One-dimensional Water Quality Model Research Articles

Applicability Analysis on the Improved One-Dimension Steady-State River Water Quality Model

Guanzhong Segment of Wei River was studied in this article. Based on water quality observational data (ammonia-nitrogen) and hydrology observational data (flow of the sections) of Guanzhong Segment of Wei River in the rainy, normal and wet season in 2006, improved one-dimensional steady-state river water quality model was calibrated. River water quality was predicted in the normal season which were compared with the observational data in 2005. The results show that the water quality computed by improved one-dimensional steady-state river water quality model is grossly consistent with the observational water quality data and the model may provide the technical supports for the response relationships of water quality and water quantity of Guanzhong Segment of Wei River.

Study on Calculations of Pollutant Adjustment Concentrations at Monitoring Sections in Water Function Zones under the Scene of Overproof Upstream Water

In 2011 the pollution receiving capacity red-line policy in No.1 document of central government made new request on up-to-standard assessments of water function zones. As the key and difficulty work in practice, overproof upstream water normally leads to unfair assessment results of downstream water function zones. In this paper, for calculating pollutant adjustment concentrations to avoid overproof upstream water effects at sections in downstream water function zones, downstream situations are classified according to influences from upstream branches, upstream sewage outlets, or whether in flood season. Equations based on one-dimensional water quality model and pollutant input-response model were put forward to deal with these situations even though downstream sections are not monitored. Calculations above included pollutant decay process, pollutant input-response relation and non-point source pollution. The results show that equations could be used in up-to-standard assessments of water function zones and support water resources management well.

Research and Application of Pollution Control in the Middle Reach of Ashe River by Multi-Objective Optimization

Based on one-dimensional water quality model and nonlinear programming, the point source pollution reduction model with multi-objective optimization has been established. To achieve cost effective and best water quality, for us to optimize the process, we set pollutant concentration and total amount control as constraints and put forward the optimal pollution reduction control strategy by simulating and optimizing water quality monitoring data from the target section. Integrated with scenario analysis, COD and ammonia nitrogen pollution optimization wasstudiedin objective function area from Mountain Maan of Acheng to Fuerjia Bridge along Ashe River. The results showed that COD and NH3-N contribution has been greatly reduced to AsheRiverby 49.6% and 32.7% respectively. Therefore, multi-objective optimization by nonlinear programming for water pollution control can make source sewage optimization fairly and reasonably, and the optimal strategies of pollution emission are presented.

Continuous simulation of suspended sediment through a stream section

This paper presents the development of a one-dimensional stream water quality model for the continuous simulation of suspended sediment transport and deposition processes along a particular stream section. The model integrates stream hydraulics and suspended sediment transport and deposition processes. The stream hydraulic model was developed using the Muskingum-Cunge method of channel routing. The well-known suspended sediment processes have been modified and integrated with the developed hydraulic model. The developed model was applied and simulated for the Saltwater Creek, Gold Coast, Australia. Sensitivity analysis of the model showed that all the particles’ characteristics within the incoming stream flows are important for the better prediction of suspended sediment loads.

Calculation and Analysis of Water Quality Improvement Caused by Water Diversion in Nanjing Qinhuai River

To explore the impact of changes in water quality of the Nanjing Inner Qinhuai River water system in different water diversion way and to assess the transfer effect, an one-dimensional hydrodynamic and water quality model for Inner Qinhuai River was established to simulate and analysis the responds of water quality on the different nutrient loading and different diverted water. Four different water discharges diverted from Xuanwu Lake and Exterior Qinhuai River and two loads including the present load and 50% reduction were considered. The result shows the water quality can be improved significantly only as enough water is diverted and the sewage is intercept in the Middle Reach of the Inner Qinhuai River.

Water quality in Minho/Miño River (Portugal/Spain)

Minho River, also called Miño (in Spain), extends to about 300km from Spain to Portugal. The source of the river lies in Spain and in the last 75km, the river defines the border between Portugal and Spain. Under the scope of a cooperation project between North Portugal and Galicia region of Spain, titled: "Valorization of the natural resources of the Minho/Miño drainage basin", seven water-sampling campaigns were carried out during the last 2years in Minho River basin. Seven sampling sites were selected along the international stretch, and five were chosen in the main Portuguese and Spanish tributaries of Minho River. Water quality based on the physicochemical and microbial parameters was assessed. According to the Portuguese legislation for surface waters, the international section of Minho River presents a reasonably good water quality (BOD5 <5mg/L, TNK <2mg/L, and total phosphorous <1mg P/L). Valença and Louro were found to be the most polluted sampling sites and Louro the most polluted tributary (maximum values observed: TSS = 26mg/L, BOD5 = 6.6mg O2/L, COD = 20.8mg O2/L, total nitrogen = 9.9mgN/L; minimum value observed: OD = 1.3mg O2/L). A one-dimensional stream water quality model QUAL2Kw was calibrated using data measured in field surveys along the international stretch of Minho River. QUAL2Kw was also used to predict the impact of flow conditions, discharges, and tributaries on the water quality of international stretch of Minho River, essential to establish proposals for management and planning of Minho River Basin.

Simulations of water quality and oxythermal cisco habitat in Minnesota lakes under past and future climate scenarios

A deterministic, process-oriented, dynamic and one-dimensional year-round lake water quality model, MINLAKE2010, was developed for water temperature (T) and dissolved oxygen (DO) simulations to study impacts of climate warming on lake water quality and cisco fish habitat. The DO model is able to simulate metalimnetic oxygen maxima in vertical DO profiles of oligotrophic lakes. The model was calibrated with profile data from the 28 study lakes in Minnesota; two-thirds of them are deep mesotrophic/oligotrophic lakes that support cisco, a coldwater fish species. The average standard error of estimate against measured data was 1.47 °C for T and 1.50 mg/L for DO. Oxythermal habitat parameter TDO3 (T at DO = 3 mg/L) was determined from simulated daily T and DO profiles under past and future climate scenarios in the 28 study lakes. Average annual maximum TDO3 (TDO3AM) for the 28 study lakes is projected to increase on the average of 3.2 °C under the MIROC 3.2 future scenario, while the occurrence day of TDO3AM is not much different under past and future climate scenarios. Both physical processes (mixing characteristics related to lake geometry ratio) and trophic status control temperature and DO characteristics and then affect cisco habitat in a lake.

Oxythermal habitat parameters and identifying cisco refuge lakes in Minnesota under future climate scenarios using variable benchmark periods

Fish habitat in lakes is strongly constrained by water temperature (T) and available dissolved oxygen (DO). With climate warming both of these water quality parameters will change. A fish habitat simulation model was developed to calculate an oxythermal habitat variable, TDO3, i.e. water temperature at 3mg/L of DO, from simulated daily T and DO profiles and used to determine potential refuge lakes for lake herring or cisco (Coregonus artedi) in Minnesota. Daily T and DO profiles were simulated using a deterministic, unsteady, one-dimensional (vertical) year-round lake water quality model (MINLAKE2010) that was developed specifically for transparent deep lakes. Profiles for thirty Minnesota cisco lakes were simulated with the MINLAKE2010 model using recorded (1961–2008) weather data or projected future climate scenarios (CGCM 3.1 and MIROC 3.2) as model input. The average of daily TDO3 values (called ATDO3VB) over a 31-day sliding or variable benchmark period (VB), was first calculated from daily TDO3 values. The annual maximum of ATDO3VB was retained for each simulated lake and year, and the average of 47 ATDO3VB values (called AvgATD3VB) obtained for the 1962–2008 simulation period was compared to oxythermal stress criteria for cisco determined from the analysis of field data. Isopleths of AvgATD3VB were interpolated for the 30 simulated lakes on a plot of Secchi depth vs. lake geometry ratio used as indicators of trophic state and summer mixing conditions, respectively. Marking the 620 Minnesota lakes with identified cisco populations on the plot of AvgATD3VB allowed to partition the 620 lakes into the three tiers depending on where they fell between the isopleths: lakes with AvgATD3VB≤11°C (Tier 1 lakes) were selected to be most suitable for cisco; lakes with 11°C<AvgATD3VB≤17°C (Tier 2 lakes) had suitable habitat for cisco; and non-refuge lakes with AvgATD3VB>17°C (Tier 3 lakes) would support cisco only at a reduced probability of occurrence or not at all. About 160 existing cisco lakes were thus projected to be suitable refuge lakes (Tier 1 plus Tier 2) under the two future climate scenarios. The remaining lakes were projected to loose their cisco supporting ability. The methodology to identify the refuge lakes was applied to a cisco kill that occurred in 18 cisco lakes in Minnesota in the hot summer of 2006, and was able to identify the majority of these lakes as non-refuge lakes.

Research on Water Environmental Capacity of Urban River: A Case Study of Tuohe River in Suzhou City, Northern Anhui Province

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.

Calculation and Analysis of the Water Environment Capacity for the Yuanhe River in Jiangxi Province, China

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.

Natural purification effects in the river in consideration with domestic wastewater pollutant discharge reduction effects

The first social experiment program in Japan to reduce domestic wastewater pollutant discharge by “soft interventions” in households has been conducted in the Yamato-gawa River drainage area since 2005. The Yamato-gawa River has been listed as one of the worst water quality rivers in Japan because of the larger annual average BOD. “Hard interventions” including deployment of wastewater treatment facilities and artificial installation of natural purification facilities in the river has been conducted in these years to improve river water quality. At the first Yamato-gawa River social experiment program (YR-SEP) in March 2005, BOD at the monitoring point near the river mouth decreased about 6% during the Program. Natural purification effect along the river was evaluated in this article with one-dimensional water quality model for the six river sections. Larger biological oxygen consumption rate, k b, was estimated in the sections with artificially installed natural purification facilities. The effect of “soft interventions” in households in the YR-SEP was estimated as 25% BOD decrease in the nearest monitoring point to the river mouth, when all the households participate in the Program and BOD discharge reduction rate with “soft interventions” in households was 40%.

Water quality assessment and meta model development in Melen watershed – Turkey

Istanbul, being one of the highly populated metropolitan areas of the world, has been facing water scarcity since the past decade. Water transfer from Melen Watershed was considered as the most feasible option to supply water to Istanbul due to its high water potential and relatively less degraded water quality. This study consists of two parts. In the first part, water quality data covering 26 parameters from 5 monitoring stations were analyzed and assessed due to the requirements of the “Quality Required of Surface Water Intended for the Abstraction of Drinking Water” regulation. In the second part, a one-dimensional stream water quality model with simple water quality kinetics was developed. It formed a basic design for more advanced water quality models for the watershed. The reason for assessing the water quality data and developing a model was to provide information for decision making on preliminary actions to prevent any further deterioration of existing water quality. According to the water quality assessment at the water abstraction point, Melen River has relatively poor water quality with regard to NH 4 +, BOD 5, faecal streptococcus, manganese and phenol parameters, and is unsuitable for drinking water abstraction in terms of COD, PO 4 3−, total coliform, total suspended solids, mercury and total chromium parameters. The results derived from the model were found to be consistent with the water quality assessment. It also showed that relatively high inorganic nitrogen and phosphorus concentrations along the streams are related to diffuse nutrient loads that should be managed together with municipal and industrial wastewaters.

Prediction of Water Quality of Huangpu River Using a Tidal River Network Model

The Huangpu River is the largest river in Shanghai. It exerts great influence on this metropolitan due to the role of the metropolitan's largest drinking water source and the direct scenery waters bordering the venues of World Exposition Shanghai China 2010 (World EXPO 2010), so a series of water environment rehabilitation projects will be carried out during the eleventh five-year plan (2006–2010). The one-dimensional and two-dimensional coupling hydrodynamic and water quality model—RMA2 and RMA4—developed by the United States Army Corps of Engineers, was modified and applied to develop a Shanghai tidal river network model in order to assess the Huangpu River's water quality by 2010; in which the COD decaying rate, nitrification rate, BOD5 decaying rate, sediment oxygen demand, and re-aeration rate were calibrated. The calibrated results of these coefficients were 0.10–0.25 d−1, 0.03–0.07 d −1, 0.10–0.15 d −1, 1.0–10.0 g m −2 d −1, and 0.15–0.20 d −1, respectively. According to China's National Surface Wa...

A quasi-2D flood modeling approach to simulate substance transport in polder systems for environment flood risk assessment

In flood modeling, many one-dimensional (1D) hydrodynamic and water quality models are too restricted in capturing the spatial differentiation of processes within a polder or system of polders and two-dimensional (2D) models are too demanding in data requirements and computational resources, especially if Monte-Carlo techniques are to be used for model uncertainty analyses. The first goal of this paper is to show the successful development of a quasi-2D modeling approach which still calculates the dynamic wave in 1D but the discretisation of the computational units is in 2D, allowing a better spatial representation of the flow and substance transport processes in the polders without a large additional expenditure on data pre-processing and simulation processing. The models DYNHYD (1D hydrodynamics) and TOXI (sediment and micro-pollutant transport) were used as a basis for the hydrodynamic and water quality simulations. An extreme flood event on the Elbe River, Germany, with a proposed polder system variant was used as a test case. The results show a plausible differentiation of suspended sediment and zinc concentrations within the polders both spatially and temporally. This fulfills the second goal of this research. The third goal of this work is to provide an example methodology of carrying out an environmental risk assessment in inundated areas by flood waters, as required by the European Union floods directive. The deposition of zinc in polders was used for this example, due to its high contamination potential in the Elbe River. The extended quasi-2D modeling system incorporates a Monte-Carlo uncertainty analysis to assess the environmental impact of heavy metal deposition in the polders during extreme flooding. The environmental risk computed gives a 48% chance of exceeding the inspection value of 500 mg zinc/kg sediment for a flood such as the August 2002 event.

Application of automated QUAL2Kw for water quality modeling and management in the Bagmati River, Nepal

The Bagmati River in Kathmandu Valley (Nepal) receives seven major polluted tributaries. Discharges of wastewaters containing degradable organics and nutrients have resulted in decrease in DO concentrations along its course. A one-dimensional stream water quality model QUAL2Kw was calibrated and confirmed using the data in 2000. The model represented the field data quite well with some exceptions. The sensitivity analysis showed the model was highly sensitive for water depth and moderate to point sources flow, TN, CBOD and nitrification rate. The model was applied to simulate various water quality management strategies during critical period to maintain the targeted water quality criteria (minimum DO at or above 4 mg/L; maximum CBOD, TN, TP and temperature at or below 3, 2.5 and 0.1 mg/L and 20 °C, respectively, and pH range 6.5–8.5) considering: (i) pollution loads modification (ii) flow augmentation and (iii) local oxygenation. Except for CBOD, all the stated quality limits were achieved with 30 mg/L CBOD, 5 mg/L TN, 0.25 mg/L TP limits at point sources and with flow augmentation of 1 m 3/s and local oxygenations at three critical locations. The simulated maximum CBOD was 8.5 mg/L. It was considered reasonable for the developing country, Nepal, as the European water quality with maximum CBDO of 3 mg/L is difficult to achieve. The results showed the local oxygenation is effective to maintain minimum DO concentrations in the river. The combination of wastewater modification, flow augmentation and local oxygenation is suitable to maintain the acceptable limits of water quality criteria.

Evaluating alternative river management options in the tidal Ouse using the QUESTS1D model

The tidal Ouse forms a significant part of the Humber river system in Eastern England, which provides the largest UK fresh water source to the North Sea and a valuable habitat for fish. However it suffers from dissolved oxygen (DO) sag in summer, exacerbated by the industrial effluent discharged at Selby. A one-dimensional water quality model, QUESTS1D, as utilized by the Environment Agency (EA) has been used to evaluate the effectiveness of management options based on exploiting spatial distribution of the assimilative capacity of the river as an alternative to implementing more stringent effluent consents. Significant improvements in water quality of the tidal Ouse are predicted compared to the effects of tightening effluent consents. A system of water quality functions is derived in this paper for quicker and more direct predictions of water quality, which will be useful in future research when combined with other analyses. Taking account the assimilative capacity in policy making, this paper suggests that a combined water management framework should be applied to ensure the required water quality.

Water quality modeling and pollution control for the Eastern route of South to North water transfer project in China

South to North Water Transfer Project in China is the largest project over centuries to solve the water shortage problem in vast areas of northern China. It comprises of three routes: the eastern, central and western route and this study mainly focused on the eastern route. As water quality is the key factor for the eastern route, this paper examined the main factors influencing water quality of the main route south of the Yellow River, by investigating the point source, non-point source (diffusive source) and internal source pollutions along the main eastern route and in its drainage basins, and assessing the current water quality in the waterways. According to the complicated and combined systems of rivers and lakes in this route, one-dimensional water quantity and quality model for rivers and two-dimensional model for lakes were developed to simulate the hydrodynamic and pollutant transport processes. The numerical method and model algorithm were described. The values of model parameters were estimated by using field-monitoring data along the main route and the inverse modeling technique. Established models were employed to predict the degradations of COD Mn and NH 4 +-N in the main stream, under the conditions of current pollution loads and different hydrologic conditions. Schemes were present for controlling total quantities of pollutants from point source and non-point source along the main route to secure water quality for the eastern route.

Lake Water Quality Model with Focus on Cyanobacteria

The cause of cyanobacteria’s growth and dominance in certain eutrophic lakes is explored via a water quality model application. The one-dimensional lake water quality model includes nitrogen, phosphorus, silica, three phytoplankton groups and zooplankton. Lake Washington was used as the case study due to its unique history of eutrophication during a large wastewater nutrient loading period from in the 1960s and subsequent recovery. Sampling data for a 20-year period surrounding the eutrophication includes speciation of phytoplankton. Results indicate that nutrient loading, specifically phosphorus was the main factor for the persistent dominance of Oscillatoria in Lake Washington. Other key conditions and cyanobacteria traits are analyzed and discussed.

DEVELOPMENT AND TESTING OF WATERSHED-SCALE MODELS FOR POORLY DRAINED SOILS

Two watershed-scale hydrology and water quality models were used to evaluate the cumulative impacts of landuse and management practices on downstream hydrology and nitrogen loading of poorly drained watersheds. Field-scalehydrology and nutrient dynamics are predicted by DRAINMOD in both models. In the first model (DRAINMOD-DUFLOW),field-scale predictions are coupled to the canal/stream routing and in-stream water quality model DUFLOW, which handlesflow routing and nutrient transport and transformation in the drainage canal/stream network. In the second model(DRAINMOD-W), DRAINMOD was integrated with a new one-dimensional canal and water quality model. The hydrologyand hydraulic routing components of the models were tested using data from a 2950 ha drained managed forest watershedin the coastal plain of eastern North Carolina. Both models simulated the hydrology and nitrate-nitrogen (NO3-N) loadingof the watershed acceptably. Simulated outflows and NO3-N loads at the outlet of the watershed were in good agreement withthe temporal trend for five years of observed data. Over a five-year period, total outflow was within 1% of the measured value.Similarly, NO3-N load predictions were within 1% of the measured load. Predictions of the two models were not statisticallydifferent at the 5% level of significance.

Dynamic in-stream fate modeling of xenobiotic organic compounds: a case study of linear alkylbenzene sulfonates in the Lambro River, Italy.

Using a conceptual hydraulic model, a one-dimensional dynamic river water quality model has been developed to assess the short-term fate of linear alkylbenzene sulfonates (LAS) in the river compartments water and benthic sediment. The model assumes local equilibrium sorption and that both dissolved and sorbed chemical are available for biodegradation. To investigate the interaction of nutrient dynamics and organic contaminant fate, the model is coupled with a basic water quality model. On the basis of the Lambro River (Italy) as a case study, the result shows that the model predictions agree well with the measured data set. The model output sensitivity to model parameters has been tested, and the results depict that the model is highly sensitive to the biodegrading parameters. Also, a comparison of a steady state with a dynamic simulation and the effect of nutrient dynamics on the LAS fate in the Lambro River as a scenario analysis are presented. The results indicate the usefulness of the proposed model for the short-term simulation of organic contaminant fate in unsteady environmental conditions.