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1. increased water depth detritus dissolution hydrolysis and oxidation detritus dissolution and hydrolysis of CBODgiow oxidation and denitrification plant death hydrolysis and settling f organic nitrogen hydrolysis and phytoplankton respiration nitrification and plant photosynthesis nitrification of ammonia denitrification and plant photosynthesis plant death hydrolysis and settling f organic phosphorus hydrolysis and phytoplankton respiration plant photosynthesis and settling if sorption onto settleable particulate matter such as iron oxyhydroxides occurs photosynthesis respiration death and settling plant death dissolution and settling death natural die off and light and settling plant respiration organic nitrogen and organic phosphorus hydrolysis and denitrification nitrification Also affected by plant photosynthesis but this can be or Dependent on alkalinity total inorganic carbon dissolved carbon dioxide 1 CBODst oxidation and plant respiration plant photosynthesis Calculated from the DO reaeration rate Italic text parameters which are calculated by the model or set during calibration rather than input to the model Page 13 of 19 Integrated Water Resources Management Documents AN1 5 6 Calibration may be useful for reaches such as reservoirs that behave differently 6 1 The calibration process It is standard practice to begin with the2. default parameters unless measured values are available then adjust them e the model is run with the as necessary during calibration available data and initial estimates of reaction rates settling velocities etc Calibration is an iterative process When adjusting the reaction rates and settling velocities during calibration care should be taken to ensure that the e the co located modelled and resulting values remain realistic observed values are compared Examples of realistic reaction rates and settling velocities can be found in e the estimated calibration standard texts e g Bowie et al 1985 parameters are adjusted until a reasonable match is achieved between modelled and observed values lf there is concern over a particular value sensitivity tests can be conducted During sensitivity testing a range of values are used for the uncertain parameter and the differences in the model results are assessed This can give an indication Values for substance concentrations flow rates and or water depths are typically compared during calibration Qual2K stores observed data for of how critical that particular value is li 1 E Il bb h l a yenow Cera eNeets Observed data values should NOT be Note that tributaries should be changed during calibration calibrated before attempting to calibrate the main river This is because the tributary discharge will affect the river water quality The calibration proc
3. Integrated Water Resources Management Documents China UK WRDMAP Integrated Water Resources Management Document Series Advisory Note 1 5 Use of Qual2K Water Quality Model in IWRM Planning May 2010 gt as L Bien wua OD Ae a h ail Department For ch _ ak 4 D F D International A Ww A Development Mott MacDonald CHINA WATER Integrated Water Resources Management Documents Integrated Water Resources Management IWRM Basics after Global Water Partnership Ecological sustainability Enabling environment Policies e Legislation e Fora and mechanisms for participation e International inter provincial co operation Allocation Regulations Economic Tools Management boundaries e Capacity building Economic efficiency Social Equity Driving Elements of Integrated Water Resources Management Regulation and Control Environmental Social Considerations tt Considerations Water Resource Water Use Water Resources Assessments Norms Demands Water Permits Water Resources Management Resource Charges and Institutional Water Tariffs Economic Considerations IT Considerations Financial Resources Second figure after WRDMAP Integrated Water Resources Management Documents Summary This document is aimed at practitioners of water resources management who are_ interested in employing the Qual2K water quality
4. dimensional model and so it is assumed to be well mixed in the vertical and lateral directions It is a steady state model so the flow and water quality cannot evolve over time Diurnal variations in water quality due to the diurnal variation in temperature and sunlight can be simulated 3 3 How the model functions Full details of the model s functionality are given in the user guide Chapra et al 2006 an overview is given here Qual2K is written in an _ Excel spreadsheet with VBA macros and a FORTRAN program to undertake the calculations The user enters hydraulic water quality and climatic data see Section 3 4 Figure 2 shows examples of typical inflows discharges and abstractions that can be included in the model For all inflows and discharges both a flow rate and water quality values must be provided For abstractions only a flow rate is necessary Figure 3 shows examples of typical hydraulic parameters that may be included in the model This includes dimensions of river cross sections dimensions and parameters to describe weirs dams or waterfalls and the bed slope along the river Where sufficient data is available rating curves can also be included into the model Guidance is given in the Qual2K user manual on how to describe hydraulic structures in the model In a Qual2K model the river is divided into several reaches then each reach is divided into a user specified number of elements
5. Abstractions and discharges can be positioned at any point along the river If a weir dam or waterfall is to be included in the model this must be positioned at the end of the reach and that reach must consist of only one element Data at inflows are needed for the model s calculations and can be entered into the model Headwater Diffuse Sources and Point Sources worksheets Physical dimensions and descriptors of the reaches should also be entered into the Reach worksheet Water quality and flow data for calibration should be entered into the yellow Hydraulics Data Temperature Data and WQ Data worksheets These values are not used in the model calculations but are plotted on the output graphs for comparison with the model output during the calibration Process Page 3 of 19 Integrated Water Resources Management Documents Figure 2 Typical inflows and outflows required for a river water quality model Upstream boundary Tributary J Inflow inflows Direction of flow Population sewage outflow gt Downstream boundary Industrial abstraction and runoff abstraction and discharge Figure 3 Hydraulic data required for a one dimensional model Upstream boundary J Inflow Direction of flow Reservoirs amp dams outflow Nw Downstream boundary Bed slope Cross sections amp water level Page 4 of 19 Integrated Water Resources Managem
6. Water Quality Modelling for Water Protection Example 1 5 Water Quality Modelling in Chaoyang Liaoning Province Advisory Note 1 7 Designing a Monitoring Programme for Water Quality Modelling Advisory Note 8 4 Inter agency Agreements for Collaborative Water Quality Management Where to find more information on IWRM recommended websites Ministry of Water Resources www mwr gov cn Global Water Partnership www gwpforum org WRDMAP Project Website www wrdmap com Integrated Water Resources Management Documents China UK WRDMAP IWRM Document Series materials English and Chinese versions are available on the following project website WRDMAP Project Website www wrdmap com Advisory Services by Mott MacDonald UK leading a consultancy team comprising DHI Water and Environment HTSPE UK IWHR IECCO Comprehensive Bureau CIAD China Agricultural University Tsinghua University CAAS IEDA CAS CWRR Gansu WRHB and Liaoning WRHB Qld Department For PEKE FID ees AAA CHINA WATER ee Mott MacDonald
7. on the quality of the water flowing over the weir and coefficient b is based on the shape of the weir O gt e ETR Rating curves Qual2K allows rating curves of the form V aQ and H aQ where V is the ae average velocity Q is the flow rate H Qual2K can use a simplified cross section is the water level and a b a and are for weirs dams and waterfalls coefficients and exponents respectively The values are entered Describing weirs into the Reach or Headwater worksheets as appropriate Qual2K models weirs dams and waterfalls in the same way For each Rating curves were derived for structure the model requires the height Chaoyang Gauging Station by creating and width in metres and two best fit curves for the data which fit coefficients a and b The coefficients the Qual2K format for rating curves should be estimated using Table 7 in See Figure 8 below Figure 8 Example of rating curve H 0 11Q gt 4 O Oo gt O Q 9 o gt Sa eD 10 Flow rate m s Page 11 of 19 Integrated Water Resources Management Documents 5 3 How to estimate data Learning how to estimate successfully takes practice When estimating try to e Keep it simple use a fast and straightforward process e Base estimates on data from similar locations where possible e Base estimates on local knowledge and experience visit the s
8. 00 30000 25000 20000 15000 10000 5000 0 Ammonia ug l N 15 10 Distance from downstream end of Shijia River km Page 17 of 19 Integrated Water Resources Management Documents Box 4 Example report structure 1 Introduction o Background o Purpose of Modelling o Description of Catchment including map and photographs o Aims and Objectives 2 Data o Data Availability list all monitoring locations and positions on map list of all parameters available o Data Processing explanation of treatment of data e g median values used o Data Estimation explanation of method for estimating each value including initial pre calibration estimate 3 Model Setup o Model Schematic overlaid on map o Model Overview explanation of what data was used where in the model 4 Model Calibration o Overview of Calibration Process o Description of Adjusted Values explanation of values adopted for calibration and dummy parameters including explanations of their estimation o Calibration Results graphs showing how well the results match the observed data 5 Scenarios o Scenario 1 description of scenario how the model was adjusted presentation of results and discussion o Scenario 2 etc same for each scenario 6 Conclusions o Conclusions summary of conclusions from model calibration results and scenario runs o Assumptions Summary of assumptions and estimati
9. actitioners of integrated water resources management IWRM may find water quality modelling useful for informing decisions about pollution control such as discharge permitting or demand management such as abstraction permitting A model can be used to test what if scenarios which can demonstrate the effect on water quality in a river due to changes in abstractions and discharges or changes in flow volumes e g drought conditions Conversely discharge and abstraction limits to achieve specific river water quality targets can be investigated using a water quality model Water quality models can be used for a variety of different purposes including analysing pollutant spills and predicting long term water quality in rivers This document focuses on the Qual2K model and how it can be used Further details of the model are available in the user guide Chapra et al 2006 For an overview of how water quality modelling is currently used and opportunities for future use in China see Thematic Paper 1 5 Use of Water Quality Modelling for Water Protection Examples shown in this document are from work undertaken with Qual2K in Chaoyang Liaoning Province For further details see Example 1 5 Water Quality Modelling in Chaoyang Liaoning Province Page 1 of 19 Integrated Water Resources Management Documents 2 Overview of the Modelling Process An overview of a typical modelling process is shown in Fi
10. and or water quality calculations are made Some models are cell based instead and calculate values at cell centres Numerical models use equations without an exact solution Numerical typically computational methods are used to solve the equations A relationship between flow and water depth at a specific location A length of river usually between two nodes A hypothetical situation modelled by adjusting input parameters to predict a possible future water quality e g river water quality resulting from a stricter discharge permit When conditions do not change with time an equilibrium condition Integrated Water Resources Management Documents Document Reference Sheet Bibliography Bartram J and Ballance R 1996 Water quality monitoring Spon London UK http www who int water_sanitation_health resourcesquality wqmonitor en index html Bowie G L et al 1985 Rates Constants and Kinetics Formulations in Surface Water Quality Modeling 2nd ed US EPA document EPA 600 3 85 040 http www ecy wa gov programs eap models rates_and_constants index html Chapra S C 1997 Surface Water Quality Modelling McGraw Hill Chapra S C Pelletier G J and Tao H 2006 QUAL2K Documentation and Users Manual Civil and Environmental Engineering Dept Tufts University Medford MA http www epa gov athens wwatsc html qual2k html Related materials from the MWR IWRM Document Series Thematic Paper 1 5 Use of
11. edure usually raises questions about data gaps ways to deal with these issues are described below 6 2 What can be adjusted during calibration During calibration any estimated values can be adjusted within realistic bounds The reaction rates and settling velocities for the water quality parameters are typically user estimated parameters They can be set for the entire model in the Rates worksheet or for individual reaches in the Reach Rates worksheet which Locals and construction in the Daling River Page 14 of 19 Integrated Water Resources Management Documents 6 3 What if calibration cannot be achieved Sometimes changing typical calibration values such as Mannings n and reaction rates within reasonable values cannot force the model to match the observed data In this situation the first action should be to check the input data and data processing again The assumptions should also be checked and revisited to ensure realistic values When calibration in this manner is not possible it may be because some e Groundwater infiltration volumes e Individual abstractions e Individual discharges In the longer term data should be collected for these missing values however in the first instance the missing values can be estimated during the calibration process and the estimates introduced to the model as dummy values Model results can therefore indicate the scale of the una
12. ent Documents Hydraulic and hydrological data required 3 4 Data requirements Qual2K requires water quality hydraulic and climatic data and parameters for its calculations Additional information can be found in the Qual2k user manual Chapra et al 2006 It is possible to use estimates of many data values if measured values are not available the effect of this is to reduce the accuracy of the model output Page 5 of 19 Flow rates m s at headwaters point discharges abstractions and diffuse discharges abstractions Dimensions for each river reach reach length bed width bank slopes and bed slope Locations for upstream and downstream ends of each reach Height width and shape of any weirs dams and waterfalls Rating curve parameters where available e g at gauging stations Manning s n for river reaches Rainfall runoff data Integrated Water Resources Management Documents AN1 5 Water quality data required at headwaters point sources and diffuse sources e Temperature C e Nitrate NO ug l of N e Conductivity usiemens e Organic Phosphorus ug l of P e Inorganic Solids mg l dry weight e Inorganic Phosphorus ug l of P e Dissolved Oxygen mg l of O2 e Phytoplankton ug l e CBODslow mg l of O2 e CBODfast mg l of O2 e Detritus POM mg l dry weight e Pathogens cfu 100 ml e Organic Nitrogen ug l of N e Alkalinity mg l
13. esult baseline For scenario modelling the values adjusted during calibration e g reaction rates should be retained The scenario runs undertaken should depend on the questions that the model is being used to answer Typical scenario runs are e Changes to discharges from individual enterprises to inform discharge permitting e Changes to abstraction volumes for individual enterprises to inform abstraction permitting e Removal of artificial discharges and abstractions to estimate of the natural water quality e Decrease in headwater inflows and rainfall runoff to inform drought management planning The results of the scenario test should be compared with the baseline results see Box 3 for an example 8 Model Results 8 1 Interpreting results Always discuss the results with people who know the local area and water quality They may be able explain data discrepancies and may notice unrealistic possibly erroneous data values The results from the calibration process may indicate where there are gaps in the data or where there are unknown processes occurring Results from the scenario testing predict future water quality based on the scenario conditions This can be used to test proposed permitting conditions 8 2 Reporting Preparation of a final report is the conclusion of the model development and operation process The final report should be a synopsis of the different stages of the modellin
14. g process A thorough report of the modelling study will be a useful record of the following for anyone wanting to use the model in the future e What data was used and how it was processed e Estimated values and how they were estimated e The calibration process including which values were adjusted and why e The model results the interpretation of these and the conclusions An example report structure is shown in Box 4 Page 16 of 19 Integrated Water Resources Management Documents Box 3 Example of scenario testing in Chaoyang Many individual enterprises discharge into the Shijia tributary that joins the Daling River just downstream of Chaoyang A scenario was modelled to investigate the ammonia load from two paper mills The concentration of ammonia was approximately halved for both mills from 200 mg l to 100 mg l The predicted ammonia concentrations in the Shijia river were compared Figure 10 The change to the discharge of the smaller mill mill 1 0 7 l s did not have as much impact as the change in the larger mill 2 70 i s because of the relative sizes of the discharges Although this was a hypothetical scenario it clearly demonstrates the usefulness of the scenario modelling process to investigate the effects of possible discharge permits Figure 10 Scenario and baseline comparison Model baseline Scenario Mm NH4 ugN L data O Minimum NH4 data O Maximum NH4 data 45000 40000 350
15. gure 1 The steps listed are described in more detail in the remainder of this booklet The modelling process should always begin with a planning phase which should establish the questions to be answered using the model and the availability of information Data is input to the model and assumptions are made where no data is available The model is calibrated based on the available data Figure 1 Overview of modelling process Model set up and calibration is an iterative process The results usually raise questions about data gaps which allow the investigators to focus their attention on a particular data set Following calibration the model can be used to test possible future scenarios The model results should be analysed carefully and reported thoroughly Discussions with stakeholders such as other organisations involved in water management are important throughout the modelling process Page 2 of 19 Integrated Water Resources Management Documents 3 Qual2K Overview 3 1 Obtaining the model The Qual2K model is developed for the United States Environmental Protection Agency USEPA You can download a zip file containing the latest version of the model and supporting documentation for free from http Awww epa gov Athens wwatsc ht ml qual2k html Note that the user manual is in English Model development is ongoing and updates are issued on the website 3 2 The model theory The Qual2K model is a one
16. ite perhaps some parameters can be guessed from local knowledge e Consult the literature there may be an approximation that can be adopted e g Box 1 Estimated data values should be clearly marked as such e g use bold red text in the model for estimated values A record should always be kept of how values were estimated even if it just says Mr Liu suggested this value based on his experience 5 4 Quality control Checking incoming data Data should be checked as soon as it is received Any errors or omissions will be easier to correct straight away Begin by reviewing and checking the data This may be most easily accomplished by plotting the data as a visual aid Ask yourself e ls the data believable If you are not familiar with local water quality ask someone who is e ls the data consistent E g is a high water temperature observed with a low air temperature Is the data unexpectedly dramatically different at one location e ls the data similar to the data from last time Compare with the last sampling round or with data from a year ago e ls there any data missing Check the data against the map of sampling points is everything there Keeping records Always record what data has been received and any changes made to the data such as data processing correction of erroneous data etc as well as any assumptions made This will help you to trace back through what wa
17. ith tributaries or at physical features such as dams which must be included in the model to represent the hydraulics appropriately Care must be taken to represent the hydraulics of the water bodies Page 7 of 19 Integrated Water Resources Management Documents appropriately so that the change in conditions from one node to the next can be successfully modelled For example if a river system under study using a 1D model contains a large reservoir model nodes and cross sections must be included to allow the volume of the reservoir to be represented In large reservoirs residence time is sufficient for significant water quality changes to occur during the reservoir transit It is therefore necessary to include suitable cross sections within the reservoir so that the model is able to approximately reproduce the time delay and therefore the decay processes taking place within the reservoir body In such a circumstance just including a cross section upstream of the reservoir and one immediately downstream of the dam would lead to erroneous results from the model downstream of the reservoir as the storage volume of the reservoir would be grossly under represented The reservoir dam must also be included in the model to allow the reservoir reach es to fill up with water 4 4 Stakeholder involvement It is beneficial to involve other stakeholders throughout the project but particularly at the planning stage Stakeholder
18. ld be from the same sampling round or a long term average If no data is available for a particular inflow for that monitoring round then the data may be estimated based on other data if available Observed data values should NOT be changed during calibration Figure 6 Cross section for low flows 5 S B gt o lt a Distance fiom Eftbank Q 5 2 Simplifications for Qual2K Simplified cross sections Qual2K requires a simplified cross section that is defined by the bed width and the slope of each bank This information can be taken from survey data or estimated during site visits For a low water level it would be inappropriate to simplify the entire cross section shown in Figure 7 A more suitable approach is to simplify the small channel in which the water actually flows at this flow rate Figure 6 shows a small part of the surveyed cross section which represents the river at low flow on which a simplified cross section has been superimposed A simplified cross section for use during high flows is shown in Figure 7 The estimation of the simplified cross section is simply done by eye with the aid of a graphical comparison in an Excel spreadsheet Figure 7 Cross section for high flows 170 270 Distance fiom kftbank Page 10 of 19 Integrated Water Resources Management Documents AN1 5 the Qual2K user guide Chapra et al 2006 Coefficient a is based
19. model as a tool to assist in that management An overview of the modelling process is given here including a description of the Qual2K model it s data requirements and functionality as well as how to approach a modelling project from scoping the study to reporting the results This document covers the following topics Overview of the modelling process Overview of the Qual2K model Planning the modelling work Data processing and estimation Calibration Modelling different scenarios Interpreting and reporting model results Further uses of the model This document is part of a series addressing aspects of integrated water resources management IWRM under which water quality is increasingly viewed as a Critical component It should be read in conjunction with Thematic Paper 1 5 Use of Water Quality Modelling for Water Protection and Example 1 5 Water Quality Modelling in Chaoyang Liaoning Province The Ministry of Water Resources have supported the Water Resources Demand Management Assistance Project WRDMAP to develop this series to support WRD WAB at provincial municipal and county levels in their efforts to achieve sustainable water use 1 Introduction Water pollution is a health hazard to people and can be damaging to the environment Water quality modelling can be used to better understand sources of pollution and to understand how the quality of the receiving waters can be improved Pr
20. of CaCO3 e Ammonia NH ug l of N e pH Page 6 of 19 Water quality and flow measurements are also required at locations throughout the model for calibration The reaction rates and settling velocities for the water quality parameters are typically user defined parameters Default values for the reaction rates and settling velocities are provided in Qual2K but may be adjusted during calibration Climatic data required e Air temperature e Wind speed e Dew point temperature e Percentage cloud cover e Percentage shade Integrated Water Resources Management Documents 4 Planning the Model The modelling process should always begin with a planning phase which should establish the questions to be answered using the model 4 1 Mapping When planning your model always start with map s of the area preferably using GIS software Include as many of the following things as possible on the map s e River and tributary centrelines e Digital elevation map DEM e Catchment boundary e Reservoirs and lakes e Flow gauging stations e Water quality monitoring points e Areas of habitation e Pollution discharge locations e Abstraction locations where water is extracted from the river not the location of the entity with the abstraction license e Structures affecting the flow e Drinking water supply zones e Agricultural areas e Groundwater abstractions As you develop the model you should also include
21. on the map s e Model boundaries e Model nodes and reaches numbered as in the model e Contributing catchment for each model reach e Names or identification labels for any discharges monitoring points etc as included in the model Using these maps throughout the modelling will help with planning the model processing the data calibrating the model and analysing the results 4 2 Model scope A scoping phase should be undertaken before any modelling or data collection The following questions should be considered e What questions do we want the model to help us answer e What information and data is available e Where should we focus in on e g highly polluted reaches Using your map and the answers to these questions you can decide what area the model will cover 4 3 Model schematisation During the scoping stage the model schematisation should be determined Schematisation describes how the model will be used to represent the water bodies being studied This includes identification of the location of the boundaries nodes and reaches required as well as how to represent features such as reservoirs or coastal influences Model boundaries and calibration nodes are usually determined by the locations of gauging stations because of the need for flow and water quality data as model input Other nodes can be positioned at particular locations of interest where a result is required at confluences w
22. ons made in the model o Limitations what the model is appropriate for what it should not be used for Appendix A Detailed User Guide Information for someone else to pick up and run the model It should include the names and locations of all the different model files and instructions on how to run the model Appendix B Detailed Results Tables Full results tables to allow someone to check whether they have completely reproduced the model results Page 18 of 19 Integrated Water Resources Management Documents AN1 5 9 Further Use of the Model Development of a water quality model can incur a high cost The model should therefore be considered as a valuable capital asset This type of 1D water quality model should be developed with a view to continually updating the model as new data becomes available This new data might be the result of e Focussed data collection for expanding the model e Investigation into missing data such as ungauged discharges e Regular routine monitoring The calibration process should be repeated each time new data is included in the model The model should be reviewed periodically to ensure it still adequately represents the river system This review should be reported with evidence to back up the conclusions If changes are required to the model these should also be documented Presentation of model results in Chaoyang Liaoning Page 19 of 19 Integrated Wate
23. r Resources Management Documents Document Reference Sheet Glossary Baseline Boundaries Calibration Cross section DEM Dummy value GIS Headwater Manning s n Node Numerical Rating curve Reach Scenario Steady state Calibrated model result showing the existing conditions The edges of a model for a 1D model upstream and downstream boundaries are required Data is required to establish conditions at the boundaries typically flow water level and water quality conditions Calibration is the process whereby estimated model parameters e g reaction rates are adjusted so that the result agrees with the available data Profile of the river bed and banks perpendicular to flow direction Digital Elevation Model a GIS based data set comprised of topographic data Estimated value to account for an unknown or ungauged discharge or abstraction e g dummy diffuse abstraction to model groundwater infiltration Geographical Information System software for storing and displaying spatially referenced data e g ArcGIS software The upstream end of a watercourse Model headwaters may be located in the middle of a river in this case it is the upstream boundary of the model Roughness coefficient used in open channel flow equations It is estimated from the channel conditions and optimised during calibration Many models use nodes which are point locations at which the hydraulic
24. s done if you need to find an error or check an assumption Check data processing Data processing work should always be checked independently Mistakes are easy to make and can be difficult to find later a lot of time can be saved by checking the data processing early Page 12 of 19 Integrated Water Resources Management Documents Table 1 Interdependencies between water quality determinands Parameter Water temperature Conductivity Inorganic Solids Dissolved Oxygen Reaeration CBODs ow CBODrast Organic Nitrogen Ammonia NH4 Nitrate NO3 Organic Phosphorus Inorganic Phosphorus Phytoplankton Detritus Pathogens Alkalinity pH Total inorganic carbon Dissolved CO Dependency increases due to decreases due to Affected by conduction convection affected by air temperature and wind speed Solar radiation shade and cloud cover and atmospheric long wave radiation air temperature evaporation affected by water and air temperatures hydrolysis settling plant photosynthesis and reaeration if water is under saturated CBOD st oxidation nitrification plant respiration and reaeration if water is over saturated DO saturation is dependent on the water temperature increased water temperature leads to saturation at lower DO concentration dams weirs waterfalls In other reaches can be specified by the user otherwise increased water velocity increased wind speed
25. s might include other agencies with some responsibility for water quality such as municipal provincial and county level EPB WAB and Hydrological Bureaux Benefits from stakeholder involvement e Efficiency multiple organisations using a single model can reduce costs e Information sharing the more data available the better so share and discuss information between all stakeholders e Improve model acceptance people who have been involved in the modelling are more likely to believe and understand the results Involving stakeholders in the mapping stage Page 8 of 19 Integrated Water Resources Management Documents Figure 4 Example of map showing rivers reservoirs catchment boundary and DEM Innea Mongolian utonomous meet en oa Betpiac Ci t Chaoyans Cit o Jinzhou Ci tyi Huludac Cit Herer Tree Figure 5 Example of map of the reach to be modelled and monitoring locations 120 00 E Loi AK IR HEK YF AIGISA YE 41 48 0 N 41 360 N i fA EF RG 41 24 0 N EEE FRA TIE Page 9 of 19 Integrated Water Resources Management Documents 5 Data Processing and Estimation 5 1 How to use observed data Observed data should be used at model headwaters and for individual enterprises point sources Other observed data should be included in the yellow data sheets for calibration Data sets should be consistent i e all data shou
26. vailable information such as ungauged pollution discharges or groundwater infiltration information is missing such as Box 2 Calibration example During calibration of the Chaoyang model it became clear that large amounts of water are lost along some reaches of the main river These losses were determined based on local knowledge to be due to groundwater infiltration which is exacerbated by local groundwater abstraction for irrigation An estimate of this infiltration was included in the Qual2K model as a dummy diffuse abstraction to match the flows observed in the river The results of this rough calibration are shown in Figure 9 At some other locations there was a clear discrepancy between the observed data and the model results it was assumed that this was due to unknown abstractions and discharges These were included as dummy point sources in the model Figure 9 Effect of infiltration estimate on model predicted flows a without infiltration b with estimate of infiltration Flow cumecs ee N WO A na NW 160 120 RN Distance from downstream end of model km RO 40 Page 15 of 19 Integrated Water Resources Management Documents 7 Scenario Testing A new scenario may be modelled by making a change to some input data e g the water quality of a discharge and comparing the new model result scenario with the calibrated model r
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