scholarly journals Modeling of extreme risk in river water quality under climate change

2018 ◽  
Vol 9 (3) ◽  
pp. 512-524 ◽  
Author(s):  
S. Rehana ◽  
C. T. Dhanya

Abstract A river water quality management model under average climatic conditions may not be able to account for the extreme risk of low water quality which is more prominent under an increase in river water temperature and altered river flows. A modeling framework is developed to assess the risk of river low water quality extremes by integrating a statistical downscaling model based on Canonical Correlation Analysis, risk quantification model based on Frank Archimedean Copula function and multiple logistic regression model integrated with a river water quality simulation model, QUAL2 K. The results reveal that the combination of predicted decrease in low flows of approximately 57% and increase in maximum river water temperatures of approximately 1.2°C has shown an increase of about 46% in risk of low water quality conditions for the future scenarios along Tunga-Bhadra River, India. The extreme risk of low water quality is observed to increase by 50.6% for the period 2020–2040 when compared with the current extreme conditions of 4.5% and average risk conditions of about 3% for the period 1988–2005. The study captured the occurrence of extremes of low water quality with evidence of a strong link between climate and water quality impairment events.

1996 ◽  
Vol 34 (12) ◽  
pp. 33-40 ◽  
Author(s):  
Y. Hosoi ◽  
Y. Kido ◽  
H. Nagira ◽  
H. Yoshida ◽  
Y. Bouda

The inflow of pollutant load from urban areas and the stagnation of water due to sea water intrusion cause the deterioration of river water quality in tidal zone. In order to improve water quality, various measures such as the reduction of pollutant load by sewage systems, discharge control from sewage treatment plants considering river flow, nutrient removal by aquatic plants, and the dredging of bottom sediments have been examined. The choice of these measures depends on the situation of the river environment and finances. In this study, a field survey was carried out in a typical urban river basin, first. Secondly, on the basis of this survey, a mathematical model was formed to simulate flow and water quality. Several purification alternatives designed for the investigated river basin were comparatively evaluated from the viewpoint of the effect of water quality improvement and their cost. Finally, they were prioritized. Through this case study, a planning process of river water quality management was shown.


2020 ◽  
Author(s):  
Dipankar Dwivedi ◽  
Carl Steefel ◽  
Michelle Newcomer ◽  
Bhavna Arora ◽  
Ilhan Özgen-Xian ◽  
...  

2020 ◽  
Vol 42 (10) ◽  
pp. 452-462
Author(s):  
Jinhyo Lee ◽  
Hyunju Ha ◽  
Manho Lee ◽  
Mokyoung Lee ◽  
Taeho Kim ◽  
...  

Objectives : 17 water quality measurement networks (WQMNs, tributaries) in Seoul were analyzed by using NSFWQI and cluster analysis to provide basic data for future river water quality management so that citizens could easily and comprehensively understand the water quality information on the rivers in Seoul.Methods : For the past 3 years (2015~2017), in order to estimate WQI, 9 items, DO (% sat), Fecal coliform, pH, BOD, Temperature change (TC), TP, NO3-, Turbidity and Total solids, were selected from among the 19 water quality data measurement items produced monthly from 17 WQMNs in Seoul. WQI was derived and graded using NSFWQI and cluster analysis was performed using Ward Linkage Method, SOM (Self Organizing Map).Results and Discussion : Water quality of most water quality monitoring networks was BOD Ⅱ grade (slightly good) or higher and TP Ⅲ grade (normal) or higher according to the standard of water quality and water ecosystem river living environment, and NSFWQI was also 64 (Medium)~89 (Good). All showed good water quality. NSFWQI does not show a significant difference by season, so it is believed that it is affected by anthropogenic sources rather than seasonal effects. As a result of examining the correlation between NSFWQI and water quality level according to environmental standards, it was confirmed that R2 has a relatively good correlation with 0.78, and there is no clear difference between the two groups, and through this, it was found that the currently implemented water quality rating system and NSFWQI are well matched. As a result of cluster analysis using ward linkage method and SOM for 17 WQMNs, it was largely divided into 6 groups according to water quality characteristics.Conclusions : It is important to manage pollution sources to systematically manage river water quality as a water resource. It is therefore expected that by converting from the complicated and various water quality information such as is found in this study into a simple water quality index and grouping, the river water quality can be easily understood and can be utilized in the future as basic data for water quality management in Seoul.


2012 ◽  
Vol 15 (4) ◽  
pp. 71-86
Author(s):  
Thang Viet Le ◽  
Triet Minh Lam ◽  
Tan Manh Le ◽  
Tai Manh Pham

The article proposed an appropriate organization modeling for Sai Gon river water quality management based on the analysis having scientific and practical basic about aspects have done and aspects limited of LVS management organization (LVS environmental protection Committee) in past time, lesson learnt from effective LVS management performance of countries in the world as well as based on actual study changes in Sai Gon river water quality in many years and practically coordination management and environmental protection river among local area along river basin. The proposed modeling is feasible and practical aim to protect Sai Gon river water source serving for different purposes such as supply water for domestic demand, industry, irrigation, river landscape – tourism, and waterway etc., towards sustainable development of local area along river basin.


2009 ◽  
Vol 59 (3) ◽  
pp. 407-416 ◽  
Author(s):  
Bob Crabtree ◽  
Sarah Kelly ◽  
Hannah Green ◽  
Graham Squibbs ◽  
Gordon Mitchell

Complying with proposed Water Framework Directive (WFD) water quality standards for ‘good ecological status’ in England and Wales potentially requires a range of Programmes of Measures (PoMs) to control point and diffuse sources of pollution. There is an urgent need to define the benefits and costs of a range of potential PoMs. Water quality modelling can be used to understand where the greatest impact in a catchment can be achieved through ‘end of pipe’ and diffuse source reductions. This information can be used to guide cost-effective investment by private water companies and those with responsibilities for agricultural, industrial and urban diffuse inputs. In the UK, river water quality modelling with the Environment Agency SIMCAT model is regarded as the best current approach to support decision making for river water quality management and planning. The paper describes how a SIMCAT model has been used to conduct a trial WFD integrated catchment planning study for the River Ribble catchment in the North West of England. The model has been used to assess over 80 catchment planning scenarios. The results are being used support a national assessment of the cost-effectiveness of proposed PoMs.


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