Flood Phase Research Articles

Environmental history of Lake Mariout at the ‘Marea’/Philoxenite archeological site, northern Egypt, during the Hellenistic–early Islamic periods as seen by fossil diatoms

ABSTRACTDiatom analysis of sediments obtained from five cores drilled in Lake Mariout and the ‘Marea’/Philoxenite archeological site southwest of Alexandria, Egypt, allows us to reconstruct the lake's environmental history during the Hellenistic–early Islamic periods. The distribution pattern and the variation in relative abundance of recognized diatoms differentiated each core section into characteristic zones. These zones are interrupted by periods of poor preservation or non‐diatom deposition that coincide with fluctuating lake phases of freshwater flooding of the Nile during humid warm episodes and arid phases associated with a reduction in the Nile's water influx that provides Lake Mariout with fresh water. A rising water level of Lake Mariout is estimated from the great abundance of riverine, planktonic Aulacoseira species. A lowering of water level was linked to a high abundance of brackish water taxa and/or periods of non‐diatom deposition. Furthermore, the absence of diatoms at two intervals in Core 1 is associated with silty clay with an abundance of gypsum crystals which point to falling water lake levels with increasing temperature during dry periods. However, the intervals of poor preservation or no diatoms in other cores at ‘Marea’/Philoxenite are presumably related to the coarser nature of the sediment that indicate a major lake level lowstand, a high‐energy depositional environment together with increased salinity and alkalinity. By comparing the diatom data in the examined cores, it is clear that the Aulacoseira granulata assemblage zone is characteristic of the Roman and Byzantine periods, which reflects relatively rising water levels due to Nile water inflow via the Canopic Nile branch and thus the connection between the canal and lake during this time. Furthermore, the predominance of Aulacoseira granulata with some pollution‐tolerant taxa indicates extensive human occupation during the Roman–Byzantine periods, which is evidenced by increased nutrient concentration with higher input of humic substances due to human activities and their influence on the lake ecosystem.

Understanding Tidal Jet Vortices Over Complex Bathymetry via Numerical Modeling and Drone Observation: Match and Mismatch in the Vortex Dynamics Under Idealized and Realistic Topographic Settings

AbstractThe formation and evolution of tidal jet vortices over complex bathymetry were investigated using numerical modeling and in situ observation. Delft3D FM simulation on an unstructured grid system, complemented by field measurements using recreational drones captured tidal dynamics in the Uldolmok Strait, known for its strong tidal currents up to 6.0 m/s and turbulent whirlpool formation. This study particularly focused on temporal changes in whirlpools near their narrowest points. Modeling across the entire strait showed current velocity fields consistent with field observations, revealing significant temporal and spatial variability influenced by strait geometry and bathymetry. Whirlpools induced by tides were identified by setting a swirl strength threshold, with their centroids and equivalent spherical diameters pinpointed. It was observed that larger whirlpools, upon reaching critical size, were entrained and shifted with the tidal jet at about half its maximum velocity, while smaller vortices separated from the nearshore boundary layer remained nearly stationary. Focusing on the initiation of whirlpools and their relations with the coastline and bathymetry, a targeted field survey using a recreational drone measured surface flow fields in detail near the strait's narrowing region. During the ebb phase, shallow regions exhibited numerous smaller eddies due to increased energy dissipation, showing a dual power‐law scaling in the size distribution of eddies, contrasting with the single scaling exponent observed during the flood phase. The study underscored the role of coastline and bathymetry in developing whirlpools and shaping their dynamics, providing insights into complex tidal interactions in the natural coast.

Multi‐Parameter Investigation of Cretaceous to Palaeocene Sedimentary Sequences in the Anambra and Niger Delta Basins, Nigeria: Organic Matter Characterisation, Palynofacies and Implications for Palaeoclimate and Sea‐Level Changes

ABSTRACTThe Anambra Basin of Nigeria, part of the larger West and Central African Rift System (WCARS) across Africa, contains primarily Cretaceous to Palaeocene shallow to marginal marine and freshwater sedimentary deposits. The organic‐rich deposits of the Cretaceous Nkporo and Mamu formations within the Anambra Basin and the Palaeocene Imo Formation of the Niger Delta Basin constitute important conventional source rocks. Despite its economic significance, research on organic matter characterisation, palynofacies, sea‐level fluctuations, palaeoclimate, hydrogeography, basin restriction, palaeobathymetry and the factors controlling organic matter preservation remains largely undocumented. The here presented new inorganic and organic geochemical and organic petrography data of the Cretaceous to Palaeocene deposits serve to refine the regional interpretation at a basinal scale and within the supra‐regional context of the WCARS. Geochemical palaeotemperature proxies suggest a warm and humid tropical palaeoclimate during the Late Cretaceous within the study area. Furthermore, the measured TOC values indicate poor to very good organic content. Palynofacies analysis revealed high abundances of opaque and translucent phytoclasts and low amounts of palynomorphs with negligible amorphous organic matter (AOM) in the studied mudrocks. Two palynofacies groups suggest shallow‐marine conditions in a proximal shelf setting and a heterolithic oxic basin. The palynofacies of the upper Imo Formation reveal higher percentages of dinoflagellate cysts during the early highstand phase, with equidimensional, opaque phytoclasts representing the maximum flooding phase, accompanied by warmer conditions. Additionally, abundant terrestrial phytoclasts, Deltoidospora spp., Classopollis spp. and geochemical indicators collectively indicate warm tropical climatic conditions consistent with geochemical interpretations. The palaeobathymetry reconstructions suggest a shallow seaway during the Upper Cretaceous in the Anambra Basin.

Research on the timing for subsequent water flooding in Alkali-Surfactant-Polymer flooding in Daqing Oilfield based on automated machine learning

Determining the optimal timing for subsequent water flooding in Alkali-Surfactant-Polymer (ASP) flooding is essential to maximizing both the technical and economic outcomes of oilfield blocks. This study identified eight critical parameters that influence the benefits of ASP flooding and established parameter ranges based on data from completed blocks and actual field measurements. The optimal timing for subsequent water flooding was determined by evaluating cumulative net profit variations throughout the ASP flooding lifecycle. Given the complexity and high-dimensional nature of evaluating multiple parameters across diverse blocks, a machine learning-driven optimization model was developed. This model enhances work efficiency by automating complex analyses. However, predictive uncertainties and limitations remain due to the variability in oilfield development and the potential for unpredictable changes in reservoir conditions, external market factors and so on, which may affect the model’s results. The model was applied to six blocks in the Daqing oilfield currently in the chemical flooding phase, where injection schemes, such as extending the polymer slug, were adjusted according to the model’s optimized results. These adjustments yielded an increase in cumulative net profit of 224.9 million CNY compared to the original scheme, with a potential total increase of 752.1 million CNY by the end of the flooding process.

Improved phenology-based rice mapping algorithm by integrating optical and radar data

Improved phenology-based rice mapping algorithm by integrating optical and radar data

Outburst flood events since the Last Glacial Maximum in the Hutiao Gorge of Jinsha River: Geomorphological evidence from eddy gravel bars

Outburst flood events since the Last Glacial Maximum in the Hutiao Gorge of Jinsha River: Geomorphological evidence from eddy gravel bars

Impact of joint dispatch of reservoir group on water pollution incident in drinking water source area

To reduce the harm of water contamination incidents in drinking water source areas (DWSAs) and explore feasible approaches, the research developed a hydrodynamic water quality model for DWSAs based on two dimensional water quality and quantity equations, Geographic Information System (GIS), and Digital Elevation Model (DEM). The Heshangshan Drinking Water Source Area (HDWSA) in the Three Gorges Reservoir Area (TGRA) was selected as the research area, with total phosphorus (TP) as the representative pollutant in the water. The research investigated the changes in TP content during various hydrological phase under pollution incident, compared the duration and trends of TP concentration exceeding standard value before and after joint reservoir group dispatch. The results showed that the migration speed of TP pollutants varied from slowest to fastest in the following order: dry phase, recession phase, storage phase, and flood phase. Under pollution incident condition, the time demanded for TP content to meet standard value in each water phase was 36 min (dry phase), 33 min (recession phase), 30 min (storage phase), and 27 min (flood phase). The joint dispatch group 1-3 shortened the time required to meet standard value by 6-13 min (dry phase), 5-11 min (recession phase), 4-9 min (storage phase), and 3-7 min (flood phase). The trend of TP concentration before and after joint dispatch showed four stages: significant increase, sharp decrease, rapid decrease, and slow decrease. Joint dispatch of reservoir group can effectively reduced the TP concentration in DWSA under pollution incident.

Resilient coral reef ecosystems: The case study of turbid-mesophotic coral buildups during the Late Oligocene Warming Event (Tertiary Piedmont Basin, NW Italy)

Resilient coral reef ecosystems: The case study of turbid-mesophotic coral buildups during the Late Oligocene Warming Event (Tertiary Piedmont Basin, NW Italy)

Changes in community composition and prey capture of web-building spiders during rice field development

Changes in community composition and prey capture of web-building spiders during rice field development

A Study on the Rainfall-Storage Volume-Target Water Level Curve for Flood Control on the Small Size Dam: Case study for Goesan Dam

Dams in South Korea serve various functions, including water supply, hydropower, and transportation; in particular, they are responsible for a significant portion of flood control. This study aims to propose a methodology that field engineers can easily utilize to assess the hydrological conditions of small dams that require simultaneous discharge during flood inflow due to limited storage capacity. Therefore, the relationship between rainfall, storage volume, and target water level was established for dams. This relationship is represented as a curve and is based on the storage volume during the rising phases of floods. Historical data of the Goesan Dam, located in the Dalcheon Basin of the Han River, including inflow, discharge, and rainfall were collected at 10-minute intervals. Analysis was conducted on four major flood events occurring since 2018. The proposed methodology was applied to derive the rainfall-storage volume-target water level curve for the Goesan Dam. Subsequently, the appropriate flood response water level for the Gosan Dam was calculated, and its applicability was examined.

Suspended particulate matter dynamics at the interface between an estuary and its adjacent coastal sea: Unravelling the impact of tides, waves and river discharge from 2015 to 2022 in situ high-frequency observations

Suspended particulate matter dynamics at the interface between an estuary and its adjacent coastal sea: Unravelling the impact of tides, waves and river discharge from 2015 to 2022 in situ high-frequency observations

Flood Prediction System Using IOT & Artificial Neural Network

Floods pose significant challenges as one of nature's most devastating disasters, making the development of accurate forecast model’s complex. This issue has led to severe consequences such as crop loss, population displacement, damage to infrastructure, and disruption of essential services. Advanced research on flood prediction models has played a crucial role in providing policy recommendations, mitigating risks, reducing human casualties, and minimizing property damage caused by floods. In this context, we propose an Internet of Things (IoT)-based flood prediction and forecasting model that prioritizes energy efficiency. Given the limited battery and memory capacity of IoT sensor nodes, we employ an energy-saving strategy within the fog layer, leveraging data diversity to minimize energy consumption. Additionally, cloud technology offers an effective storage solution. To accurately calibrate flood phases, we investigate climatic factors such as humidity, temperature, rainfall, as well as water body parameters including water flow and elevation. Neural networks are commonly used in constructing forecast systems, as they can replicate the complex calculations involved in flood physical processes, resulting in improved performance and cost-effectiveness. In our approach, the Artificial Neural Network (ANN) technique is employed for flood forecasting, and the effectiveness of different algorithms, such as Logistic Regression and Decision Tree, is assessed by comparing them to ANN. Accuracy values are computed using a classification report assessment, and graph parameters are carefully evaluated. Ultimately, our proposed system utilizes the ANN technique to train a predictive model by examining the dataset. This model generates real-time flood risk forecasts through a user-friendly graphical interface.

Boreal (Eemian) Transgression in the Northeastern White Sea Region: Multiproxy Evidence from Bychye-2 Section

Reconstructing interglacial marine environments helps us understand the climate change mechanisms of the past. To contribute to this body of knowledge, we studied a high-resolution 455 cm-thick sediment sequence of the Boreal (Eemian) marine beds directly overlying Moscovian (Saalian) moraine in the Bychye-2 section on the Pyoza River. We analyzed lithological and microfossil (foraminifers, ostracods, pollen, aquatic palynomorphs) variations at the studied site. Stratigraphical zonation is based on the local and well-established regional pollen zones, correlated with the western European pollen zones. The studied marine beds accumulated from the end of the Moscovian glacial (>131 ka) until ca. 119.5 ka. We distinguished three successive phases: a seasonally sea-ice-covered, relatively deep, freshened basin in the initial rapid flooding stage (>131–130.5 ka); a deep basin in the maximum flooding phase with less extensive sea ice cover (130.5–130.25 ka); and a shallow basin with reduced sea ice cover (130.25–119.5 ka). According to a pollen zone comparison with other sites, the regional glacioisostatic rebound started ca. 130 ka. The diverse warm-water assemblages of benthic foraminifers and ostracods containing typical Baltic Sea species occurred during the regression, mainly 128–124 ka, thus giving evidence for a relatively long-lasting connection between the White and Baltic Seas.

Sediment fluxes within salt marsh tidal creek systems in the Yangtze Estuary

Sediment fluxes within salt marsh tidal creek systems in the Yangtze Estuary

Food consumption of the urban population in a municipality in the Legal Amazon, during climate events of flood and drought: a comparative study

The aim of this study was to compare the food consumption of the population of Coari, Amazonas State, Brazil, according to the NOVA Classification, during the hydrological phases of drought and flooding of the Amazon rivers. An epidemiological, population-based, cross-sectional study was carried out. The sample consisted of 457 adult individuals. Data were collected in two stages using a sociodemographic instrument, a 24-hour food recall and a food frequency questionnaire adapted to local habits. The data were analyzed using the statistical program R version 4.2.4, using Pearson's chi-square, Fischer's exact and Bhapkar's tests. The sample was predominantly female (drought = 70%/flood = 71.2%) and brown (drought = 65.4%/flood = 66.2%). Most of the interviewees ate meals (breakfast, lunch and dinner). Afternoon snacks were the most common intermediate meal, especially during flooding (274/70.2%). In natura or minimally processed foods predominated at the three main meals (95%). Ultra-processed foods were consumed little or not at all and were mentioned especially during the drought (152/33.3%; p = 0.007). On the other hand, consumption of regional foods (tucumã, beiju, tapioca flour and açaí) increased during the flood (p < 0.001). Consumption of in natura or minimally processed foods continues to be the mainstay of the diet in the interior of Amazonas, with a predominance of regional foods during the flood and processed and ultra-processed foods during the drought, demonstrating the influence, albeit subtle, of the hydrological phases on the food consumption of this population.

Impact of a Large Shallow Semi‐Enclosed Lagoon on Freshwater Exchange Across an Inlet Channel

AbstractThe impact of a large shallow semi‐enclosed lagoon on freshwater exchange across an inlet channel is investigated using an idealized numerical model. Lagoons are often found between a river mouth and the ocean; we focus on those where the river discharge rate is small and the inlet channel is narrower and deeper than the lagoon. Tides generate freshwater and oceanic‐water plumes across the channel; a stratified freshwater plume forms in the ocean from the late ebb to early flood phase, while a vertically well‐mixed oceanic‐water plume forms in the lagoon from the late flood to early ebb phase. The shallow depth of the lagoon increases the flow speed of the oceanic‐water plume, which results in the formation of a sharp and vertically well‐mixed salinity front within the lagoon. When this front moves toward the ocean during the ebb phase, vertical mixing increases where the bathymetry deepens and freshwater encounters oceanic water below. Without a dredged bottom slope, the impact of mixing would be greatly reduced within the shallow lagoon and channel, as the shallow depth would limit the subsurface intrusion of oceanic water. The narrow channel further causes the flow to converge and accelerate, enhancing both internal shear‐driven and bottom boundary‐layer mixing at the channel and increasing freshwater plume thickness where it enters the ocean. Sensitivity experiments showed that the role of tidal pumping in freshwater exchange across the channel increases when the lagoon area and tidal mixing increase and when the estuarine Richardson number decreases.

Efecto de las fluctuaciones del nivel hidrométrico sobre el fitoplancton en tres lagunas isleñas en el área de la confluencia de los ríos Paraná y Paraguay

.The phytoplankton of three island ponds (Los Pájaros, Catay and Turbia) (27°25’S; 58°45’W) in the begening of Paraná river floodplain were studied. These ponds are periodically flooded by the river. Catay pond was in pennanent contact with the riverwhile the other two were flooded during high water periods.Sampling was carried out during 1978-1980. Cell counts were madeby the U termohl method. Population density and diversity and were analyzed. Cell density were comparatively highest (1733, 2084 and 1028 ind. ml4 in Pájaros, Catay and Turbiaponds, respectively) either when hydrometric level was slowly increasing or after small flood phases. On the contrary, cell density were lowest in coincidence with strong flooding phases (83,73 and 57 ind. mi'1, respectively). Catay pond, the one which is in pennanent contact with the river showed highest both population density and diversity. During high water periods strong similarity ainong three ponds were observed.In Pájaros and Catay ponds Chlorophyceae (Monoraphidium, Schroederia and Scenedesmus), Ciyptophyceae (Cryp tomonas spp.) and Diatomophyceae A ulacoseira granúlala) were dominant. In the Turbia pond Euglenophyceae (Traclielomonasvolvocina) and Cryptophyceae (Cryptomonas spp.) were dominant.Nannoplankton represented between 60 and 90% of the total in all the studied ponds.

Rice straw biochar and lime regulate the availability of heavy metals by managing colloid-associated- but dissolved-heavy metals

Heavy metal (HM) pollution has extensively spread in agricultural soils, posing potential threats to food safety and human health. Biochar and lime are two amendments used to remediate the soils contaminated with HMs. However, colloids have been shown to increase the mobility of HMs in paddy soils. Nevertheless, limited investigations have been made into the impact of biochar and lime on the formation of colloid-associated (colloidal) HMs in paddy soils. In this study, column and microcosm incubation experiments were conducted to examine how biochar and lime affected the availability of HMs (arsenic, cadmium, copper, iron, manganese, lead, and zinc) in different layers of paddy soils. The results revealed that biochar significantly inhibited the formation of colloidal HMs in the soil flooding phase, whereas the lime increased the colloidal HMs. These colloids containing HMs were identified as poorly dissolved metal sulfides. When the soil was drained, colloidal HMs transformed into dissolved forms, thereby improving the availability of HMs. Biochar decreased HM availability by reducing colloidal- but dissolved- HMs, whereas lime had the opposite effect. Hence, biochar demonstrated a stable and reliable remediation ability to decrease HM availability in paddy soil during flooding and drainage processes. In conclusion, this study highlighted that biochar efficiently reduced HM availability by mitigating the formation of colloidal HMs during flooding and their transformation into dissolved HMs during drainage in paddy soils.

A dynamic simulation tool for ship's response during damage-generated compartment flooding

A dynamic simulation tool for ship's response during damage-generated compartment flooding

Observation Capability Evaluation Model for Flood-Observation-Oriented Satellite Sensor Selection

Satellite sensors are one of the most important means of collecting real-time geospatial information. Due to their characteristics such as large spatial coverage and strong capability for dynamic monitoring, they are widely used in the observation of real-time flood situation information for flood situational awareness and response. Selecting the optimum sensor is vital when multiple sensors exist. Presently, sensor selection predominantly hinges on human experience and various quantitative and qualitative evaluation methods. Yet, these methods lack optimization considering the flood’s spatiotemporal characteristics, such as different flood phases and geographical environmental factors. Consequently, they may inaccurately evaluate and select the inappropriate sensor. To address this issue, an innovative observation capability evaluation model (OCEM) is proposed to quantitatively pre-evaluate the performance of flood-water-observation-oriented satellite sensors. The OCEM selects and formulates various flood-water-observation-related capability factors and supports dynamic weight assignment considering the spatiotemporal characteristics of the flood event. An experiment involving three consecutive flood phase observation tasks was conducted. The results demonstrated the flexibility and effectiveness of the OCEM in pre-evaluating the observation capability of various satellite sensors across those tasks, accounting for the spatiotemporal characteristics of different flood phases. Additionally, qualitative and quantitative comparisons with related methods further affirmed the superiority of the OCEM. In general, the OCEM has provided a “measuring table” to optimize the selection and planning of sensors in flood management departments for acquiring real-time flood information.