Water quality modeling in the watershed-based approach for waste load allocations

1998 ◽  
Vol 38 (10) ◽  
pp. 165-172 ◽  
Author(s):  
Ruochuan Gu ◽  
Mei Dong
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Water Quality Modeling ◽  
Point Sources ◽  
Low Flow ◽  
Quality Analysis ◽  
Management Approach ◽  
Water Quality Control ◽  
Quality Modeling ◽  
Waste Load

The conventional method for waste load allocations (WLA) employs spatial-differentiation, considering individual point sources, and temporal-integration, using a constant flow, typically 7Q10 low flow. This paper presents a watershed-based seasonal management approach, in which non-point source as well as point sources are incorporated, seasonal design flows are used for water quality analysis, and WLA are performend in a watershed scale. The strategy for surface water quality modeling in the watershed-based approach is described. The concept of seasonal discharge management is discussed and suggested for the watershed-based approach. A case study using the method for the Des Moines River, Iowa, USA is conducted. Modeling considerations and procedure are presented. The significance of non-point source pollutant load and its impact on water quality of the river is evaluated by analyzing field data. A water quality model is selected and validated against field measurements. The model is applied to projections of future water quality situations under different watershed management and water quality control scenarios with respect to river flow and pollutant loading rate.

scholarly journals Water quality modeling of the Medellin river in the Aburrá Valley

DYNA ◽  
2015 ◽  
Vol 82 (192) ◽  
pp. 195-202
Author(s):  
Lina Claudia Giraldo Buitrago ◽  
Carlos Alberto Palacio ◽  
Rubén Darío Molina ◽  
Rubén Alberto Agudelo García
Keyword(s):  
Water Quality ◽  
Waste Treatment ◽  
Positive Impact ◽  
Treatment Plant ◽  
Water Quality Modeling ◽  
Low Flow ◽  
Critical Conditions ◽  
Quality Modeling ◽  
Waste Treatment Plant

Water quality modeling intends to represent a water body in order to assess their status and project the effects of different measures taken for their protection. This paper presents the results obtained from the Qual2kw model implementation in the first 50 kilometers of the Aburrá-Medellín River, in their most critical conditions of water quality, which correspond to low flow rates. After the model calibration, three recovery scenarios (short-term, medium-term and long-term) were evaluated. In the first scenario the sanitation only improved in some streams, in accordance with the Plan of Sanitation and Management of Discharges that was considered. Medium and long-term scenarios, with the operation of the new Water Waste Treatment Plant (WWTP) of the Bello municipality and an increase in the sewage collection, were considered. The obtained results show the positive impact of the operation of the WWTP of Bello in the balance of BOD5, dissolved oxygen and nitrogen.

scholarly journals Selection of Optimum Pollution Load Reduction and Water Quality Improvement Approaches Using Scenario Based Water Quality Modeling in Little Akaki River, Ethiopia

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 584
Author(s):  
Zelalem Abera Angello ◽  
Beshah M. Behailu ◽  
Jens Tränckner
Keyword(s):  
Water Quality ◽  
Quality Improvement ◽  
Management Practices ◽  
Water Quality Modeling ◽  
Point Sources ◽  
Load Reduction ◽  
Pollution Load ◽  
Water Quality Improvement ◽  
Quality Modeling ◽  
Akaki River

The collective impacts of rapid urbanization, poor pollution management practices and insufficient sanitation infrastructure have driven the water quality deterioration in Little Akaki River (LAR), Ethiopia. Water quality modeling using QUAL2Kw was conducted in the LAR aimed at selecting the optimal water quality improvement and pollution load reduction approaches based on the evaluation of five scenarios: modification of point sources (PS) load (S1), modification of nonpoint sources (NPS) load (S2), simultaneous modification of PS and NPS load (S3), application of local oxygenators and fish passages using cascaded rock ramps (S4), and an integrated scenario (S5). Despite the evaluation of S1 resulting in an average load reduction of Biochemical Oxygen Demand (BOD) (17.72%), PO4-P (37.47%), NO3-N (19.63%), the water quality objective (WQO) in LAR could not be attained. Similarly, though significant improvement of pollution load was found by S2 and S3 evaluation, it did not secure the permissible BOD and PO4-P pollution load in the LAR. Besides, as part of an instream measure, a scenario evaluated using the application of rock ramps (S4) resulted in significant reduction of BOD load. All the individual scenarios were not successful and hence an integration of scenarios (S5) was evaluated in LAR that gave a relatively higher pollutant load reduction rate and ultimately was found a better approach to improve pollution loads in the river. In conclusion, pollution load management and control strategy integrally incorporating the use of source-based wastewater treatment, control of diffuse pollution sources through the application of best management practices and the application of instream measures such as the use of cascaded rock ramps could be a feasible approach for better river water quality management, pollution reduction, aquatic life protection and secure sustainable development in the LAR catchment.

scholarly journals Development of Optimal Management Strategies for the Interception System Using River Water Quality Modeling

2018 ◽  
Vol 175 ◽  
pp. 03024
Author(s):  
Chen-Yao Ma ◽  
Yi-Chu Huang ◽  
Chih-Ming Kao
Keyword(s):  
Water Quality ◽  
Management Strategies ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Water Quality Modeling ◽  
Water Bodies ◽  
Quality Analysis ◽  
Quality Model ◽  
Quality Modeling ◽  
The Impact

This study adopted the water quality model [Water Quality Analysis Simulation Program (WASP)] to simulate and evaluate the impacts of the opening and closure of an interception system at the tributary of Love River on mainstream water quality. The gates were opened respectively for 4, 12, and 24 hours to assess the impact on biochemical oxygen demand (BOD) and ammonia nitrogen (NH3-N) in the water bodies of Love River. The WASP model was used to evaluate the self-purification capacity of the river. According to the results of the model estimation, it takes 5 days for NH3-N and BOD in the water bodies of Love River to return to normal and for the water to restore its original water quality after the closure of the Baozhu Ditch gate. Results of this study can be used as a reference for Love River watershed management, and the WASP modeling can be applied for decision makers to develop appropriate management strategies of the interception system.

scholarly journals SWAT Modeling of Non-Point Source Pollution in Depression-Dominated Basins under Varying Hydroclimatic Conditions

2018 ◽  
Vol 15 (11) ◽  
pp. 2492 ◽  
Author(s):  
Mohsen Tahmasebi Nasab ◽  
Kendall Grimm ◽  
Mohammad Bazrkar ◽  
Lan Zeng ◽  
Afshin Shabani ◽  
...  
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Assessment Tool ◽  
The United States ◽  
Water Quality Modeling ◽  
Water Quantity ◽  
Basic Scenario ◽  
Calibration And Validation ◽  
Calibration Scheme ◽  
Quality Modeling

Non-point source (NPS) pollution from agricultural lands is the leading cause of various water quality problems across the United States. Particularly, surface depressions often alter the releasing patterns of NPS pollutants into the environment. However, most commonly-used hydrologic models may not be applicable to such depression-dominated regions. The objective of this study is to improve water quantity/quality modeling and its calibration for depression-dominated basins under wet and dry hydroclimatic conditions. Specifically, the Soil and Water Assessment Tool (SWAT) was applied for hydrologic and water quality modeling in the Red River of the North Basin (RRB). Surface depressions across the RRB were incorporated into the model by employing a surface delineation method and the impacts of depressions were evaluated for two modeling scenarios, MS1 (basic scenario) and MS2 (depression-oriented scenario). Moreover, a traditional calibration scheme (CS1) was compared to a wet-dry calibration scheme (CS2) that accounted for the effects of hydroclimatic variations on hydrologic and water quality modeling. Results indicated that the surface runoff simulation and the associated water quality modeling were improved when topographic characteristics of depressions were incorporated into the model (MS2). The Nash–Sutcliffe efficiency (NSE) coefficient indicated an average increase of 30.4% and 19.6% from CS1 to CS2 for the calibration and validation periods, respectively. Additionally, the CS2 provided acceptable simulations of water quality, with the NSE values of 0.50 and 0.74 for calibration and validation periods, respectively. These results highlight the enhanced capability of the proposed approach for simulating water quantity and quality for depression-dominated basins under the influence of varying hydroclimatic conditions.

River water quality modeling using continuous high frequency data allows disentangling whole-stream nitrogen uptake and release pathways

2020 ◽  
Author(s):  
Jingshui Huang ◽  
Michael Rode
Keyword(s):  
Water Quality ◽  
River Water ◽  
High Frequency ◽  
N Uptake ◽  
Benthic Algae ◽  
Water Quality Modeling ◽  
River Water Quality ◽  
Low Flow ◽  
High Frequency Data ◽  
Quality Modeling

<p>River water quality models offer studying spatio-temporal variation and processes of nitrogen (N) turnover. However, the infrequent temporal resolution of monitoring data commonly limit the reliability of modeling instream N processing. These limitations of the temporal data resolution can result in equifinality of model parameter sets and considerable uncertainties due to insufficient ability of validating internal turnover processes. The combination of emerging high frequency monitoring techniques and water quality modeling may support continuous quantification of instream N processing pathways with higher reliability.</p><p>In this study, we set up a hydrodynamic and river water quality model (WASP 7.5.2) in the 27.4-km reach of the 5<sup>th</sup> order river Bode in Central Germany for a 5-year period (2014-2018). High frequency data (15-min interval) of discharge, nitrate, dissolved oxygen (DO) and Chlorophyll-a (Chl-a) at the upstream and downstream station were used as model inputs and for model testing, respectively. Chl-a and DO data were used for disentangling uptake via phytoplankton and benthic algae. Furthermore we identified the most important N-removal and release processes including denitrification, excretion from phytoplankton and benthic algae at daily, seasonal and annual scales.</p><p>The PBias of lower than 20% between the simulated and measured high-frequency values for the four variables showed general good performance of the model. Results showed that on an annual scale, net N uptake efficiency ranged from 0.2-17.2% and increased with decreasing discharge resulting in highest value for the extreme low-flow year 2018. Among seasons, net uptake efficiency was found to be the highest in summer. Over 50% of the N loading was taken up at the extreme low flow in the summer of 2018. The contributions of each pathway to total N uptake decreased from assimilatory uptake via benthic algae, denitrification, and assimilatory uptake via phytoplankton. However, in the extreme low-flow summer of 2018, the importance of denitrification was largely increased compared to former years. Besides, in autumn, the reach became a net N source, because remineralization of N from benthic algae surpassed uptake processes.</p><p>Our study highlights the value of high frequency data to support river water quality modeling allowing continuous quantification of whole-stream N uptake and release pathways.</p>

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