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Freshwater shortages in coastal regions are intensifying due to rapid urbanisation, economic growth, and climate variability, particularly in deltaic areas where rivers meet the sea. This study evaluates the feasibility of implementing a Coastal Reservoir (CR) as an innovative solution to increase freshwater availability without relying on desalination. Using the Brisbane River Estuary (BRE), Australia, as a case study, the research examines critical factors such as freshwater inflow, seawater intrusion, and reservoir volume requirements. A three-dimensional hydrodynamic model (MIKE 3) was calibrated and validated using observed data from the 2008 and 2011 flow events. Simulation results indicate that a freshwater discharge of 150 m3/s during a spring-neap tidal cycle effectively pushes saline water out of the estuary. The CR can store 300 GL/year of freshwater with 92% reliability, meeting Southeast Queensland's (SEQ) annual water demand of 440 GL during drought conditions combined with existing infrastructure. During its initial filling phase, the CR can flush 95% of saltwater within 240 days, using a steady inflow of 150 m3/s. The findings demonstrate the technical feasibility of CRs as a sustainable and practical water management strategy for mitigating freshwater shortages in BRE and other similar coastal regions. [ABSTRACT FROM AUTHOR]

Coastal areas have become the primary location for nuclear power plant sites due to the convenience of seawater cooling. In China, the diffusion range of thermal discharge water has always been a hot research topic as the basis for sea use areas. The main physical process of heat loss in the numerical simulation of thermal discharge from power plants is heat exchange between the water surface and air. Currently, the methods for calculating this heat loss include the heat flux method and the water surface heat exchange coefficient method. Taking a power plant in Zhejiang as the research object, the MIKE 3 temperature–salinity module (heat flux method) and MIKE ECO Model (water surface heat exchange coefficient method) were used for modeling, and the diffusion of thermal discharge water under different modules was compared and analyzed. The results show that the calculated area of the water temperature rise envelope between the two modules differed significantly under the same conditions. The surface 4 °C temperature rise area, as calculated using ECO Model, was 45.8% smaller than that of the temperature–salinity module. The MIKE 3 temperature–salinity module can simulate the heat accumulation of water under thermal buoyancy, producing a significant thermal stratification phenomenon; the ECO module does not accurately represent the heat exchange process between the water surface and the air, and it does not adequately capture the significant vertical stratification that occurs in real-world scenarios. On this basis, this study not only lays a foundation for further exploring the impact of thermal discharge water from this powerhouse on the structure of surrounding marine biological communities and dissolved oxygen content in water bodies but also provides scientific evidence for the selection of modules when simulating thermal discharge water with the MIKE model. [ABSTRACT FROM AUTHOR]

A simulation investigation on the flow domain and particle movement pattern in the dispersion stage of dust explosion experiment were conducted using CFD simulation based on Euler–Lagrange approach. A new solver that couples two phases was developed based on the default solver rhoPimpleFoam from the OpenFOAM tool kit. Three sizes of particles 25 μm, 125 μm and 250 μm were simulated and studied. The simulation results of dust front propagation were evaluated by the experiment data. Particles with smaller diameters tended to move slower. Due to the high turbulence, flow vortices in the lower part of the dispersion domain were identified. These vortices gradually became larger with time and the decrease of inflow velocity. Uneven distribution of particles along with the equipment and high concentration of particles between the discharge electrodes were found in the simulation. Furthermore, particles with higher velocity favored the middle position in the tube. These facts suggested that the ignition delay time for particles larger than 125 μm should be higher than 60 ms.

A simulation investigation on the flow domain and particle movement pattern in the dispersion stage of dust explosion experiment were conducted using CFD simulation based on Euler–Lagrange approach. A new solver that couples two phases was developed based on the default solver rhoPimpleFoam from the OpenFOAM tool kit. Three sizes of particles 25 μ m , 125 μ m and 250 μ m were simulated and studied. The simulation results of dust front propagation were evaluated by the experiment data. Particles with smaller diameters tended to move slower. Due to the high turbulence, flow vortices in the lower part of the dispersion domain were identified. These vortices gradually became larger with time and the decrease of inflow velocity. Uneven distribution of particles along with the equipment and high concentration of particles between the discharge electrodes were found in the simulation. Furthermore, particles with higher velocity favored the middle position in the tube. These facts suggested that the ignition delay time for particles larger than 125 μ m should be higher than 60 ms. [ABSTRACT FROM AUTHOR]

The external nutrient loading significantly affects large shallow lakes, particularly those with intricate rive networks. In Lake Taihu, pollutant discharge standards have traditionally been quantified based on water environmental capacity, while neglecting the response characteristics of algal growth in different regions to boundary inputs. For that analysis, this study first estimated the river pollutant loadings of 16 most significant inflow and outflow rivers of Lake Taihu from 2008 to 2020 and explored the correlations between inflow water quality parameters and lacustrine chlorophyll-a levels. Results highlighted the significant influence of high river input of permanganate values in spring on the chlorophyll-a levels in the lake. Based on this, this study proposed the hypothesis that reducing the inflow concentration of permanganate in spring would inhibit algal growth, which was further validated using coupled hydrodynamic and ecological models. The simulation results indicated that the reduction of permanganate inflow concentration during spring would significantly decrease chlorophyll-a concentration in spring and summer, especially leading to a notable impact on peak values. However, due to variations in background concentrations among rivers, the extent of reduction in lake chlorophyll-a levels showed significant spatial differences. Additionally, analysis of extracted algal bloom areas revealed that there still remained a relatively high risk of algal blooms occurring in the main regions, particularly during autumn when inflow pollutant concentrations increased rapidly. These findings emphasized the importance of formulating reasonable exogenous reduction schemes, which should consider the concentration and variation trend of inflow pollutants, as well as the response characteristics of algal bloom growth in different lake zones to the boundary.

In this study, MIKE 3 model was used to simulate flow pattern and salinity distribution in Urmia Lake. About two decades ago, a causeway was constructed in the lake. The causeway has a 1.25-km opening and divides the lake into northern and southern basins. To perform the simulation, different influential variables such as the discharge of inflow rivers, wind speed, variation in water density, bed roughness, air temperature, relative humidity, cloud coverage, and heat flux through water surface were taken into account. Using the available water level data, salinity, and current velocity, the numerical model was calibrated and validated. Results revealed that the northern part of the lake was saltier due to the negligible entrance of fresh water into the northern part as well as the construction of causeway which restricts water exchange between the northern and southern parts of the lake. Results also showed that density-driven currents are dominant and that the fresher surface water layer in the southern part moves north and circulates counterclockwise in the northern portion of the lake, increasing water salinity and density. This water then moves to deeper layers and circulates back to the southern part. [ABSTRACT FROM AUTHOR]

Este artículo propone una metodología para la selección guiada de un modelo hidrodinámico para el estudio de los procesos físicos en un embalse, fundamentada en criterios cualitativos y cuantitativos, la cual fue aplicada para estudiar la variabilidad espacial de la estructura térmica en el embalse tropical de Riogrande II. La metodología considera tres etapas: i) definición y búsqueda, ii) preselección y iii) selección. Como resultado los modelos DELFT3D y MIKE3 fueron implementados y se compararon los perfiles de temperatura simulados con aquellos medidos entre el 23 y el 27 de marzo de 2010. ELCOM fue definido como modelo de referencia para comparar las series de tiempo de la profundidad media de la termoclina, la profundidad media de la capa de mezcla y su temperatura media. Para apoyar la selección final se utilizó tres estadísticos: i) el índice de concordancia (d1), ii) el MAE y iii) RMSE, cuyos resultados indicaron que el modelo DELFT3D es para este caso la mejor alternativa.

Over the past 30 years, reclamation projects and related changes have impacted the hydrodynamics and sediment transport in the Bohai Sea. Three-dimensional tidal current models of the Bohai Sea and the Yellow Sea were constructed using the MIKE 3 model. We used a refined grid to simulate and analyze the effects of changes in coastline, depth, topography, reclamation, the Yellow River estuary, and coastal erosion on tidal systems, tide levels, tidal currents, residual currents, and tidal fluxes. The simulation results show that the relative change in the amplitude of the half-day tide is greater than that of the full-day tide. The changes in the tidal amplitudes of M2, S2, K1, and O1 caused by coastline changes accounted for 27.76-99.07% of the overall change in amplitude from 1987 to 2016, and water depth changes accounted for 0.93-72.24% of the overall change. The dominant factor driving coastline changes is reclamation, accounting for 99.55-99.91% of the amplitude changes in tidal waves, followed by coastal erosion, accounting for 0.05-0.40% of the tidal wave amplitude changes. The contribution of changes in the Yellow River estuary to tidal wave amplitude changes is small, accounting for 0.01-0.12% of the amplitude change factor. The change in the highest tide level (HTL) is mainly related to the amplitude change, and the correlation with the phase change is small. The dominant factor responsible for the change in the HTL is the tide amplitude change in M2, followed by S2, whereas the influence of the K1 and O1 tides on the change in the HTL is small. Reclamation resulted in a decrease in the vertical average maximum flow velocity (VVAM) in the Bohai Sea. Shallower water depths have led to an increase in the VVAM; deeper water depths have led to a decrease in the maximum flow velocity. The absolute value of the maximum flow velocity gradually decreases from the surface to the bottom, but the relative change value is basically constant. The changes in the tidal dynamics of the Bohai Sea are proportional to the degree of change in the coastline. The maximum and minimum changes in the tidal flux appear in Laizhou Bay (P-LZB) and Liaodong Bay (P-LDB), respectively. The changes in the tidal flux are related to the change in the area of the bay. Due to the reduced tidal flux, the water exchange capacity of the Bohai Sea has decreased, impacting the ecological environment of the Bohai Sea. Strictly controlling the scale of reclamation are important measures for reducing the decline in the water exchange capacity of the Bohai Sea and the deterioration of its ecological environment. [ABSTRACT FROM AUTHOR]

The goal of this paper is to quantify the atmospheric influence, i.e. the influence of wind in particular, on the sea dynamics in the Rijeka Bay (Adriatic Sea). This quantification is important for city sewage disposal and dispersion as well as surface pollution dispersion. We compare the effect of jugo (sirocco) and bora winds on a calm period. The resulting simulations show that the bora conveys the surface layer of sea water out of the bay through the Middle and the Great Gate while deep cold water enters the bay through the same gates. The mean vertical upward velocity component close to the coast is about 1 mm s-1. This is sufficient to rise cold water near the city of Rijeka to the surface in three hours and to significantly cool the surface layer during summer. For the south-east wind (jugo) the situation is reverse: the warmer surface sea water enters the bay through the Middle and the Great Gate, while the colder bottom sea water exits the bay through the Middle and the Great Gate, accumulating the warmer sea water in the bay. In the case of no wind the surface velocity vectors (at depths of 0.5 m) are disordered and do not follow any particular pattern while the movements at 12 m, 24 m, 36 m, 48 m, and 60 m show dominant flow from the western coast (of the island Krk) toward the eastern coast of the Istrian peninsula. [ABSTRACT FROM AUTHOR]

This paper used a specialist software package to produce a detailed model of the River Mersey estuary, which can be subjected to a range of simulated tidal conditions. The aim of this research was to use the validated model to identify the optimal location for the positioning of a tidal turbine. Progress was made identifying a new optimal site for power generation using velocity data produced from simulations conducted using the MIKE 3 software. This process resulted in the identification of site 8, which sits mid-river between the Morpeth Dock and the Albert Dock, being identified as the favoured location for tidal power generation in the River Mersey. Further analysis of the site found that a 17.2-m diameter single rota multidirectional turbine with a 428-kW-rated capacity could produce 1.12 GWh annually. [ABSTRACT FROM AUTHOR]

As part of the Terawatt project, two regional-scale hydrodynamic models of the Pentland Firth & Orkney waters were developed using unaltered commercially-available software (MIKE 3 and Delft3D), in order to investigate the suitability of such software for predicting the effects of tidal stream energy development. Realistic scenarios for tidal energy extraction were implemented in each, and the predictions of the models with and without turbines compared. Similar predictions were made of depth-averaged current speed (spatial correlation of R 2 = 0.95 ), but bed stress in one model was more than double that in the other due to the use of different values for bed resistance. The effects of energy extraction are consistent between the models at a regional scale but show considerable local differences. We conclude that these model codes are suitable for broad-scale assessment of the effects of energy extraction but that caution, and more detailed survey data, is required at fine scales. [ABSTRACT FROM AUTHOR]

We report the development of a prototype tool for modeling the risks of spreading of non-indigenous invasive species via ballast water. The tool constitutes of two types of models: a 3D hydrodynamical model calculates the currents in the North Sea and Danish Straits, and an agent-based model estimates the dispersal of selected model organisms with the prevailing currents calculated by the 3D hydrodynamical model. The analysis is concluded by a postprocessing activity, where scenarios of dispersal are combined into an interim estimate of connectivity within the study area. The latter can be used for assessment of potential risk associated with intentional or unintentional discharges of ballast water. We discuss how this prototype tool can be used for ballast water risk management and outline other functions and uses, e.g., in regard to ecosystem-based management and the implementation of the EU Marine Strategy Framework Directive. [ABSTRACT FROM AUTHOR]

Abstract: A comparison of two three-dimensional numerical modeling systems for tidal elevations and velocities in the coastal waters is presented. The two modeling systems are: (1) the Princeton Ocean Model (POM) and (2) the MIKE 3 flow model. The model performance results for Singapore''s coastal waters show that the predicted tidal elevations from the two hydrodynamic modeling systems are almost identical and are in very good agreement with field measurement data. The simulated tidal current velocities match well with field measurement data at the selected stations, but it seems that the POM provides the slightly better simulation, compared to the MIKE 3 flow model. The depth profiles of the velocities obtained from the two modeling systems may be greatly different at some time, due to the vertical diffusion coefficient calculated from different turbulent sub-models in the two modeling systems. The POM generally predicts larger peak tidal velocities. The maximum speed differences for the model results from the two modeling systems occur in the top and differ from time to time and from location to location, reaching up to 20%. [Copyright &y& Elsevier]

Abstract: Øresund is a narrow sound between Denmark and Sweden in Northern Europe. The sound has a complex hydrography with two- or three-layer stratifications, sometimes with opposite directed currents in the different layers. The complicated hydrography makes it difficult to investigate sediment dynamics by use of traditional field-work based methods. In this study the three-dimensional modelling system MIKE 3 was applied in order to quantify the dynamics of the fine-grained sediment in Øresund over a year. The model simulated the complex hydrodynamics including stratification satisfactorily. The simulated suspended sediment concentrations were low, generally not exceeding 20 mg l−1. Over the year 2000 the model computed an annual accumulation of 136,000 tons of sediment. Both the sediment concentrations and the overall accumulation of fine-grained sediment are in accordance with previously published results. This study presents some general hydrodynamic and sedimentological characteristics from the sound. The hydrodynamic characteristics were well reproduced, making the hydrodynamic model ideal for the sediment transport study. The description of the sedimentology of the sound is in some aspects new and is therefore not directly verified by data. The overall result is believed to be representative for the area and the model has given information on sedimentological transport patterns. This study demonstrated that generic numerical cohesive sediment transport models are capable of simulating hydrodynamics and cohesive sediment dynamics in complicated estuarine environments and of establishing reliable sediment budgets. [Copyright &y& Elsevier]