Numerical Treatment of a Modified MacCormack Scheme in a Nondimensional Form of the Water Quality Models in a Nonuniform Flow Stream

Two mathematical models are used to simulate water quality in a nonuniform flow stream. The first model is the hydrodynamic model that provides the velocity field and the elevation of water. The second model is the dispersion model that provides the pollutant concentration field. Both models are formulated in one-dimensional equations. The traditional Crank-Nicolson method is also used in the hydrodynamic model. At each step, the flow velocity fields calculated from the first model are the input into the second model as the field data. A modified MacCormack method is subsequently employed in the second model. This paper proposes a simply remarkable alteration to the MacCormack method so as to make it more accurate without any significant loss of computational efficiency. The results obtained indicate that the proposed modified MacCormack scheme does improve the prediction accuracy compared to that of the traditional MacCormack method.

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A Numerical Treatment of Nondimensional Form of Water Quality Model in a Nonuniform Flow Stream Using Saulyev Scheme

Mathematical Problems in Engineering ◽

10.1155/2011/491317 ◽

2011 ◽

Vol 2011 ◽

pp. 1-15 ◽

Cited By ~ 9

Author(s):

Nopparat Pochai

Keyword(s):

Water Quality ◽

Hydrodynamic Model ◽

Dispersion Model ◽

Uniform Flow ◽

Water Quality Model ◽

Quality Model ◽

Explicit Schemes ◽

Advection Dispersion ◽

Assessment Problems ◽

Flow Stream

The stream water quality model of water quality assessment problems often involves numerical methods to solve the equations. The governing equation of the uniform flow model is one-dimensional advection-dispersion-reaction equations (ADREs). In this paper, a better finite difference scheme for solving ADRE is focused, and the effect of nonuniform water flows in a stream is considered. Two mathematical models are used to simulate pollution due to sewage effluent. The first is a hydrodynamic model that provides the velocity field and elevation of the water flow. The second is a advection-dispersion-reaction model that gives the pollutant concentration fields after input of the velocity data from the hydrodynamic model. For numerical techniques, we used the Crank-Nicolson method for system of a hydrodynamic model and the explicit schemes to the dispersion model. The revised explicit schemes are modified from two computation techniques of uniform flow stream problems: forward time central space (FTCS) and Saulyev schemes for dispersion model. A comparison of both schemes regarding stability aspect is provided so as to illustrate their applicability to the real-world problem.

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Coupled 1D Hydrodynamic-Water Quality Model of Kobadak-Sibsa River System for Salinity

International Journal of Environmental Science and Development ◽

10.18178/ijesd.2021.12.10.1355 ◽

2021 ◽

Vol 12 (10) ◽

pp. 311-315

Author(s):

A. Haque ◽

◽

K. M. A. Hossain ◽

N. Shadia

Keyword(s):

Water Quality ◽

Drinking Water ◽

Hydrodynamic Model ◽

Dispersion Model ◽

Tuning Parameter ◽

Roughness Coefficient ◽

Salinity Intrusion ◽

Quality Model ◽

Advection Dispersion ◽

Good Agreement

Salinity intrusion creates severe problems in agriculture and drinking water sources in the floodplain of tidal rivers due to low upstream flow and climate changes. This study focuses on 1-D advection-dispersion modeling of the Kobadak-Sibsa river by HEC-RAS. This work has been carried out in simulation of temporal distribution of salinity concentration in different locations which help to identify which location exceeds the chloride limit of drinking water of 1000 ppm and chloride limit in agricultural water limit of 1500 ppm. The hydrodynamic model was coupled with 1D salinity modeling. The calibration was done for the month June 2016. Then the validation was done using the data of July 2015. It has been found a good agreement between simulated and observed water level for Manning’s roughness coefficient as 0.021. Once the hydrodynamic model was calibrated and validated, the 1D advection-dispersion model was performed and calibrated and validated for the year 2016 and 2015 for different dispersion coefficients (D) for different reaches as a tuning parameter. It has found that the higher the dispersion co-efficient the higher the salinity concentrations that the dispersion co-efficient varied from 25 m2/s to 9000 m2/s which showed good agreement between simulated and observed salinity data. From December salinity gradually increases and reaches its peak in April or May. Maximum salinity concentration has been determined in different locations by simulating this model. This hydrodynamic and water quality coupled modeling can be helpful for lesson learning to prevent salinity intrusion in the Kobadak river.

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Numerical Simulations of Water Quality Measurement Model in an Opened-Closed Reservoir with Contaminant Removal Mechanism

International Journal of Differential Equations ◽

10.1155/2018/1343541 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Kaboon Thongtha ◽

Jaipong Kasemsuwan

Keyword(s):

Water Quality ◽

Numerical Simulations ◽

Hydrodynamic Model ◽

Dispersion Model ◽

Quality Measurement ◽

Water Quality Model ◽

Contaminant Removal ◽

Removal Mechanism ◽

Quality Model ◽

Water Quality Measurement

The mathematical simulation of water contaminant measurement is often used to assess the water quality. The monitoring point placement for water quality measurement in an opened-closed reservoir can give accurate or inaccurate assessment. In this research, the mathematical model of the approximated water quality in an opened-closed reservoir with removal mechanism system is proposed. The water quality model consists of the hydrodynamic model and the dispersion model. The hydrodynamic model is used to describe the water current in the opened-closed reservoir. The transient advection-diffusion equation with removal mechanism provides the water pollutant concentration. The water velocity from the hydrodynamic model is plugged into the dispersion model. The finite difference techniques are used to approximate the solution of the water quality model. The proposed numerical simulations give a suitable area of zonal removal mechanism placement. The proposed simulations also give the overall and specified approximated water quality for each point and time when the exit gate is opened on the different periods of time. In addition, the proposed techniques can give a suitable period of time to open the exit gate to achieve a good agreement water quality by using contaminant removal mechanism.

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Nutrient Speciation and Refractory Compounds in Water Quality Models

Water Intelligence Online ◽

10.2166/9781780408323 ◽

2016 ◽

Vol 15 (0) ◽

pp. 9781780408323-9781780408323

Author(s):

D. L. Clark ◽

G. Hunt ◽

M. S. Kasch ◽

P. J. Lemonds

Keyword(s):

Water Quality ◽

Quality Models ◽

Refractory Compounds ◽

Water Quality Models

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Applying Probabilistic Water Quality Standards in River Basin Water Quality Optimization Models

Water Quality Research Journal ◽

10.2166/wqrj.1974.004 ◽

1974 ◽

Vol 9 (1) ◽

pp. 25-29

Author(s):

M. B. Bayer

Keyword(s):

Water Quality ◽

River Basin ◽

Treatment Plant ◽

Oxygen Demand ◽

Minimum Cost ◽

Water Quality Standards ◽

Quality Optimization ◽

Basin Water ◽

Do Concentration ◽

Water Quality Models

Abstract This paper describes a method of applying probabilistic DO (dissolved oxygen) and BOD (biochemical oxygen demand) standards in river basin water quality models. Maximum likelihood estimators for the DO and BOD concentrations variances for each reach are used to obtain a lower bound for BOD so that the probability of violating specified DO and BOD standards is less than Θ per cent in any reach. These boundary values for DO and BOD concentrations are incorporated into a nonlinear water quality optimization model for finding the minimum cost set of wastewater treatment plant efficiencies required to meet DO and BOD standards. The method also provides the minimum DO concentration and the maximum BOD concentration which may be expected to occur 1-Θ of the time for any reach.

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The Use of Water Quality Models in Belgium

Water Science & Technology ◽

10.2166/wst.1987.0011 ◽

1987 ◽

Vol 19 (7) ◽

pp. 1197-1202 ◽

Cited By ~ 2

Author(s):

A. Van Der Beken

Keyword(s):

Water Quality ◽

Quality Models ◽

Water Quality Models

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Relative Performance of 1-D Versus 3-D Hydrodynamic, Water-Quality Models for Predicting Water Temperature and Oxygen in a Shallow, Eutrophic, Managed Reservoir

Water ◽

10.3390/w13010088 ◽

2021 ◽

Vol 13 (1) ◽

pp. 88

Author(s):

Xiamei Man ◽

Chengwang Lei ◽

Cayelan C. Carey ◽

John C. Little

Keyword(s):

Water Quality ◽

Water Temperature ◽

Water Quality Model ◽

Relative Performance ◽

Bubble Plume ◽

Quality Model ◽

Quality Models ◽

Management Interventions ◽

Water Quality Models ◽

D Model

Many researchers use one-dimensional (1-D) and three-dimensional (3-D) coupled hydrodynamic and water-quality models to simulate water quality dynamics, but direct comparison of their relative performance is rare. Such comparisons may quantify their relative advantages, which can inform best practices. In this study, we compare two 1-year simulations in a shallow, eutrophic, managed reservoir using a community-developed 1-D model and a 3-D model coupled with the same water-quality model library based on multiple evaluation criteria. In addition, a verified bubble plume model is coupled with the 1-D and 3-D models to simulate the water temperature in four epilimnion mixing periods to further quantify the relative performance of the 1-D and 3-D models. Based on the present investigation, adopting a 1-D water-quality model to calibrate a 3-D model is time-efficient and can produce reasonable results; 3-D models are recommended for simulating thermal stratification and management interventions, whereas 1-D models may be more appropriate for simpler model setups, especially if field data needed for 3-D modeling are lacking.

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