High Water Levels Research Articles

Prediction of impulse waves generated by the potential failure of large deposits in the Rumei Reservoir, Lancang River, China

The impulse wave generated by the reservoir landslide seriously endangers the surrounding safety. In this paper, the failure mode of a large deposit in Rumei Reservoir, China was first explored by centrifuge test. Thereafter, a physical model based on Froude similarity (scale 1:200) and a numerical model based on fluid‒solid coupling were constructed. The failure motion process and the generated impulse waves of the deposits at high (2895 m) and low (2750 m) water levels are studied in detail. The results of the two models are similar. The velocity and wave height of the deposits at the 2750 m water level are greater than those at the 2895 m water level. The maximum wave heights generated in the river under both conditions exceed 46 m and 22 m, respectively, and the maximum run-ups formed on the opposite bank are 71 m and 30 m, respectively. This also suggests that landslides in the near field area are dangerous. Waves at both water levels will not overtop the dam, but attention should be given to the effect of the first wave at the 2895 m water level on the dynamic water pressure in the key area of the dam.

High Capacity and Reversible Fragile Watermarking Method for Medical Image Authentication and Patient Data Hiding.

The exchange of medical images and patient data over the internet has attracted considerable attention in the past decade, driven by advancements in communication and health services. However, transferring confidential data through insecure channels, such as the internet, exposes it to potential manipulations and attacks. To ensure the authenticity of medical images while concealing patient data within them, this paper introduces a high-capacity and reversible fragile watermarking model in which an authentication watermark is initially generated from the cover image and merged with the patient's information, photo, and medical report to form the global watermark. This watermark is subsequently encrypted using the chaotic Chen system technique, enhancing the model's security and ensuring patient data confidentiality. The cover image then undergoes a Discrete Fourier Transform (DFT) and the encrypted watermark is inserted into the frequency coefficients using a new embedding technique. The experimental results demonstrate that the proposed method achieves great watermarked image quality, with a PSNR exceeding 113dB and an SSIM close to 1, while maintaining a high embedding capacity of 3 BPP (Bits Per Pixel) and offering perfect reversibility. Furthermore, the proposed model demonstrates high sensitivity to attacks, successfully detecting tampering in all 18 tested attacks, and achieves nearly perfect watermark extraction accuracy, with a Bit Error Rate (BER) of 0.0004%. This high watermark extraction accuracy is crucial in our situation where patient data need to be retrieved from the watermarked images with almost no alteration.

Context dependence of grassland plant response to arbuscular mycorrhizal fungi: The influence of plant successional status and soil resources

Abstract Many of the disturbance‐sensitive, late successional plant species in grasslands respond to arbuscular mycorrhizal (AM) fungi more positively via growth and establishment than plants that readily establish in disturbed areas (i.e. early successional species). Inoculation with AM fungi can therefore aid the establishment of late successional species in disturbed areas. If the differential benefit of AM fungi to late versus early successional plants is context‐dependent, however, this advantage could be diminished in high phosphorus (P) post‐agricultural soils or in future climates with altered precipitation. In this greenhouse experiment, we tested if late successional plant species are less plastic in their reliance on AM fungi than early successional plants by growing 17 plant species of different successional status (9 early and 8 late successional) in full factorial combinations of inoculated or uninoculated with AM fungi, with ambient or high P levels, and with low or high levels of water. AM fungi positively affected the biomass of the 17 grassland plant species, but across all environments, late successional plant species generally responded more positively to AM fungi than early successional plants species. AM fungal growth promotion and change in below‐ground biomass allocation was generally diminished with P fertilizer across all plant species, and while there was significant variation among plant species in the sensitivity of AM fungal responsiveness to P fertilization, this differential sensitivity was not predicted by plant successional status. The role of AM fungi in plant growth promotion was not generally altered by variation in watering, however late successional plant species allocated a greater proportion of their biomass below‐ground in response to AM fungi in low versus high water conditions. Synthesis. Overall greater responsiveness to arbuscular mycorrhizal (AM) fungi by late successional species is consistent with an important role of AM fungi in plant succession, even while AM fungi are less impactful overall in high P soils. However, the increase in responsiveness of below‐ground allocation of late successional species to AM fungi in low water conditions suggests that successional dynamics may be more dependent on AM fungi in future climates that feature greater propensity for drought.

Hydrological-driven changes in the phytoplankton community structure under nutrient stress in island river ecosystems

While the spatiotemporal dynamics of phytoplankton community structures in river ecosystems have been extensively studied, their primary driving factors remain elusive, particularly at the watershed scale. This research examined the phytoplankton community structure across three watersheds of an island and concurrently analyzed its response to water level fluctuations (WLFs). The phytoplankton density was notably higher at elevated water levels, registering an increase of 1.29 times in Nandu River, 1.34 times in Changhua River, and 1.28 times in Wanquan River. Notably, the middle reaches of the Changhua River recorded the highest phytoplankton density (4.46 × 108 cells/L). Broadly speaking, Cyanophyta, Chlorophyta, and Bacillariophyta remained the predominant phytoplankton across varied water levels. Dominant phytoplankton species varied with water levels; however, the most prevalent species consistently belonged to the Cyanophyta group, primarily Microcystis or Merismopedia, with dominance ranging between 0.17 to 0.38 (low water level) and 0.18 to 0.32 (high water level). Enhanced phytoplankton diversity and richness were observed at higher water levels, correlating with increased concentrations of NH4+-N, NO3−-N, and PO43− in the river water. Consequently, nutrient fluctuations driven by hydrodynamics significantly influence the phytoplankton community structure in island river ecosystems.

Spatial and Temporal Variability in the Bottom Sediment Characteristics of a Shallow Lake under Backwater Separation and Application of Effective Microorganisms

Lake Konin is a small and shallow lake under the influence of highly eutrophic riverine waters. Feeding the lake as a backwater during high water level periods, the River Obra had exerted a decisive impact on lake water quality, and thus a new dike with a closing device was created. Protective measures were followed by the application of Effective Microorganisms (EM), aiming at a reduction in nutrient concentrations and CyanoHABs. Positive changes in the ecosystem were initiated (increased phytoplankton diversity), but cyanobacteria blooms were still present due to high nutrient content. Some changes were observed in the lake sediments (phosphorus (P) and its fractions, P in pore waters, organic matter and experimental assessment of internal P loading) studied before and during treatment. A slight increase in P content in sediments was noted, as a result of an increase in the Res-P fraction. Simultaneously, a decrease in the most mobile fractions was observed. Summer internal P load was reduced from 5.4 kgP d−1 before the treatment to less than 1 kgP d−1 in the first year, but increased again in the second year to 4.5 kgP d−1. Similarly to lake water quality, positive changes were induced in the lake sediments; nevertheless, they still acted as an important source of nutrients for primary producers. Additional restoration methods shall be considered, as combined treatments used simultaneously are reported to be the most effective for water quality improvement.

Dual-Column Stopped-Flow GC Method for Quantification of Permanent Gases, Water, and Organic Acids from a Single Injection.

Analysis of permanent gases and organic acids is typically performed with separate methods due to challenges in achieving sufficient resolution when using GC columns that are chemically compatible with acids. We developed a method to analyze samples containing high levels of water, organic acids, oxygenates, and permanent gases (CO, CO2, and C2H4) using a single injection. Resolution is achieved using two columns: (1) an HP-FFAP column resistant to water and acids, which separates compounds based on hydrogen-bonding affinity, and (2) a GS-CarbonPLOT column capable of separating permanent gases. We employed a column isolation methodology using rotary valves to allow a heart cut of permanent gases, which coelute off the HP-FFAP column, to be trapped on the CarbonPLOT column. After separation and analysis of water, organic acids, and oxygenates via the HP-FFAP column, flow is resumed on the CarbonPLOT column, and the permanent gases are separated independently. By utilizing the unique combination of columns and the stopped-flow sequence, we achieved separation and quantification of the wide array of compounds occurring during lactic acid dehydration to acrylic acid from a single injection without the need for a sophisticated flow modulator or multiple GCs or detector arrays. This GC apparatus serves as an economical in-line analysis method for our catalytic studies and is applicable to a wide array of samples relevant to biobased fuels and chemicals.

Untangling the coupling effect of water quality and quantity on lake algal blooms in Lake Hulun from a dual perspective of remote sensing and sediment cores

Algal blooms and sediment diatoms are crucial indicators of lake water ecology, influenced by water quantity and quality. However, the coupled effects of water quality and quantity changes on algal blooms are still unclear, especially for lakes in cold and arid regions. This study assessed the long-term variations in algal blooms in Hulun Lake using a novel approach combining remote sensing and sediment core samples for diatom analysis. Two mutation points from the structural change test were identified in approximately 2000 and 2010 for algal bloom area (MBE) and sediment diatom richness, indicating asynchronous algal blooms. A structural equation model (SEM) demonstrated that water level (WL) changes were the dominant influencing factor, co-driving the variations in algal blooms and sediment diatoms in conjunction with total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD). The results revealed nonlinear relationships between the lake WL, TN, Chla, and COD. The water level of 543 m emerged as a critical threshold affecting the relationship between water quality and quantity. Distinct differences in this relationship were observed when water levels were above or below this threshold. These variations became particularly pronounced during periods of high and low water levels. The results provide novel insights into the dynamics of algal blooms and can further support lake ecosystem conservation and management.

Study on flood level forecasting of tidal reach in Puyang River basin

Abstract The downstream section of the Puyang River is a tidal river reach subject to both upstream floods and downstream tides. This combined impact results in an unstable relationship between water level and discharge at the forecast station, making flood level forecasting challenging. This paper took the Linpu station on the Puyang River in Zhejiang Province as the research object. Based on the historical flood data, the cause of high water levels at Linpu station was analyzed. The flood levels at Linpu station were decomposed into flood increments and basic tidal levels. Using the multiple regression method, the prediction formula for upstream flood-induced water level increments was obtained. A flood level forecasting method based on the flood increment was developed. The result of the scheme accuracy evaluation indicates that this method has good forecasting performance. The flood level forecasting method for the tidal channel proposed in this paper has a simple structure and high accuracy, which provides a scientific basis for the prevention and control of flood and drought hazards and the decision-making of project scheduling in the tidal river.

Road and Bridge Blocking System in Flood Situation

Abstract: The system uses hydraulic or mechanical barriers that can be quickly opened in response to rising water levels, preventing access to barriers and bridges. Up to date data from weather forecasters and water gauges provide effective protection to ensure closure times before flooding reaches critical levels. In addition, the central control centre provides timely updates to the public via mobile and digital signage applications, encouraging collaboration with emergency services and local authorities. The purpose of this document is to provide guidance to highway authorities and other relevant organisations on road drainage. One problem that arises during floods is the closure of roads due to flooding, especially on roads located near rivers and canals. Most brides give the height above the highest water level, but the approach to the bridges often does not give the required height. As a result, the road was flooded while the bridge was standing

Genotoxicity in the goldfish of TiO2 nanoparticles combined with high CO2 levels

TiO2 nanoparticles are photocatalytic, generate reactive oxygen, and can be harmful to aquatic biota. We have studied the toxic effects of nTiO2 combined with high CO2 levels in water. We exposed goldfish to environmentally relevant concentrations of nTiO2 and CO2 levels. Comet assay results showed that DNA breaks increased at high CO2 concentration, but no effect of nTiO2 concentrations was seen. Micronucleus assays showed no significant micronucleus formation. Histopathological alterations were seen in the gills but not in the liver.

Using ARIMA and ETS models for forecasting water level changes for sustainable environmental management

It is vital to provide useful hydrological forecasts for urban and agricultural water management, hydropower generation, flood protection and management, drought mitigation and alleviation, and river basin planning and management, among other things. This paper introduces a simple and flexible hydrological time series forecasting framework. Predicting water levels is crucial, given the need for sustainable environmental management. The prognosis should be reasonable to persuade individuals to take proper precautions. While many methods have been developed to predict water levels, here the effectiveness of two approaches to predicting river water levels was assessed. For this purpose, nine years of data were used, which were divided into input data (2014–2021) and validation data (2022), on water levels in the Morava e Binçës river for the Vitia station, in the form of monthly time series records, to identify the best model among those used and to identify the information necessary for water resource management and hazard control. Models Autoregressive Integrated Moving Average(ARIMA) and Error Trend and Seasonality, or Exponential Smoothing (ETS), were examined using the R package to determine the most accurate. The results indicate the applicability of both models, as evidenced by the Root Mean Square Error (RMSE) and the Mean Absolute Error (MAE). The predictive analysis based on historical water levels allowed the identification of distinct periods characterized by high and low water levels between 2022 and 2024, which is important for the area in question due to the numerous flood events occurring here.

Fee structure and equity fund manager’s optimal locking in profits strategy

We study the effects of fee structures on fund managers’ strategies for locking in profits. Utilizing the optimal stopping time method, we identify two critical portfolio value thresholds that signal when a manager will choose to lock in profits. Fee components such as management fees, self-investment ratios, and high-water marks significantly influence these decisions. Specifically, higher management fees are associated with increased risk aversion, leading to a narrower continuation region, indicating a preference for lower risk. Conversely, performance fees encourage greater risk-taking. We use the S&P 500 Index and NASDAQ Composite index as representatives of managers’ portfolios and apply our model to illustrate how managers adjust their profit-locking strategies in response to their desired rewards.

DEM-based pluvial flood inundation modeling at a metropolitan scale

The global increase in urban flooding presents a substantial challenge that affects communities across the globe. This study introduces a post-flood inundation modeling framework tailored to pluvial floods on a metropolitan scale. We employ a dual drainage modeling approach for enhanced accuracy. The framework comprises two primary components: a Storm Water Management Model (SWMM) for simulating water movement within the storm drain system, and an advanced DEM-based flood inundation module that leverages SWMM results to predict flood inundation areas. Compared to the conventional flood spreading models commonly used in dual drainage modeling, this module incorporates high-resolution DEM cells into the surface flow routing processes, allowing to capture intricate surface terrain complexities. Additionally, the proposed module considers direct rainfall impacts on pluvial flood inundation mapping, resulting in enhanced accuracy. To evaluate the proposed model's accuracy, a two-step validation approach has been implemented. This includes comparing the proposed model results with both the high water marks measured in the aftermath of Hurricane Harvey and the flood depth map generated by a hydrodynamic model. The findings affirm the effectiveness of our proposed framework for post-flood inundation mapping within metropolitan settings. This method provides a dependable approach to urban flood modeling and represents an advancement in addressing the challenges associated with urban flooding.

Methanogenic Potential of Sewer Microbiomes and Its Implications for Methane Emission.

The sewer system, despite being a significant source of methane emissions, has often been overlooked in current greenhouse gas inventories due to the limited availability of quantitative data. Direct monitoring in sewers can be expensive or biased due to access limitations and internal heterogeneity of sewer networks. Fortunately, since methane is almost exclusively biogenic in sewers, we demonstrate in this study that the methanogenic potential can be estimated using known sewer microbiome data. By combining data mining techniques and bioinformatics databases, we developed the first data-driven method to analyze methanogenic potentials using a data set containing 633 observations of 53 variables obtained from literature mining. The methanogenic potential in the sewer sediment was around 250-870% higher than that in the wet biofilm on the pipe and sewage water. Additionally, k-means clustering and principal component analysis linked higher methane emission rates (9.72 ± 51.3 kgCO2eq m-3 d-1) with smaller pipe size, higher water level, and higher potentials of sulfate reduction in the wetted pipe biofilm. These findings exhibit the possibility of connecting microbiome data with biogenic greenhouse gases, further offering insights into new approaches for understanding greenhouse gas emissions from understudied sources.

Carbon emission from the Lower Ob River floodplain during spring flood

Carbon emission from Arctic rivers constitutes a positive feedback between the climate warming and C cycle. However, in case of rivers with extensive floodplains, the impacts of temporary water bodies and secondary channels on CO2 exchange with atmosphere, compared to the main stem and tributaries, remain strongly understudied. In order to quantify the relative role of various water bodies of the Arctic river basin in the C cycle, the hydrochemical variables and greenhouse gases GHG concentrations and fluxes were measured within the floodplain of the largest Arctic River, Ob, in its low reaches located in the permafrost zone. These included the main stem, secondary channels, tributaries and floodplain lakes sampled over a 900 km north-south transect (25,736 km2 of the main stem and adjacent floodplain area; 7893 km2 water surface) during peak of spring flood (May 2023). In addition to main stem and tributaries, providing less than a half of overall C flux, floodplain lakes and secondary channels acted as important factor of C emission from the floodplain water surfaces. Multi-parametric statistical treatment of the data suggested two main processes of C emission from the Ob River floodplain waters: terrestrial organic matter-rich flooded wetlands (fens) provided elevated pCO2, whereas the sites of possible groundwater discharge in the secondary channels decreased the CO2 fluxes due to more alkaline environments, rich in labile metals and anionic elements.Based on available high-resolution Landsat-8 images, which matched the period of field work, it was found that the total water coverage of the floodplain during spring 2023 was 30 % of overall territory, compared to 18 % during the baseflow. Based on chamber-measured CO2 fluxes (1.56 ± 0.47 g C-CO2 m−2 d−1), overall CO2 emissions during 2 months of the spring flood from the entire Lower Ob River floodplain water surfaces including the main stem amounted to 0.73 ± 0.25 Tg C. Diffuse CH4 flux represented <1 % of total C flux. The main stem of the Ob River accounted for 34 % and 18 % of CO2 and CH4 emissions, respectively, whereas the floodplain lakes provided 59 % and 50 % of CO2 and CH4 emission, respectively. Considering that the low reaches of the Ob River represent >70 % of total river basin floodplain, and that during some years, the entire floodplain can be covered by water, emissions from the river – if assessed solely from summer (July–August) measurements – can be at least 3 times underestimated. It is therefore important to account for extended water surface during high water levels on Arctic rivers when assessing global riverine C emissions.

Climate-driven decline in water level causes earlier onset of hypoxia in a subtropical reservoir

Hypoxia, especially in the bottom water, is occurring in deep and stratified reservoirs worldwide, threatening aquatic biodiversity, ecosystem functions and services. However, little is known about the timing of onset and ending of hypoxia, especially in subtropical reservoirs. Based on five-year (from April 2015 to January 2020) sampling of a subtropical monomictic deep reservoir (Tingxi Reservoir) in southeast China, we found the evidence of about 40 days earlier onset of hypolimnion hypoxia during low water level periods in dry years compared to wetter high water level years. We explored the effects of stratification and mixing conditions on hypoxia, cyanobacterial biomass, and nutrient dynamics; and revealed the physical and biochemical conditions that drove hypoxia. The results indicated that 1) The decline in water level increased the intensity of thermal stratification, resulting in 40 days earlier onset of hypolimnion hypoxia in dry years than in wet years; 2) The decline in water level expanded the extent of hypoxia by promoting nutrient accumulation and phytoplankton biomass growth; 3) Warmer climate and less precipitation (drought) significantly promoted the risk of hypoxic expansion and endogenous phosphorus release in subtropical reservoirs. We suggest that more attention needs to be paid to the early onset of hypoxia and its consequences on water quality in subtropical stratified reservoirs during low water level periods in a changing climate.

Advancing regional flood mapping in a changing climate: A HAND‐based approach for New Jersey with innovations in catchment analysis

AbstractRegional flood mapping poses computational and spatial heterogeneity challenges, exacerbated by climate change‐induced uncertainties. This study focuses on creating a state‐wide flood mapping solution with enhanced accuracy and computational speed to support regional flooding hazard analysis and the assessment of climate change, using New Jersey as a case study. The Height Above Nearest Drainage (HAND) framework was employed for large‐scale flood mapping. The model was validated against high water marks (HWMs) collected after Hurricane Irene. Based on the National Water Model (NWM), synthetic rating curves in HAND were calibrated by tuning Manning's roughness, aligning the predicted and observed flood depths. The roughness values were generalized across the state from the validated water basins to the ungauged ones, using a multivariate regression with the hydrologic and geographic information. To map the future climate‐change‐induced flooding, a correlation between NOAA historical precipitation totals and NWM flow data from 2010 to 2020 was established to link precipitation and runoff. This study also invented a novel method for correcting catchment discontinuities, inherent in the HAND model, based on a computer vision scheme, the Sobel filter. The modeling results show that average and worst‐case storm events have the potential to increase 10%–50% in the state, where mountain areas and major river banks would be exposed to this impact more significantly.

Plant growth and physiological responses of the invasive plant Acmella radicans to contrasting light and soil water conditions

Acmella radicans (Jacquin) R.K. Jansen is a new invasive species record for Yunnan Province, China, as of 2017 and little is known about its invasion mechanisms. To better understand its invasive strategies, we investigated the growth, physiological and soil nutrient use parameters of the invader under combined conditions of light (25%, 50%, 75%, and 100% of light availability) and soil water content (full, high, medium, and low soil water content) in the glasshouse. The results showed that light level, soil water content and their interaction had a significant effect on all plant morphological, physiological and soil nutrient parameters for A. radicans (P < 0.05). For the most part, plant height, total branch length, leafstalk length, leaf area, inflorescence number, seed number, leaf biomass, stem biomass, aboveground biomass, and total biomass of A. radicans were significantly increased with increased shading rate and soil water content and were generally greater at intermediate light levels and intermediate to high soil water levels. Under high-irradiance conditions, the chlorophyll content was greatly reduced compared to other treatments. We also observed that leafstalk length, leaf area, Pn, chlorophyll a, and chlorophyll b of A. radicans were markedly increased with increased shading rate and soil water content, and were generally highest under intermediate irradiance and soil water conditions, but many plant physiological parameters also exhibited relatively high values under waterlogging conditions. The concentrations of organic matter, available N and available K of A. radicans soils at high-irradiance and full-high soil water content treatments and medium-irradiance and high-medium soil water content treatments were often less than those of other treatments indicated that hypothetically soil absorption was increased by moderate shading and high soil water. This was the first study demonstrating that A. radicans thrives best under moderate light conditions in combination with high soil water. Furthermore, we surmised that its higher phenotypic and physiological plasticity contributes to its invasion success.

Potential Use of Portulaca Plant Species in Removing Estradiol Hormone Pollutants in the Surface Water of Bengawan Solo River

Bengawan Solo River water is a source of drinking water and raw materials for the government of Surakarta city, but the water has been mixed with domestic, industrial, and agricultural wastes. The waste contains estradiol-17 derived from urine and feces, both from livestock and humans as well as industries around the sub-watershed Bengawan Solo River. The content of estradiol-17 in the Bengawan Solo sub-watershed is quite high. This study is the first conducted in Bengawan Solo River to look at natural estrogens that are very rarely studied in the environment, which are likely could cause several health effects in humans and wildlife due to their relatively strong estrogenic potential and high levels in wastewater and river water. Therefore, research on the elimination of these compounds using effective, energy-efficient, and low-maintenance technologies for water treatment such as phytoremediation is highly expected. The purposes of this study were to identify estradiol, to measure the estradiol levels through HPLC tests as well as to test the effectiveness of phytoremediation with Portulaca plant as biological agents. The results show that the water of Bengawan Solo River contained estradiol substances ranging from 3.88 ppm to 5.76 ppm. The Portulaca plant species was effective at eliminating estrogenic waste up to 99.89%.

The Timing, Magnitude, and Relative Composition of Extreme Total Water Levels Vary Seasonally Along the U.S. Atlantic Coast

AbstractThe annual maximum (AM) method, which subsamples time series to retain the maximum event per year, and the peak‐over‐threshold (POT) method, which extracts values exceeding a threshold to define extremes, have long histories in determining flood event frequency. In practice, extreme value distributions applied to AM and POT events often assume that the data comes from the same statistical population. Locations across the world, like the United States (U.S.) Atlantic coastline, however, experience high coastal water levels driven by various individual processes and storms with different driving mechanisms during different seasons. This research investigates when extreme total water levels (TWLs) occur during the year along the U.S. Atlantic coast and whether individual components, like waves, tides, and storm surge, contributing to TWLs vary across regions and during the year. From 1980 to 2020, extreme TWLs occurred during the extratropical and tropical seasons, with the relative proportion of extreme TWLs occurring during the extratropical season increasing northward. Still water levels drive spatial variability in extreme TWL magnitude, while wave climate drives differences in extreme TWL magnitude between extratropical and tropical seasons. Month‐to‐month variability in the composition of extreme TWLs varies more than spatial variability, highlighting the importance of understanding the components driving extremes at different times of the year. Variations across storm seasons in the processes contributing to extreme TWLs may have implications for how large‐scale changes to the climate impact hazards along open sandy coastlines and influence the robustness of extrapolating rare events from models fit to a single population.