scholarly journals Assessment of Water Quality Profile Using Numerical Modeling Approach in Major Climate Classes of Asia

Author(s):  
Muhammad Mazhar Iqbal ◽  
Muhammad Shoaib ◽  
Hafiz Umar Farid ◽  
Jung Lyul Lee

A river water quality spatial profile has a diverse pattern of variation over different climatic regions. To comprehend this phenomenon, our study evaluated the spatial scale variation of the Water Quality Index (WQI). The study was carried out over four main climatic classes in Asia based on the Koppen-Geiger climate classification system: tropical, temperate, cold, and arid. The one-dimensional surface water quality model, QUAL2Kw was selected and compared for water quality simulations. Calibration and validation were separately performed for the model predictions over different climate classes. The accuracy of the water quality model was assessed using different statistical analyses. The spatial profile of WQI was calculated using model predictions based on dissolved oxygen (DO), biological oxygen demand (BOD), nitrate (NO3), and pH. The results showed that there is a smaller longitudinal variation of WQI in the cold climatic regions than other regions, which does not change the status of WQI. Streams from arid, temperate, and tropical climatic regions show a decreasing trend of DO with respect to the longitudinal profiles of main river flows. Since this study found that each climate zone has the different impact on DO dynamics such as reaeration rate, reoxygenation, and oxygen solubility. The outcomes obtained in this study are expected to provide the impetus for developing a strategy for the viable improvement of the water environment.

2017 ◽  
Vol 49 (4) ◽  
pp. 1042-1055 ◽  
Author(s):  
Shushobhit Chaudhary ◽  
C. T. Dhanya ◽  
Arun Kumar

Abstract Calibration is the most critical phase in any water quality modelling process. This study proposes a sequential calibration methodology for any water quality model using reach-specific estimates of model parameters, which would aid in the improved prediction of river water quality characteristics. The proposed methodology accounts for the heterogeneity of river reaches, i.e., diverse characteristics of different reaches on the river stretch. The water quality model, QUAL2K, is coupled with MATLAB, a computing platform, to facilitate sequential estimation of reach-wise model parameters using a grid-based weighted average optimization. The Delhi segment of the Yamuna River is selected as study river stretch. Observations of water quality variables, dissolved oxygen and biochemical oxygen demand are used to calibrate and validate QUAL2K. Desirable performance measures are obtained during the calibration and the validation period. The methodology proves superior to the existing calibration methodologies applied over the study region. The proposed technique also captures the system behaviour effectively, through a systematic, efficient and user-friendly way. The proposed approach is expected to aid decision-makers in formulating better reach-wise management decisions and treatment policies by providing a simpler and efficient way to simulate water quality parameters.


2021 ◽  
Vol 9 (2) ◽  
pp. 103-110
Author(s):  
Nguyen Thanh Giao

Surface water sources play an important role in human and biological activities and the socio-economic development of the region. Therefore, the assessment of water quality and determination of the causes of water pollution in Sao river is essential for good management of the surface water environment. The study was conducted from July to December 2020. Water samples were collected at the time of low tide to evaluate the water quality indicators of temperature, pH, conductivity (EC), dissolved oxygen (DO), biological oxygen demand (BOD), total suspended solids (TSS), ammonium (N-NH4+), orthophosphate (P-PO43-) and coliform. The source of pollution was determined by direct interviews with households living near Sao river. The results showed that surface water quality in Sao river had signs of organic pollution and microbiological pollution due to BOD, TSS, N-NH4+, P-PO43-, coliform exceeded the allowable limits of National Technical regulation on surface water quality (QCVN 08-MT:2015/BTNMT, column A1). The results of the interview revealed that 70% of respondents said that water was seriously polluted and the main sources of pollution were domestic solid waste and domestic wastewater. Therefore, to improve surface water quality in Sao river, solid waste and wastewater management is urgently required. It is necessary to promote the monitoring and management of water quality with the participation of local authorities and communities.


Author(s):  
Anant Patel ◽  
Karishma Chitnis

Abstract Rivers are critical to human life because they are strategically significant in the world, providing primary water supplies for various purposes. Rivers are the prime importance of any country as most of the cities are settled near the river. Due to developmental activities and increase in population, it will results into huge waste generation. Surface water quality is affected because of increasing urbanization and industrialization. The aim of this research is to examine the effect of climate change and industrialization on the water quality of the Sabarmati river using a mathematical model. For this study four important town along the lower Sabarmati River have been considered and water quality data was considered from 2005 to 2015. In this study different water quality parameters were considered to derive water quality model. Results shows the water quality in downstream after Ahmedabad city is worst compare to the other location where the Maximum WQI is 0.71 at Rasikapur and average WQI is 0.50 for the same location for last 15 year. It has been observed that effect of monsoon and also by comparing time scale water quality model role of regulations for industrialization also plays important role in quality of Sabarmati river.


2007 ◽  
Vol 11 (1) ◽  
pp. 623-633 ◽  
Author(s):  
D. B. Boorman

Abstract. A method of model evaluation is presented which utilises a comparison with a benchmark model. The proposed benchmarking concept is one that can be applied to many hydrological models but, in this instance, is implemented in the context of an in-stream water quality model. The benchmark model is defined in such a way that it is easily implemented within the framework of the test model, i.e. the approach relies on two applications of the same model code rather than the application of two separate model codes. This is illustrated using two case studies from the UK, the Rivers Aire and Ouse, with the objective of simulating a water quality classification, general quality assessment (GQA), which is based on dissolved oxygen, biochemical oxygen demand and ammonium. Comparisons between the benchmark and test models are made based on GQA, as well as a step-wise assessment against the components required in its derivation. The benchmarking process yields a great deal of important information about the performance of the test model and raises issues about a priori definition of the assessment criteria.


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