Winter Flooding Research Articles

Understanding the organizing scales of winter flood hydroclimatology and the associated drivers over the coterminous United States

Understanding the organizing scales of winter flood hydroclimatology and the associated drivers over the coterminous United States

Forty years of climatic and Human Management Controls on Winter Flooding of Rice Fields in Albufera of Valencia wetland, Spain

The structure and ecological functions of wetlands depend on their hydrological regimes, which are influenced by various natural factors such as precipitation, geomorphology, vegetation and evapotranspiration. However, alterations caused by climate change have a significant impact on these hydrological cycles. Rice cultivation, especially in coastal lagoons, is also an activity that significantly modifies these cycles. This study analyzes the effect of human management and climate change on the winter flooding of rice fields in the Albufera Natural Park in Valencia (Spain), using four decades of Landsat imagery. The Normalized Difference Water Index (NDWI) was used to determine the flooded area and to develop an equation to estimate the flood level with an Normalized Root Mean Square Error (nRMSE) of 15.39%. The results made it possible to calculate the flooding water volume. A decreasing trend in winter precipitation was associated with climate change, as well as a reduction in flooded area not related to precipitation, suggesting a significant influence of human management of the area. Although precipitation affects the amount of water stored in winter, there is no consistent trend over time. The practice of flooding rice fields in winter benefits both agriculture and biodiversity, in addition to other activities such as hunting. The results underline the importance of integrated management involving all stakeholders in the conservation of these ecosystems. Environmental monitoring, with remote sensing as a key tool, is essential for effective and sustainable management of these areas.

Environmental fate and aquatic risk assessment of oxyfluorfen in California rice fields.

The herbicide oxyfluorfen [OXY; 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene] recently emerged as a potential solution to combat herbicide resistance in California rice. Proposed as a preemergent applied preflood to soil, products are in development for use with OXY-tolerant rice strains. Currently, OXY is not registered for use with rice and its use in or near aquatic resources is restricted due to its high aquatic toxicity. Before OXY may be registered for use in California rice fields, its potential fate and aquatic risk must be evaluated. Particularly important is the identification of the minimum period water must be held on the field (water holding period) necessary for OXY to dissipate below levels of concern. In this assessment, the environmental fate of OXY and its risk to aquatic organisms under simulated California rice field conditions are characterized. The Pesticides in Flooded Applications Model (PFAM) was used to estimate environmental concentrations based on anticipated use patterns and water management practices in California (e.g., winter flooding, turnover, water holding, etc.). Two California rice field soil conditions were simulated in addition to standard soil conditions used in ecological risk assessment for rice. Results suggest OXY is likely to concentrate in sediment, dissipate slowly, and persist. Water holding period had little effect on paddy and release water concentrations. Risks from water column exposure were generally below levels of concern (LOC) for aquatic animals, whereas risks to aquatic plants, algae, and benthic invertebrates exceeded LOCs under all conditions evaluated. California rice field soil conditions were also associated with less risk compared with standard conditions. Reduced application rates were sufficient to reduce risk to acceptable levels in some situations. However, holding times up to 30 days had no effect on risk outcomes, suggesting water management needs of growers should be strongly considered when stipulating water holding periods for OXY.

The Habitat Alteration of Corrigiola Litoralis L. (Strapwort) on the Elbe River Driven by Climate Change

ABSTRACTThis study aims to determine the possible future development of areas suitable for Corrigiola litoralis L. (strapwort) at six research sites on the part of the Elbe River near the border with Germany under considered climate change. We have combined hydrological and hydraulic approaches with outputs from climate models representing future climate patterns to meet these objectives. The hydrological models used in this study were BILAN, GR4J and TUW, while the hydraulic calculations were performed using HEC‐RAS. Climate data were derived from 216 climate models and grouped according to the projected change in mean temperature. Areas suitable for strapwort were identified based on conditions that reflect the ecological requirements of the species. The results show that increasing average temperatures and subsequent water level fluctuations will increase the number of seasons suitable for strapwort and its area of occurrence. These areas will emerge above water level for a longer period, extending the growing season of strapwort and increasing its reproductive capacity. At the same time, winter flooding of the sites will remain, which is likely to suppress perennial species that would competitively exclude strapwort. Regarding hydrological models, GR4J and TUW were consistent in their results. In contrast, due to the different structure, the BILAN model showed a different response to rainfall inputs, and the results were inconsistent with those of the above models. This finding highlights the need to select an appropriate hydrological model. In contrast, the sensitivity of the results to climate model variability was found to be relatively low.

Spatial Variation of Changes in Extreme Discharge Seasonality Across the Northeastern United States

ABSTRACTThe Northeast United States exhibits significant spatial heterogeneity in flood seasonality, with spring snowmelt‐driven floods historically dominating northern areas, while other regions show more varied flood seasonality. While it is well documented that since 1996 there has been a marked increase in extreme precipitation across this region, the response of flood seasonality to these changes in extreme precipitation and the spatial distribution of these effects remain uncertain. Here we show that, historically, snowmelt‐dominated northern regions were relatively insensitive to changes in extreme precipitation. However, with climate warming, the dominance of snowmelt floods is decreasing and thus the extreme flood regimes in northern regions are increasingly susceptible to changes in extreme precipitation. While extreme precipitation increased everywhere in the Northeastern United States in 1996, it has since returned to near pre‐1996 levels in the coastal north while remaining elevated in the inland north. Thus, the inland north region has and continues to experience the greatest changes in extreme flooding seasonality, including a substantial rise in floods outside the historical spring flood season, particularly in smaller watersheds. Further analysis reveals that while early winter floods are increasingly common, the magnitude of cold season floods (Nov‐May) have remained unchanged over time. In contrast, warm season floods (June‐Oct), historically less significant, are now increasing in both frequency and magnitude in the inland north. Our results highlight that treating the entire Northeast as a uniform hydroclimatic region conceals significant regional variations in extreme discharge trends and, more generally, climate warming will likely increase the sensitivity of historically snowmelt dominated watersheds to extreme precipitation. Understanding this spatial variability in increased extreme precipitation and increased sensitivity to extreme precipitation is crucial for enhancing disaster preparedness and refining water management strategies in affected regions.

Effect of winter flooding on navel orangeworm and spider mites in almond orchard

Effect of winter flooding on navel orangeworm and spider mites in almond orchard

Dune elongation and hunting strategy during the Terminal Pleistocene (Ramonian): Insights from Mizpor Ashalim, northwestern Negev dunefield margins, Israel

Dune elongation and hunting strategy during the Terminal Pleistocene (Ramonian): Insights from Mizpor Ashalim, northwestern Negev dunefield margins, Israel

Evaluation of the incident management system of a bigger city during the winter flood 2023/24 in northern Germany: Organized (ir)responsibility in the pre-disaster phase

Evaluation of the incident management system of a bigger city during the winter flood 2023/24 in northern Germany: Organized (ir)responsibility in the pre-disaster phase

Flood frequency analysis using mean daily flows vs. instantaneous peak flows

Abstract. In many cases, flood frequency analysis (FFA) needs to be carried out on mean daily flows (MDF) instead of instantaneous peak flows (IPF), which can lead to underestimation of design flows. Typically, correction methods are applied to the MDF data to account for such underestimation. In this study, we first analyse the error distribution of MDF-derived flood quantiles over 648 catchments in Germany. The results show that using MDF instead of IPF data can lead to underestimation of the mean annual peak flow (MHQ) by up to 80 % and mainly depends on the catchment area but appears to be influenced by gauge elevation as well. This relationship is shown to differ for summer vs. winter floods. To correct such underestimation, different linear models based on predictors derived from MDF hydrograph and catchment characteristics are investigated. Apart from the catchment area, a key predictor in these models is the event-based ratio of flood peak to flood volume (p/V ratio) obtained by the MDF data. The p/V models applied to either MDF-derived events or statistics seem to outperform other reference correction methods. Moreover, they require a minimum data input, are easily applied, and are valid for the entire study area. The best results are achieved when the L moments of the MDF maximum annual series are corrected with the proposed model, which reduces the flood quantile errors by up to 60 %. The approach behaves particularly well in smaller catchments (<500 km2), where reference methods fall short. However, the limit of the proposed approach is reached for catchment sizes under 100 km2, where the hydrograph information from the daily series is no longer capable of approximating instantaneous flood dynamics and gauge elevations below 100 m, where the difference between MDF and IPF floods is very small.

Are extreme floods on the Danube River becoming more frequent? A case study of Bratislava station

Abstract In this study, strong and extreme flood events were analysed on the basis of long-term daily runoff records of winter and summer floods in the Danube River between 1876 and 2020, using the peaks-over-threshold method. Based on the results, the following conclusions can be made: (1) There is a downward trend in strong winter floods, but it is not statistically significant. Additionally, there is an upward trend in summer floods, but this is not statistically significant. (2) There are statistically significant upward trends in extreme events for both the winter and summer seasons. The results have implications for flood protection and disaster management on the Danube River. Regulation of assets in flood-prone areas is essential for minimising economic damage. Public awareness of increasing extreme summer floods is vital for prevention. This study suggests that effective flood risk analysis requires (i) a local- to regional-scale approach to account for spatial variability and (ii) advanced statistical tools for robust detection of climate extremes and estimation of their occurrence rates.

Characterization of the benthic biogeochemical dynamics after flood events in the Rhône River prodelta: a data–model approach

Abstract. At the land–sea interface, the benthic carbon cycle is strongly influenced by the export of terrigenous particulate material across the river–ocean continuum. Episodic flood events delivering massive sedimentary materials can occur, but their short-term impact on carbon cycling is poorly understood. In this paper, we use a coupled data–model approach to estimate the temporal variations in sediment–water fluxes, biogeochemical pathways and their reaction rates during these abrupt phenomena. We studied one episodic depositional event in the vicinity of the Rhône River mouth (NW Mediterranean Sea) during the fall–winter of 2021/22. The distributions of dissolved inorganic carbon (DIC), sulfate (SO42-) and methane (CH4) were measured in sediment porewaters collected every 2 weeks before and after the deposition of a 25 cm sediment layer during the main winter flood event. Significant changes in the distribution of DIC, SO42- and CH4 concentrations were observed in the sediment porewaters. The use of an early diagenetic model (FESDIA) to calculate biogeochemical reaction rates and fluxes revealed that this type of flood event can increase the total organic carbon mineralization rate in the sediment by 75 % a few days after deposition. In this period, sulfate reduction is the main process contributing to the increase in total mineralization relative to non-flood deposition. The model predicts a short-term decrease in the DIC flux out of the sediment from 100 to 55 mmolm-2d-1 after the deposition of the new sediment layer with a longer-term increase by 4 %, therefore implying an initial internal storage of DIC in the newly deposited layer and a slow release over relaxation of the system. Furthermore, examination of the stoichiometric ratios of DIC and SO42- as well as model output over this 5-month window shows a decoupling between the two modes of sulfate reduction following the deposition – organoclastic sulfate reduction (OSR) intensified in the newly deposited layer below the sediment surface, whereas anaerobic oxidation of methane (AOM) intensified at depth below the former buried surface. The bifurcation depth of sulfate reduction pathways, i.e., the sulfate–methane transition zone (SMTZ), is shifted deeper by 25 cm in the sediment column following the flood deposition. Our findings highlight the significance of short-term transient biogeochemical processes at the seafloor and provide new insights into the benthic carbon cycle in the coastal ocean.

Pediatricians' perceptions and preferences for disaster education: A survey from the Washington, DC, Maryland, and Virginia area.

This study aimed to understand pediatricians' experiences with disasters, their perceptions of potential threats, and their preferences for disaster education. This is a survey study. The increasing frequency of disasters highlights the need for specialized care for vulnerable populations, particularly children. Pediatricians play a crucial role in disaster preparedness, but they are underprepared due to insufficient disaster-specific education. A survey was conducted among pediatricians in Washington, DC, Maryland, and Virginia. We collected data on personal disaster experiences, perceived threats, and preferences for educational resources. Descriptive statistics and odds ratios (OR) were used to analyze the data. One hundred and four pediatricians responded. The majority were attending physicians (88 percent) in healthcare or academic settings (73 percent), predominantly Millennials or Generation X (91 percent). Most respondents (82 percent) worked over 20 clinical hours per week. Commonly experienced disasters included winter storms, hurricanes, floods, power outages, and infectious disease outbreaks. However, cyberattacks (OR 25.9, p < 0.0001) and mass shootings (OR 2.71, p < 0.01) were perceived as major threats despite limited direct experiences. Preferred educational resources differed between routine practice and disaster settings, with a notable preference for digital sources like social media during disasters (OR 3.11, p = 0.0005). There is a need for targeted disaster education for pediatricians. Specific areas of concern include cyberattacks and mass shootings. Digital platforms to provide timely and relevant information were more preferred during disasters. Future efforts should focus on developing and disseminating educational content through preferred formats and outlets to better meet pediatricians' needs.

Temporal changes in the frequency of flood types and their impact on flood statistics

Standard flood frequency analysis assumes stationarity of flood conditions, i.e., no change of the distribution over time. However, long-term variability in climate and anthropogenic impacts question this assumption. Consequently, more and more non-stationary models are considered in flood frequency analyses. Yet, most of them only consider a change-point or trend in the magnitude of flood peaks while ignoring changes in the underlying flood geneses. Recent climate reports suggest such a change in frequency of certain flood-generating factors, e.g., the increase of frequency of heavy-rainfall events. In this study, flood types are applied to detect changes in the meteorological drivers of flood regimes. By application of a robust change-point test for the variance based on Gini’s Mean Difference, significant changes in the frequency of occurrence of certain flood types are detected. A clear tendency to more frequent heavy-rainfall floods and less snowmelt-induced floods is observed for many catchments in Central Europe. A special focus is laid on the shifts in winter floods, which occur less often and are replaced by rainfall-driven floods. The impacts of such changes on flood statistics are demonstrated by several approaches. Though the magnitude of flood peaks does not (necessarily) change, the changing frequency of floods leads to changing flood quantiles. Quantile estimations from traditional statistical analyses of annual series are compared to results of type-based flood statistics. It is shown how standard models are more affected by these changes because they are not able to compensate for changes in the frequency of individual flood types.

Benthic contribution to seasonal silica budgets in two macrotidal estuaries in North-Western France

The paper aims to build seasonal silica budgets in two macrotidal estuaries, the Elorn and Aulne estuaries of the Bay of Brest (North-Western France), based on modeling and measurements, in order to increase our understanding of the silica (Si) cycle at land-sea interfaces. A diagenetic model was developed to quantify benthic Si fluxes, e.g. aSiO2 deposition fluxes that are difficult to assess through direct measurements. Sediment cores were also seasonally sampled at six stations to provide data essential to parametrize and validate the model. Vertical profiles of porosity, burrowing depth, biodiffusive coefficients, concentrations of amorphous silica (aSiO2) and silicic acid (Si(OH)4 and the proportion of reactive aSiO2 were measured. The results show that sites sampled along the Elorn and Aulne estuaries constitute significant net Si deposition areas (1-4.5 mmol Si m-2 d-1), particularly in the upstream during winter and in midstream and downstream during summer. Year round, reprecipitation is negligible (&amp;lt; 3%) while burial accounts for the retention of ~ 30-80% of deposited aSiO2. In winter, burial dominates the benthic Si budget. As surface-integrated benthic Si fluxes are low compared to riverine aSiO2 fluxes, the Si export to coastal waters is high (93%) during winter. In contrast, in summer, burial accounts for 38% of river Si fluxes, and Si(OH)4 flux from the sediment is high as a result of enhanced benthic recycling and bioirrigation. Internal estuarine processes, e.g., benthic and pelagic primary production, dissolution and benthic Si fluxes, surpass river fluxes in magnitude during summer. Overall, we conclude that the Elorn and Aulne macrotidal estuaries are efficient filters of Si, retaining about 4-38% of river Si fluxes, and even 6-67% when accounting for retention in intertidal marshes, but with massive exports occurring during winter floods.

Keeping Water in Climate-Changed Headwaters Longer

Climate-change projections for California confidently describe a future with warmer temperatures, more evaporative demand, less snow, more rain, earlier and flashier runoff and streamflow, and drier summer conditions. The future of annual precipitation is much less certain, but a fairly unanimous projection of drier, more drought-prone conditions punctuated by occasional stronger-than-historical storms is almost as common among projections as is the warming itself. Rather than focusing on the less certain annual precipitation changes, we recommend more focus on keeping water in the headwaters longer. Doing so will involve reducing winter flood flows from headwater catchments, reducing the summer aridification (and wildfire risks) there, salvaging some groundwater recharge that would likely otherwise be lost, and overall, perpetuating headwater (and downstream) hydrologies under more historical and natural conditions. Among the available near-term adaptation strategies for keeping water in the headwaters longer, we discuss several examples here: (1) an increased emphasis on soils and percolation management as a priority and co-benefit in forest-health restoration activities; (2) beaver-population restoration or proliferation of beaver-inspired infrastructures; and (3) upstream-focused, forecast-informed reservoir-operation (FIRO) strategies.

Beyond the local climate change uplift – The importance of changes in spatial structure on future fluvial flood risk in Great Britain

Widespread spatially coherent flood events can cause severe damage and disruption. Climate change has the potential to change the severity and frequency of such events. Despite this, assessment of future fluvial flood risk typically gives little to no consideration to potential changes in the spatial structure of future events. To understand the significance of this gap, climate model simulations are coupled with a national hydrological model to identify event spatially coherent present and future flood events. A statistical Empirical Copula is used to generate a large number of unseen events and linked to a national flood risk simulation model. The research finds that including changes in the spatial structure of flood events materially increases projected changes in risk when compared to conventional approaches based on local uplifts alone; increasing the projected change in Expected Annual Damage across Great Britain by a factor of ~ 1.5. The event-based approach is also shown to provide new insights into the extreme distribution fluvial risk including single event damage, damage seasons, and damage years. The results suggest the 1-in-100-year winter flood may increase from £1.3b to £2.1b, and the 1-in-100 year single event damage may rise from £1.1b today to £1.7b by the 2080s given a 4 °C rise in Global Mean Surface Temperature (assuming current adaptation policies continue and no population growth). Consequently, the findings suggest a much greater emphasis is needed on spatial ‘flood events’ if future risk is to be understood and adaptation responses appropriately framed.Graphical abstract

Revealing the Key Drivers Conducive to the “Once‐In‐A‐Century” 2021 Peninsular Malaysia Flood

AbstractIn December 2021, Super Typhoon Rai caused significant devastation to the South Philippines and East Malaysia. In the meantime, an unprecedented flood event occurred in Peninsular Malaysia at 2,000 km west of the typhoon's path, causing comparable socioeconomic impacts as Rai. Record‐breaking 3‐day precipitation was received by Peninsular Malaysia during 16–18 December. Based on the storm tracking results, this study identified two mesoscale convective systems (MCSs) that were directly responsible for the flooding. The two MCSs were directly initiated by a tropical depression and sustained by an elongated easterly water vapor corridor originating from the Super Typhoon Rai. The return period and joint frequency analysis of key drivers indicate that the 3‐day downpour was more severe than a “once‐in‐a‐century” event. Historical records suggest such anomalous moisture channel has become more frequent in Southeast Asia, which alarms heightened attention in forecasting winter flood.

Soil carbon mineralization, enzyme activities, and crop residue decomposition under varying soil moisture regimes

AbstractIn the Lower Mississippi River Basin, farmlands are flooded in late fall and winter by impeding drainage to provide a habitat for migratory birds stopover. A laboratory incubation study was conducted to study the influence of temporary wetting of these soils on carbon (C) and nitrogen (N) mineralization from residue decomposition. Surface soils (0–15 cm) were collected from fields with clay and silty clay loam soils. Both soils were incubated with five crop residues—corn (Zea mays), soybean (Glycine max), cotton (Gossypium hirsutum), sorghum (Sorghum bicolor), and sweet potato (Ipomea batatus)—at 50% and 100% water holding capacity (WHC). Soil carbon dioxide (CO2) efflux was measured during 74 days of incubation. Soil moisture had the largest effect on soil CO2 efflux and most of the enzyme activities followed by residue and soil type. Cumulative soil CO2 efflux was reduced by 46% at 100% WHC compared to 50% WHC. Clay soil had higher cumulative CO2 efflux, aryl sulfatase, aryl phosphatase, and β‐N‐acetyl glucose aminidase activities than silty clay loam soil. Residue type had the largest effect on post‐incubation soil inorganic‐N, remaining biomass, and residue C and residue N. Sweet potato residue had the lowest remaining biomass, significantly lower than cotton, corn, and sorghum, but statistically similar to soybean. After incubation, residue N concentration had a positive association with cumulative CO2 efflux and a negative association with remaining residue biomass percentage. Winter flooding might limit the loss of soil C as CO2 depending on the crops grown and soil type.

Integrating multisource information to delineate oasis farmland salinity management zones in southern Xinjiang, China

Integrating multisource information to delineate oasis farmland salinity management zones in southern Xinjiang, China

Decadal shifts in the population growth, regeneration, and health of Taxodium distichum in swamps of the Cache River Watershed, Illinois

Decadal shifts in the population growth, regeneration, and health of Taxodium distichum in swamps of the Cache River Watershed, Illinois