Water Environmental Model Research Articles

A new assessment method for water environment safety and its application

The Three Gorges Reservoir area is recognized by its vast size, dense population, bustling economic and social activities along its banks, and by the significant volume of waterway traffic. These factors make it with a high risk of water pollution accidents, posing a serious threat to water environmental safety. Therefore, it is imperative to conduct a water environmental safety assessment in this region to ensure the safety of the water environment. In the present work, the Driving-Pressure-State-Impact-Response-Risk Water Environmental Safety model was proposed, and a comprehensive water environmental safety assessment system was established. The Water Environment Safety Index was introduced to measure the degree of water environment safety. This model synthesized multiple factors and their interrelationships, enabling a more accurate assessment of water environment safety. By adopting scientifically rigorous evaluation criteria, this assessment method enhanced the reliability and credibility of the results obtained. The water environment safety in the 22 counties and districts of the Three Gorges Reservoir area of Chongqing region from 2017 to 2021 was assessed in terms of temporal changes and spatial differentiation. In general, the overall water environment safety situation in the Three Gorges Reservoir area of Chongqing region is relatively safe, but a few counties/districts (such as Wanzhou District, Jiangjin District, etc.) are still in Warning. Spatially, the water environmental safety condition was relatively better in the northeast compared to the southwest. The main factors threatening water environment safety include: 1) the consequence of the Three Gorges Project, 2) severe soil erosion, 3) industrial, agricultural, and domestic pollution, and 4) frequent water pollution accidents. The present work provided a new method for conducting water environment safety assessments, which is expected to positively contribute to further research in this field.

Hydrodynamics, Diagenesis and Hypoxia Variably Drive Benthic Oxygen Flux in a River‐Reservoir System

AbstractBenthic oxygen flux with complex spatiotemporal variations is essential for the global budget of carbon dioxide and the regional security of water quality and ecology, but its dominant driver under different circumstances has yet to be identified. In this study, a parametric scheme of oxygen flux was proposed and validated with aquatic eddy correlation measurements and then coupled with a diagenesis model and a water environment model. The coupled model was applied to a river‐reservoir with significant environmental gradients in hydrodynamics, diagenesis, and hypoxia, which are three factors that competitively drive the variation in benthic oxygen flux. The results indicate that hydrodynamics dominate the flux in the riverine and thalweg areas, diagenesis is the dominant driver of the lacustrine and bank areas, and hypoxia shows dominance only in the hypolimnetic anoxic area. In general, diagenesis is the dominant driver of oxygen flux in river‐reservoirs, followed by hydrodynamics, both of which are more prominent than hypoxia. If the operated reservoir experiences a wet year, the dominance of hydrodynamics tends to increase, while that of diagenesis and hypoxia decreases. The three divers exhibit similar but more stable dominance in riverine systems than in reservoirs, while diagenesis becomes the exclusive driver of oxygen fluxes in lacustrine systems.

An optimization framework for basin-scale water environmental carrying capacity

The interaction between water environment and social economy at a basin scale is complex and challenging to quantify. To address this issue, this study proposes an integrated framework that builds parametric connections among water, contaminants, administrative regions, and social activities. The framework, known as the water environmental carrying capacity (WECC) optimization framework, effectively captures the intricacy of the interaction and integrates socio-economic parameter structure relationships, a water environmental model, a WECC optimization model, and a sensitivity analysis of regulatory parameters. Applied to the Anhui-Huaihe Basin in mid-eastern China, the framework considers nine administrative regions and three economic factors: industry, agriculture, and GDP per capita (pGDP). Results show that the current water environmental carrying capacity of the watershed is insufficient to meet socio-economic development requirements. After optimization, the WECC for industry, agriculture, and pGDP in the region increased by 22.40%, 26.59%, and 15.08% respectively. Overall COD and NH4–N discharge decreased by 13.6% and 14.7% respectively, effectively reducing pollution loads in rivers and enhancing sustainable development potential. At the regional scale, optimization for industry, agriculture, and pGDP exhibited different characteristics, but all aimed to improve efficiency by reducing the K value (pollution discharge/output value ratio). Regions with industrial treatment rates (αwt) below 0.8 should prioritize increasing treatment rates, while those above 0.8 should consider industrial upgrading for enhanced efficiency. For agriculture, important sensitive parameters for farming and livestock breeding are the proportion of high standard farmland (αs) and the scale breeding ratio (αb), which should be increased to above 0.15 and 0.83 respectively for all regions to achieve agricultural optimization. For pGDP optimization, the focus is on improving living environments and reducing pollution discharge, with crucial measures including collecting and treating rural domestic sewage, where the rural toilet improvement rate (αt) in each region should be increased to 0.78 or above. The results emphasize the need for both interregional allocation and intraregional planning to achieve comprehensive basin optimization and a harmonious balance between regional development and water environment.

Assessing effect of best management practices in unmonitored watersheds using the coupled SWAT-BiLSTM approach

In order to enhance the simulation of BMPs (Best Management Practices) reduction effects in unmonitored watersheds, in this study, we combined the physically-based hydrological model Soil & Water Assessment Tool (SWAT) and the data-driven model Bi-directional Long Short-Term Memory (Bi-LSTM), using the very-high-resolution (VHR) Land Use and Land Cover (LULC) dataset SinoLC-1 as data input, to evaluate the feasibility of constructing a water environment model for the Ba-River Basin (BRB) in central China and improving streamflow prediction performance. In the SWAT-BiLSTM model, we calibrated the top five SWAT parameters sorted by P-Value, allowing SWAT to act as a transfer function to convert meteorological data into base flow and storm flow, serving as the data input for the Bi-LSTM model. This optimization improved the Bi-LSTM's learning process for the relationship between the target and explanatory variables. The daily streamflow prediction results showed that the hybrid model had 9 regions rated as "Very good," 2 as "Good," 2 as "Satisfactory," and 1 as "Unsatisfactory" among the 14 regions. The model achieved an NSE of 0.86, R2 of 0.85, and PBIAS of −2.71% for the overall daily streamflow prediction performance during the verification period of the BRB. This indicates that the hybrid model has high predictive accuracy and no significant systematic bias, providing a sound hydrodynamic environment for water quality simulation. The simulation results of different BMPs scenarios showed that in the scenarios with only one BMP measure, stubble mulch had the best reduction effect, with average reductions of 17.83% for TN and 36.17% for TP. In the scenarios with a combination of multiple BMP measures, the combination of stubble mulch, soil testing and formula fertilization, and vegetative filter strip performed the best, achieving average reductions of 42.71% for TN and 50.40% for TP. The hybrid model provides a novel approach to simulate BMPs' reduction effects in regions without measured hydrological data and has the potential for wide application in BMP-related decision-making.

Regional Water Stress Forecasting: Effects of Climate Change, Socioeconomic Development, and Irrigated Agriculture—A Texas Case Study

Climate change, socioeconomic development, and irrigation management are exacerbating water scarcity in many regions worldwide. However, current global-scale modeling approaches used to evaluate the impact of these factors on water resources are limited by coarse resolution and simplified representation of local socioeconomic and agricultural systems, which hinders their use for regional decision making. Here, we upgraded the irrigation water use simulation in the system dynamics and water environmental model (SyDWEM) and integrated it with the water supply stress index (WaSSI) ecosystem services model. This integrated model (SyDWEM-WaSSI) simulated local socioeconomic and agricultural systems to accurately assess future water stress associated with climate change, socioeconomic development, and agricultural management at subbasin levels. We calibrated the integrated model and applied it to assess future water stress levels in Texas from 2015 to 2050. The water stress index (WSI), defined as the ratio of water withdrawal to availability, was used to indicate different water stress levels. Our results showed that the integrated model captured changes in water demand across various sectors and the impact of climate change on water supply. Projected high water stress areas (WSI > 0.4) are expected to increase significantly by 2050, particularly in the Texas High Plains and Rolling Plains regions, where irrigation water use was projected to rise due to the impact of climate change. Metropolitan areas, including Dallas, Houston, Austin, and San Antonio, were also expected to experience increased domestic water demand, further exacerbating water stress in these areas. Our study highlights the need to incorporate socioeconomic planning into water resources management. The integrated model is a valuable tool for decisionmakers and stakeholders to evaluate the impacts of climate change, socioeconomic development, and irrigation management on water resources at the local scale.

Dynamic Coupling Model of Water Environment of Urban Water Network in Pearl River Delta Driven by Typhoon Rain Events

Typhoon rain dominates meteorology-rainfall-runoff-environmental factor changes at the regional scale and regulates water resources in the river network area by means of multi-field coupled meteorological, hydrological, and geographic models, shaping complex water resources and water environment scenarios in the Pearl River Delta. Because of limitations in the monitoring capacity of the typhoon process, quantifying the ephemeral processes and spatial heterogeneity information of typhoon rain events is difficult, which makes the degree of research on typhoon rainfall-runoff transformation processes low and the progress in regional water resources and water environment evaluations based on typhoon events slow. In this study, typhoon rain event data, namely, remote-sensing spectra, measured water quality parameters, and meteorological factors, in the Pearl River Delta during 2022 were first collected. Next, a dynamic coupling model between typhoon rain events and the water network environment was established to simulate and predict the water environment conditions of the Zhongshan City water network controlled by the regulation of typhoon rain events. By inputting the quantitative data of the typhoon rain events, the water environment conditions of the river network in Zhongshan City after the typhoon rain events were simulated and output. The results showed that the distribution of dissolved oxygen concentrations and ammonia nitrogen concentrations were consistent: the concentration was highest in the central urban area, which is more urbanised than other areas, and it was lowest in the area far from the urban centre. Moreover, under the influence of Typhoon Ma-on, the water environment of the Zhongshan City water network changed over time: dissolved oxygen concentrations decreased and then increased, and ammonia nitrogen concentrations increased and then decreased. The water quality prediction model proposed in this study helps to improve the understanding of the dynamic impact of typhoon rain on the water quality of an urban water network in the Pearl River Delta and is conducive to improving the formulation of water environment control strategies during typhoon transit.

Water-Energy-Carbon Nexus: Greenhouse Gas Emissions from Integrated Urban Drainage Systems in China.

Greenhouse gas (GHG) emissions from integrated urban drainage systems (IUDSs), including sewer, wastewater treatment plants (WWTPs), and receiving water systems, have not yet been integrated due to the lack of modeling tools. Here, we updated the computable general equilibrium-based System Dynamics and Water Environmental Model (CGE-SyDWEM), a recently developed model simulating the water-energy-carbon nexus at the watershed level, to calculate the direct and indirect (electricity use and external) GHG emissions from IUDSs considering carbon mitigation strategies and water engineering practices. The updated CGE-SyDWEM was applied to an estuary watershed in Shenzhen, the fourth largest city in China. With increasing socio-economic development and water infrastructure systems upgrading, GHG emissions are projected to increase from 129.2 (95% CI: 95.9-162.5) kt in 2007 to 190.7 (144.8-236.6) kt in 2025, with 89% from WWTPs (direct: 17%; electricity use: 65%; and external: 7%), 10% from the sewer (direct: 1% and electricity use: 9%) and 1% from receiving waters (direct). Carbon mitigation can reduce GHG emissions by 7% and emission intensity by 6% by 2025, with 63% contributed by external emission reduction from chemical uses. The integrated model can aid water, energy, and carbon decision-makers in finding cost-effective solutions for water and energy security in the future.

Distribution of heavy metals influenced by pumped storage hydropower in abandoned mines: Leaching test and modelling simulation

Renewable energy generation varies frequently, making it difficult to match electricity demand. Pumped storage hydropower plants can alleviate this problem by reducing the unevenness of renewable energy generation. It is a new exploration of energy storage methods to construct pumped storage hydropower plants by using underground goaf of abandoned mines and mining subsidence water area. However, the construction of lower reservoirs using underground goaf areas of abandoned mines can lead to potential heavy metal pollution. To assess the impact of using abandoned mines for pumped storage hydropower on the downstream surface water environment, this work first analyzed the release characteristics of heavy metals from underground goaf and surface dump through field sampling and leaching tests, then constructed a water-environment model of the downstream surface water based on the experimental results and water environment theory, and finally simulated and analyzed the impact of underground pollutants pumped to the surface on downstream surface water-quality in typical hydrological years. The maximum error between the simulated values and measured values of the hydrodynamic model was 0.1, and the overall error was within a reasonable range (±0.2 m). The comparison between simulated values and measured values of heavy metal concentration in water quality model showed RMSE values ranged from 0.003 to 0.81, with an average of 0.4; the SI ranged from 0.84 to 0.95, with an average of 0.89. During the simulation of low, normal, and high flow years, pollution downstream was concentrated near the drainage outlet, and the underground pollutants pumped to the surface influenced the concentration of heavy metals there. After a period of drainage, the concentration of heavy metals decreased. Drainage volume was an important factor affecting the concentration of heavy metals downstream surface water. These results prove that the water environment model established based on MIKE21 is reliable and can provide guidance for the simulation and control of heavy metal pollution in the utilization of abandoned mines for pumped storage hydropower. This work provides a reproducible idea and method to assess the impact of using abandoned mines and mining subsidence water area for pumped storage hydropower on downstream surface water and ensure the safety of the ecological environment.

Simulation of diffuse source polluted water environment based on MIKE21: A case study of the urban section of the Bai river

Abstract Affected by urban construction and industrial discharge, the diffuse source pollution of river water environment in urban sections is becoming more and more serious. The use of numerical models can accurately and efficiently simulate the process of diffuse source pollution and analyze its evolution. Based on MIKE21, the urban river water environment model of the Bai river is constructed. After parameter calibration, it is proved that the model has high accuracy. Based on the discharge of this river section in 2018, the river diffuse source pollution is simulated under three hydrological conditions, and the BP neural network is used to simulate the river diffuse source pollution. Network assessment of water quality in dry years. The results showed that the four water quality indicators showed the spatial distribution characteristics of upstream>urban section>downstream, and the river water quality in the year showed the temporal distribution characteristics of flood season better than a non-flood season. The mean value of the coefficient of certainty R2 reaches 0.94 when comparing the simulated and measured values, which indicates that the model has high applicability and satisfactory fit. If the water quality of the water year does not meet the standard, the diffuse source pollution discharge should be reduced from May to October. This study can provide reference and guidance for urban river diffuse source pollution control.

Simulation study on the impact of ecological water replenishment on reservoir water environment based on Mike21——Taking Baiguishan reservoir as an example

In recent years, ecological water replenishment has become the main means to improve the water environment of the reservoir. Considering the complexity of the water characteristics of the reservoir, it is very necessary to simulate the impact of water replenishment on the water environment. Based on the two-dimensional water environment mathematical model theory, the water environment model of Baiguishan Reservoir was constructed by Mike21. Under the conditions of 6 different ecological water replenishment scenarios, the evolution characteristics and improvement of the water environment of the reservoir were analyzed. Finally, the cloud model was used to comprehensively evaluate the results and compare them. Come up with the best ecological water replenishment plan. The results show that the strong convective diffusion phenomenon caused by the large flow of water replenishment makes the water quality show a cascade distribution, and the water quality improvement rate can reach up to 40.01%. Optimal; the water body with large flow replenishment has better fluidity and reoxygenation ability, which improves the self-purification ability of the water body. The comparison with the actual replenishment effect shows that the effect of large flow and short duration is better under the same replenishment amount. The quantitative analysis results of pollutants under different scenarios can provide a scientific basis for the construction of the South-to-North Water Diversion Project and the ecological restoration of the reservoir.

Assessing effects of non-point source pollution emission control schemes on Beijing's sub-center with a water environment model

A high-quality water environment is a strategic demand for constructing Beijing's Sub-center. Controlling non-point source (NPS) pollution is the key to water environment management in Beijing's Sub-center. We developed a water environment model of Beijing's Sub-center using MIKE 11. Ammonia-Nitrogen and Total Phosphorus concentrations and Chemical Oxygen Demand were used as pollution indicators. Water quality response to the control of agricultural and urban NPS pollution under different scenarios was predicted. The effects of different scenarios were evaluated. Results show that water quality in Beijing's Sub-center can be considerably improved by controlling emissions of NPS pollution. Reducing agricultural NPS pollution is the key to reducing Ammonia-Nitrogen and Total Phosphorus concentrations and improving water quality. Results also demonstrate that water quality response varies with land use type. This study aims to provide reliable and practical information to support water pollution control in Beijing's Sub-center, especially NPS pollution. This water environment model fills the gap in the NPS pollution simulation in rivers in Beijing's Sub-center and promotes the application of the water environment model in water pollution management.

Hydrodynamic zones and the influence of microorganisms on nitrogen transformation in the diverging area of branched rivers

Diverging area is widespread in river networks, and understanding its biogeochemical process characteristics is of great significance to river ecological restoration and environmental quality improvement. Microbial communities affected by hydrodynamics play an important role in biogeochemical processes, but their relationship in diverging area is little known. Here, the composition of microbial community and its feedback to hydrodynamics and nitrogen conversion in the diverging area of river networks were first studied by coupling ecological theory, biogeochemical theory, microbial DNA sequencing and mathematical model of water environment. The results showed that there were five hydrodynamic zones with significant velocity differences in the diverging area, namely low velocity zone, maximum velocity zone, stagnant zone, separation zone, and deflection zone. According to the flow velocity grouping, there were significant differences in the microbial diversity and abundance among low velocity group, maximum velocity group and stagnant group had significant differences (p < 0.05, stress = 0.1207). In the low velocity group, Firmicutes was the dominant phylum which had a highest abundance and may promot the conversion of organic nitrogen into ammonia nitrogen. In the maximum velocity group, Bdellovibrionota was the dominant phylum which had a highest abundance and may promot the conversion of nitrate and nitric oxide to nitrogen. In the stagnant zone, Methylomirabilota was the dominant phylum which had a highest abundance and may promot the conversion of nitrogen into nitrate and ammonium. In addition, dissolved oxygen was the most sensitive environmental factor for shaping microorganisms and nitrogen conversion in the diverging area of the river networks by canonical correlation analysis. The denitrifying bacteria Rhodocyclaceae, was shown to negatively correlated with the flow velocity. This research improves the scientific basis for the study of the ecosystem in river networks, which will guide the construction of river ecological projects.

Sub-Watershed Parameter Transplantation Method for Non-Point Source Pollution Estimation in Complex Underlying Surface Environment

The prevention and control of non-point source pollution is an important link in managing basin water quality and is an important factor governing the environmental protection of watershed water in China over the next few decades. The control of non-point source pollution relies on the recognition of the amount, location, and influencing factors. The watershed nonpoint source pollution mechanism model is an effective method to address the issue. However, due to the complexity and randomness of non-point source pollution, both the development and application of the watershed water environment model have always focused on the accuracy and rationality of model parameters. In this pursuit, the present study envisaged the temporal and spatial heterogeneity of non-point source pollution caused by the complex underlying surface conditions of the watershed, and the insufficient coverage of hydrological and water quality monitoring stations. A refined watershed non-point source pollution simulation method, combining the Monte Carlo analytic hierarchy process (MCAHP) and the sub-watershed parameter transplantation method (SWPT), was established on the basis of the migration and transformation theory of the non-point source pollution, considering the index selection, watershed division, sub-watershed simulation, and parameter migration. Taking the Erhai Lake, a typical plateau lake in China, as the representative research object, the MCAHP method effectively reduced the uncertainty of the weights of the watershed division indexes compared to the traditional AHP method. Furthermore, compared to the traditional all watershed parameter simulation (AWPS) approach, the simulation accuracy was improved by 40% using the SWPT method, which is important for the prevention and control of non-point source pollution in large-scale watersheds with significant differences in climatic and topographic conditions. Based on the simulation results, the key factors affecting the load of the non-point source pollution in the Erhai watershed were identified. The results showed that the agricultural land in Erhai Lake contributed a majority of the load for several reasons, including the application of nitro phosphor complex fertilizer. Among the different soil types, paddy soil was responsible for the largest pollution load of total nitrogen and total phosphorus discharge into the lake. The zones with slopes of 0–18° were found to be the appropriate area for farming. Our study presents technical methods for the assessment, prevention, and control of non-point source pollution load in complex watersheds.

Study on the coupling model of urbanization and water environment with basin as a unit: A study on the Hanjiang Basin in China

The urbanization process of the Hanjiang Basin is speeding up and facing many challenges. It is necessary to take active actions to realize the balance between urbanization development and water environment protection. This paper aims to establish a comprehensive evaluation model of urbanization and water environment (UAWE) and explore the development of UAWE in the Hanjiang Basin in China from 2010 to 2018. In terms of methodology, these evaluation models are combined with the Coupling coordination degree model (CCDM), Exploratory Spatial Data Analysis (ESDA), and Geographically and Temporally Weighted Regression (GTWR) to measure and analyze the coupling degree (CD) and spatiotemporal heterogeneity of UAWE. Our findings include the following: (1) From 2010 to 2018, in all regions of the Hanjiang Basin, urbanization showed a gradual upward trend. Among Them, the comprehensive urbanization index (CUI) of Xiangyang increased by 25.37%. (2) The comprehensive water environment index (CWEI) presents a fluctuating growth, with the rate of increase in Jingmen's reaching 17.44%. (3) There is heterogeneity in time and space between cities in the Hanjiang Basin, and the positive interaction effect of UAWE is mainly focused on the middle and lower reaches of the Hanjiang River. (4) Coupling coordination degree (CCD) in the basin shows an increasing trend, and the areas with high CCD are mainly concentrated in Xiangyang and Xiantao. (5) ESDA shows that the CCD among cities in the basin has spatial correlation and heterogeneity, and the regions with similar CCD tend to be distributed centrally in space.

Seasonal Distribution Characteristics and Health Risk Assessment of Heavy Metals in Surface Water of Qingjiang River

In order to assess the health risks of heavy metals in surface water of Qingjiang River, surface water samples were taken at designed cross-sections of the river and analyzed for Cr, Cu, Zn, Pb, Cd, As, and Mn. Health risks from these heavy metals for adults and children in wet and dry seasons were compared by water environmental health risk assessment model of the USEPA. It found that the main excessive element is Mn, concentrating in the Danshui, Yantouxi, and Pingluoxi, the slightly excessive element is As, the concentration of Mn was above national standard, and it mainly distributed in Danshui, Yantouxi, and Pingluoxi, As was slightiy over the standard, and it concentrated in Wujiahe, The content of heavy metals during wet season were all higher than those during dry season. Cr, Cu, Zn, and Cd are mainly originated from the nature, Pb and As are separately mainly originated from traffic and agriculture, Mn originated from mining mainly in the downstream, while it has natural source from upper to middle. The health risks of heavy metals in surface water to adults and children in wet season are higher than those in dry season. The main health risk area was the midstream. As was the highest health risk element and children were the most preventive group. Specially, people in towns who drink the water from midstream should pay more attention.

Design and Application of Automatic Monitoring System of Water Environment Using GIS

in order to achieve more effective management and monitoring of water environment, an automatic monitoring system is designed for the water environment of Heihe River Basin in Zhangye through GIS (geographic information system). The EFDC (environmental fluid dynamics code) model is used to establish the automatic monitoring model of water environment, and the annual average data of permanganate index of Yingluoxia, Gaoya hydrological station, and Liubaqiao in Heihe River Basin from 2015 to 2019 are used to fit and verify the water quality model. The trend suggests that the simulated data of the three observation points are close to the measured data. The fitting degree reveals that the R index of fitting curve of Liubaqiao is 0.793, while that of Yingluoxia, and Gaoya hydrological station is higher than 0.8, with good fitting degree. The average relative error between the simulated value and the measured value of permanganate index (mg/L) is small, the change trend is basically consistent, and the prediction error is small. The model is successfully established and applied to the automatic monitoring and early warning system of total phosphorus index.

Mountain Lake Evaporation: A Comparative Study between Hourly Estimations Models and In Situ Measurements

The quantification of evaporation is very important for water resource management, determination of water availability and environmental modeling. Evaporation (E) is a key component of the hydrological cycle, which becomes more relevant under a changing climate scenario, where increases in temperature and E are projected on a regional scale. This study evaluated the hourly applicability of 21 methods to estimate E in a mountain lake. Models were grouped as combination, solar radiation-temperature and mass transfer methods. Estimated E by all models were compared to three measurement campaigns with an eddy covariance system in Lake Laja during the month of January (22 to 28), March (17 to 23) and November (09 to 15) of 2016. The average evaporated water during the measurement sessions were 3.40, 3.38 and 1.89 mm d−1, respectively. Best model performance was obtained with models whose main E principles are heat flow and water vapor flow. The best performance in this group was the Penman model using a calibrated wind function with a determination coefficient (R2) of 0.91, Nash–Sutcliffe coefficient (NS) of 0.9, and index of agreement (W) of 0.98. Comparing daytime and nighttime hours, it was found that the daytime E in the lake is best explained by the product of the vapor pressure deficit and wind speed, while the nighttime E was explained by the flow of heat in the water. The results highlight the importance of the analysis of diurnal dynamics of water flux and energy stored in water to better understand the E in water bodies.

Robust Subsampling ANOVA Methods for Sensitivity Analysis of Water Resource and Environmental Models

Sensitivity analysis is an important component for modelling water resource and environmental processes. Analysis of Variance (ANOVA), has been widely used for global sensitivity analysis for various models. However, the applicability of ANOVA is restricted by this biased variance estimator. To address this issue, the subsampling based ANOVA method are developed in this study, in which multiple subsampling(single-, multiple- and full-subsampling) techniques are proposed to diminish the effect of the biased variance estimator of ANOVA. Two case studies including one simplified regression model and one hydrological model are used to illustrate the applicability of the proposed approaches. Results indicate that: (1) the subsampling procedures effectively diminish the biases resulting from traditional ANOVA method; (2) among the proposed subsampling approaches, the full-subsampling ANOVA has the most robust performance; (3) compared with Sobol’s method, the subsampling ANOVA methods can significantly reduce the calculation requirements while achieve similar sensitivity characterization for model parameters. This study serves as a first basis for the application of subsampling ANOVA methods to sensitivity analysis for water resource and environmental models.

A structurally integrated water environmental modeling system based on dual object structure.

The GIS-based water quantity and water quality model is widely used to provide decision-making supports for water resource and water quality management. However, the existing integration patterns of GIS and model system mainly depend on data communication between themselves which may lead to low operating efficiency and time-consuming model setup. In this paper, a generalized data structure (dual object structure (DOS)) which can store the data of GIS objects and model objects together is proposed and realized for the first time, avoiding frequent data communication during the period of numerical simulation and result expression, realizing the fusion of GIS objects and model objects at the data structure level, improving the operating efficiency of the system. Finally, the water quantity and water quality modeling software (digital basin simulation system (DBSS)) based on DOS was developed by using C++ language. The software has been applied successfully in large-scale river basins of China, and one of the cases was demonstrated to show the application process and the outstanding results.

Спектры комбинационного рассеяния света глицина и их моделирование в дискретно-континуальной модели сольватной оболочки воды

Annotation. The Raman spectra of glycine in crystalline form and in aqueous solution were obtained. The model of stabilization of the zwitterion state of glycine with a single water molecule connected by hydrogen bonds with the –COO- and –NH3+ groups is proposed. It is shown that quantum chemical calculations at the level of B3LYP/6-311++G(3df,2p) using the discrete-continuum model of water environment of glycine complexes Gly + n H2O (n = 1–3) provide a good description of the Raman spectra of glycine.