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Strong rainfalls and river floods are becoming increasingly frequent and intense in southern Europe. Mediterranean coastal lagoons, due to their hydrological characteristics, could mitigate the consequences of such events, whose effects on sediment biogeochemistry are poorly studied, yet. To provide insights on this, we investigated short-term changes in organic matter quantity, composition, nutritional quality, degradation rates, and turnover time in a lagoonal benthocosm. Both flooding and recovery phases increased the sedimentary organic load and turnover time, whereas phytopigment contents and C degradation rates were not affected. The biochemical composition varied during both phases, with an increase in carbohydrate and lipid after the flooding, and an increase in protein and chlorophyll-a after its recovery. Our results suggest that even sudden changes in salinity caused by floods and their recovery can increase sedimentary organic loads, with minor effects on their nutritional quality. The observed effects of the flooding persist in the short-term also after the recovery of the salinity, when the substrates are pre-eminently of heterotrophic origin. Our results suggest that extreme, even if short-lasting, episodic events of flooding and recovery can severely alter the benthic trophic status of coastal lagoons, having possible effects on benthic trophodynamics. [ABSTRACT FROM AUTHOR]

Tsunami inundation maps are crucial for understanding the impact of tsunamis and planning mitigation measures. Our research focuses on creating a database of stochastic tsunami scenarios along the Chilean subduction zone and probabilistic inundation maps for 11 coastal cities. We divided the Chile-Perú subduction zone into four seismic segments based on historical seismicity. Stochastic rupture scenarios, ranging from 8.0 to 9.6 magnitudes, were generated using the Karhunen-Loeve expansion. The Stochastic Reduced Order Model (SROM) helped select representative tsunami scenarios for each segment and magnitude bin. We then used the NEOWAVE model to simulate these scenarios to an inundation level, creating probabilistic tsunami maps for various return periods. Our findings reveal that local geography significantly influences tsunami inundation, with some areas facing high inundation risks while others experience minimal impacts. As a result, a uniform planning and design criterion across the entire country is not advisable; site-specific studies are necessary. These probabilistic scenarios can provide tailored solutions for different Chilean coastal cities, enhancing their resilience. Additionally, this research marks the first comprehensive probabilistic tsunami hazard analysis for the Chilean coast, considering multiple seismic sources, marking a crucial step toward full tsunami risk assessment for coastal communities. [ABSTRACT FROM AUTHOR]

In the regional flood frequency analysis, the selection of important site characteristics and a suitable number of clusters have a significant role in finding homogeneous regions. Generally, it is difficult to determine the exceedance threshold value or the number of average peaks per year (λ) in Partial Duration Series (PDS), and this difficulty is intensified in the context of regional frequency analysis, though, there are only limited studies to report this difficulty. In the present study, the Mahanadi basin is divided into homogeneous regions by using fifteen effective variables by applying different clustering techniques. Factor analysis has been introduced in finding suitable site variables. Out of fifteen variables, nine variables are selected based on factor analysis loadings. Two hard clustering techniques i.e. Hierarchical (HC), K-Means Clustering (KM) along with the Fuzzy C-Mean Clustering (FCM) techniques are used for finding out the possible number of clusters. To validate the results we used cluster validation indices to locate the optimal number of clusters. Results of the homogeneous region found from the FCM and KM hard clustering approach are more accurate and more robust than HC. The suitability of many frequency distributions to be used in the regional frequency is inspected. The results confirmed that the Generalized Pareto (GP) best described the PDS in the study area and also, show that the best PDS/GP performance is found in almost all the values of λ (2, 2.5, and 3). To test the homogeneity and to identify the best-fit frequency distribution, a regional L-moment algorithm is used. A unique regional flood frequency equation is developed which estimates the flood quantiles of ungauged catchments for each region of the basin and an index flood is also specified concerning catchment characteristics by using the multiple linear regression approach for designing small and medium hydraulic structures in the basin. The results are compared with the previous studies of flood frequency in this basin. [ABSTRACT FROM AUTHOR]

Floods are one of the most dangerous natural disasters that humanity has ever faced. In this study, a modified version of D number technique as a suitable form of multi-criteria decision-making (MCDM) approaches was proposed to prioritize flooding in the Sad-Kalan watershed of Iran using some flood related criteria. The proposed method can overcome some shortcomings and uncertainties of the existing MCDM methods. In order to evaluate the performance of the method regarding flood prioritization, its results were compared with the analytic hierarchy process (AHP) technique as mostly frequently used MCDM method. The findings demonstrate that the modified version of D number method provides better results than AHP method. In spite of inherent advantages of D number method, the advantages of the proposed method in relation to existing MCDM are as follows: 1- considering the local and global importance of used criteria, 2- reducing the uncertainty in decision makers' judgments using employing the concept of Picture fuzzy-AHP, 3- considering the degree of consistency in evaluation of decision makers into calculations. Furthermore, the method is flexible and can be used in any region of the world. [ABSTRACT FROM AUTHOR]

This paper moves across the ecological assemblages of the Periyar basin in Kerala. It argues that the connectivities and unintentional designs that emerge bespeak the Anthropocene in its regional and political peculiarities. The river has never been a conduit of water alone. The narrative builds broadly on ecological relations entrenched in history, most visibly as hydrological regimes. Such regimes are significant because of the riparian densities that articulate the geo‐morphology. The different entanglements in ecology, as well as the successive productions of natures, gain significance as 'recognitions' during rupture events like the large floods. In contemporary contexts, the versatile flows of capital dissolve markers and boundaries and reconfigure regions in terms of capital. Vikasanam or new urban reforms, apart from political policies, are also ecological designs that normalise exceptions, otherwise reserved for special economic zones. The frictions with new materiality, post dam floods and hydrological controls, during developmental and neoliberal post developmental phases, become moments of recognition, making and unmaking sense of place. [ABSTRACT FROM AUTHOR]

Open-channel junctions pose a risk associated with flooding and erosion. However, despite the numerous studies concerning the channel junctions, the bed and flow field evolutions at junctions for flood conditions have yet to be investigated. To address this research gap, this paper investigates the evolutions of the bed and flow field during a flood event at a right-angled open-channel junction utilizing three-dimensional (3D) computational fluid dynamics (CFD) modeling. The transient Reynolds-averaged Navier–Stokes (RANS) equations with the renormalized group (RNG) k–ϵ as the turbulence closure for the flow field, the Meyer-Peter and Muller equation for bed-load sediment transport rate, the convection–diffusion equation for the sediment concentration distribution, and the sediment continuity equation for the bed evolution are used in the numerical model. The model simulates the characteristics bed morphology at the junction with reasonable accuracy compared with the available laboratory data. Three scenarios (Scenarios 1, 2, and 3) were considered by applying the triangular flood wave at the inlet of the tributary channel, main channel, and both channels, respectively. The quasi-equilibrium deformed bed channel junction with steady inflow conditions of the validation case was considered as the initial condition for the flood flow simulations. The simulated results show that the junction bed is deformed considerably due to the significant increase in bed shear stress during a flood event. The deepest scour area gradually grows wider during the passage of the flood wave. The maximum value of the scour increased by 24.4%, 14.6%, and 31.2% in Scenarios 1, 2, and 3, respectively. The findings of the study improve the understanding of the junction hydrodynamics and bed morphological features for flood conditions. [ABSTRACT FROM AUTHOR]

Australia is one of the regions strongly affected by the El Niño‐Southern Oscillation (ENSO). The recent 2020–2023 La Niña event was marked by record‐breaking rainfall and flooding across eastern Australia. The continuous wet conditions during the triple La Niña motivated us to explore the impacts of single‐year and multi‐year ENSO events on Australian rainfall using observational data sets. We find that, while there is no difference in the rainfall impacts during single or double El Niño events, Australian rainfall tends to increase in the third year of triple La Niña events compared to the first and second years. The enhanced rainfall impact during the third La Niña year occurs despite no strengthening of La Niña in the tropical Pacific, suggesting that other processes such as local rainfall‐soil moisture feedback may play a role in prolonging the effects of multi‐year La Niña events in Australia. Plain Language Summary: Australia is strongly affected by the El Niño‐Southern Oscillation (ENSO), with rainfall more likely to increase during La Niña and below‐average rainfall more common during El Niño. The recent 2020–2023 multi‐year La Niña was marked by continuous wet conditions across eastern Australia, leading to record‐breaking rainfall and flooding. Multi‐year La Niña events, where La Niña occurs in two or three consecutive austral summers, happened in about 50% of all La Niña events, including five triple La Niña events since 1900. We explored the impacts of multi‐year ENSO events on Australian rainfall and found that, while there is no difference in the rainfall impacts during single or double El Niño events, rainfall tends to increase in the third year of triple La Niña events compared to the first and second years. This rainfall increase occurs despite no strengthening of La Niña in the tropical Pacific Ocean, suggesting that local processes such as feedback between high/saturated soil moisture and rainfall may play a role in prolonging the effects of multi‐year La Niña events in Australia. Key Points: Eastern Australia tends to experience record‐breaking rainfall and flooding during La Niña eventsRainfall impact of multi‐year El Niño‐Southern Oscillation (ENSO) persists during double and triple events, despite no strengthening of ENSOAustralian rainfall increases in the third year of triple La Niña likely due to soil moisture‐rainfall feedback [ABSTRACT FROM AUTHOR]

Limited availability of hydrometeorological data and lack of data sharing practices have added to the challenge of hydrological modelling of large and transboundary catchments. This research evaluates the suitability of latest near real-time global precipitation measurement (GPM)-era satellite precipitation products (SPPs), IMERG-Early, IMERG-Late and GSMaP-NRT, for hydrological and hydrodynamic modelling of the Brahmaputra Basin. The HEC-HMS modelling system was used for the hydrological modelling of the Brahmaputra Basin, using IMERG-Early, IMERG-Late, and GSMaP-NRT. The findings showed good results using GPM SPPs for hydrological modelling of large basins like Brahmaputra, with Nash–Sutcliffe efficiency (NSE) and R2 values in the range of 0.75–0.85, and root mean square error (RMSE) between 7000 and 9000 m3 s−1, and the average discharge was 20611 m3 s−1. Output of the GPM-based hydrological models was then used as input to a 1D hydrodynamic model to assess suitability for flood inundation mapping of the Brahmaputra River. Simulated flood extents were compared with Landsat satellite-captured images of flood extents. In critical areas along the river, the probability of detection (POD) and critical success index (CSI) values were above 0.70 with all the SPPs used in this study. The accuracy of the models was found to increase when simulated using SPPs corrected with ground-based precipitation datasets. It was also found that IMERG-Late performed better than the other two precipitation products as far as hydrological modelling was concerned. However, for flood inundation mapping, all of the three selected products showed equally good results. The conclusion is reached that for sparsely gauged large basins, particularly for trans-boundary ones, GPM-era SPPs can be used for discharge simulation and flood inundation mapping. [ABSTRACT FROM AUTHOR]

Urban floods caused by extreme rainstorm events have increased in recent decades, particularly in concave-down bridge zones. To simulate urban flooding processes accurately, an integrated urban flood model (IUFM) was constructed by coupling a distributed urban surface runoff model based on the cellular automata framework (CA-DUSRM), a widely used pipe convergence module in the storm water management model (SWMM), with an inundation module that describes the overflow expansion process associated with terrain and land-cover. The IUFM was used in a case study of the Anhua Bridge (a typical concave-down overpass) study area in Beijing, China. The spatial-temporal variations in flood depth modeled by the IUFM were verified to be reliable by comparison with actual measurements and other simulations. The validated IUFM was used to obtain temporal variations in flood range, depth, and volume under four rainstorm scenarios (return periods of 3-year, 10-year, 50-year, and 100-year). The results showed that the surface runoff process, overflow from drainage networks, and overflow expansion process could affect the flooding status by changing the composition and spatial configuration of pervious or impervious patches, drainage capacity, and underlying surface characteristics (such as terrain and land-cover). Overall, although the simulation results from the IUFM contain uncertainties from the model structures and inputs, the IUFM is an effective tool that can provide accurate and timely information to prevent and control urban flood disasters and provide decision-making support for long-term storm water management and sponge city construction. [ABSTRACT FROM AUTHOR]

A growing number of studies have linked the incidence of leptospirosis with the occurrence of flood events. Nevertheless, the interaction between flood and leptospirosis has not been extensively studied to understand the influence of flood attributes in inducing new cases. This study reviews leptospirosis cases in relation to multiple flood occurrences in Kerala, India. Leptospirosis data were obtained for three years: 2017 (non-flood year) and two years with flooding—2018 (heavy flooding) and 2019 (moderate flooding). We considered the severity of flood events using the discharge, duration and extent of each flooding event and compared them with the leptospirosis cases. The distribution of cases regarding flood discharge and duration was assessed through descriptive and spatiotemporal analyses, respectively. Furthermore, cluster analyses and spatial regression were completed to ascertain the relationship between flood extent and the postflood cases. This study found that postflood cases of leptospirosis can be associated with flood events in space and time. The total cases in both 2018 and 2019 increased in the post-flood phase, with the increase in 2018 being more evident. Unlike the 2019 flood, the flood of 2018 is a significant spatial indicator for postflood cases. Our study shows that flooding leads to an increase in leptospirosis cases, and there is stronger evidence for increased leptospirosis cases after a heavy flood event than after a moderate flooding event. Flood duration may be the most important factor in determining the increase in leptospirosis infections. [ABSTRACT FROM AUTHOR]

Flooding is a recurring issue in India, affecting 10–15 states annually during monsoon season and coastal regions due to cyclones. Microwave satellite data from SAR sensors like RISAT-1A, launched in February 2022, offers near real-time flood mapping crucial for relief efforts. Various acquisition modes, including medium resolution ScanSAR (MRS) mode, coarse resolution ScanSAR (CRS) mode and fine resolution Strimap (FRS) mode, provide suitable resolutions for flood mapping. Case studies demonstrate the behaviour of the backscatter coefficient in flood pixels, essential for flood map preparation. Validation against optical datasets shows a high accuracy of 91% in CRS, 94% in MRS and 94% in FRS, which is acceptable for near real-time mapping. The 67 and 91 flood maps were generated in 2022 and 2023 respectively, aiding state and central disaster management. [ABSTRACT FROM AUTHOR]

This article investigates the effects of socio-demographic characteristics of the 2010 flood victims, their flood exposure, and social and formal support on post-flood subjective recovery. It seeks to illuminate the factors best correlating with life recovery feelings of the respondents. Regression analysis of survey data showed that period of return to home, annual income, family size, material damage, and social support significantly correlated with the life recovery of respondents. More specifically, the period of return to home and material loss had a negative connection with life recovery feelings of flood victims while the annual income of the respondents, family size, and social support had a positive correlation on their life recovery feelings. Analysis also revealed that formal disaster support had a very negligible correlation with life recovery. However, social support helped to lessen the negative effects of material damage on the life recovery feelings of the survivors. The correlation of annual income with life recovery feelings remained almost constant and significant in all the regression models, showcasing the importance of personal resources to recover from disaster. The study concludes that although both social and formal support are pivotal for post-flood subjective recovery, they face serious limitations. More nuanced longitudinal studies are required to understand the contours of long-term life recovery process. [ABSTRACT FROM AUTHOR]

In the summer of 2022, Pakistan experienced a severe flood event that brought great destruction to the local people and ecosystem. However, there is no comprehensive study on the process, spread and causes of this flood. Therefore, we combined multiple satellite gravity data, meteorological data, hydrological data, and satellite remote sensing data to conduct a thorough investigation and study of this flood. The results show that a 20-year time series of the terrestrial water storage change based multiple gravity data has the high accuracy and reliability, which is used for detecting the flood. The flood propagated through meteorological system (three months), agricultural system (six months) and terrestrial ecosystems (five months), respectively, and the two southern provinces (Balochistan and Sindh) are the most affected by the flood, whose flood severity is 6.955 and 9.557, respectively. The center of the severe flood is located at the border region between the above two province. The severe flood is attributed primarily to the global extreme climate events (La Niña and negative Indian Ocean Dipole events) that altered the transport path of water vapor in the Indian Ocean, causing large amounts of water vapor to converge over Pakistan, resulting in heavy precipitation, and secondarily to the melting of extensive glacier in the mountainous of northern Pakistan as a result of the high temperature in March-May 2022. The above results contribute to the understanding of the mechanism of the impact of extreme climate events on the regional climate, and provide some references for the study of severe floods. [ABSTRACT FROM AUTHOR]

Islands and analogous insular habitats are found in several ecological contexts. With the exception of oceanic islands, however, the contribution of these insular habitats to regional biodiversity remains poorly investigated, especially in tropical regions. We investigated the understory spider assemblages in an Amazonian river archipelago to evaluate the contribution of fluvial islands to regional spider diversity.We collected spiders on 30 islands ranging from 1 to 1527 ha and at 23 sites in mainland habitats represented by continuous igapó flooded forests and terra firme forests. Spiders were collected by shaking the vegetation over a white sheet during a standardised time of 30 min.From 1404 adult individuals, we identified 290 spider species or morphospecies, with 150 species being recorded on the fluvial islands, 122 in the igapó flooded forests and 103 in the terra firme forests. Spider assemblages of fluvial islands exhibit lower alpha diversity and equitability compared with mainland habitats. The species composition of fluvial islands was significantly distinct from that of mainland habitats, even when compared with neighbouring igapó flooded forests. Several families and species of spider were significantly associated with a particular habitat, including 8 families and 10 species identified as indicators of fluvial islands.Fluvial islands effectively contribute to regional diversity since their spider fauna is not a mere impoverished subset of species from mainland habitats. Events that alter the flood pulse in Amazonian rivers (e.g., construction of hydroelectric dams) could threaten the unique biological assemblages of the floodplain habitats, especially the fluvial islands. [ABSTRACT FROM AUTHOR]

Accurate assessment of surface water from satellite and remote sensing data plays an important role in water and flood management and supporting natural ecosystems and human development. Remote sensing imagery has significantly advanced in water extraction methods, particularly in water index, classification, and sub-pixel analysis. Water-index-based approaches offer notable advantages such as speed and convenience among these methods. The unique characteristics of surface water and flooded areas, including their extensive coverage and dynamic nature, make the water index particularly effective for monitoring large regions. However, the complexity of land surfaces in aquatic environments presents challenges that hinder accurate water extraction. These challenges differ across various factors, such as shadows in urban and mountainous areas, small water bodies, muddy water, and water leakage in unshaded regions. The current study introduces a novel Flood/Water Extraction Index (FWEI) for identifying water and flooded areas to address these challenges. The FWEI utilizes the average ratio of visible and near-infrared bands derived from Sentinel-2 images. The proposed index utilizes images with 10-m and average visible bands and more effectively compensates for errors arising from spectral and spatial changes. Therefore, it demonstrates strong performance by more accurately mapping muddy and clear water within small water bodies and narrow rivers. The performance of the offered FWEI index is compared with other indices, including the Normalized Difference Water Indices (NDWI-G, NDWI-F), Modified NDWI (MNDWI-1, MNDWI-2), and the Automatic Water Extraction Index (AWEInsh) without shadow. While other indices excel in specific scenarios, such as built-up or non-built-up areas, and bare lands versus vegetated areas, the FWEI index demonstrates consistently high accuracy and stability in extracting surface water across diverse backgrounds. The FWEI index achieves an average Overall Accuracy (OA) of 94.26% for water extraction and 93.11% for flood extraction. In comparison, the AWEInsh attains an OA of 90.48% and 90.39%, NDWI-F performs at 86.69% and 86.55%, MNDWI-1 at 77.21% and 75.82%, MNDWI-2 at 76.12% and 75.42%, and NDWI-G at 75.26% and 74.78%, respectively. The integration of visible spectral bands with the near-infrared band proves instrumental in enhancing the accuracy of water derivation in complex and expansive environments. [ABSTRACT FROM AUTHOR]

In 1954, a devastating flood struck the entire Yangzi River basin, causing the first major natural disaster in the newly established People's Republic of China (PRC). The young regime had just embarked on its First Five-Year Plan, aimed at achieving rapid economic development and industrialization. The flood swept across several provinces, displaced populations, and submerged farmlands, posing both a new challenge and an opportunity for the regime to shape the socioeconomic landscape of the affected regions. This article uses a localized perspective to examine how the rural society of Hubei Province, the hardest-hit area, responded to the disaster. The central government's self-help doctrine delegated much power to local governments and communities. Local officials and rural cadres had considerable leeway in managing the relief campaign as they simultaneously followed the state macroeconomic policy of rural collectivization. The 1954 flood in Hubei Province serves as a case study that illustrates the complexities of disaster management in the early years of the PRC. [ABSTRACT FROM AUTHOR]

A significant research focus is placed on identifying animal species and areas at future risk to human‐induced alterations of the environment and long‐term changes in climatic conditions. Yet, the extent to which exposure to extreme climatic events and intense human pressure can increase the risk of harmful impacts on species remains poorly investigated. Focusing on terrestrial mammals in China, one of the world's megadiverse countries, we investigated patterns of contemporary exposure to floods and human pressures and determined their taxonomic representation and distribution across three major area‐based conservation schemes, namely, national nature reserves (NNRs), priority areas for biodiversity conservation (PABCs), and key biodiversity areas (KBAs). Among the 440 species assessed with moderate or high exposure to floods, 327 (∼75%) also qualified as moderate or high in exposure to intense human pressure. These species mainly belong to the orders Chiroptera, Eulipotyphla, and Rodentia. Likewise, there were 305, 311, and 311 species with moderate or high exposure to flood and intense human pressure represented across NNRs, PABCs, and KBAs, respectively. Our findings support the prioritization of KBAs for expansion of site‐based protection efforts such as NNRs in China, considering threats to species from exposure to adverse effects from both extreme climate and human pressure. [ABSTRACT FROM AUTHOR]

Landslides are a severe geohazard around the world. When moving soil masses discharge into a large water body, a tsunami can be generated and exacerbate the devastating effects of the landslide as well as extend the affected area. In this study, based on on-site geological investigation and monitoring, a numerical depth-averaged, two-phase model is established for a hypothetical tsunami in the Suofengying reservoir induced by the potential Bianjiazhai landslide in China which has been previously identified as critical. The analysis of the simulation results shows that the maximum wave amplitude measured at gauge point closest to the landslide is 31 m, and the tsunami reaches the reservoir's dam about 66 s after the landslide initiation. The inundation map provides potential risk areas that could be affected if a landslide occurs with the anticipated characteristics. Under similar conditions, the research results will help guide reservoir operation and landslide-tsunami disaster prevention. Simultaneously, examining the sequence of events in the tsunami disaster chain facilitates the analysis of the fundamental physics governing the propagation of tsunamis within reservoirs. This analysis contributes to the prediction and prevention of landslide-induced tsunami disasters occurring along reservoir banks. [ABSTRACT FROM AUTHOR]

In July 1951, the American Midwest experienced one of its worst floods in its history up to that point, resulting in hundreds of millions of dollars in damages and the displacement of hundreds of thousands of people. While ostensibly a national issue, the natural disaster also drew the attention of hundreds of German citizens who donated to the relief effort. In the letters accompanying their donations, these Germans emphasized that they wanted to submit a token of their gratitude to the American people and begin to pay back a fraction of what they felt they owed for American humanitarian assistance in the immediate postwar era. Though the American government did not solicit these donations, it saw value in help publicising the donations and their letters. Locked in a propaganda battle with the Soviet Union, American authorities promoted these donations not only as evidence of German-American friendship, but also as evidence that their humanitarian policy at the dawn of the Cold War had achieved significant cultural, political, and diplomatic goals throughout Germany. [ABSTRACT FROM AUTHOR]

Multipath effect largely affects the performance of GPS positioning since it is related to the surrounding environment of the GPS station and cannot be effectively corrected by the empirical model. In particular, the multipath effect increases during flood due to the reflection and refractive of water performing higher than that of dry soil. Thus, in order to improve the performance of SPP (signal point positioning) during flood, the multipath effect should be considered and mitigated. The quantities related to multipath effect are analyzed by using data sets collected during flood, which includes the CNR (carrier-to-noise ratio) and MP (pseudorange multipath). In addition, the performance of SPP during a flood is evaluated, results show that the decreased percentages of SPP in the three components are approximately 25.00 % for E, 17.91 % for N, and 21.48 % for U, respectively. To mitigate the influence of multipath induced by flood, the correlation between the CNR, MP, and elevation angle (EA) is investigated in theory. Results indicate that the correlation between CNR and MP is much greater than the correlation between MP and EA. Thus, a new method based on an improved multi-CNR weight strategy and the sidereal filtering method is proposed to mitigate the multipath effect. The performance of the proposed method is assessed by using real data sets. Experimental results show that the average correlation between the multipath correction model and multipath error can reach approximately 0.65. After applying the proposed method, the accuracy of MP and SPP can be effectively improved, and the average improvement rate of the MP and three components are approximately 16.84 % and 14.76 % compared with the original results, respectively. It should be noted that this proposed method is also suitable for static SPP applications in other multipath environments, such as the environment obscured by trees. [ABSTRACT FROM AUTHOR]

In July to August 2022, Pakistan suffered historic flooding while record-breaking heatwaves swept southern China, causing severe socioeconomic impacts. Similar extreme events have frequently coincided between two regions during the past 44 years, but the underlying mechanisms remain unclear. Using observations and a suite of model experiments, here, we show that the upper-tropospheric divergent wind induced by convective heating over Pakistan excites a barotropic anomalous anticyclone over eastern China, which further leads to persistent heatwaves. Atmospheric model ensemble simulation indicates that this dynamic pathway linking Pakistan flooding and East Asian heatwaves is intrinsic to the climate system, largely independent of global sea surface temperature forcing. This dynamic connection is most active during July to August when convective variability is large over Pakistan and the associated divergent flow excites barotropic Rossby waves that propagate eastward along the upper troposphere westerly waveguide. This robust waveguide and the time delay offer hopes for improved subseasonal prediction of extreme events in East Asia. [ABSTRACT FROM AUTHOR]

The world is witnessing a difficult time trying to circumscribe the spread of COVID-19 pandemic. The situation has become even more challenging as several natural disasters and emergencies coincided with this pandemic and created a situation of concurrent emergency. Effectively managing concurrent emergencies are extremely challenging. Only by utilizing and applying the knowledge gathered while combating a real-life concurrent emergency, one can further be prepared to face such emergencies. Hence, this study intends to identify the critical success factors (CSFs) having a major role in effective management of concurrent emergencies and evaluate the indispensable links among the factors. Twelve CSFs are identified from Pareto analysis, for which feedback from 46 experts involved in the management of emergencies is utilized. In addition, the revised rough-decision making trial and evaluation laboratory (rough-DEMATEL) approach is suggested to analyze the indispensable links among the CSFs and further, these factors are ranked based on the average vector length. The recent case of concurrent emergency in Bangladesh- floods amid a pandemic is considered to establish the applicability of this method. The findings of this research reveal that to handle concurrent emergencies 'Incremental improvement of proactive measures', 'Resilient supply chain and logistics network', and 'Government leadership and military cooperation' are the most critical factors to concurrent emergency management (CEM). These CSFs play a major role in ensuring the effectiveness of CEM. Thus, this study can be a building block in developing an effective CEM plan for the policymakers, managers, and practitioners. [ABSTRACT FROM AUTHOR]

Losses from catastrophic floods are driving intense efforts to increase preparedness and improve response to disastrous flood events by providing early warnings. Yet accurate flood forecasting remains a challenge due to uncertainty in modeling, calibrating, and validating a useful early warning system. This paper presents the Requisitely Simple (ReqSim) flood forecasting system that includes key variables and processes of basin hydrology and atmospheric forcing in a data-driven modeling framework. The simplicity of the modeling structure and data requirements of the system allows for customization and implementation in any medium to large rain-fed river basin globally, provided there are water level or discharge measurements at the forecast locations. The proposed system's efficacy is demonstrated in this paper through providing useful forecasts for various river basins around the world. This include 3–10-day forecasts for the Ganges and Brahmaputra rivers in South Asia, 2–3-day forecast for the Amur and Yangtze rivers in East Asia, 5–10-day forecasts for the Niger, Congo and Zambezi rivers in West and Central Africa, 6–8-day forecasts for the Danube River in Europe, 2–5-day forecasts for the Parana River in South America, and 2–7-day forecasts for the Mississippi, Missouri, Ohio, and Arkansas rivers in the USA. The study also quantifies the effect of basin size, topography, hydrometeorology, and river flow controls on forecast accuracy and lead times. Results indicate that ReqSim's forecasts perform better in river systems with moderate slopes, high flow persistence, and less flow controls. The simple structure, minimal data requirements, ease of operation, and useful operational accuracy make ReqSim an attractive option for effective real-time flood forecasting in medium and large river basins worldwide. [ABSTRACT FROM AUTHOR]

Recently, discontinuous polymer flooding has been proposed and successfully applied in some offshore oilfields. The performance of discontinuous polymer flooding depends on various operational parameters, such as injection timing, polymer concentrations, and crosslinker concentrations of four types of chemical slugs. Because the number of the operational parameters are large and they are nonlinearly related, the traditional reservoir numerical simulation might not simultaneously obtain the optimal results of these operational parameters. In this study, to simulate the discontinuous polymer flooding processes, a simulation model was built using a commercial reservoir simulator (CMG STARS), in which the mechanisms of the four types of chemical slugs were considered, such as polymer viscosification, adsorption, and degradation. Then, a PSO–ICA algorithm was developed by using the PSO algorithm to improve the exploration ability of the ICA algorithm. The codes were written with MATLAB and linked to CMG STARS to perform optimization processes. Finally, the PSO–ICA algorithm was compared with the ICA and PSO algorithms on benchmark functions to verify its reliability and applied to optimize a discontinuous polymer flooding process in a typical offshore oilfield in Bohai Bay, China. The results showed that the developed PSO–ICA algorithm had lower iteration numbers, higher optimization accuracy, and faster convergence rate than these of PSO and ICA, indicating that it was an effective method for optimizing the operational parameters of discontinuous polymer flooding processes. Compared to the continuous polymer flooding, the discontinuous polymer flooding had a higher oil production rate, a lower water cut, and a lower residual oil saturation. The net present value of the optimal scheme of discontinuous polymer flooding reached 7.49 × 108 $, which is an increase of 6% over that of the scheme of continuous polymer flooding. More research including selecting more reasonable parameters of the PSO–ICA algorithm to increase its optimization accuracy and convergence rate, comparing with other available optimization algorithms, and verifying the performance of the optimal scheme of discontinuous polymer flooding in the practical offshore oilfield will be required in the future. [ABSTRACT FROM AUTHOR]

Global warming is exacerbating flood hazards, making the robustness of flood risk management a critical issue. Without considering future scenarios, flood risk analysis built only on historical knowledge may not adequately address the coming challenges posed by climate change. A comprehensive risk analysis framework based on both historical inundations and future projections to tackle uncertainty is still lacking. In this view, a scenario-based, data-driven risk analysis framework that for the first time integrates recent historical floods and future risk trends is here presented, consisting of flood inundation-prone and high-risk zones. Considering the Poyang Lake Eco-Economic Zone (PLEEZ) in China as the study area, we reproduced historical inundation scenarios of major flood events by using Sentinel-1 imagery from 2015 to 2021, and used them to build the risk baseline model. The results show that 11.7% of the PLEEZ is currently exposed to the high-risk zone. In the SSP2-RCP4.5 scenario, the risk would gradually decrease after peaking around 2040 (with a 19.3% increase in high-risk areas), while under the traditional fossil fuel-dominated development pathway (SSP5-RCP8.5), the risk peak would occur with a higher intensity about a decade earlier. The attribution analysis results reveal that the intensification of heavy rainfall is the dominant driver of future risk increase and that the exploitation of unused land such as wetlands induces a significant increase in risk. Finally, a hierarchical panel of recommended management measures was developed. We hope that our risk analysis framework inspires newfound risk awareness and provides the basis for more effective flood risk management in river basins. [ABSTRACT FROM AUTHOR]

The geomorphological impact of base-level lowering on ephemeral alluvial streams has been extensively investigated through fieldwork, experimentation, and modeling. Yet, the understanding of hydrological parameters governing the dynamics of the stream's geometry during discrete flood events is lacking due to limited direct measurements of flood-scale erosion/deposition. The emergence of novel remote sensing methods allows for quantifying morphological modifications caused by floods in alluvial streams. This study utilizes drone surveys and hydrological data to quantitatively investigate the relation between channel evolution in alluvial tributaries draining to the receding Dead Sea and the hydrological characteristics of flash floods. Drone-based photogrammetric surveys were conducted before and after 25 floods, over a period of four years, to generate centimeter-scale Digital Elevation Models (DEM) and orthophoto maps of two major streams. The outcomes of these DEMs are maps of ground elevation changes (erosion/deposition), thalweg longitudinal profiles, and channel cross sections, revealing the incision/aggradation along and across the streams. Statistical comparison of results with flow hydrographs identified potential relations linking the hydrological characteristics of each flood and the corresponding geomorphological modifications. Peak discharge emerged as the primary factor influencing sediment removal, leading to more efficient sediment evacuation and a negative sediment budget with increased discharge. Water volumes of floods also exhibited a secondary effect on the sediment budget. The chronological order of floods, whether first or later in the season, was identified as the primary factor determining incision magnitude. Knickpoints formed at the streams' outlets during the dry period, when lake-level drops, amplifying the impact of the first flood. These findings have potential implications for infrastructure planning and environmental management in the context of climate change and altered water runoff. The research highlights the efficiency of drone-based photogrammetry for cost-effective and timely data collection, providing invaluable flexibility for field research. [ABSTRACT FROM AUTHOR]

This paper presents a building‐level post‐hazard functionality model for communities exposed to flood hazards including the interdependencies between the population, buildings, and infrastructure. An existing portfolio of building archetypes is used to model the post‐hazard physical flood functionality of different building typologies within the community with the goal of supporting resilience‐informed decision‐making. Specific fragility‐based flood functionality curves were developed for this portfolio to quantify the exceedance probability of a prescribed set of functionality states. While the physical functionality of buildings is significant to the total functionality of a building and community resilience assessment, the functionality of utilities such as power and water along with the accessibility of the household to essential services such as schools and hospitals is crucial to measure their total functionality. Therefore, functionality models for essential infrastructure were developed to assess housing unit‐ and building‐level functionality following flood hazards. This model also accounts for the functionality of the road network following a flood hazard to identify the level of accessibility of households to different services (e.g., schools, hospitals, gas stations, shopping centers, etc.). The main novelty of this paper is the ability to quantify the total functionality of buildings based on a socio‐physical formulation after including the interdependencies between the functionality of the physical systems and the subsequent functionality of the socio‐economic systems, which is key to measuring resilience at the community level. This was evident from the analysis results using a testbed community of Lumberton, NC, showing that the physical functionality is not sufficient to quantify the total post‐hazard functionality of buildings and that the functionality of other subsystems such as utilities and accessibility to essential services are also needed to quantify the total functionality of buildings and the livability of households. [ABSTRACT FROM AUTHOR]

The rise in sea levels, driven by global climate change, poses a significant threat to cultural heritage in coastal regions. Traditional risk assessment methods, focusing on direct inundation, often fail to consider the crucial impact of socio-economic factors, which are significantly vulnerable to sea level rise. To bridge this gap, this study introduces an innovative Sea Level Rise Cultural Heritage Impact Assessment Model (SLR-CHIA Model), a novel approach that integrates both land inundation and socio-economic aspects. This comprehensive model evaluates potential risks to various types of cultural heritage in coastal China, including intangible cultural heritage, relics, and traditional villages. The study's findings are striking: (1) About 7.79% of coastal villages, 53.94% of relics, and 2.53% of intangible cultural heritage are potentially at high risk in a 100-year sea level rise event; (2) Relics in the Eastern coast and villages in the Southern coast are most vulnerable; (3) Different types of cultural heritage rely on diverse principal factors for protection, resulting in varied risk levels under sea level rise conditions. The SLR-CHIA Model provides a vital methodological framework for evaluating cultural heritage risks in other global regions. [ABSTRACT FROM AUTHOR]

This study investigates the impact of the Madden–Julian Oscillation (MJO) on the extreme rainfall events across 11 eastern coastal stations during the northeast monsoon season (November to March) over the Philippines from 1979 to 2019. The contribution of synoptic systems to these extreme rainfall events such as tropical cyclones (TCs), low‐pressure systems (LPS), cold surges (CS), and other disturbances as they coincide with a strong and active MJO were quantified. The results show that the probability of extreme rainfall occurrence increases first to as much as 20% in the southernmost stations in Phase 4. Then, it increases to more than 60% in central‐eastern stations in Phase 6. The extreme rainfall events were then classified into: MJO‐only, TC‐MJO, TC‐nonMJO, LPS‐MJO, LPS‐nonMJO, CS‐MJO, CS‐nonMJO, and others. The percentage contribution of MJO only, TC‐MJO, LPS‐MJO, and CS‐MJO to the total extreme rainfall events ranges from 9% to 16%, 0% to 3%, 2% to 4%, 1% to 9%, respectively. The relationship between MJO and flooding events in the Philippines was also examined. About 28 flood events or 266 flooding days were identified during the analysis period, wherein 50% of these events coincidentally occurred during strong and active phases of MJO. [ABSTRACT FROM AUTHOR]

This study aims to further enhance the oil recovery of reservoirs in the Zhong-2 Block of the Gudao Oilfield by identifying the most effective microbial-flooding activator systems and applying them in the field. We began by analyzing the structure of the reservoirs' endogenous microbial communities to understand the potential impact of microbial flooding. This was followed by determining commonly used activator systems based on their abilities to stimulate oil-displacement functional bacteria. Through laboratory experiments on oil displacement efficiency and sweep characteristics, we determined the optimal activator injection method (injection ratio) and the requisite bacterial concentration for maximal microbial-flooding efficacy. Finally, we selected the optimal activator systems and applied them to field tests. Our findings suggest the target block is highly receptive to microbial-flooding. In terms of performance, the activator systems ranked as No. 3 > No. 4 > No. 1 > No. 2. Interestingly, a deep activator system, when compared to the top-performing No. 3 system, exhibited a higher bacterial concentration peak and longer peaking duration. Optimal oil displacement effects were observed at a 1:4 vol ratio between the No. 3 activator and deep activator systems, with bacterial concentrations of up to 106 cells/mL or above. Field tests with the selected activator systems, following a specific injection protocol, demonstrated a notable increase in oil production and a reduction in water cut. [ABSTRACT FROM AUTHOR]

After the flood of 1927, the US government decided to master the Mississippi River. Nowhere was this state-sponsored determination more evident than in the lower Mississippi River delta. An historical examination of a cluster of Catholic churches in Pointe Coupée Parish, Louisiana, permits some understanding of how physical and material alterations to landscapes are not easily traced, especially when we consider the temporal and spatial scales of change to the Mississippi over the last one hundred years. In that time, Catholics of Pointe Coupée Parish managed to retain, erase, and revise aspects of their bonds to a river once central to the lives of their ancestors. This is not at all surprising, as the fallibility of memory is made apparent every time we try to tell stories about our pasts. Pointe Coupée Parish is one site where we can explore how alterations to a landscape have an impact not only on the trajectory of a Catholic community's future, but also on access to its past. Absences of memory in the living, combined with the erasure of material remains in modified landscapes, challenge us to consider how we might account for the relationship between Catholicism and the built environment throughout American history. [ABSTRACT FROM AUTHOR]

Nonhydrostatic models have proven their superiority in describing tsunami propagation over trans-oceanic distances and nearshore transformation because of their good dispersion and nonlinearity properties. The novel one-layer nonhydrostatic formulations proposed by Wang et al. [Phys. Fluids 35, 076610 (2023)] have been rederived in the spherical coordinate system incorporating Coriolis effects to enable the application of basin-wide tsunami propagation. The model was implemented using the fractional step method, where the hydrostatic step was solved by a Godunov-type finite-volume scheme, and the nonhydrostatic step was obtained with the finite-difference method. Additionally, a two-way grid-nesting scheme was employed to adapt the topographic features for efficient computation of tsunami propagation in deep ocean and coastal inundation. Furthermore, graphics processing unit (GPU)-parallelism technique was incorporated to further optimize the model performance. An idealized benchmark test as well as three experiments of regular and irregular waves, solitary, and N-waves transformations have been simulated to demonstrate the superior performance of the current GPU-accelerated grid-nesting nonhydrostatic model. Finally, the model has been applied to reproduce the 1964 Prince William Sound Tsunami, its propagation across the North Pacific and induced inundation in the Seaside. [ABSTRACT FROM AUTHOR]

Flooding constitutes a major problem for the inhabitants of Douala City in general and those of the Tongo Bassa watershed (TBW) in particular. Faced with this situation, public authorities need to put in place measures to mitigate the vulnerability of populations to these disasters. This article aims to map flooding risk areas in the TBW using the geographic information system, field data (historical flood points), remote sensing data (Sentinel II image) and the frequency ratio model. The map produced shows that 1.41, 8.88, 28.51, 33.86 and 27.33% of the basin area are respectively delimited into very low, low, medium, high and very high flood vulnerability classes. High and very high flooding risk areas (those where flooding is most likely to occur) occupy more than half of the basin (61.19%). These areas are characterized by significant imperviousness, low altitudes, weak slopes, significant proximity to watercourses and clayey soils. Most of the houses in the basin (66.92%) are located in areas affected by these two levels of exposure (high and very high). With respective success and prediction accuracy rates of 89 and 96.78%, a certain confidence deserves to be placed on the map of flooding risk areas produced. [ABSTRACT FROM AUTHOR]

Scavenging dynamics are influenced by many abiotic and biotic factors, but there is little knowledge of how scavengers respond to extreme weather events. As carrion is a major driver of the organisation and structure of food webs within ecological communities, understanding the response of scavengers to extreme weather events is critical in a world that is increasingly subject to climate change. In this study, vertebrate scavenging and carcass persistence rates were quantified in the Simpson Desert of central Australia; a system that experiences major fluctuations and extremes in weather conditions. Specifically, a total of 80 adult red kangaroo (Osphranter rufus) carcasses were placed on the landscape and monitored using remote sensor cameras. This included 40 carcasses monitored before and then 40 carcasses monitored after a major flooding event. The carcasses were monitored equally before and after the flood across different seasons (warm and cool) and in dune and interdune habitats. Overall, a total of 8124 scavenging events for 97,976 visitation minutes were recorded for 11 vertebrate species within 30 days of carcass placement pre- and post-flood. Vertebrate scavenging increased post-flood in the warm season, especially by corvids which quadrupled their scavenging events during this time. There was little difference in carcass persistence between habitats, but carcasses persisted 5.3-fold longer post-flood in warm seasons despite increased vertebrate scavenging. The results demonstrate that a flood event can influence scavenging dynamics and suggest a need to further understand how seasons, habitats and extreme weather events can drive changes in carrion-based food webs. [ABSTRACT FROM AUTHOR]

Uniformitarian theories of Martian history present many problems. A Biblical alternative is proposed that includes the Day-4 cratering hypothesis and Mars' crustal magnetism. Greatly reduced magnetism in the centers of the four largest impact craters suggests that most large Mars impacts occurred during the Genesis Flood. These impacts, and subsequent volcanism generated by them, produced a climate with sufficient liquid water for the Martian floods. A young age for Mars is supported by several geological observations. Rapid flooding can explain the valley networks and the outflow channels and provide a tighter volume estimate of around a 100 m Global Equivalent Layer (GEL). The flood water was absorbed into the subsurface and into hydrated minerals. That temporary atmosphere disappeared as water vapor precipitated out and the atmosphere cooled. Precipitation also absorbed CO2 and SO2 which helps account for their atmospheric disappearance. [ABSTRACT FROM AUTHOR]

Serving as a crucial part of the Yangtze River Basin (YRB)'s flood control system, Flood Detention Areas (FDAs) are vital in mitigating large-scale floods. Urbanization has led to the development of urban FDAs, but significant losses could ensue if these FDAs are activated. With improved reservoirs and embankments, flood pressure in the middle reaches has lessened, posing challenges in balancing flood control and economic benefits. This paper presents a comparative analysis of land use, GDP, and population in FDAs and adjacent cities, enhancing our understanding of their disparities and interrelations. Using the Analytic Hierarchy Process (AHP)–Entropy Weight Method (EW)–Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) comprehensive evaluation method, we assess changes in flood control and economic values in FDAs. The results show a conflict between flood control and economic policies in FDAs, highlighting their underestimated economic potential, especially in urban areas. This study identifies differences in economic development across FDAs and a strong correlation between flood control value and inundation rates. Based on evaluations and simulations of the 1954 flood, we provide recommendations for the FDAs' construction plan, which serves the development and flood management of the YRB and offer insights for similar assessments elsewhere. [ABSTRACT FROM AUTHOR]

Natural hazards can present a significant risk to road infrastructure. This infrastructure is a fundamental component of the transportation infrastructure, with significant importance. During emergencies, society heavily relies on the functionality of the road infrastructure to facilitate evacuation and access to emergency facilities. This study introduces a versatile, multi-scale framework designed to analyze accessibility within road networks during natural hazard scenarios. The first module of the framework focuses on assessing the influence of natural hazards on road infrastructure to identify damaged or blocked road segments and intersections. It relies on near real-time information, often provided by citizen science through Volunteered Geographic Information (VGI) data and Natural Language Processing (NLP) of VGI texts. The second module conducts network analysis based on freely available Open Street Map (OSM) data, differentiating between intact and degraded road networks. Four accessibility measures are employed: betweenness centrality, closeness centrality, a free-flow assumption index, and a novel alternative routing assumption measure considering congestion scenarios. The study showcases its framework through an exemplary application in California, the United States, considering different hazard scenarios, where degraded roads and connected roads impacted by the hazard can be identified. The road extraction methodology allows the extraction of 75% to 100% of the impacted roads mentioned in VGI text messages for the respective case studies. In addition to the directly extracted impacted roads, constructing the degraded network also involves finding road segments that overlap with hazard impact zones, as these are at risk of being impacted. Conducting the network analysis with the four different measures on the intact and degraded network, changes in network accessibility due to the impacts of hazards can be identified. The results show that using each measure is justified, as each measure could demonstrate the accessibility change. However, their combination and comparison provide valuable insights. In conclusion, this study successfully addresses the challenges of developing a generic, complete framework from impact extraction to network analysis independently of the scale and characteristics of road network types. [ABSTRACT FROM AUTHOR]

Climate change seriously threatens human systems, properties and livelihoods. Global projections suggest a continuous increase in the frequency and severity of weather events, with severe outcomes. Although the trends and impacts are highly variable depending on location, most studies tend to concentrate on either the urban or rural areas, with little focus on peri-urban areas. Yet, in Sub-Saharan Africa, peri-urban areas display unique characteristics: inadequate infrastructure, unplanned development, weak governance, and environmental degradation, all of which exacerbate flood impact and thus need academic attention. This study contributes to filling this gap by assessing the flood vulnerability of roads in peri-urban Accra and its implications for mobility. Based on the fieldwork, the study delineated and analysed potential zones within the research locations. The researchers calculated roads' absolute and relative lengths, using a spatial overlay (intersection) of potentially flooded roads with the total road network within the grid cells of 500 m by 500 m. These measures were adopted and used as exposure measures. The findings revealed that over 80% of roads with lengths between 100 m and 500 m were exposed to floods. Some areas had higher exposure indices, with absolute road lengths ranging from 1.5 km to 3.2 km and relative road lengths between 0.8 and 1.0. There were significant variations in road exposure between and within neighbourhoods. Depending on the depth and duration of the floodwater, residents may be unable to access their homes or carry out their daily activities. In conclusion, this study highlights the differential vulnerability of peri-urban areas to road flooding and recommends targeted provision of flood-resilient infrastructure to promote sustainable development. [ABSTRACT FROM AUTHOR]

Floods are consistently ranked as the most financially devastating natural disasters worldwide. Recent flood events in the Netherlands, Caribbean, and US have drawn attention to flood risks resulting from pluvial and fluvial sources. Despite shared experiences with flooding, these regions employ distinct approaches and flood management strategies due to differences in governance and scale—offering a three-site case study comparison. A key, yet often lacking, factor for flood risk and damage assessments at the parcel level is building elevation compared to flood elevation. First-floor elevations (FFEs) are a critical element in the vulnerability of a building flooding. US-based flood insurance policies require FFEs; however, data availability limitations exist. Drone-based FFEs were measured in all locations to assess the flood vulnerabilities of structures. Flood vulnerability profiles revealed 64% of buildings were vulnerable to a form of inundation, with 40% belonging to "moderate" or "major" inundation, and inundation elevation means (IEMs) of −0.55 m, 0.19 m, and 0.71 m within the US, Netherlands, and Puerto Rico sites, respectively. Spatial statistics revealed FFEs were more responsible for flood vulnerabilities in the US site while topography was more responsible in the Netherlands and Puerto Rico sites. Additional findings in the Puerto Rico site reveal FFEs and next highest floor elevations (NHFEs) vulnerable to future sea level rise (SLR) flood elevations. The findings within the Netherlands provide support for developing novel multi-layered flood risk reduction strategies that include building elevation. We discuss future work recommendations and how the different sites could benefit significantly from strengthening FFE requirements. [ABSTRACT FROM AUTHOR]

Extreme precipitation events, which are common natural hazards, are expected to increase in frequency due to global warming, leading to various types of floods, including pluvial floods. In this study, we investigated the probabilities of maximum 3-day precipitation amount (Rx3day) occurrences during spring in the Vojvodina region, covering both past (1971–2019) and future (2020–2100) periods. We utilized an ensemble of eight downscaled, bias-corrected regional climate models from the EURO-CORDEX project database, selecting the RCP8.5 scenario to examine future Rx3day amounts. The probabilities of occurrences of Rx3day were modeled using the GEV distribution, while the number of events where Rx3day in spring exceeds specific thresholds was modeled using the Poisson distribution. The results indicate that Rx3day with a ten-year return period during the spring months is expected to increase by 19% to 33%. Additionally, the probabilities of having more than one event where Rx3day exceeds thresholds are projected to rise by 105.6% to 200.0% in the future compared to the historical period. The analysis comparing the design values of Rx3day with future projections for the period 2020–2100 revealed that 51 drainage systems are likely to function without difficulties under future climate conditions. However, for the remaining 235 drainage systems, an increased risk of pluvial flooding was identified, as their design precipitation amounts are lower than the future projections. This study reveals that analyzing extreme rainfall events in the context of climate change yields crucial information that facilitates effective planning and policy making in water management, particularly flood protection. [ABSTRACT FROM AUTHOR]

To ensure water use and water resource security along "the Belt and Road", the runoff and hydrological droughts and floods under future climate change conditions in the upper Heihe River Basin were projected in this study, based on the observed meteorological and runoff data from 1987 to 2014, and data from 10 GCMs from 1987 to 2014 and from 2026 to 2100, using the SWAT model, the Standardized Runoff Index, run length theory, and the entropy-weighted TOPSIS method. Both the multi-GCM ensemble (MME) and the optimal model were used to assess future hydrological drought and flood responses to climate change. The results showed that (1) the future multi-year average runoff from the MME was projected to be close to the historical period under the SSP245 scenario and to increase by 2.3% under the SSP585 scenario, and those from the optimal model CMCC-ESM2 were projected to decrease under both scenarios; (2) both the MME and the optimal model showed that drought duration and flood intensity in the future were projected to decrease, while drought intensity, drought peak, flood duration, and flood peak were projected to increase under both scenarios in their multi-year average levels; (3) drought duration was projected to decrease most after 2080, and drought intensity, flood duration, and flood peak were projected to increase most after 2080, according to the MME. The MME and the optimal model reached a consensus on the sign of hydrological extreme characteristic responses to climate change, but showed differences in the magnitude of trends. [ABSTRACT FROM AUTHOR]

To investigate the relationship between grain sizes, seepage capacity, and oil-displacement efficiency in the Liushagang Formation of the Beibuwan Basin, this study identifies the multistage pore-throat structure as a crucial factor through a comparison of oil displacement in microscopic pore-throat experiments. The two-phase flow evaluation method based on the LieHorne model is utilized to effectively characterize and quantify the seepage characteristics of different reservoirs, closely relating them to the distribution of microscopic pores and throats. It is observed that conglomerate sandstones at different stages exhibit significant heterogeneity and noticeable differences in seepage capacity, highlighting the crucial role played by certain large pore throats in determining seepage capacity and oil displacement efficiency. Furthermore, it was found that the displacement effects of conglomeratic sandstones with strong heterogeneity were inferior to those of conventional homogeneous sandstone, as evidenced by multiple displacement experiments conducted on core samples with varying granularities and flooding systems. Subsequently, core-based experiments on associated gas flooding after water flooding were conducted to address the challenge of achieving satisfactory results in a single displacement mode for reservoirs with significant heterogeneity. The results indicate that the oil recovery rates for associated gas flooding after water flooding increased by 7.3%e16.4% compared with water flooding alone at a gas eoil ratio of approximately 7000 m³/m³. Therefore, considering the advantages of gas flooding in terms of seepage capacity, oil exchange ratio, and the potential for two-phase production, gas flooding is recommended as an energy supplement mode for homogeneous reservoirs in the presence of sufficient gas source and appropriate tectonic angle. On the other hand, associated gas flooding after water flooding is suggested to achieve a more favorable development effect compared to a single mode of energy supplementation for strongly heterogeneous sandstone reservoirs. [ABSTRACT FROM AUTHOR]