scholarly journals Water Supply-Water Environmental Capacity Nexus in a Saltwater Intrusion Area under Nonstationary Conditions

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 346
Author(s):  
Dedi Liu ◽  
Yujie Zeng ◽  
Yue Qin ◽  
Youjiang Shen ◽  
Jiayu Zhang

Due to water supply increase and water quality deterioration, water resources are a critical problem in saltwater intrusion areas. In order to balance the relationship between water supply and water environment requirements, the nexus of water supply-water environment capacity should be well understood. Based on the Saint–Venant system of equations and the convection diffusion equation, the water supply-water environment capacity nexus physical equation is determined. Equivalent reliability is employed to estimate the boundary design water flow, which will then lead to a dynamic nexus. The framework for determining the nexus was then applied to a case study for the Pearl River Delta in China. The results indicate that the water supply-water environment capacity nexus is a declining linear relationship, which is different from the non-salt intrusion and tide-impacted areas. Water supply mainly relies on freshwater flow from upstream, while water environmental capacity is affected by both the design freshwater flow and the water levels at the downstream boundary. Our methods provide a useful framework for the quantification of the physical nexus according to the water quantity and water quality mechanisms, which are useful for freshwater allocation and management in a saltwater intrusion area or the tail area of cascade reservoirs.

2021 ◽  
Vol 236 ◽  
pp. 03018
Author(s):  
Sudi Gao ◽  
Yueying Luo ◽  
Tan Yang

Based on the randomness and ambiguity characteristics of the river water environment system, as well as the lack and inaccuracy of data information, the water environment system parameters are defined as triangular fuzzy numbers. On this basis, by fuzzing the parameters of the conventional deterministic model, a fuzzy model for calculating river water environmental capacity is established. According to this model, the river water environment capacity in the form of triangular fuzzy numbers can be calculated. According to the requirements of a given level of credibility, the water environment capacity can be further converted from triangular fuzzy numbers to interval values. Research shows that compared with conventional deterministic methods, the results obtained are more scientific and reasonable


2011 ◽  
Vol 281 ◽  
pp. 137-140 ◽  
Author(s):  
Mao Lan Wang ◽  
Bin Luo ◽  
Wen Bin Zhou

Yuanhe River is a major source of drinking, irrigation, industrial, hydropower generation, and recreational water for the circumjacent city. It has more serious water pollution problems because it flows through some heavy industry cities. So basis of the river water environment functional zones combined the various water quality data and the monitoring hydrological data, the water environment capacity of the Yuanhe River was calculated by using the one-dimensional water quality model. The results show that the water environment capacity is 112650 t/yr for chemical oxygen demand (COD) and 3265 t/yr for ammonium nitrogen (NH3-N). Most of the control units have residual water environment capacity, only individual control units have the serious water pollution and its residual capacity of COD and NH3-N is below 0, so it is necessary to strengthen the pollution control of these control units.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 587
Author(s):  
Qiuxia Ma ◽  
Yong Pang ◽  
Ronghua Mu

In recent years, due to unsustainable production methods and the demands of daily life, the water quality of the Yangtze River has deteriorated. In response to Yangtze River protection policy, and to protect and restore the ecological environment of the river, a two-dimensional model of the Jiangsu section was established to study the water environmental capacity (WEC) of 90 water environment functional zones. The WEC of the river in each city was calculated based on the results of the water environment functional zones. The results indicated that the total WECs of the study area for chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP) were 251,198 t/year, 24,751 t/year, and 3251 t/year, respectively. Among the eight cities studied, Nanjing accounted for the largest proportion (25%) of pollutants discharged into the Yangtze River; Suzhou (11%) and Zhenjiang (12%) followed, and Wuxi contributed the least (0.4%). The results may help the government to control the discharge of pollutants by enterprises and sewage treatment plants, which would improve the water environment and effectively maintain the water ecological function. This research on the WEC of the Yangtze River may serve as a basis for pollution control and water quality management, and exemplifies WEC calculations of the world’s largest rivers.


2012 ◽  
Vol 610-613 ◽  
pp. 2745-2750 ◽  
Author(s):  
Long Xi Han ◽  
Fen Fen Yan ◽  
Hui Peng ◽  
Jun Jie Gao ◽  
Man Man Pan

Methods for calculation of water environment capacity can be divided into two types in general, one type is ideal water environment capacity method and the other is pollution source generalization method. This paper proposes another way of generalization, uniform generalization method, assuming that distribution of the amount of pollutants discharged is uniform in the lengthways direction. In consideration of the practical demand for administration of water resources protection, a formula for calculation of water environment capacity for different combinations of environment function regions is presented,based on the water quality targets of function regions, with the numerical or analytical methods of 1-D water quality model. The proposed method provides a simple and effective method for water resources management and planning.


2011 ◽  
Vol 356-360 ◽  
pp. 867-870 ◽  
Author(s):  
Shu Ling Huang ◽  
Yong Zhang ◽  
Qi Li ◽  
Dong Sheng Xu

Water environmental capacity is an important base for making the river pollution control, weakening the pollution source and realizing the water-function target. Analyses on the present situation of water quality in Suzhou reach of Tuohe River are conducted. The hydrological characteristics, the contamination characteristics and the water environment status were investigated. Combined with the design procedure of the water environment capacity, one-dimensional water quality model was selected to calculate and analyze the water environmental capacity of Tuohe River. The results showed that the water environmental capacity of BOD5 is 1231.16t/a, CODCr is 4289.73t/a and NH3-N is 377.3t/a. The current water quality of Tuohe River was good in general, most of the river’s sections have residual water environmental capacity and it is necessary to carry out total pollution reduction plans (especially for COD) in future with the population growth and socio-economic development.


2011 ◽  
Vol 10 ◽  
pp. 2754-2759 ◽  
Author(s):  
Yan Bangyou ◽  
Xing Jiusheng ◽  
Tan Huiru ◽  
Deng Shaoping ◽  
Tan Yinning

Author(s):  
Huang ◽  
Zhang ◽  
Tong

The water quality target management of the control unit is a convenient and direct technology for water environment management and the development direction of water environment management in China, involving control unit division and water environment capacity calculation. Taking the Taihu Lake Basin in Jiangsu Province as an example, we propose herein the basic principle of the division of a regional control unit in a plain river network and the method of analyzing the rationality of the control unit division. On this basis, the Taihu Lake Basin in Jiangsu Province was divided into 70 control units. To calculate the water environmental capacity in the plain river network area, we established a water environmental capacity calculation framework based on multiple targets of lakes and rivers, and proposed the goal of water quality "double compliance" of the water environmental functional zone and the assessment section. For this study, we calculated the regional water environmental capacity using the mathematical model of the Taihu Lake Basin’s water environmental capacity, and the water environmental capacities of the 70 control units were allocated by the weight coefficient method, which established water area and functional division length. The research results described herein were applied to the pollution permit management of the Taihu Lake Basin in Jiangsu Province. It provides important technical support for the establishment of a pollution permit system based on the total capacity to improve environmental quality.


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