat of flood disruption, particularly in terms of human mobility. Commuters are vulnerable to bad weather, as it is difficult to cancel trips even in extreme weather conditions. Using Shanghai’s automobile commuting population as an example, we categorized commuters by travel distance and income level to assess disruptions and delays due to floods, considering future sea level rise. The results show that local flooding disrupts commuting patterns by affecting roadways, with disruption decreasing with distance from the flooded area. This offers a mobility perspective on the indirect impacts of floods. During baseline flood events, long-distance commuters and the low-income group are most affected, while short-distance commuters and the high-income group are less impacted. As sea level rises, floods will threaten all commuting groups, especially the high-income group. Using inaccessibility-commuting delay bivariate maps, this study revealed how socioeconomic differences impact mobility recovery after floods under climate change. The research highlights the differential impacts of floods on various socioeconomic groups in the context of climate change, offering insights for future urban planning and disaster mitigation strategies.

Nature-Based Solutions (NbSs) to Improve Flood Preparedness in Barcelona Metropolitan Area (Northeastern Spain)

This paper presents a novel study of the Nature-based Solutions (NbSs) approach to analyze and propose mitigation measures for extreme floods. The study area is the Llobregat River in Catalonia, which crosses urban areas. We have selected one section in the final stretch of 4.5 km in the Barcelona Metropolitan Area. The section has suffered several damages in the last floods (e.g., 2016, 2018 and 2019), and we propose measures to reduce flood risk. Therefore, we proposed the following three specific objectives: (a) the identification of critical areas in the river stretches; (b) the identification of NbS opportunities and utilities; and (c) the mitigation measures in concrete areas from NbSs. The effectiveness of a NbS is based on the 2D simulation of the Gloria flood event (20–21 January 2020) with HEC-RAS software (version 6.0) for the better management of stormwater, and it is influenced by design and placement aspects; however, the better use of NbSs can improve flood mitigation and enhance urban resilience.

Hybrid Modeling for In Situ Artificial Fish Spawning Ground Stabilization

ABSTRACTErosion generally reduces the resilience of replenished gravel in rivers. As a result, structures are sometimes added to modify the upstream flow and stabilize artificial spawning grounds. In particular, rows of boulders can be placed around the replenishment area to limit the transport of replenished gravel during flood events. This study aims to optimize the arrangement of these rows, based on field experiments as well as physical and numerical models. A combined hydro‐sedimentary numerical model is calibrated and validated by comparing simulated and measured morphological evolutions in nine laboratory experiments. The results show that boulders positioned downstream of the replenishment slow down the flow above the replenishment, decreasing shear stress over the gravel. The stabilization efficiency depends on both the positioning of the boulders and the arrangement of the replenished surface. To achieve sustainable spawning, prospective scenarios using the numerical model highlight the need to limit the width of the replenishment area. Experiments demonstrated that when the replenishment area spans the entire width flume, the erosion rate is significantly higher compared to a narrower replenishment area placed close to the edges. This effect is attributed to increased flow velocities in the center of the channel, leading to increased shear stress and gravel erosion.

The effects of secondary currents in tight bends on large wood transport in rivers: Lesson learned from Versilia flood in 1996

AbstractThe presence and dynamics of large wood (LW) in river systems, particularly for streams flowing through forested areas, play a significant role in shaping river morphology and influencing flood events. This paper focuses on the numerical reproduction of observed LW trajectories during a flood event in the Versilia River in 1996 in Italy. The study reach, located near Pietrasanta in Tuscany, includes a tight river bend named S. Bartolomeo. During the event, more than two thousand cubic meters of transported wood were observed at this location. In addition, due to the collapse of the outer levee, six million cubic meters of water exited the river corridor, causing the flooding of Pietrasanta. The 2D Lagrangian model Iber‐Wood was used for the numerical simulation of this event. In particular, two versions of the model were used: the original one (IB‐NSC) and the enhanced version (IB‐SC) which simulates the effects of secondary currents on LW dynamics. The results validated the applicability of the enhanced version to simulate real‐world conditions and showed that the IB‐SC model improves the agreement between observed and simulated LW trajectories by more than 20% compared to the IB‐NSC model. Examining the influence of the breach on the LW trajectories, it appears that the presence of LW during the overtopping flow intensified and accelerated the erosion process, resulting in a rapid breach formation. This study therefore highlights the importance of including secondary current effects on LW transport for the development of flood risk assessments and river management strategies, particularly in channelized rivers with tight bends or meanders.

Evaluating levee setback distance for the co-benefits of groundwater recharge and riparian ecosystem function

Constructed levees are designed to protect anthropogenic developments from destructive flooding events, but their construction has reduced groundwater recharge, increased flood risk severity under levee failure, increased the incision of river channels, and deteriorated riparian habitat. To reverse these impacts, levee setbacks are often designed to reduce flood risk and provide the opportunity to restore ecohydrological function, while groundwater recharge is rarely considered because it may require relatively detailed groundwater system analysis. In this study, we evaluated 100 heterogeneous hydrogeology realizations to estimate recharge with high-conductivity pathways (HCPs) under varying flood flows for a range of levee setback distances to identify the trade-offs in groundwater recharge and floodplain habitat. We find that on a regional scale, total recharge potential increases with setback distance, with the largest gains up to 1,400 m where there are outcropping HCPs and sufficient flow to inundate more of the setback area. In contrast, the recharge per unit area (i.e., the average daily recharge divided by setback area) generally decreases as levee setback increases, but there are local increases in the recharge per unit area at 1,400 m where HCP recharge may sufficiently offset the larger area. There is a median 10%–40% reduction in peak streamflow with increasing setback distance, which would aid flood risk reduction, but the increased area leads to decreasing depth due to flow losses and increased spreading of flood water. Ultimately, the decision for levee setback distance will depend on local conditions and management goals, as we find that increasing recharge will reduce the floodplain depth necessary for ecosystem function. Our results highlight the opportunity to consider groundwater recharge benefits in levee setback feasibility studies in semi-arid regions impacted by floods and groundwater overdrafts so that setback distance designs can achieve integration of flood risk reduction, riparian habitat, and groundwater recharge.

Tectonic anabranching of Brahmaputra River system: implications on survival of world’s largest inhabited river island Majuli

Brahmaputra is a large, tropical, trans-boundary river with high sediment load and has the unique distinction of possessing both largest and smallest inhabited river islands. Majuli is the largest inhabited river island situated in the Indian state of Assam and bounded by Brahmaputra on the south, Subansiri River on the northwest, and the Kherkatia River (anabranch of Brahmaputra) on the northeast. The island was formed during a flooding event in 1750 with a sudden change in the course of the Brahmaputra from a low energy meandering to a high energy braided river and subsequent capture of one of its tributaries. The island is a part of the Brahmaputra alluvium squeezed between active Himalayan and Indo-Burmese orogenic belts in an intricate tectonic regime. The dominant flow path of Brahmaputra is controlled by the crustal scale reorganization in this part of the world. The tectonic factors that controlled the anabranching process and created the island, is at present acting as the destroyer of the same by the means of unabated erosion. The erosion pattern of the two rivers viz. Brahmaputra and Subansiri were studied and areas with marked selective erosion have been found. From a combined study of satellite imaging, bathymetric survey and mapping, it is found that the lobate shaped erosions in the study areas are restricted to traces of the tectonic elements related to the Himalayan thrust system through which the rivers are trying to anabranch.

Impacts of LULC and climate change on runoff and sediment production for the Puyango-Tumbes basin (Ecuador-Peru)

Climate change will cause alterations in the hydrological cycle, a topic of great relevance to the scientific community due to its impacts on water resources. Investigating changes in hydrological characteristics at the watershed level in the context of climate change is fundamental for developing mitigation and adaptation strategies against extreme hydrological events. This study aimed to analyze the impacts of climate change on flow and sediment production in the Puyango-Tumbes watershed. Projected climate data from CMIP6 were used, corrected through a bias adjustment process to minimize discrepancies between model data and historical observations, ensuring a more accurate representation of climate behavior. The analysis combined two representative climate change scenarios (SSP2-4.5 and SSP5-8.5) with two land use and land cover (LULC) scenarios: (a) an optimistic scenario with reduced anthropogenic effects (LULC_1985) and (b) a pessimistic scenario reflecting future impacts (LULC_2015). The SWAT model estimated future flow and sediment production for two periods (2035-2065 and 2070-2100), following model calibration and validation against the reference period 1981-2015 at three hydrometric stations: Pindo, Puyango, and El Tigre, located in Ecuador and Peru. The simulations revealed a significant increase in sediment generation under the pessimistic scenario SSP5-8.5, followed by SSP2-4.5, while lower sediment yields were observed in the optimistic scenarios. Even in the best-case scenario (optimistic SSP2-4.5), sediment yields remained substantially higher than the reference conditions. Additionally, higher flows were anticipated in some scenarios, with the El Tigre station in the lower watershed being the most affected area. These findings underscore the high probability of more frequent flooding events due to increased sediment yields and flow variability. The results highlight the urgent need for implementing adaptation measures, such as improved land use management and hydrological infrastructure, to enhance social resilience and mitigate the impacts of climate change in the watershed.

Mapping Rural Household Vulnerability to Flood-Induced Health Risks in Disaster-Stricken Khyber Pakhtunkhwa, Pakistan

This study maps the rural household vulnerability to flood-induced health risks in flood-affected Khyber Pakhtunkhwa (KPK), Pakistan, focusing on the devastating 2022 flood. Using data from 600 households in the severely impacted districts of Khyber Pakhtunkhwa province (including Charsadda and Nowshera), this research examines the influence of demographic, socioeconomic, and infrastructural factors on household vulnerability. This study assesses household vulnerability to flooding and health issues using logistic regression. The current study findings revealed that female-headed households, those with younger heads, and families with lower educational levels are particularly vulnerable. Income disparities significantly shape coping capacity, with wealthier households more likely to adopt effective risk-mitigation strategies. Proximity to functioning healthcare facilities emerged as a crucial factor in reducing vulnerability, as these households faced fewer health hazards. Conversely, households in areas where health and water infrastructure were damaged experienced higher risks of disease outbreaks, including cholera and malaria, due to water contamination and inadequate sanitation. This study highlights the urgent need for resilient infrastructure, strengthened public health systems, improved health education, and enhanced water and sanitation services to mitigate flood-induced health risks. Policymakers are urged to sustainable development practices by adopting gender-sensitive disaster management strategies, prioritizing educational initiatives, and fostering community support networks to enhance resilience to future flood events in KPK.

A framework for flood inundation extraction based on microwave and optical remote sensing images

IntroductionEffective monitoring and evaluation of floodwaters are essential for disaster prevention and mitigation. The flood inundation range can be obtained by using traditional simulation methods, but these methods still have shortcomings. This work proposes an optimization method for traditional methods.MethodsThis study aims to introduce an effective solution for the rapid and accurate extraction of flood inundation areas, emphasizing the enhancement of extraction speed and dynamic monitoring throughout the flood event. The solution uses a normalized difference water index (NDWI), a refined threshold method, and a filtering process for microwave (radar) images. Sentinel-1 SAR (Synthetic Aperture Radar) and Sentinel-2 MSI (Multi-spectral Image) images served as the primary data sources. The Sentinel-2 images were preprocessed to extract pre-flood water bodies, while the Sentinel-1 SAR images were processed using the proposed filtering method to identify post-flood inundation areas.ResultsThe application and validation of this framework are demonstrated through the case of the 2020 flood event in Tongling, Anhui Province. The framework’s performance was validated through comparison with ground truth data, yielding high kappa accuracies of 98% for optical images and 89% for Synthetic Aperture Radar. The findings highlight the framework’s ability to capture high-accuracy changes in flood inundation areas and to characterize the dynamic process of flood inundation area changes.DiscussionThis study contributes to the field by enhancing the extraction speed and scope of water bodies from SAR images and improving the quality of microwave remote sensing data processing. It offers valuable insights for emergency rapid response and situational awareness in the context of extreme weather events and associated flood disasters.

Seismic performance of continuous rigid-frame bridges affected by flood-induced scour

River-crossing bridges in high-intensity seismic regions can be vulnerable to the combined action of earthquake and flood hazards; in particular, flood-induced scour of the substructure can have a notable influence on the seismic behavior of bridge structures. Currently, long-span continuous rigid-frame bridges are widely used to cross large rivers worldwide, yet related studies on their seismic performance under flood-induced scour have been lacking. This paper focuses on the effects of time-varying flood-induced scour on the seismic performance of long-span continuous rigid-frame bridges incorporating complex thin-walled reinforced concrete piers with pile group foundations. A detailed finite element (FE) model for a representative bridge structure is developed and the scour depth risk of the bridge is evaluated under several flood events for different return periods. The influence of flood-induced scour on the pile-soil interaction is examined throughout the bridge service life. Detailed seismic fragility assessment is carried out through nonlinear time-history analyses using a large suite of 100 seismic records. Particular focus is given to evaluate the time-varying scour effects on the pile and soil deformations as well as on the component and system level seismic fragility functions. It is shown that the total flood-induced scour depth exhibits a nonlinear increasing trend with the increase in service time, particularly in the initial 10 years of the bridge service life. The deformations of the scoured piles, within a depth of 20 m, are also shown to increase significantly with the increase in service time. The results indicate that the scour has a pronounced effect on both the component and system level seismic fragility functions. Importantly, although the piles (or pile groups) are typically designed to remain elastic under seismic loading, they are shown to be subjected to significant inelastic demands and governing damage levels as a result of time-varying flood-induced scour effect. Overall, this study provides a methodology to assess the time-varying seismic fragility of the scoured long-span rigid-frame bridges with complex thin-walled reinforced concrete piers, which can enhance the multi-hazard time-varying seismic resilience assessment for bridge structures with similar configurations.

A New Method for Analyzing Storm Event Discharge‐Concentration Hysteresis: The Upper Yangtze River as an Example

AbstractThe analysis of hydrological and sediment dynamics during flood events offers a new perspective on material transport within basins and the management of rivers. The literature has highlighted the hysteretic nature of material transport at the event scale, which arises from temporal differences in the transport of materials (flow and sediment). Current hysteresis research methods fall short in effectively assessing the complex events. This study leverages suspended‐sediment and discharge data from the upper Yangtze River to show proof‐of‐concept for hysteresis studies using Dynamic Time Warping (DTW) algorithm, a time series analysis tool. To evaluate the efficacy of the method, extensive assessments were undertaken using a combination of synthetic data and basin data with over 700 flood events. The proposed index effectively captures and quantifies hysteresis relationships associated with flood events, making it a versatile tool for hysteresis studies. We also similarly tested the robustness of the method and the application to complex events, and the results were satisfactory. Furthermore, we explored the hysteretic features of flood events in the studied basin. The results revealed that a proportion ranging from 50% to 60% flood events exhibit sediment peak leading pattern, indicating that in the upper Yangtze River, sediment peaks tend to occur in a leading pattern. The operation of reservoirs profoundly impacts the dynamics of sediment transport, resulting in an increased proportion (from 27% to 54%) of sediment peaks lagging behind discharge peaks. These study findings can be used to improve hysteresis study methods and contribute to the understanding of hydrological and sediment transport characteristics.

Impact of extreme rainfall and flood events on harmful cyanobacterial communities and ecological safety in the Baiyangdian Lake Basin, China

Globally, climate change has intensified extreme rainfall events, leading to substantial hydrological changes in aquatic ecosystems. These changes, in turn, have increased the frequency of harmful algal blooms, particularly those of cyanobacteria. This study examines cyanobacterial community dynamics in the Baiyangdian Lake Basin, China, after heavy rainfall and flooding events. The aim was to clarify how such extreme hydrological events affect cyanobacterial populations in floodplain ecosystems and assess related ecological risks. The results demonstrated a significant increase in cyanobacterial diversity, exemplified by an increase of the Shannon diversity index from an average of 1.7 to 2.1 (p < 0.05). Following heavy rainfall and subsequent flooding, the average relative abundance of cyanobacteria in the microbial community increased from 7.59 % to 9.62 %, along a notable rise in the abundance of harmful cyanobacteria. The community structure exhibited notable differences after flooding, showing an increase in species richness, but a decrease in community tightness and clustering, as well as a reduction in niche overlap among harmful cyanobacteria. Environmental factors such as dissolved oxygen, water temperature, and pH were identified as crucial predictors of harmful cyanobacterial community differences and abundance variations resulting from flooding. These findings provide a critical framework for predicting ecological risks associated with the expansion of bloom-forming cyanobacteria in large shallow lake basins, particularly under intensified rainfall and flooding events. This insight is essential to anticipate potential ecological disruptions in sensitive aquatic ecosystems.

A Low-Cost Ultrasonic Sensor for Online Monitoring of Water Levels in Rivers and Channels

The measurement of flow parameters in rivers and channels is essential for anticipating floods, hydraulic modeling, and conducting water resource management studies. However, the high cost of existing equipment has resulted in a shortage of monitoring stations compared to actual requirements. This research focused on developing and validating a low-cost, highly accurate ultrasonic device that minimizes malfunctions for online monitoring of water levels in channels and streams. Considering the availability of components, cost, and the reported resolution of the product, the GY-Us42 sensor was selected for constructing the level gauge. The sensor operates within a range of 20 cm to 720 cm with a measurement accuracy of approximately 1 mm. The device integrates several error reduction mechanisms to enhance accuracy, including averaging multiple readings and temperature correction techniques. Laboratory data and field data gathered by both staff and shaft encoder were used for device validation. After constructing the main prototype and conducting various tests, multiple devices were installed in different locations within the Tehran rivers, and water depth data were collected over a specific period. Subsequently, data from other field sensors were also collected and used for device validation and accuracy assessment. The results indicate that the device's average error is below 3%, with a Root Mean Squared Error (RMSE) of 5.00 cm during field tests, demonstrates that the constructed device is an efficient tool for measuring water levels in streams, particularly during flood events.

A review of paleofloods in the middle-lower reaches of the Yangtze River during the Holocene: Processes, causes and effects

The understanding of the flooding processes in the entire basin of the middle-lower reaches of the Yangtze River (MLRYR) during the Holocene remains elusive. This is primarily attributed to the constraints posed by site-scale data characterized by limited spatiotemporal resolutions, compounded by conflicting results of the reconstructed Holocene paleoflood records in some of the previous studies. In this study, by synthesizing 114 paleoflood data with robust evidence of flood occurrence (including timing and location of flood occurrence), we comprehensively reconstructed the first continuous Holocene paleoflood record that cover the entire basin of the MLRYR. The results show that at the onset of the Holocene, flood frequency peaked notably in the middle reaches of the Yangtze River (MRYR), with no corresponding peak observed in the lower reaches of the Yangtze River (LRYR). However, in both the MRYR and LRYR, a significant flood frequency peak emerged around 8.0 ± 0.5 ka BP, and scarce flood occurrences appeared approximately 7.5–5.0 ka BP. This scarcity shifted abruptly to a surge in flood frequency from 5.0–4.0 ka BP. Following this, the MRYR witnessed three successive peaks in flood frequency, occurring at approximately 3.0 ka BP, 1.8 ka BP, and 1.0 ka BP, respectively. In contrast, flood events in the LRYR were infrequent during the 3.0–2.0 ka BP period, followed by a surge in frequency from 2.0 ka BP onwards. We further explored the driving mechanisms of paleofloods in the MLRYR and found that floods were more likely to occur during periods of weakened EASM, characterized by wet and unstable climate conditions in the MLRYR. Marine erosion may be also a key factor in the lack of geological evidence for palaeofloods during the early Holocene. Additionally, variations in the ISM and human activities during the late Holocene have significantly influenced the occurrence of floods in the MLRYR. By comparing the paleoflood frequency with the spatial distribution and number of archaeological sites in the MLRYR, respectively, we propose that the period of flood scarcity during the middle Holocene may have facilitated the development of rice agriculture and the prosperity of ancient settlements. In contrast, during flood-prone period, ancient societies adapted and coped with floods by migrating to higher terrain during the early Holocene and implementing simple hydraulic engineering techniques during the late Holocene.

Strategies for Teaching Natural Hazards to Children in Rural Communities

This research focuses on teaching strategies for natural hazards in rural educational communities, centring on El Abanico, a seismic region in Argentina with a history of destructive earthquakes. Geomorphological, tectonic, and climatic processes amplify hazards, while socio-economic factors, including a predominantly agricultural economy, informal housing, reliance on irrigation, and limited services, increase community vulnerability.The Tierra del Fuego School serves students from diverse socio-economic backgrounds, and its structure was severely affected by seismic and flood events in 2021. An assessment revealed deficiencies in disaster risk management within the community. In response, an intervention was implemented at the school using educational strategies focused on natural hazards, distinct from formal classroom learning and adapted to the rural context. This intervention engaged children aged 9 to 11 over a year.The objective was to explore children’s understanding of hazards in their territory, develop knowledge through interaction with the physical environment, encourage children’s expression and experiential knowledge, formulate disaster response strategies, foster resilience and preparedness, and analyse the potential for replicating these initiatives in other rural communities.The findings revealed a significant increase in knowledge of natural hazards and risk prevention among both students and teachers. The project culminated in the creation of a book that amplified the children's voices and disseminated the seismic history of the region, fostering improved seismic risk management. The educational strategies are replicable in other rural schools and can positively influence disaster risk reduction strategies while enhancing community resilience.