Variation Characteristics of Water Environmental Capacity in Poyang Lake under the Scheduling of Three Gorges Reservoir

[Objective] The aim was to study the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir.[Method] Choosing chemical oxygen demand (COD),total nitrogen (TN) and total phosphorus (TP) as the control indexes of pollutants in Poyang Lake,the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir were analyzed based on the water environment mathematical models of organic compounds and nutrients.[Result] After the operation of Three Gorges Project,high water level in Poyang Lake lasted for a long time in flood season when Three Gorges Reservoir increased discharge volume,while water level went down obviously with the accelerating of recession flow when reservoir decreased discharge volume to store water,so Three Gorges Project had obvious effects on the hydrological regime of Poyang Lake.In 2009,when Three Gorges Reservoir stored water,the water environmental capacity of COD,TN and TP in Poyang Lake in October decreased by 14.0%,15.4% and 15.4% compared with those before operation,while they increased by 3.64%,4.88% and 4.88% in August when reservoir discharged water to prevent flood.[Conclusion] The study could provide scientific foundation for the water pollution control and water environment management of lakes.

Study on Water Environmental Capacity of Shennongjia

Water environmental capacity is the important basis to set local and professional emission standards for waters, and is also the work basis of ecological planning. Firstly, the general information of river system in Shennongjia was introduced. Then, the concept and general model of water environmental capacity were elaborated. Finally, we used the analytical solution to estimate the water environmental capacities of COD and NH3-N in Shennongjia, and concrete measures for water environmental protection were put forward.

Flow Calculation of Water Environmental Capacity Controlling Units in a Small Watershed Based on GIS Technology

[Objeetive] We aimed to calculate the flow of controlling units in a small watershed based on GIS technology. [Method] Hydrologic analysis on Qingyi River was conducted by using ArcGIS9.0, and the controlling units with response of water-land were divided according to the riv- er monitoring sections of Xuchang City; considering the wastewater entering the river and the water from its upper reach, the runoff of controlling sections in the driest month （ with guarantee rate of 90% ） was calculated by means of isoline, runoff coefficient and hydrologic analogy method, and the calculated value of Gaocun Bridge section in Linying was contrasted with the measured value in 2010. [Result] The results showed that the cal- culated value and measured value of Gaecun Bridge section in Linying in the driest month of 2010 were 6.03 and 5.93 m^3/s respectively, with relative error of 1.69%, which revealed that the result of calculated runoff was reasonable. [ Conclusion] The way to divide controlling units was reason- able, and the calculation result of runoff was accurate and can meet the precision of water environment capacity calculation.

Integrated water risk early warning framework of the semi-arid transitional zone based on the water environmental carrying capacity (WECC)

Water risk early warning systems based on the water environmental carrying capacity(WECC)are powerful and effective tools to guarantee the sustainability of rivers.Existing work on the early warning of WECC has mainly concerned the comprehensive evaluation of the status quo and lacked a quantitative prejudgement and warning of future overload.In addition,existing quantitative methods for short-term early warning have rarely focused on the integrated change trends of the early warning indicators.Given the periodicity of the socioeconomic system,however,the water environmental system also follows a trend of cyclical fluctuations.Thus,it is meaningful to monitor and use this periodicity for the early warning of the WECC.In this study,we first adopted and improved the prosperity index method to develop an integrated water risk early warning framework.We also constructed a forecast model to qualitatively and quantitatively prejudge and warn about the development trends of the water environmental system.We selected the North Canal Basin(an essential connection among the Beijing-Tianjin-Hebei region)in China as a case study and predicted the WECC in 25 water environmental management units of the basin in 2018–2023.We found that the analysis of the prosperity index was helpful in predicting the WECC,to some extent.The result demonstrated that the early warning system provided reliable prediction(root mean square error of 0.0651 and mean absolute error of 0.1418),and the calculation results of the comprehensive early warning index(CEWI)conformed to the actual situation and related research in the river basin.From 2008 to 2023,the WECC of most water environmental management units in the basin had improved but with some spatial differences:the CEWI was generally poor in areas with many human disturbances,while it was relatively good in the upstream regions with higher forest and grass covers as well as in the downstream areas with larger water volume.Finally,through a sensitivity analysis of the indicators,we proposed specific management measures for the sustainability of the water environmental system in the North Canal Basin.Overall,the integrated water risk early warning framework could provide an appropriate method for the water environmental administration department to predict the WECC of the basin in the future.This framework could also assist in implementing corresponding management measures in advance,especially for the performance evaluation and the arrangement of key short-term tasks in the River Chief System in China.

Analysis of the Water Environmental Capacity of Zhongba-Nyingchi Section of the Yarlung Tsangpo River

The Yarlung Tsangpo River,the longest river in Tibet,houses most of the population and economy in Tibet Autonomous province.Under the rapid development of economy and society in Tibet,the pollution in the Yarlung Tsangpo River basin has rapidly increased.Evaluating water quality and water environmental capacity is needed for water resource management in Tibet.This study used a single factor evaluation method to evaluate water quality of the Zhongba-Nyingchi section of the Yarlung Tsangpo River based on measured data of CODcr, NH3-N and TP in the study area.Based on these data,determinations of ideal water environmental capacity, emissions of pollutants and remaining water environmental capacity of the study area were made by a one-dimensional steady water quality model under either section-head control or cross-section control.The data indicate that most of the monitoring sections in the study area experienced good water quality.The three pollutants all had large remaining water environmental capacity generally,but TP exceeded state levels in the two upstream functional areas,and levels above state standards of CODcr and TP were found in several calculation cells of the two downstream functional areas.Therefore,emissions of pollutants need to be reduced to protect the water environment quality of the Yarlung Tsangpo River.

Parameter determination to calculate water environmental capacity in Zhangweinan Canal Sub-basin in China

Zhangweinan canal sub-basin （ZWN） has the most serious water resource shortage and water pollution problems in north of China. To calculate the water environmental capacity in ZWN, determination methods for design flow rates and degradation coefficients were discussed in this study. Results showed that 90% and 50% hydrological guarantee flow rates were suitable to be the design flow rates for rainy and dry seasons, respectively. Degradation coefficients of CODMn and NH3-N were 0.25 day^-1 and 0.15 day^-1 for branch streams and 0.5 day^-1 and 0.25 day^-1 for mainstreams, respectively in ZWN. With one-dimensional water quality simulation model, water environmental capacities were calculated to be 82,139 tons/yr for CODMn and 2394 tons/yr for NH3-N in ZWN.

Study on urban water environmental support capacity

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The concept, connotation and method of representation of watershed water environment carrying capacity （WWECC）

Based on the relationship between water environment system and human society, water environment carrying capacity （WECC） probes into supporting ability of complex water environment system to the human society. Recent years, due to the shortage of water resources and serious water pollution in several watersheds in China, the research of watershed water environment carrying capacity （WWECC） becomes very important. The conception, connotation and method of representation of WWECC are discussed deeply in this paper. It shows that WWECC is a kind of index that instructs whether the water environment system in watershed can continue to support the development of social economy and ecology, it is dimensionless number.

Carrying capacity of water environment in public tourism resources based on matter-element model

When water environmental carrying capacity of public resource tourist attraction is studied, the two action subjects of tourists and local residents should be discussed, and comprehensive consideration must be given to the influence of these two on water environment. On the basis of water resource carrying capacity and water quality carrying capacity, water environmental carrying capacity index of public resource tourist attraction was constructed, the model for the water environmental carrying capacity of public resource tourist attraction was established on the basis of matter-element model and analytical hierarchy process. By applying this method, water environmental carrying capacity situation of a certain public resource tourist attraction can be gained, moreover, situations about several aspects of water environmental carrying capacity can be evaluated.

Water environmental planning for new zone of economic-technological development in China

This paper analyzes the characteristics of water environmental planning in New Zone for EconomicTechnological Development (NZETD) in China and presents the task, procedure and method of the planning study Based on these analyses, the concept of Water Environmental Support Capacity (WESC) is put forward and the corresponding quantitative method is proposed to achieve the objective of coordinating the relationship between water environment and economic development As a case study, a comprehensive analysis and integrated water pollution control planning are made for the New Zone of EconomicTechnological Development in Benxi City in China Based on the costbenefit analysis and feasibility study of the planning alternatives, the comprehensive indexes of WESC are calculated and applied to evaluate the water pollution control planning alternatives

Safety Evaluation of Water Environment Carrying Capacity of Five Cities in Ningxia Based on Ecological Footprint of Water Resources

[Objectives]To make safety evaluation of water environment carrying capacity of five cities in Ningxia based on ecological footprint of water resources.[Methods]With the help of the grey relational model,15 indicators were selected from the natural,economic,and social aspects,and the most influential factors in the three fields were selected.Based on the concept of ecological priority,the water resources carrying capacity of the five cities in Ningxia from 2010 to 2019 was calculated with the help of the water resources ecological footprint model.Then,the indicators of the water resources ecological footprint model were coupled with the existing indicators to establish a comprehensive evaluation indicator system.Finally,the changes of the water environment carrying capacity of the five cities in Ningxia were analyzed with the help of the principal component analysis(PCA).[Results]The ecological pressure of water resources and the ecological deficit of water resources in the five cities were relatively large.Specifically,Yinchuan City had the most obvious deficit of water resources but good carrying capacity;Zhongwei City had a large ecological deficit of water resources,poor carrying capacity,and the largest ecological pressure index of water resources;Guyuan City had low water resources ecological deficit,water resources ecological carrying capacity and water resources ecological pressure index.[Conclusions]Through the analysis of the coupling indicator system,it can be seen that the water environment carrying capacity of the five cities is in an upward trend,indicating that the water environment in each region tends to become better.

Water Environment Carrying Capacity of New Zhengdong District in Zhengzhou City

Taking sections of the Dongfeng Canal, the Xionger River and the Wei River in New Zhengdong District for example, this paper applied water environment capacity to analyze the carrying capacity of surface water environment in the east development zone of the city. The analysis shows that carrying capacity of surface water environment in the study area is not good, carrying capacity of 3 studied waters for TP, BOD_5 and COD is approaching to the limit. New Zhengdong District, in terms of industrial structure, should promote the projects with less water consumption, less or no discharge of wastewater, and also should enhance the sewage treatment, improve recycling rate of the reclaimed water, and reduce the negative impact of sewage and pollutant discharge on environment.

Industrial and Agricultural Effects on Water Environment and Its Optimization in Heavily Polluted Area in Taihu Lake Basin, China

The deteriorating water quality in the Taihu Lake Basin has attracted widespread attention for many years, and is correlated with a sharp increase in the quantity of pollutant discharge such as agricultural fertilizers and industrial wastewater. In this study, several factors were selected for evaluating and regionalizing the water environmental capacity by ArcG1S spatial analysis, including geomor- phologic characteristics, water quality goals, water body accessibility, water-dilution channels, and current water quality. Then, the spa- tial optimization of agriculture and industry was adjusted through overlay analysis, based on the balance between industrial space and water environmental capacity. The results show that the water environmental capacity gradually decreases from the west to the east, in contrast, the pollution caused by industrial and agricultural clustering is distributes along Taihu Lake, Gehu Lake and urban districts. The analysis of the agricultural space focuses on optimizing key protected areas of the Taihu Lake Basin, and the shores of Gehu Lake, optimally adjusting the second protected areas of the Taihu Lake Basin, and generally adjusting the urban areas of Changzhou and Wuxi cities. The analysis of industrial space focuses on optimizing the downtowns of Changzhou and Wuxi cities, optimally adjusting key protected areas and second protected areas of the Taihu Lake Basin, and generally adjusting the south and southwest of Gehu Lake. Lastly, some schemes of industrial and agricultural layouts and policies for the direction of industrial and agricultural development were proposed, reflecting a correlation between industry and agriculture and the water environment.

Impact of hydroelectric projects on river environment: Analysis of water quality changes in Ningxia Reach of Yellow River

In this paper, the relationship between hydroelectric projects and the river environment is analyzed. Recently, the large-scale regulation of runoff by large hydroelectric projects in the Ningxia Reach of the Yellow River has altered natural runoff processes, causing an increase in the probability of low discharge and an overall adjustment of riverbed evolution and river characteristics. During low-flow years, the combined effects of these two changes can weaken the self-purification capacity and reduce the water environmental capacity of the river. This is one of the main reasons for the recent decrease of water quality in the Ningxia Reach. This research shows that it is necessary to implement river training projects to maintain stable flow paths, not only for adjusting river regimes and for flood control, but also for increasing the self-purification capacity and the water environmental capacity of the river. Methods and proposals for coordinating the operation of hydroelectric projects with the protection of the river environment are presented in the interest of promoting sustainable development.

Removing ammonium from water and wastewater using cost-effective adsorbents:A review

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution.These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented.