Transport Model Results Research Articles

Coalescence sum rule and the electric charge- and strangeness-dependences of directed flow in heavy ion collisions

The rapidity-odd directed flows (v1) of identified hadrons are expected to follow the coalescence sum rule when the created matter is initially in parton degrees of freedom and then hadronizes through quark coalescence. A recent study has considered the v1 of produced hadrons that do not contain u or d constituent quarks. It has constructed multiple hadron sets with a small mass difference but given difference in electric charge Δq and strangeness ΔS between the two sides, where a nonzero and increasing Δv1 with Δq has been proposed to be a consequence of electromagnetic fields. In this study, we examine the consequence of coalescence sum rule on the Δv1 of the hadron sets in the absence of electromagnetic fields. We find that in general Δv1≠0 for a hadron set with nonzero Δq and/or ΔS due to potential v1 differences between u¯ and d¯ and between s and s¯ quarks. We further propose methods to extract the coefficients for the Δq- and ΔS-dependences of the direct flow difference, where a nonzero constant term would indicate the breaking of the coalescence sum rule. The extraction methods are then demonstrated with transport model results.

Lead and Zinc Groundwater Contaminant Transport Modelling Using MT3DMS in Xaysomboun Province, Lao PDR

Contaminant transport modelling is commonly applied in the Groundwater Modelling System (GMS). Modular Three-Dimensional Multispecies Transport (MT3DMS) package is one of other packages, developed by the U.S. Geological Survey, this research presents the employing of the M3TDMS package as excellent tools to establish the 3D conceptual model of contaminant transport modeling, simulate and predict the multispecies of Lead and zinc substances which transport in the groundwater, there are 15 boreholes that were observed and monitored, the results of the contaminant transport modeling was found the Lead(Pb) contaminant transport with initial concentrations of 3.96 mg/l at borehole MB48 as point source, the concentration reduced to 0.1 mg/l, after 3,650 days simulation. The initial zinc (Zn) concentration of 0.886 mg/l at borehole CV04 decreases to 0.023 mg/l after 3,650 days simulation.

Determination of BVOCs based on high time-resolved measurements in urban and forest areas in Japan

Biogenic volatile organic compounds (BVOCs) with high photochemical activity and short atmospheric lifetimes are major contributors to tropospheric ozone and other photochemical air pollution. Although several studies have been conducted on BVOC emissions in Japan, no comprehensive observations have been made to determine the actual state of BVOCs in the atmosphere. Therefore, we conducted time-resolved measurements of atmospheric BVOCs in urban and forested areas throughout the year. The concentrations of BVOCs were higher in summer than in the other seasons. Isoprene concentrations were higher during hours with higher temperatures and solar radiation. However, there were also months and times of the year when monoterpenes showed high concentrations, which indicates that the behavior of the BVOC components differed depending on the time of the year. The results of the propylene equivalent concentration indicated that BVOCs considerably contributed to tropospheric ozone production. The year-long observations of BVOCs in this study contribute to our understanding of the actual status of atmospheric BVOC concentrations and components and the uncertainty in the calculation results of chemical transport models.

Precipitation trend increases the contribution of dry reduced nitrogen deposition

Given the leveling off in oxidized nitrogen emissions around the world, the atmospheric deposition of reduced nitrogen (NHx = NH3 + NH4+) has become progressively critical, especially dry deposition, which presents great threats to plant growth. A combination of historical deposition data of measured wet NHx and modeled dry NHx in China suggests that dry NHx deposition has been increasing substantially (4.50% yr−1, p < 0.05) since 1980. Here, chemical transport model (WRF-EMEP) results indicate that variation in NH3 emissions is not a dominant factor resulting in the continually increasing trends of dry NHx deposition, while climate change-induced trends in precipitation patterns with less frequent light rain and more frequent consecutive rain events (with ≥2 consecutive rainy days) contribute to the increase in dry NHx deposition. This will continue to shift NHx deposition from wet to dry form at a rate of 0.12 and 0.23% yr−1 (p < 0.05) for the period of 2030–2100 in China under the RCP4.5 and RCP8.5 scenarios, respectively. Further analysis for North America and Europe demonstrates results similar to China, with a consistent increase in the contribution of dry NHx deposition driven by changing precipitation patterns from ~30% to ~35%. Our findings, therefore, uncover the change of precipitation patterns has an increasing influence on the shifting of NHx deposition from wet to dry form in the Northern Hemisphere and highlight the need to shift from total NHx deposition-based control strategies to more stringent NH3 emission controls targeting dry NHx deposition in order to mitigate the potential negative ecological impacts.

A numerical assessment on the managed aquifer recharge to achieve sustainable groundwater development in Chaobai River area, Beijing, China

Intensive groundwater exploitation has depleted groundwater storage and led to a series of geo-environmental problems in Beijing Plain, China. Managed Aquifer Recharge (MAR) has been endorsed to mitigate the groundwater storage depletion and achieve groundwater sustainability. A pilot MAR has been tested in the Chaobai River catchment since 2015. An innovative large-scale MAR consisting of 9 cascade terraced infiltration ponds was proposed and its effectiveness was assessed in this study using an integrated modelling approach. The integrated model coupled the regional and local transient flow and transport processes. The transient regional flow model simulated historical groundwater level declines and storage depletion in the Beijing Plain from 1995 to 2018. The coupled regional and local flow model was used to simulate the pilot MAR test in the Chaobai River from 2015 to 2018. A significant groundwater level increase was observed nearby the pilot MAR since 2015. The transport model results indicate that approximately 40% of the infiltrated water was captured by pumping wells in the No.8 well field. The models were further used to assess the long-term effects of the large-scale MAR from 2020 to 2050. The simulation results show that the groundwater system will reach a new equilibrium state under the implementation of the large-scale MAR scheme. Almost 91% of the abstracted water in the No. 8 well field will come from the MAR infiltration. The proposed large-scale MAR is very effective in restoring the depleted aquifer storage and maintaining the groundwater abstraction in the No.8 well field. However, with the increase of the groundwater level, the infiltration rate of several ponds will decrease. Therefore, it is important to maintain a dynamic balance between artificial recharge and groundwater abstraction in order to achieve a sustainable long-term MAR operation in the region.

Evolution of the Reaction and Alteration of Granite with Ordinary Portland Cement Leachates: Sequential Flow Experiments and Reactive Transport Modelling

The construction of a repository for the geological disposal of radioactive waste will include the use of cement-based materials. Following closure, groundwater will saturate the repository, and the extensive use of cement will result in the development of a highly alkaline porewater, pH &gt; 12.5; this fluid will migrate into and react with the host rock. The chemistry of the fluid will evolve over time, initially with high Na and K concentrations, evolving to a Ca-rich fluid, and finally returning to the natural background groundwater composition. This evolving chemistry will affect the long-term performance of the repository, altering the physical and chemical properties, including radionuclide behaviour. Understanding these changes forms the basis for predicting the long-term evolution of the repository. This study focused on the determination of the nature and extent of the chemical reaction, as well as the formation and persistence of secondary mineral phases within a granite, comparing data from sequential flow experiments with the results of reactive transport modelling. The reaction of the granite with the cement leachates resulted in small changes in pH and the precipitation of calcium aluminium silicate hydrate (C-(A-)S-H) phases of varying compositions, of greatest abundance with the Ca-rich fluid. As the system evolved, secondary C-(A-)S-H phases redissolved, partly replaced by zeolites. This general sequence was successfully simulated using reactive transport modelling.

Studies on navigational depth of a shipping channel using numerical modelling and bathymetric analysis in the Hooghly estuary, India

ABSTRACT Availability of navigational draft along the shipping channel is essential for effective freight transport of any port for its economic sustenance. Rangafala channel is one of the main channels leading to Kolkata port. The primary objective of this research work is to find the critical and vulnerable positions in the navigation channel. A Cartesian grid-based, two-dimensional, depth-averaged, finite volume model has been developed using existing bathymetry, water level, sediment data, and appropriate boundary conditions in hydrodynamic and sediment transport modelling. The developed model is first calibrated using observed velocity data, and then, it has been validated with observed water level data at the Haldia gauge station. The validated model has been simulated for 6-month boundary values, and it has been experienced that the depth-averaged model velocity is relatively high throughout the channel. The hydrodynamic and sediment transport model results suggest that the channel remains self-maintained, and only a few locations experience little deposition. Eleven years of channel bathymetric data are used to complement the simulated model results. It is observed that the required draft for navigation has always been maintained along the Rangafala channel.

Dynamics of electron internal transport barrier formation at the H–L transition on EAST

The dynamics of electron-internal transport barrier (e-ITB) formation is studied in the hybrid plasma of neutral beam injection and lower hybrid wave heating on EAST. The e-ITB is observed to be repetitively formed at the H–L transition, where the relaxation process of core radiation triggers an increase in neutron yield and core electron temperature. A reversed q-profile is beneficial for generating the barrier, identified by the appearance of reversed shear Alfvén eigenmodes (RSAEs). The dimensionless parameter of the normalized Larmor radius is estimated to visualize the dynamic behavior of the e-ITB. It is found that the e-ITB forms once the electron exceeds 0.014, and the RSAEs are accompanied by the e-ITB formation. The barrier foot moves inwards until the L–H transition occurs, where the H-mode pedestal or type-I edge localized mode (ELM) strongly influences the e-ITB intensity. The results of thermal transport modeling show a significant reduction in the core thermal transport coefficient in the electron channel while maintaining a nearly unchanged ion transport level as the e-ITB evolves.

Impact of the Revetment on the Seashore in the Region of Babie Doły (KM 93.6–93.9), Poland

The present paper addresses the litho-dynamic and morpho-dynamic processes in the coastal zone of Babie Doły (KM 93.6–93.9), Poland. As a background, the history of coastal engineering measures in this area is described. The impact of post-war structures on the seashore is analysed on the basis of historical maps, supported by results of the sediment transport modelling. Shore regression is caused by the so-called downstream erosion behind the headland with remains of rock palisade structures. The possible consequences for the seashore resulting from the removal of the analysed revetment are discussed. The paper also presents recommendations to the relevant authorities for the future.

Evolution of the Reaction and Alteration of Mudstone with Ordinary Portland Cement Leachates: Sequential Flow Experiments and Reactive-Transport Modelling

The construction of a repository for geological disposal of radioactive waste will include the use of cement-based materials. Following closure, groundwater will saturate the repository and the extensive use of cement will result in the development of a highly alkaline porewater, pH &gt; 12.5; this fluid will migrate into and react with the host rock. The chemistry of the fluid will evolve over time, initially high [Na] and [K], evolving to a Ca-rich fluid, and finally returning to the groundwater composition. This evolving chemistry will affect the long-term performance of the repository, altering the physical and chemical properties, including radionuclide behaviour. Understanding these changes forms the basis for predicting the long-term evolution of the repository. This study focused on the determination of the nature and extent of the chemical reaction, as well as the formation and persistence of secondary mineral phases within a mudstone, comparing data from sequential flow experiments with the results of reactive transport modelling. The reaction of the mudstone with the cement leachates resulted in small changes in pH with the precipitation of calcium aluminium silicate hydrate (C-(A-)S-H) phases of varying compositions. As the system evolves, secondary C-(A-)S-H phases re-dissolve and are replaced by secondary carbonates. This general sequence was successfully simulated using reactive transport modelling.

How Do Fractures Influence Hyporheic Exchange in Sedimentary Rock Riverbeds?

AbstractBedrock rivers represent a hydrogeological environment in which surface water flows along an exposed bedrock surface. Studies of hyporheic exchange have exclusively involved rivers composed of unconsolidated fluvial sediments, leaving a critical knowledge gap. This study evaluates the conditions that could support bedform‐scale hyporheic exchange within a fractured sedimentary bedrock river based on field data collected near Guelph, Canada. Hyporheic exchange at the bedform‐scale was evaluated by numerically modeling the migration of a conservative solute tracer through a bedrock riverbed within a two‐dimensional vertical cross‐section along the flow direction. A stochastic discrete fracture‐matrix framework was developed to represent measured subsurface fractured bedrock properties, producing a probabilistic distribution of potential hyporheic exchange pathways. Flow and transport model results indicate that: (a) bedform‐scale hyporheic exchange within a bedrock river exists with high fluid flow velocities in fractures, yet long solute residence times due to diffusion across the fracture‐matrix boundary; (b) the coincidence of fractures and hydrodynamic head gradients across the riverbed controls the spatial extent of bedform‐scale hyporheic exchange; and (c) the potential variability in hyporheic exchange residence time is large (i.e., tens of years) due to the inherent variability in facture network properties. Our field‐based numerical study indicates that the average (median) residence time may not be a good proxy for the potential natural attenuation capacity of a fractured sedimentary bedrock riverbed and that hyporheic exchange has the potential to emplace surface water contaminants within the fractured porous rock matrix that could become a long‐term source of trace contaminants.

Transport modeling in the development of a complex transport scheme on the example of the city of Kyiv (Ukraine)

The object of research is a complex transport scheme using the example of the city of Kyiv (Ukraine). The comprehensive transport scheme of the city of Kyiv provides for a variant design of the city’s transport system. In transport planning and design, for a qualitative assessment of planning decisions, predictive transport models of cities are most often used, which describe the macroscopic parameters of the traffic flow. The proposed options were tested on a transport model. The main task of this model is the modeling of transport correspondence, where the volume of traffic by public transport is about 80-90 % of the total volume of traffic. For this, a model was developed, with the help of which the level of loading of the main network, the volume of transport work, and the total number of passengers carried by public transport were analyzed. When choosing the optimal option, let’s took into account such parameters as the average speed of the traffic flow, general transport delays, and the total number of passengers transported by public transport. As well as the average distance of travel, the average time for the implementation of transport correspondence on public transport, the cost of unproductive loss of time by residents of the city, and so on. Based on the results of transport modeling, the optimal option for the development of the city’s transport system was selected, which provides for the completion of the construction of existing road transport infrastructure facilities, the construction and development of the backbone network, systems outside the street rail transport, and optimization of the public transport route network. The complex transport scheme of the city of Kyiv, which was created using modern technologies in the field of transport modeling, allows to analyze and determine the effectiveness of the implementation of various measures for the development of the city’s transport infrastructure. Transport modeling has shown the feasibility of providing initial data for the feasibility study of investment projects, the arrangement of road transport infrastructure facilities, the improvement of traffic management schemes, the arrangement of new public transport routes.

Validation of WRF-Chem Model and CAMS Performance in Estimating Near-Surface Atmospheric CO2 Mixing Ratio in the Area of Saint Petersburg (Russia)

Nowadays, different approaches for CO2 anthropogenic emission estimation are applied to control agreements on greenhouse gas reduction. Some methods are based on the inverse modelling of emissions using various measurements and the results of numerical chemistry transport models (CTMs). Since the accuracy and precision of CTMs largely determine errors in the approaches for emission estimation, it is crucial to validate the performance of such models through observations. In the current study, the near-surface CO2 mixing ratio simulated by the CTM Weather Research and Forecasting—Chemistry (WRF-Chem) at a high spatial resolution (3 km) using three different sets of CO2 fluxes (anthropogenic + biogenic fluxes, time-varying and constant anthropogenic emissions) and from Copernicus Atmosphere Monitoring Service (CAMS) datasets have been validated using in situ observations near the Saint Petersburg megacity (Russia) in March and April 2019. It was found that CAMS reanalysis data with a low spatial resolution (1.9° × 3.8°) can match the observations better than CAMS analysis data with a high resolution (0.15° × 0.15°). The CAMS analysis significantly overestimates the observed near-surface CO2 mixing ratio in Peterhof in March and April 2019 (by more than 10 ppm). The best match for the CAMS reanalysis and observations was observed in March, when the wind was predominantly opposite to the Saint Petersburg urbanized area. In contrast, the CAMS analysis fits the observed trend of the mixing ratio variation in April better than the reanalysis with the wind directions from the Saint Petersburg urban zone. Generally, the WRF-Chem predicts the observed temporal variations in the near-surface CO2 reasonably well (mean bias ≈ (−0.3) − (−0.9) ppm, RMSD ≈ 8.7 ppm, correlation coefficient ≈ 0.61 ± 0.04). The WRF-Chem data where anthropogenic and biogenic fluxes were used match the observations a bit better than the WRF-Chem data without biogenic fluxes. The diurnal time variation in the anthropogenic emissions influenced the WRF-Chem data insignificantly. However, in general, the data of all three WRF-Chem model runs give almost the same CO2 temporal variation in Peterhof in March and April 2019. This could be related to the late start of the growing season, which influences biogenic CO2 fluxes, inaccuracies in the estimation of the biogenic fluxes, and the simplified time variation pattern of the CO2 anthropogenic emissions.

Vulnerability assessment, transport modeling and simulation of nitrate in groundwater using SI method and modflow-MT3DMS software: case of Sminja aquifer, Tunisia

Like most North African countries, Tunisia is characterized by a harsh arid and semi-arid climate with scarce water resources and poor water quality on most of its territory. The quality of groundwater is not immune to pollution. Sminja aquifer, located in Zaghouan district in Northeastern Tunisia, has been used to meet Zaghouan agglomeration needs for drinking purposes and irrigation uses. On the other hand, the region has suffered from inefficient usage and mismanagement of water resource due to appropriate legal, political, and economic frameworks to take into consideration the regional vulnerability to climate change and population growth. The application of the Susceptibility Index (SI) makes it possible to evaluate the impact of agricultural activities on the water quality in Sminja aquifer, using five parameters [depth of water (D), net recharge (R), aquifer media (A), topography (T) and Land use (LU)]. Modular three-dimensional multispecies transport model was used to assess, simulate and predict pollution transport of nitrate. The vulnerability index's spatial distribution shows that the most vulnerable area was found in the extreme north of the Sminja aquifer. It shows that a high vulnerability characterizes 21% of the study area (70 < SI < 60). The moderate to high vulnerability areas to pollution occupied 12% of the aquifer and the moderate to low vulnerability zones occupied 67% of the total area. The outputs of the SI reflect a good correlation with the measured nitrate concentrations. After calibration completion, the MT3DMS transport model results showed a good correlation between measured and simulated nitrate concentrations. The predict scenarios show that the nitrate propagates in all the aquifer, from the irrigated area to the non-irrigated area.

Interdisciplinary analysis of larval dispersal for a coral reef fish: opening the black box

Many marine animals have a biphasic life cycle in which demersal adults spawn pelagic larvae with high dispersal potential. An understanding of the spatial and temporal patterns of larval dispersal is critical for describing connectivity and local retention. Existing tools in oceanography, genetics, and ecology can each reveal only part of the overall pattern of larval dispersal. We combined insights from a coupled physical-biological model, parentage analyses, and field surveys to span larval dispersal pathways, endpoints, and recruitment of the convict surgeonfish Acanthurus triostegus. Our primary study region was the windward coast of O‘ahu, Hawai‘i. A high abundance of juvenile A. triostegus occurred along the windward coast, with the highest abundance inside Kāne‘ohe Bay. The output from our numerical model showed that larval release location accounted for most of the variation in simulated settlement. Seasonal variation in settlement probability was apparent, and patterns observed in model simulations aligned with in situ observations of recruitment. The bay acted as a partial retention zone, with larvae that were released within or entering the bay having a much higher probability of settlement. Genetic parentage analyses aligned with larval transport modeling results, indicating self-recruitment of A. triostegus within the bay as well as recruitment into the bay from sites outside. We conclude that Kāne‘ohe Bay retains reef fish larvae and promotes settlement based on concordant results from numerical models, parentage analyses, and field observations. Such interdisciplinary approaches provide details of larval dispersal and recruitment heretofore only partially revealed.

Effects of Fe-rich acid mine drainage on percolation features and pore structure in carbonate rocks

Acid mine drainage (AMD) poses significant ecological, environmental and geological challenges worldwide, especially in more vulnerable karst areas. However, the impact of AMD on percolation features and pore structure of carbonate strata is poorly understood, despite its importance for the evolution of carbonate aquifer as well as karst groundwater quality. To fill this knowledge gap, field investigations, core-flooding experiments, reactive transport modeling and pore structure studies [mercury intrusion porosimetry (MIP) and nitrogen physisorption analysis] were conducted to understand the geochemical processes and associated pore development in carbonate strata exposed to Fe-rich AMD. Our field investigation shows that the AMD is characterized by low pH values (2.4–3.8), high contents of sulfate (1457–4217 mg/L), Fe (100–830 mg/L, Fe3+/Fe2+) and heavy metals, that can potentially leak into carbonate strata. The major findings of this study include: (1) core-flooding experiments reveal that the interaction of carbonate rock with AMD causes a rapid elevation of solution pH and simultaneous precipitation of Fe3+/Fe2+ as iron (oxy)hydroxides or (oxy)hydroxy sulfates within the rock; (2) the results of reactive transport modeling suggest that ferrous iron has a longer transport distance than ferric iron in the carbonate core plug, and then it precipitates to fill the pore space; and (3) despite the precipitation, the flooding of AMD increases the overall permeability of cores by creating large numbers of pores with throat diameter between 0.001 and 10 μm. We also found that the interaction of AMD with the carbonate rock might stimulate the formation of preferential flow channel(s). Our results have been incorporated into a conceptual model, built to illustrate the geochemical processes and mechanisms involved. Our research has important applications in AMD treatment for coal-mining industries, and for local governments devising strategies for karst water resource protection and management.

Spatio-Temporal Variations of Atmospheric NH3 over East Asia by Comparison of Chemical Transport Model Results, Satellite Retrievals and Surface Observations

Atmospheric ammonia (NH3) plays an important role in the formation of secondary inorganic aerosols, the neutralization of acid rain, and the deposition to ecosystems, but has not been well understood yet, especially over East Asia. Based on the GEOS-Chem model results, the IASI satellite retrievals, the in-site surface observations of a nationwide filter pack (FP) network over Japan and the long-term high resolution online NH3 measurements at Fukuoka of western Japan, the spatio-temporal distributions of atmospheric NH3 over East Asia was analyzed comprehensively. A significant seasonal variation with a summer peak was found in all datasets. Comparison between the satellite retrievals and model simulations indicated that the IASI NH3 vertical column density (VCD) showed good consistency with GEOS-Chem results over North and central China, but had large differences over South China due to the effect of clouds. Over the Japan area, GEOS-Chem simulated NH3 concentrations successfully reproduced the spatio-temporal variations compared with in-situ observations, while IASI NH3 VCD retrievals were below or near the detection limit and difficult to obtain a reasonable correlation for with model results. The comprehensive analysis indicated that there were still some differences among different datasets, and more in-situ observations, improved satellite retrievals, and high-resolution model simulations with more accurate emissions are necessary for better understanding the atmospheric NH3 over East Asia.

UNIFORM PRINCIPLES OF ORGANIZATION OF RAIL FREIGHT TRANSPORTATION OPERATIONS

Improving the operational efficiency of transport is one of the main catalysts for raising the quality of life and socio-economic development. The prevailing global trends are aimed at establishing logistic chains from producers to consumers. The cross-border movement of world production within the framework of globalization, the deepening of integration processes between countries highlight the issues of developing a methodology for planning and evaluating international transport corridors from various points of view, and economic, technical, social, environmental and other aspects. The urgent issue is the harmonization of the technical and regulatory framework for the organization of «seamless» transportation, the synchronization of the technological cycles of various modes of transport, including operation of multimodal transport hubs. A large number of studies are dedicated to the modelling and control of traffic flows, new methods of forecasting the transport situation using the results of computer dynamic transport modelling, analysis of existing infrastructure resources and elimination of bottlenecks in the existing railway system (including through the expansion of the railway network and innovative methods of traffic control).Hence the achievement of target parameters of efficiency of production activity of all participants in railway transportations is possible through qualitative changes in the system of the organization of transportation process, the objective of the research was to study technological aspects of improvement of quality of functioning of the transport system in relation to activity of the Russian railways.The research applied methods of system analysis of scientific and technical data and technical and economic indicators of complex systems.The issues of implementation of end-to-end principles of transportation process management are considered, the concept of «technological polygon of transportation process management» is expanded. The analysis and grouping of methods for improving the efficiency of railway transport was carried out with regard to improving the operation quality indicators and refined model of rolling stock management, increasing the efficiency of the use of traction equipment, profiling of railway itineraries in respect of the preferred types of traffic, establishing sections well-provided for safe passage of freight trains and synchronized with the operation ranges of locomotives, organizing freightage in wagons withincreased axle load, removing barriers and restrictions in the power supply sector, etc.The transition to the «polygon» model of the organization of the technological process, the unification and optimization of the use of available resources, and, as a result, the reduction of risks of losses from transportation, service provision and unplanned use of resources are effective tools to improve the quality of rail operations.

Impact of sea level rise on estuarine salt water intrusion–A numerical model study for Changjiang Estuarine

A 3D and high-resolution salinity transport numerical model of Changjiang Estuary with unstructured mesh was established using the MIKE3. The salinity transport model results were tested and verified by the observed data in Changjiang Estuary, the statistics of correlation coefficient are in good values. And then, the verified salinity transport model was used to study the impact of sea level rise on saltwater intrusion in the Changjiang Estuary. The results show that the entire North Branch was flooded with high saline water and a large amount of salt water spill over from the North Branch into the South Branch, which caused the South Branch with a high-low-high saddle-shaped distribution. With the rise of sea level, salt rocks such as the North Branch, the South Branch, and the North Channel moved upstream to varying degrees, strengthening the saltwater intrusion in the eastern Changjiang River. The high saline waters from North Branch spill over into South Branch also increased. The isohaline of North Branch South Branch and North Channel move to upstream, and move downstream in South Channel, North Passage and South Passage. The high salt water from the North Branch into the South Branch increased the salinity of the upper section of the South Branch.

Numerical Simulation of Multi-Water-Source Artificial Recharge of Aquifer: A Case Study of the Mi-Huai-Shun Groundwater Reservoir

Artificial recharge is an effective way to alleviate water shortages and excessive groundwater exploitation. In this study, to explore environmental changes of surface water and groundwater during multi-water-sources recharge process, numerical simulation method was applied. Local reclaimed water, treated by wetland, and water from the South-to-North Water Transfer Project (SNWTP) were used to recharge groundwater reservoir in Mi-Huai-Shun District (Miyun District, Huairou District and Shunyi District). The Flow Model results showed that the accumulated loss of the groundwater resource in the Mi-Huai-Shun area from 2007 to 2016 reached – 1.784 × 109 m3. All the water sources contribute to the recharge of groundwater, raising the groundwater level and increasing the groundwater reserves. Meanwhile, the Solute Transport Model results show that different water source has different effects on the local groundwater environment. chloride concentration of reclaimed water source and wetland water source are higher than groundwater, and the artificial recharge caused the chloride concentration of groundwater in receiving area to rise. The water from the SNWTP played an important role on reducing chloride concentration due to dilution. In addition, Multi-Water-Source artificial recharge is also related to the local hydrogeological conditions. This study provides a comprehensive analysis of the impact of multi-water-source recharge on groundwater quantity and quality.