Volume Of Water Research Articles

Design, Fabrication and Preliminary Testing of a Small-Scale Cassava Starch Extraction Machine

A cassava starch extraction machine was designed and fabricated to perform a quadruplet action of grating, washing, sieving and separation. The study was necessitated based on concerns that most locally manufactured cassava processing machines are without provision for the extraction of starch. Food processors mainly depend on the manual pressing of cassava to obtain starch and this has significantly increased the cost of the product in the local market. Materials for construction were locally sourced and the machine was powered by a 2 hp electric motor through a v-belt-pulley transmission system and operating at a speed of 547 rpm. Fresh cassava tubers were harvested from Ikot Akpaden, a rural community in Mkpat Enin, Akwa Ibom, South-South of Nigeria, and used for the experiment. Results from the experiment showed that the quantity of wet starch extracted increased from 0.64 to 1.48 kg as the volume of water mixed with 2 kg of the product increased from 1 to 5 Liters. The rate of water usage and throughput capacity increased from 0.0005 to 0.0025 m3/kg and 35.29 to 46.75 kg/h respectively as volume of water increased. The optimum machine efficiency was 74%. The machine was fabricated at a cost of N 150,200 (equivalent of $100). Minimal time consumption, ease of operation and low production cost were some of the features that made the machine economically viable when compared to other conventional methods of extracting starch from cassava.

The effect of the electrodes shape in water electrolysis on the production of hydrogen

This article presents a comparative study of the production of hydrogen by the electrolysis of water using two forms of electrodes; cylindrical and flat. The objective of this comparison is to select the best type of electrolyzer to produce hydrogen for the same volume of water and the same operating voltage. An analytical study and experimental tests were carried out on a cylindrical electrolyser consisting of two concentric cylindrical electrodes separated by a variable thickness e (3.5 mm, 4 mm, 5.5 mm, 8.5 mm and 9 mm), then a flat electrolyser consisting of two flat electrodes spaced by a distance d (2 mm, 4 mm, 6 mm, 10 mm and 15 mm). For each cylindrical electrolyser there corresponds a single electrolyser with flat electrodes. The preliminary study revealed that the production of hydrogen in an electrolyzer is significantly affected by the distance separating the two electrodes and their shapes. Indeed, the comparative electrolysis results show that in each case the electrolyzer with cylindrical electrodes clearly prevails over its counterpart with flat electrodes for the same operating conditions and for the same quantity of water injected into the electrolysis.

Model-Based Analysis of the Oxygen Budget in the Black Sea Water Column

Climate change and anthropogenic impacts drastically affect the biogeochemical regime of the Black Sea, which contains the largest volume of sulphidic water in the world. The Sea’s oxygen inventory depends on vertical mixing that transports dissolved oxygen (DO) from the upper euphotic layer to deeper layers and on dissolved oxygen consumption for the oxidation of organic matter (OM) and reduced species of S, Fe, and Mn. Here we use a vertical one-dimensional transport model, 2DBP, forced by Copernicus data, that was coupled with the FABM-family N-P-Si-C-O-S-Mn-Fe Bottom RedOx Model BROM. The research objective of this study was to analyze the oxygen budget in the upper 350 m of the Sea and demonstrate the role of the parameterization of the acceleration of the sinking of particles covered by precipitated Mn(IV). The analysis of the oxygen budget revealed distinct patterns in oxygen consumption within different depths. In the oxic zone, the primary sink for DO is the mineralization of organic matter, whereas in the suboxic zone, dissolved Mn(II) oxidation becomes the predominant sink. The produced Mn(IV) sinks down and reacts with hydrogen sulphide several meters below, making possible the existence of the suboxic layer without detectable concentrations of DO and H2S.

Controlled drainage with subirrigation systems: Reduce water supply by automatic control

Controlled drainage with subirrigation (CDSI) is a viable measure to supply, retain or discharge groundwater, thereby contributing to freshwater availability in agriculture under changing environmental conditions. Relatively simple CDSI systems can be controlled manually to set a few drainage levels. More advanced systems can be controlled remotely to set any drainage level (between a technical maximum and minimum). CDSI potentially improves hydrological conditions for crop growth, but the required external water supply can be large. Therefore, the objective of this paper is to investigate whether external water supply for subirrigation can be reduced by automatic control of CDSI systems in relation to crop water demand. Field measurements of a CDSI pilot in the Dutch sandy Pleistocene uplands were combined with weather forecasts to simulate the optimal drainage level and day by day water demand and supply using the agro-hydrological Soil, Water, Atmosphere, Plant model (SWAP). Firstly, model simulations showed that the water requirement reduced by 60 mm (dry growing season), 253 mm (average growing season) and 348 mm (wet growing season) using a dynamically managed crest level (CDSI-dyn) compared to using a fixed crest level (CDSI-fix), with minor effects on crop yield. Secondly, model simulations showed that a higher hydraulic resistance to downward seepage, a higher ditch water level or deeper roots reduced the water supply (up to 100 mm). Thirdly, accepting 10 % daily crop drought and oxygen stress for CDSI-dyn reduced the water supply requirement with 235–628 mm (dry vs wet growing season) compared to CDSI-fix. In conclusion, the required water volume for CDSI could be substantially reduced by automated control of the drainage level and water supply rate, while maintaining crop yield or accepting minor reductions, which increases the potential of implementation of CDSI systems.

Experimental investigation of the melting heat transfer of phase change material-based heat sinks under mechanical agitation with a no-delay-start strategy

Phase change materials (PCMs) are commonly used for the thermal management of electronic devices, but their low thermal conductivity limits their suitability for higher heat fluxes and shorter heat storage/release durations. Existing studies on heat transfer enhancement have focused mainly on conduction and lack consideration of convection. Therefore, melting experiments on n-docosane under mechanical agitation (0–1600 RPM) were carried out. A no-delay-start strategy of agitation was achieved by submerging the paddle with the addition of water (200 and 400 mL). As the rotation speed (n) increases, the heating wall temperature (Tw) generally decreases, especially at 0–400 RPM. For 200 mL, Tw decreases by 31.2 °C from 0 to 1600 RPM at 3600 s; for 400 mL, the decrease is 29.2 °C at 5400 s. The temperature difference between the heating wall and PCM decreases remarkably under agitation, reaching only 2.7 and 1.7 °C for 200 and 400 mL, respectively, at 1600 RPM and 6300 s. The temperature field uniformity is also improved by agitation. In addition, with increasing n, the complete melting time (tc) generally decreases, while the holding time (thold) basically increases. Under agitation, the Tw values for 200 and 400 mL are generally lower than that for 0 mL, indicating that the no-delay-start strategy is feasible and advantageous. At n ≥ 800 RPM, Tw for 200 mL is greater than that for 400 mL throughout the entire melting process, while at n < 800 RPM, this trend occurs only during the solid-phase heat conduction stage. The effects of both the rotation speed and water volume depend on the combined function of the intensity of the PCM-water interface and the heat storage capacity of water. Even when the heat flux increases from 8.5 to 25.4 kW/m2, the thold can still be extended under agitation. The power consumption (Qc) of agitation increases with rotation speed, decreases with water volume, and exhibits less sensitivity to heat flux. It reaches a maximum value of 10 W at 1600 RPM. Considering factors such as Tw, thold and Qc, the optimal configuration is determined to be a water volume of 400 mL and a rotation speed of 1600 RPM. This study demonstrated that convection enhancement of PCMs with a no-delay-start strategy effectively addresses the thermal management challenges of electronic devices.

Long-distance Southern Ocean environmental DNA (eDNA) transect provides insights into spatial marine biota and invasion pathways for non-native species

The Southern Ocean surrounding Antarctica harbours some of the most pristine marine environments remaining, but is increasingly vulnerable to anthropogenic pressures, climate change, and invasion by non-native species. Monitoring biotic responses to cumulative impacts requires temporal and spatial baselines and ongoing monitoring - traditionally, this has been obtained by continuous plankton recorder (CPR) surveys. Here, we conduct one of the longest environmental DNA (eDNA) transects yet, spanning over 3000 nautical miles from Hobart (Australia) to Davis Station (Antarctica). We evaluate eDNA sampling strategies for long-term open ocean biomonitoring by comparing two water volume and filter pore size combinations: large (12 l with 20 μm) and small (2 l with 0.45 μm). Employing a broad COI metabarcoding assay, we found the large sample/pore combination was better suited to open ocean monitoring, detecting more target DNA and rare or low abundance species. Comparisons with four simultaneously conducted CPR transects revealed that eDNA detections were more diverse than CPR, with 7 (4 unique) and 4 (1 unique) phyla detections respectively. While both methods effectively delineated biodiversity patterns across the Southern Ocean, eDNA enables surveys in the presence of sea-ice where CPR cannot be conducted. Accordingly, 16 species of concern were detected along the transect using eDNA, notably in the Antarctic region (south of 60°S). These were largely attributed to hull biofouling, a recognized pathway for marine introductions into Antarctica. Given the vulnerability of Antarctic environments to potential introductions in a warming Southern Ocean, this work underscores the importance of continued biosecurity vigilance. We advocate integrating eDNA metabarcoding with long-term CPR surveys in the Southern Ocean, emphasising the urgency of its implementation. We anticipate temporal and spatial interweaving of CPR, eDNA, and biophysical data will generate a more nuanced picture of Southern Ocean ecosystems, with significant implications for the conservation and preservation of Antarctic ecosystems.

Reliability and resilience of environmental flows under uncertainty: reconsidering water year types and inconsistent flow requirements in California

Abstract Environmental water allocation in California is a complex legal process involving various government agencies and stakeholders. E-flow requirements can be based on annual runoff typologies called water year types (WYTs), which dictate water volume, timing, and duration. In this study, we examined hydropower licensing documents of the major water and power projects in the Central Sierra Nevada to catalog e-flow requirements by WYT. In this study case, we identify how WYT classification systems and categories vary across and within different basins. Additionally, we assessed the impacts of climate change on hydrology, the frequency of WYTs identified, and the reliability and resilience of e-flows using future projections (2031–2060) of 10 Global Circulation Models (GCMs). We then propose a potential adaptation strategy using a 30 year moving percentiles approach to recalculate WYTs. We identified eight WYT classifications systems were identified, and their WYT distributions statistically significantly changes across all GCMs, even though most GCMs indicate no statistically significant change in hydrology. Disparities in future impacts are observed among and within hydropower projects, with some river reaches showing negative impacts on reliability and resilience. The adaptation strategy can generally boost resilience and improve reliability, but simply updating existing WYT thresholds without flexible regulatory frameworks reconsidering WYTs and e-flows thresholds, may not yield substantial improvements. Challenges in managing e-flows in California within regulatory and hydroclimatic contexts are intricate due to the lack of standardized approaches, leading to inconsistencies and potential conflicts among stakeholders, that will likely be exacerbated by climate change. Thus, we emphasize that targeted, site-specific, and adaptive management strategies are crucial, besides the need for a harmonized and consistent approach to defining and applying WYT categories and methods and/or e-flow assessments.

Sudden change of fish functional compositions during a drought in the wet season of the middle Yangtze River, China

Climate anomalies such as drought may lead to cascading effects on river ecosystems, ultimately resulting in the change of aquatic biocenosis. Here, we investigated functional assemblies of fish communities at three sites below the Gezhouba Dam of the middle Yangtze River in China before and during a drought event from 2021 to 2022. As the drought proceeded, the richness of the fish functional groups decreased, and the abundance of demersal/invertivore species increased. These changes might indicate adaptive responses of fish communities to the reduction in water volume and shrinkage in habitat areas. The shifts in functional structure also caused fish communities to become more similar during the drought. The null model based on functional traits showed a distance effect of the fish community assembly rules. The communities close to the dam were structured more stochastically under drought stress, which may be attributed to the impact of ecological operation by cascade hydro-junctions. In contrast, the communities far away from the dam were structured by environmental filtering. Our results support the hypothesis that the natural hydrological regime is the main force driving the spatiotemporal dynamic of riverine fish assemblages, and the drought stress on fish communities may need more attention to cope with future biodiversity loss under global climate changes.

On the Role of Freshwater Budgets in the Formation of Salinity Extremes in the Ocean Interior

We propose interpreting the vertical structure of waters not only in space but also over time, taking into account the continuous variability of the ocean and the independence of temperature and salinity parameters. This approach allows us to consider, in real conditions, the entire spectrum of short- and long-term extrema of both characteristics, either separately or together at the same depth. Vertical distributions of temperature and salinity transform separately and independently of each other under the influence of heat and freshwater budgets, which change at different time scales. Each of the parameters has its own active layers with corresponding time scales. Changes in the signs of heat and freshwater budgets and subsequent changes in the characteristics of the surface layer cause the appearance and disappearance of separate extrema of temperature and salinity in the water column. Using a salinity field as an example, we have shown that each of the extrema, in their vertical distribution from the near-surface to the intermediate depths, is a temporary phenomenon with various lifetime scales and is located at the lower boundary of the corresponding active layers. In some areas of the ocean, temperature and salinity extrema exist together at the same depth. Volumes of water with such characteristics and explicit boundaries should be considered water masses.

Feasibility study of a metal hydride-based solar thermal collector system

The present study aims to assess the technical feasibility of a novel Metal Hydride-based Solar Thermal Collector (MH-STC) system. This system includes a flat-plate solar collector integrated with a metal hydride bed, a hydrogen compressor, a photovoltaic panel, a hydrogen tank, and a water storage tank. This system combines the principles of a conventional solar thermal collector with the energy storage capabilities of metal hydrides, enabling the storage of surplus thermal energy. The LaNi5 alloy was used as heat storage material. A 3D-mathematical model is established and a numerical code written in Fortran-90 is developed to simulate the dynamic behavior of the proposed solar thermal collector. It was shown that the developed 3D-model produces computational results that are consistent with experimental data. In addition, to check the accuracy of the mathematical model and numerical approach, the relative errors in the mass balance and energy balance were calculated and values of 0.054 % and 0.18 %, respectively, were obtained.The simulation results offer insights into the system's technical feasibility, revealing an overall efficiency of 90.6 %, the water temperature at the collector outlet can reach 357.3 K, and a water volume heated of 230.4 L under the considered operating conditions. Moreover, the results indicate that the proposed MH-STC system exhibits significant potential as a viable alternative for thermal storage in domestic hot water systems.

Oxyhydrogen-air explosion characteristics in water jetting propulsion

Hydrogen has attracted many researchers in the field of explosion jetting propulsion owing to its appealing advantages of zero carbon emissions, wide flammability range, and ease of preparation. However, the research gap in hydrogen explosion characteristics in water jetting scene has slowed down the advancement of the impulsive jetting propulsion field. In this work, static tests under three typical explosion jetting scenes (vertical submerged jetting, oblique submerged jetting, and aerial jetting) are conducted to reveal their explosion and thrust characteristics. The static tests results demonstrate that although the peak pressures of the aerial and vertical submerged explosion jettings are comparable, the peak thrust of the former is dramatically reduced by 40.6 %. We also find that the maximum pressure rise rate and peak pressure of the oblique submerged jetting are 22.9 % and 11.4 % lower than those of the vertical submerged jetting, respectively. Meanwhile, the peak thrust of the inclined jetting is also reduced by 14.1 % compared to the vertical jetting. High-speed photography applied to capture the evolution details of the oxyhydrogen-air explosion reveals that the preceding differences are attributed to the asymmetrical water repulsion phenomenon. Specific impulse is used to characterize the propulsion performance of the oxyhydrogen-air–water explosion jetting at varied volume fractions, and the results show that the maximum specific impulse is obtained for a given 0.45 kg thruster at 40 % water volume and 4:6 ratio of air to oxyhydrogen. The correctness of the explosion characterization metrics and thrust results are finally corroborated via the outdoor aquatic-aerial jetting propulsion tests.

Human Activities Impacts on Runoff and Ecological Flow in the Huangshui River of the Yellow River Basin, China

This study analyzed 61 years of hydrological data from the Minhe and Xiangtang Hydrological Stations (1956–2016) to examine hydrological changes and ecological flow assurance rates in the Huangshui River Basin, China. Using the Mann–Kendall trend test, IHA/RVA method, and ecological flow calculation methods, the study revealed the following results: (1) After 1994, increased human activity in the Datong River led to a measured runoff decrease compared to natural runoff. Although human activities in the Huangshui River’s main stream were present before 1972, after 1972, these activities intensified, resulting in a more pronounced decrease in the measured runoff. (2) Ecological flow analysis indicated that the main stream of the Huangshui River and the Datong River have ecological flow assurance rates of 100% for all but a few months, where the rates are 98%. The water volume is sufficiently abundant to meet ecological water demands.

Features of distribution of electric field strength and current density in the reactor during treatment of liquid media with high-voltage pulse discharges

Purpose. Development and use of a mathematical model of the stages of formation of high-voltage pulse discharges in gas bubbles in the discharge gap «rod-plane» to identify the features of the electric field intensity distribution in the reactor and determine the current density in the load during disinfection and purification of liquid media by high-voltage pulse discharges and find the most rational treatment. Methodology. To achieve this goal, we used computer modeling using the finite element method as a method of numerical analysis. An experimental reactor model was created that takes into account the dynamics of discharges in gas bubbles in water. The equations describing the system include the generalized Ampere equation, the Poisson equation and the electric displacement equation, taking into account the corresponding initial and boundary conditions, as well as the properties of materials. The dependence of the potential of a high-voltage electrode on time has the form of a damped sinusoid, and the specific electrical conductivity in a gas bubble is a function of time. Processes occurring at the front of the voltage pulse from 0 to 20 ns are considered. Results. It is shown that with an increase in conductivity and high-voltage potential to amplitude values in a gas bubble, the electric field strength in the water layer in the reactor reaches 70 kV/cm, and it is in the water layer that there is a strong electric field. The calculations show that already by 19th ns the density of conduction currents in water prevails over that of displacement currents. At the same time, additional inclusions in the water significantly affect the distribution of electric field strength and current density, creating a significant difference in their values at the boundaries of the interface between the bubble, conductive element and water. Originality. A simulation of the dynamics of transient discharge processes in a gas bubble and a layer of water with impurities was carried out, including an analysis of the distribution of the electric field strength and current density in a system with rod-plane electrodes in the phase transition section of a gas bubble-water. This approach allows us to reveal the features of processes in reactors and to investigate the influence of phase transitions on the distribution of electrophysical quantities. Practical value. Computer simulations confirm the prospect of using nanosecond discharges generated in gas bubbles within a volume of water for widespread industrial use and are of great interest for further experimental and theoretical research. References 25, figures 9.

Optimasi Human Error pada Proses Produksi Air Minum Dalam Kemasan di PT. Telaga Tanjung Pomosda Nganjuk

PT. Telaga Tanjung Pomosda, a bottled mineral water manufacturer in Nganjuk, East Java, faces challenges in maintaining high production standards and addressing operational issues such as product rejection and production process errors, impacting overall company efficiency and reputation. This study identifies operational error factors and evaluates the effectiveness of improvement methods. Research procedures utilize HTA, SHERPA, and Poka-Yoke to identify and reduce human errors in bottled mineral water production at PT. Telaga Tanjung Pomosda Nganjuk, focusing on error analysis, probability assessment, and Poka-Yoke strategy implementation. The bottled water packaging process involves critical stages such as cup packaging, pressing, and packing. Errors in each stage can result in delays, decreased water volume, imperfectly pressed lids, and packing mistakes, hindering the entire production process. Research at PT. Telaga Tanjung Pomosda identifies operator issues in machine settings, water measurement, lid positioning, task interruptions, packaging, and cup positioning, with solutions including routine checks and training to enhance product quality

A Comprehensive Inventory, Characterization, and Analysis of Rock Glaciers in the Jhelum Basin, Kashmir Himalaya, Using High-Resolution Google Earth Data

Rock glaciers are crucial freshwater resources, yet detailed knowledge about their distribution, characteristics, and dynamics in the Himalayan region is scarce. This study presents a comprehensive rock glacier inventory of the Jhelum basin, Kashmir Himalaya, India, using high-resolution Google Earth data. We identified 240 rock glaciers covering an area of 41.24 ± 2.2 km2, with ~76% classified as active, ~20% inactive, and 3.7% relict. The average areas and lengths of these rock glacier types were 0.19 km2, 0.06 km2, and 0.29 km2, and 699 m, 426 m, and 952 m, respectively. Most rock glaciers (~90%) were oriented northwards (N, NE, NW), while only 5% faced southwards (S, SE, SW). The lower limit of permafrost in the Jhelum basin is about 3316 m asl. Furthermore, we estimated the ice storage of rock glaciers in the Jhelum basin at 0.80 ± 0.13 km3, equivalent to 0.72 ± 0.12 km3 of water volume. This study enhances our understanding of permafrost distribution and the characteristics and dynamics in the basin. Given their greater resilience to climate change compared to clean glaciers, the hydrological significance of rock glaciers is expected to increase under projected climate change scenarios. This study highlights their importance as a vital water resource amidst the accelerated recession of clean glaciers.

Exploring Students Potential and Creativity Through Science Exploration with Water Rockets and a Stunning Interactive Approach

&lt;div class="page" title="Page 1"&gt;&lt;div class="layoutArea"&gt;&lt;div class="column"&gt;&lt;p&gt;&lt;span&gt;A water rocket is an educational game that requires propulsion in the form of air and water pressure. In water rockets, the air of a room will press in all directions and water flows towards lower pressure. The purpose of this research is to analyze the effect of different elevation angles and water volume on the farthest distance of parabolic motion of water rockets. This research uses an experimental study method conducted by 2nd semester students of PSDKU PGSD Kebumen. Data collection techniques using practicum and documentation. Data analysis techniques were carried out with water rocket experiments 3 times. The experimental results showed that: 1) To produce the farthest distance traveled, the water rocket uses an elevation angle of 60 ° with a fixed water volume of 400 ml. 2) The farthest distance using a volume of 600 ml with a fixed elevation angle of 45°. The results of this study can be used as student materials for science exploration and interactive approaches so as to explore the potential and creativity of students. &lt;/span&gt;&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;/div&gt;

A potential usefulness of ultra-high-resolution computed tomography in quality assurance of remote after-loading system for cervical cancer.

Intracavitary brachytherapy with a remote after-loading system (RALS) is performed as a part of radical radiation therapy in cervical cancer. The radiation source is delivered directly through an applicator placed inside the uterus or vagina. Thorough quality control is important to prevent accidents that can lead to serious irradiation error, and an applicator check is one such quality control measure. We experienced a clinical situation in which a small volume of water was observed in the lumen of a post-sterilized applicator on treatment-planning CT. Although the submersion test was negative and no air bubbles emerged from the applicator, ultra-high-resolution computed tomography (U-HRCT) showed a linear crack reaching the inside of the applicator. This abnormality was not identified on treatment-planning CT, which has lower spatial resolution than U-HRCT. In addition, no linear cracks were seen on U-HRCT images of eight other applicators considered to be free from damage. U-HRCT may have superior potential to detect applicator damage and could be useful for quality assurance of the RALS procedure.

Liquid territories: the configuration of geographic space in the cartography of the Mekong River’s catchment areas

AbstractThe role played by the Mekong River in the organization of land and people is inextricably linked with a particular spatial category. The concept of the hydrological catchment extends the space of the river far beyond the limits of the river’s perennial waterbodies, to encompass vast areas inhabited by millions of people speaking different languages. Fundamental to the estimation of precipitation and water volume, areal denotations of the Mekong’s basin, delta and floodplain have been repeatedly drawn on maps by geographers, planners, engineers and cartographers. Mapped representations of the Mekong River however are not only the result of recording the flows of water, nor the domain of a single discourse. With diverging intentions, distinct and sometimes conflicting projections of the basin, delta and floodplain have prescribed the differentiation and unification of parts of mainland Southeast Asia, to articulate liquid territories that are outside a single state’s jurisdiction. To understand how the Mekong’s catchments emerge as the geographic reference for human activities, the paper examines the technical and cultural notions that underpin the preparation of these maps. Focusing on early European maps of the Mekong’s delta and floodplain, the paper draws on the discourses of hydrology, geography, and cartography to ask what territories are produced and maintained by evoking the geography of the river’s flows.

Zoning and regulation of compound flooding in coastal cities coupled with tracer method

Urban inland rivers play a significant role in mitigating flooding. However, the influence of their discharge on urban flooding affected by different flood drivers remains to be fully explored. Taking a catchment area in Haikou City, Hainan Province, China as an example, in light of the urban flooding model coupled with the water tracer method, this study investigates the degree of inundation in each flood zone under different inland river flows. The flood zones are determined by the flooding simulation results of three cases, and then are verified by the zonation based on the tide tracer approach. Finally, the tracer method is used to study the impact of urban inland rivers on flooding and the connection of hydraulic and water volume between rivers and pipelines. The results indicate that the inundation area decreased by 3.71 % as the river flow increased from 15 to 25 m3/s. In the process of river flow rising from 5 to 45 m3/s, The average flooding depth in the rainfall-affected area climbs slowly from 0.53 m to 0.62 m; In the tidal-affected area, the average flooding depth drops from 0.52 m to 0.12 m when the inland river flow increases from 5 to 25 m3/s, and rises from 0.12 m to 0.54 m when the inland river flow continues from 25 to 45 m3/s; The percentage of pipelines grows from 18.5 % to 28.0 %. This study provides valuable scientific insights and support for flood prevention planning and flood control strategies in coastal cities.

Intermediate water circulation in the mid-latitude Northeast Atlantic over the past 13,000 years: Multi-proxy evidence from IODP Site U1391

The Antarctic Intermediate Water (AAIW) is an important contributor to the upper limb of the Atlantic Meridional Overturning Circulation (AMOC), redistributing heat, salinity, nutrients, and carbon in the Atlantic Ocean. The Mediterranean Outflow Water (MOW) transports heat and salt into the northern high-latitude Atlantic, thus playing an important role in driving the AMOC. However, the northward extent of AAIW in the Atlantic during the last deglaciation remains controversial and the Holocene variability of MOW is not well understood. In the modern east Atlantic Ocean, the northern boundary of AAIW meets the southern boundary of MOW off southern Iberia, which makes the Iberian margin an ideal region to unravel whether AAIW penetrated to the North Atlantic during the last deglaciation and the MOW dynamics during the Holocene. We present benthic foraminiferal Ba/Ca, Cd/Ca and Mg/Ca ratios, δ13C offsets between Planulina ariminensis and Globobulimina spp., and benthic foraminiferal faunal records of IODP Site U1391 drilled in the intermediate-depth Atlantic off the southwestern Iberian margin. The dominance of the Cassidulina neoteretis-Nonionella turgida assemblage, combined with low Δ13CP. ariminensis-Globobulimina spp. offsets, high Ba/Ca and Cd/Ca ratios and low Mg/Ca ratios during the Younger Dryas (YD), indicates the presence of AAIW in the mid-latitude North Atlantic intermediate waters. Going into the Holocene, the Cassidulina neoteretis - Nonionella turgida assemblage was shifted to the Melonis affinis – Bulimina marginata assemblage, accompanied by frequent occurrences of the MOW indicator Planulina ariminensis, which suggests that Site U1391 was mainly bathed by MOW. During the middle Holocene (∼9.4–6.0 ka), the relative abundance of P. ariminensis and Ba/Ca ratios decreased significantly, and the proportions of oxic species Osangularia culter, Bulimina alazanensis and Cibicidoides pachyderma increased, which were likely attributed to the influence of large volumes of oxygen-enriched North Atlantic Central Water. Between ∼6.0 ka and ∼ 3.6 ka, an increase in the relative abundance of P. ariminensis and Ba/Ca ratios, and a decrease in the relative abundance of O. culter assemblage suggest intensified MOW at Site U1391. However, from ∼3.6 ka onward MOW weakened at the study site, as evidenced by a distinct decrease in the proportion of P. ariminensis and Ba/Ca ratios. The long-term trend of MOW variations over the past 13 kyrs shows that the weakening of MOW dynamics at Site U1391 is related to the prevailing dry climates in the Mediterranean region, which is also reflected in its millennial-scale variations. Benthic Ba/Ca, Cd/Ca and Mg/Ca records exhibit high-frequency oscillations centred on periods of ∼1.8 kyrs. Lower Ba/Ca, Cd/Ca and Mg/Ca ratios suggest a weak MOW signal at Site U1391, concurrent with the Bond events during the Holocene.