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MOUSE RDII - HydroAsia

1. Y 12 MOUSE RDII ii DHI Software Copyright This document refers to proprietary computer software which is protected by copyright All rights are reserved Copying or other reproduction of this manual or the related programs is prohibited without prior written consent of DHI Water amp Environment Warranty The warranty given by DHI is limited as specified in your Software License Agreement The following should be noted Because programs are inherently complex and may not be completely free of errors you are advised to validate your work When using the programs you acknowledge that DHI has taken every care in the design of them DHI shall not be responsible for any damages arising out of the use and application of the programs and you shall satisfy yourself that the programs provide satisfactory solutions by testing out sufficient examples 1DHI is a private non profit research and consulting organization providing a broad spectrum of services and technology in offshore coastal port river water resources urban drainage and environmental engineering MOUSE RDII iv DHI Software PART 1 INTRODUCTION TO MOUSE RDII DHI Software 1 MOUSE RDII 2 DHI Software 1 1 1 2 ABOUT MOUSE RDII MODULE Key features and application domain The MOUSE Rainfall Dependent Infiltration Module RDII provides detailed continuous modelling of the complete land phase of t
2. 75 Rainfall intensity my m s 90 1 00 105 j 120 0 00 FOULFLOW 135 01 01 99 00 00 01 01 99 12 00 02 01 99 00 00 02 01 99 12 00 03 01 99 00 00 Figure 1 Different catchment response under the same rainfall due to different soil moisture conditions at the beginning of the rainfall To accomplish a description of the discharge generated in sewer systems influenced by the SRC component a computation tool that considers the effects of previous hydrological events is required For that purpose a general hydrological model MOUSE has been developed MOUSE RDII permits generation of continuous hydrographs thus allowing for accurate simulations of single events as well as simulation of very long hydrological periods MOUSE is actually a combination of the MOUSE Surface Runoff model for the description of the FRC component and NAM the hydrological model for the description of the SRC component is an abreviation of the Danish expression Nedb r Afstromnings Model This model has been developed by the Hydrological Section of the Institute of Hydrodynamics and Hydraulic Engineering at the Technical University of Denmark DHI Software BACKGROUND gt A computational hydrological model such as the continuous part of RDII is a set of linked mathematical statements describing in a simplified quantitative form the behavior of the land phase of the hydrological cycl
3. ccccccccccececececececececececececececececececececececececesececesececesesesere 12 2 2 CATCHMENT DATA AND HYDROLOGICAL 12 EUN MEE GU TANE 12 2 2 2 Definition of RDE d t n ditte ttti reo erri rete it eo ters he YHP RS 12 2 23 Boundary Data Time Series eee eee t us S ES 12 3 EXECUTION OF THE MOUSE RDII COMPUTATIONS e eee ee 12 3 1 THE RUNOFF COMPUTATION DIALOG nene nn nene nan an enese nene n ena na nere nere nere erne erne nerne 12 3 2 CHOICE OF CALCULATION TIME STEP iirerenenene nene renere nene nene renere nene nene nene nene nene nene renerne 12 33 EHE RDIEBIOTSTART ee eerte Eee SE ES SUM Pe eS PEE aaro SU e E cx eue s Bee 12 4 THE RDIL RESULT FILES TEE 12 5 GENERAL DISCUSSION sccssssissscssccsesstscssstescesteasciascosecuscivcsssescecessosdussosacsopeveessessesosssGesesssseusocsessess 12 6 SURFACE RUNOFF MODEL iissssscsocssscssssocsoseasecessossocceseosceoescccocsnseoiccescesecesosessscbscocsvessesssepesesevens 12 7 GENERAL HYDROLOGICAL MODEL RDII ccssssssscscscsssssccscocccsssssssccsccessssssscsecceesees 12 8 OVERFLOW WITHIN THE MODEL ARBA ccccsssssssssssssscccssssssscsscsccsssssssccsccessssssscceccseeees 12 9 NON PRECIPITATION DEPENDENT FLOW COMPONENTS cssssscssssssssssccssccsscssssssscces 12 REFERENCES D
4. i Bl i i 21 1 di 4 1 i 4 2 i Example of the variation of water content in the surface storage root zone storage and the groundwater storage Figure 9 DHI Software 36 Ss OVERFLOW WITHIN THE MODEL AREA In those cases when overflow occurs in the studied model area e g when simulating the discharge to the treatment plant this has to be considered when calibrating the peak flows during rainfall MOUSE RDII calculates the total generated discharge in the catchment area and is therefore not able to describe hydraulic processes like e g overflow loss of water Calibration of parameters affecting the volume in the peak flows should therefore be performed for rain events when overflow is unlikely to occur Model parameters affecting the response of the discharge for rain events when overflow occur can be calibrated against the peak flows base or width Figure 10 shows the agreement between calculated and measured discharge for a rain event when overflow occurs The example is from the catchment area to Rya treatment plant G teborg Sweden Both the agreements when only using MOUSE RDII a model area of approx 212 km2 and when MOUSE Pipe Flow Model see ref 1 and MOUSE RDII are used in combination are shown MOUSE RDU was used for describing the hydrological load inflow hydrographs whil
5. 3 2 EXECUTION OF THE MOUSE RDII COMPUTATIONS The Runoff Computation Dialog The computation is specified and started from the Runoff computation dialog Catchments Runoff Computation The computation definition is very similar to an ordinary surface runoff computation The only differences are related to the specification of HOTSTART conditions and the SRC simulation time step Optionally a result file with detailed results NOF can be specified Runoff Computation 21 xl Model Type Roi T A Curve A Close Catchment and Hydrological Data HGF Hep Additional Parameters Info Max Time Hotstart File Result File tutor CRF NOF Allow Overwrite Simulation Start 16 05 1953 18 00 00 Duration o fo jo Simulation End 16 05 1953 v 220000 Time Step FRC 300 fee Time Step SRC 4 hour Start Simulation Figure 5 The Computation Dialog Choice Of Calculation Time Step When calculating with MOUSE time steps are given separately for the Surface Runoff Model and for the rain dependent infiltration part The calculation can often be performed with a relatively long time step several hours while calculation with the Surface Runoff Model is typically performed with a time step in order of value of several minutes The time step for Surface Runoff computations is defined following the general considerations as described in MOUS
6. 1992 The hydrological model NAM The Calibration periods effect on model parameters and valuation results Thesis project Department of hydraulics Chalmers University of Technology G teborg Sweden in Swedish Gustafsson L G 1992 Modeling of urban hydrology User s guide MouseNAM VA forsk rapport nr 1993 04 VAV Stockhom Sweden in Swedish Niemczynowicz J 1984 An investigation of the areal properties of rainfall and its influence on runoff generating processes Institutionen f r teknisk vattenresurslara Lunds Tekniska H gskola Lund Sweden Wilson E M 1990 Engineering Hydrology 4th edition Macmillan Education Ltd London DHI Software 41 MOUSE RDII 42 DHI Software Ss APPENDIX 1 Examples of MOUSE RDII Parameter Sets Parameter sets obtained for a number of MOUSE RDII applications are presented in this Appendix The parameters for the response function of the surface runoff modes Time Area method A or Kinematic wave method B have not been given since the surface runoff model was not used for simulating the FRC component impervious areas etc for the presented applications The FRC component was instead simulated as a fictitious RDII area the parameters chosen so that only overland flow occurs Therefore the response for the FRC component is described using the RDI parameter CKor instead and thus given below For the RDI parameters not specified MOUSE RDI default
7. root zone storage because less water is available for the vegetation to draw water for transpiration mainly during summer period Monthly and yearly values for the different processes e g precipitation volume real evaporation and total discharge are written to an ASCII file NAMSTAT TXT after every RDII calculation It is recommended that the content of this file is studied now and then during the calibration procedure DHI Software GENERAL HYDROLOGICAL MODEL RDII Precipitation mm hour 2 500 2 000 1 500 1 000 0 500 0 000 Nov Dec Jan Feb Mar Apr 1987 1988 Temperature degrees Celsius 20 0 15 0 10 0 50 0 0 5 0 10 0 15 0 20 0 Nov Dec Jan Feb Mar Apr 1987 1988 Water content in snow storage mm 200 0 150 0 100 0 50 0 0 0 Nov Dec Jan Feb Mar Apr 1987 1988 Measured Flow Calculated Flow m3 s 2 0 1 5 1 0 JA h Me A i fem y A 0 5 A J E A m Foul Flow 0 0 Nov Dec Jan Feb Mar Apr 1987 1988 Figure 8 Example of the build up of snow cover followed by melting process and calculated and measured discharge during the same period Duvbackens treatment plant G vle Sweden DHI Software 35 MOUSE RDII Relative water content surface storage U Relative water content root zone storage L essee 1 i 1 3 1 i
8. 200 0 hours CKbf 1000 0 hours Tof 40 0 of Lmax Tif 0 0 5 of Lmax Tg 0 0 of Lmax Csnow 3 0 mm C day 46 DHI Software APPENDIX 1 EXAMPLE 5 SS Catchment area Hedesunda treatment plant G vle Sweden Aurb Afrc 2 3 km2 0 9 5 Surface runoff model Umax CKof Csnow 0 6 mm 1 0 hours 7 0 mm C day Asrc 16 1 oe RDI model Umax 10 0 mm Lmax 100 0 mm CQof 0 25 CKof 10 0 hours CKif 600 0 hours CKb 1200 0 hours Tof 0 0 of Lmax Tif 0 0 of Lmax Tg 0 0 of Lmax Csnow 7 0 mm C day DHI Software 47 Ss MOUSE RDII EXAMPLE 6 Catchment area Styrs treatment plant G teborg Sweden Aurb 1 4 km2 Afrc 0 8 5 Asrc 23 0 5 Surface runoff model RDI model Umax 0 6 mm Umax 13 0 mm Lmax 200 0 mm CKof 1 5 hours CQof 0 70 Csnow 5 0 mm C day CKof 20 0 hours CKif 600 0 hours CKbf 1500 0 hours Tof 0 0 of Lmax Tif 0 0 of Lmax Tg 0 0 of Lmax Csnow 5 0 mm C day 48 DHI Software
9. MOUSE the input data are organized in the following files n HGF file Catchments and Hydrological data file containing the catchment information parameters for the selected surface runoff model RDI parameters and initial conditions data m UND file containing time series connections of meteorological data rainfall temperature and potential evapo transpiration Catchment Data and Hydrological Parameters General The process of data specification for catchments with SRC flow component 1 e those where MOUSE RDII computation should be activated is practically equivalent to a standard runoff model definition The only additional effort is the activation of the RDI Rain Dependent Infiltration component and definition of appropriate RDI model parameters for the current catchment This implies that RDI is actually an extension of the MOUSE surface runoff models A and B adding the continuous SRC flow component to the discontinuous surface runoff hydrographs SRC The total flow from a catchment is thus obtained just as a sum of the two components The data definition process consists so of the following steps Catchment definition with fundamental catchment data This process is identical as for surface runoff models as described in MOUSE User Guide m Selection of the surface runoff model and definition of surface runoff model parameters This process is identical as for surface runoff models as descr
10. the computed and calculated time series Also there are different types of visual criteria based on visual inspection e g comparison of graphic presentations of the calculated and measured duration curves An important issue is to find the most appropriate criteria for the intended application of the model see ref 5 The choice of criteria is important since it may affect the final choice of parameter values and by that the behavior of the calibrated model Numerical criteria are however limited and therefore a visual comparison between the hydrographs is indispensable MOUSE supports visual comparison of the calculated time series with any time series of the same type contained in the time series database E g when validating the model the DHI Software 25 26 MOUSE RDII calculated discharge can be plotted on the same graph with the measured discharge and compared In the present version of MOUSE there is no automatic calculation or evaluation of specific numeric validation criteria as mentioned above If appropriate analysis of that type can be conducted so that the calculated time series are exported to a spreadsheet or some other program for further processing and comparison with measured time series Figures 6 and 7 show an example of calibration results for the catchment of Rya treatment plant in G teborg Sweden modeled as a MOUSE RDII area Calibration was performed for the years 1986 1989 and verifi
11. velocity of emptying is controlled by Csnow An increase of increases the emptying procedure This process should be addressed now and then during the whole calibration procedure Otherwise there is a risk that a snow melting phenomenon is attempted to be described through adjusting other parameters 10 The Cz coefficient establishes the ratio of groundwater catchment and surface catchment per deafult the two surfaces are equal By changing the ratio the ratio between the baseflow and other runoff components is correspondingly changed The default values of the remaining parameters 5 specific yield of the groundwater reservoir GWL minimum groundwater depth GWLBFo maximum groundwater depth causing baseflow and GWLEFL groundwater depth for unit capillary flux ate adjusted only in exceptional cases Therefore these parameters have been included into the RDII parameter set dialog in a separate box The effects of changing the default values should be well understood prior to adjustment Figure 8 shows an example of the build up of the snow cover followed by the snow melting process The calculated and measured flow reactions during the same period are shown The example is from the treatment plant at Duvbacken Gavle Sweden see ref 5 Considering the complexity of the snow melting process within urban areas a fairly good description was obtained with the RDII model Since the variation of water content
12. E RDII m3 s 25 0 Calculated Flow Measured Flow Part of the validation period 1979 84 5 0 0 0 400 0 Accumulated difference in flow 300 0 ee 200 0 100 0 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1982 m Duration curves for Validation period 1979 84 Calculated Flow 250 2 Measured Flow 1 150 CSO volume 10 0 M SPEE ST NOS 5 0 p cere UE 0 0 0 0 0 2 0 4 0 6 0 8 1 0 Relative duration Figure 7 Calibration results for the catchment of Rya G teborg Sweden Evaluation through DHI Software visual comparison of the hydrographs studies of the accumulated difference between the hydrographs and comparison between calculated and measured duration curve Ss SURFACE RUNOFF MODEL When simulating storm sewer systems or fully combined systems usually a good estimation of the area drained off by the FRC component impervious areas etc can be obtained from physical data maps etc The final model verification of a FRC should however be based upon comparison with measured discharges during rainfall To separate the Asc component Surface Runoff Model and the fast part of the SRC component Surface Runoff Component in measured discharge data with fairly high resolution in time hours is required For calibration of the parameters describing the respo
13. E User Guide This is primarily concerned about the sufficient resolution of the runoff process in time Generally the RDI simulation time step should be chosen in accordance with the resolution of precipitation data e g a time step of 24 hours could be suitable if only daily precipitation data is available However in case when precipitation data with high resolution of e g few minutes are available the RDI time step should be chosen in DHI Software 19 3 3 20 Ss MOUSE RDII accordance with the response of the discharge when raining E g an RDI time step of 2 4 hours should be chosen if the time constant CKoris given a value of 8 hours To minimize the calculation time as well as the size of the result files the calculations are performed according to the following principle The RDII simulation is carried out continuously for the whole period specified On the contrary the Surface Runoff simulation is carried out only when raining Thus the start time for the Surface Runoff calculation is set as the start time for rain hydrograph The Surface Runoff calculation continues until all the surface runoff hydrographs are regressed The RDI Hotstart There isa HOTSTART facility included in MOUSE i e the initial conditions for the various storages can be automatically taken from a former result file at a simulation start time The structure and contents of the result file used as a HOTSTART file requires that th
14. MOUSE MOUSE RDII USER GUIDE WATER amp ENVIRONMENT MOUSE RDII DHI Water amp Environment Agern All 11 DK 2970 Hersholm Denmark Tel 45 4516 9200 Fax 45 4516 9292 E mail software dhi dk Web www dhi dk and www dhisoftware com DHI Software Contents PART I INTRODUCTION TO MOUSE RDIIL sscccccssssssssssssssssssscsscosccssssssssccccessssssscccsccssessscsses 1 1 ABOUT MOUSE RDII MODULE ivsssscsssssssssscescovossessesescosscsossessevcsensecoosessosenseoseceesenecnsossesesencossoeoese 3 1 1 KEY FEATURES AND APPLICATION DOMAIN 000 000seseseeeseeeeeseseseseeeeseeeeeeseeeeeeeeeeeseeeeeeeseeeeeeeeeeeeeeees 3 1 2 SOFTWARE IMPLEMENTATION c00ccscssscsssessssseesseesseessseeseseceeeseeeeeseseeeeseeseeeeeceseeeeeteeeeeeeseeeeeeeeeeeeess 3 2 ABOUT MOUSE RDII USER MANUAL ccccsscsssssssssccssssssssccccccesssssscsccccesssssssccccccesssssssseceseesees 5 3 MOUSE RDII USER SUPPORT op 7 3 1 PRODUCESUPPORT itor ineo perenne tes er eie re ERE deu T 7 32 DHI TRAINING COURSES asernes erne 7 3 3 COMMENTS AND SUGGESTIONS cccsssssssssssssssssssssssssssssssssssssssssssssssssssususueusucacseuseeusueueusasueaseeaees 7 PART II MOUSE RDII USER MANUAL eevevonoooonovoooonoooenonooooononoooonenooneeneooeenoooeennnooeeeneroe enne 9 1 BACKGROUND v s dove 11 2 INPU Morocco 12 2 1 OVERVIEW OF THE INPUT DATA FILES
15. Part III MOUSE calibration tutorial Comprehensive calibration guide DHI Software 5 MOUSE RDII 6 DHI Software 3 1 3 2 3 3 MOUSE RDII USER SUPPORT Product Support If you have questions or problems concerning MOUSE please consult the documentation MOUSE User Guide as well as the Reference Manual first Secondly look in the Releasenote If you have access to the Internet you may also have a look at the MOUSE Home Page The MOUSE Home Page is located at http www dhisoftware com mouse If you cannot find the answer to your queries please contact your local agent In countries where no local agent is present you may contact DHI directly by mail phone fax or e mail DHI Agern All 11 DK 2970 Horsholm Denmark Phone 45 45 169 200 Telefax 45 45 169 292 e mail softwate dhi dk When you contact your local agent or DHI you should prepare the following information m The version number of MOUSE that you are using m The type of hardware you are using including available memory m The exact wording of any messages that appeared on the screen m A description of what happened and what you were doing when the problem occurred m A description of how you tried to solve the problem DHI Training Courses DHI software is often used to solve complex and complicated problems which requires a good perception of modelling techniques and the capabilities of the softwar
16. cation against independent data not affecting the choice of parameter values for the years 1979 1984 Evaluation of the model validity in this example was done through visual comparison of the hydrographs study of the accumulated difference and comparison between calculated and measured duration curve The obtained parameter values for this example are listed in Appendix I In the example related to the illustrations overflow occurs within the model area MOUSE RDII can not describe this kind of processes see Chapter 8 which complicates the choice of validation criteria see ref 5 DHI Software GENERAL DISCUSSION S Calculated flow Measured Flow PART OF THE CALIBRATION PERIOD 1986 89 ilis 10 00 700 600 400 300 25 00 20 00 15 00 5 00 0 00 Accumulated flow 500 difference As NEM m3 s 20 0 10 0 5 0 0 0 25 0 1 150 0 0 Duration curves for Calculated flow Measured flow 0 2 0 4 0 6 0 8 Relative duration 1 0 Figure 6 Calibration results for the catchment of Rya G teborg Sweden Evaluation through visual comparison of the hydrographs together with studies of the accumulated difference between the hydrographs and comparison between calculated and measured duration curve DHI Software 27 SS 28 MOUS
17. e Therefore DHI provides training courses in the use of our products A list of standard courses is offered to our clients ranging from introduction courses to courses for more advanced users The courses are advertised via DHI Software News and via DHI home page on the Internet http www dhi dk DHI can adapt training courses to very specific subjects and personal wishes DHI can also assist you in your effort to build models applying the MOUSE software If you have any questions regarding DHI training courses do not hesitate to contact us Comments and Suggestions Success in perception of the information presented in this document together with the user s general knowledge of urban sewer systems and experience in numerical modelling is DHI Software 7 MOUSE RDII essential for getting a maximum benefit from MOUSE RDII This implies that the quality of the documentation in terms of presentation style completeness and scientific and engineering competence constitutes an important aspect of the software product quality DHI will therefore appreciate any suggestion in that respect hoping that future edition will contribute to the improved overall quality of MOUSE RDII Please give your contribution via e mail fax or a letter 8 DHI Software PART II MOUSE RDII USER MANUAL DHI Software 9 MOUSE RDII 10 DHI Software Ss BACKGROUND When studying the real flow conditions in sewer systems
18. e The RDI model is a deterministic conceptual lumped type of model with moderate input data requirements see Figure 2 Spatial characterization of constitutive parts of the analyzed area is achieved through definition of sub catchments each of them described with a unique set of parameters This means that the model treats every sub catchment as one unit The parameters and variables therefore represent an average for the whole sub catchment MOUSE RDI calculates the total discharge runoff and infiltration within the catchment area This means that the hydraulic processes in the sewer system which affect the mass balance e g overflow ate not described and therefore this effect is not accounted for when the total discharge from the catchment is calculated Precipitation Evapo transpiration ot Te a RE Routing Snow Storagd Model A Time Area Model B Kinematic Wave Model C Linear Reservoir Fast Response Surface Storage Overland Flow Slow Response 8 i InterFlow Root suction Infiltration Unsaturated Zone Storage EN Routing Ground Water Capilary flux Recharge S d C Ground Water Storage ___ Slow Response Base Flow Figure 2 Schematics of the RDII Model DHI Software 13 MOUSE RDII 14 DHI Software 2 1 2 2 2 2 1 DATA INPUT Overview Of The Input Data Files For the calculation with
19. e time series in the boundary connection start at least for the maximum specified concentration time Tc earlier than the start time for the HOTSTART is specified This is required for the correct reconstruction of the surface runoff component FRC DHI Software Ss THE RDII RESULT FILES Two result files are generated by a MOUSE RDI calculation These are m CRF file containing maximally five time series for each sub catchment namely discharge calculated with the Surface Runoff Model the FRC component discharge calculated with the model the SRC component total discharge variation of water content in the surface storage for the Surface Runoff Model variation of water content in the snow storage for the Surface Runoff Model The CRF file is used as input data for a MOUSE Pipe calculation NOF file optional containing detailed information about the processes treated by a RDII model e g different flow components in the RDI model variation of water content in the different storage in the RDI model The NOF file is used for calibration of the SRC component In the CRF file the time series are saved with two various intervals the shorter one for the periods when the Surface Runoff Model is used and a larger one in the remaining periods In the two other result files the time series are saved with the larger time interval which is egual to the time step used for the RDII calculatio
20. e MOUSE Pipe Flow Model was used for describing the hydraulic processes e g overflow etc m3 s 35 0 t t BO Fa ae ka eee enr semi i MOUSE Total discharge a MOUSE RDII Excl FRC E enale tee aasa pe MOUSE RDII HD 200 pia Measured Flow E eo 19 7 20 7 21 7 21 7 1988 Figure 10 Comparison of measured discharge discharge calculated with MOUSE RDII and flow calculated with a combined MOUSE Pipe Flow Model for a heavy rainfall event where overflow occurs upstream from the measurement point A well calibrated MOUSE model can therefore be used for a rough estimation of overflow volume by studying the difference between calculated and measured discharge for heavy peak flows The credibility for such estimation is however strongly affected by the quality of measured precipitation and discharge time series DHI Software 37 MOUSE RDII 38 DHI Software Ss 9 NON PRECIPITATION DEPENDENT FLOW COMPONENTS MOUSE RDII calculates the precipitation dependent flow component Therefore both for calibration and validation other flow components should be treated outside MOUSE RDII Examples of non precipitation dependent flow components are foul flow and sea water leaking into the sewer system The foul flow is preferably estimated through daily values from produced water volumes weighted with yearly charged wa
21. e infiltration i e induces increase in the baseflow DHI Software 31 32 DHI Software Ss MOUSE RDII The measured flow peaks generally also contain the runoff from impervious areas Surface Runoff Model see Chapter 6 and comments about overflow under Chapter 8 15 adjusted against the response of the baseflow i e the build up and regression of the baseflow Adjustment against the built up of baseflow is done during and after wet periods with low evaporation Adjustment against regression is done during the start of dry periods with high evaporation preferably when baseflow is the only flow component An adjustment of CKgr does not influence the size of the discharged volume studied for a longer period but displaces the volumes in time CKor is adjusted against the response i e the shape of the peak flows This is done during periods with heavy rainfall preferably after a wet period The measured flow peaks generally also contain the runoff from impervious areas Surface Runoff Model see Chapter 6 and comments about overflow under Chapter 8 A reduction of Umax reduces the actual evapo transpiration the process responsible for reduced discharges during period with high potential evaporation The effect of reducing Umax will be largest for periods preceded by a wet period Additionally an increased overland flow is obtained as well as more water transported to the groundwater storage resulting in an delayed ef
22. ecipitation data of worse quality is used a less accurate calibration result must be accepted In this case it may be preferable to recall the purpose of the actual model application and concentrate on calibrating yearly volumes flow peaks ot base flows depending on what kind of analysis is to be performed with the model It must be remembered that MOUSE calculates the precipitation dependent flow component When comparing with measured discharge data the total measured discharge therefore has to be reduced with the flow components not being precipitation dependent e g foul flow see Chapter 5 below MOUSE calculates the total generated discharge from a catchment i e overflow within the sub catchment will also be included in the calculated discharge Therefore when comparing with measured peak flows and controlling the water balance total volume this has to be taken into consideration see Chapter 8 In principle the model validation is concerned about comparison of the computed and measured hydrographs As there are almost an infinite number of possibilities to describe level of agreement between two hydrographs it is recommended to establish some validation criteria i e a measure for accuracy of the model relevant for current application There are several types of criteria such as numeric criteria based on single values e g peak discharge volume etc or more complex numeric criteria based on statistical analysis of
23. ence of a rainfall The FRC component consists of the inflow to the sewer system and the fast flow component of the infiltration not dependent on previous hydrological conditions On the other hand characteristic of the SRC component is that it is highly dependent on the previous hydrological conditions and usually responses slowly to a rainfall The SRC component consists of the rest of the precipitation induced infiltration and dry weather infiltration inflow When performing a numerical simulation of flows in sewer systems based on a traditional approach it is difficult to describe the effects of the SRC component These effects can however be of a great importance especially when analyzing volumes e g simulation of the total inflow to the wastewater treatment plant and overflow volumes Figure 1 shows an example illustrating the influence of previous hydrological conditions for the two components and their response to a rainfall DHI Software 11 Ss MOUSE RDII 12 0 4 00 15 Rain 1 LOW SOIL MOISTURE CONTENT DRY SEASON E 30 3 00 45 5 E 5 60 H Rain 1 Rain 2 2 8 2 00 FRC 1 FRC 2 75 SRC 1 SRC 2 90 1 00 105 120 0 00 FOULFLOW 135 01 01 99 00 00 01 01 99 12 00 02 01 99 00 00 02 01 99 12 00 03 01 99 00 00 m 0 4 00 15 Rain 2 HIGH SOIL MOISTURE CONTENT WET SEASON ao 3 00 45 60 Flow m3 s
24. es can be estimated from the time of filling the root zone storage when each flow component starts discharging GENERAL HYDROLOGICAL MODEL RDII The threshold values have no effect during periods when the root zone storage is full L Lmax An increased threshold value reduces the discharge during dry periods and in the beginning of wet periods i e periods with low relative water content in the root zone storage Tc is adjusted during periods with heavy filling of the root zone storage preferably in combination with low potential evaporation and preceded by a dry period Tcis therefore an important parameter for adjusting the increase of the groundwater level in the beginning of wet periods Toris adjusted after a dry petiod at events with heavy filling of the root zone storage For example adjustment can be done for events where even larger rainfall volumes does not generate overland flow Tiris adjusted after a dry period when filling of the root zone storage preferably in combination with low potential evaporation However Tiris one of the less important parameters 9 The degree day coefficient can be estimated from analysis of the relation between temperature water content in the snow storage and measured discharge When temperature is below zero the precipitation is stored in the snow storage When temperature is above zero the content in the snow storage is emptied into the surface storage where the
25. fect of increased baseflow because of the long response time of baseflow An important behavior of the RDII model is that the surface storage must be filled up before overland flow and infiltration respectively occur Therefore during dry periods with high potential evaporation Umaxcan be estimated from how much rainfall is required for filling up the surface storage i e generating overland flow The same methodology can also be used for the periods with low potential evaporation but only if the rain event is preceded by a long dry period CKir is adjusted against the response of interflow during periods with low potential evaporation A reduction of CKrr will result in a small increase in volume during these periods The relative water content in the unsaturated zone i e root zone L Lmax controls several of the different water transports in the RDII model Since the storage capacity a influences the velocity of the filling of L towards Lmax Emax is adjusted during periods of heavy filling of the root zone storage This usually occurs during periods with low potential evaporation preferably in combination with a wet period A reduction of Lmax increases the discharge but it may decrease a little during period with very high potential evaporation The threshold values indicate at which relative water content in the root zone L Lmax overland flow interflow and baseflow respectively will be generated Therefore the threshold valu
26. flow peaks during rain events are often found to exceed the values that can be attributed to the contribution from participating impervious areas This is a consequence of the phenomenon usually named Rainfall Induced Infiltration This differs from the Rainfall Induced Inflow by the fact that it does not depend only on the actual precipitation but is heavily affected by the actual hydrological situation i e the memory from earlier hydrological events For a certain rainfall event the increase in flow will therefore differ depending on hydrological events during the previous period The Rainfall Induced Infiltration is also distinguished by a slow flow response which takes place during several days after the rainfall event From a hydrological point of view parts of the infiltration behave in the same way as the inflow Therefore classification of total hydrological loads to infiltration and inflow is not suitable for modeling approach Rather to describe appropriately the constitutive components of flow hydrographs distinguished by their hydrological behavior the following concept is used instead FRC Fast Response Component comprises the rain induced inflow and fast infiltration component SRC Slow Response Component comprises slow infiltration component Distinctive for the FRC component is that it is not influenced by the previous hydrological situation i e high or low soil moisture content It occurs as a direct consequ
27. he hydrologic cycle providing support for urban rural and mixed catchments analyses Precipitation is routed through four different types of storage snow surface unsaturated zone root zone and ground water This enables continuous modelling of the runoff processes which is particularly useful when long term hydraulic and pollution load effects are analysed Instead of performing hydrological load analysis of the sewer system only for short periods of high intensity rainstorms a continuous long term analysis is applied to look at periods of both wet and dry weather as well as inflows and infiltration to the sewer network This provides a more accurate picture of actual loads on treatment plants and combined sewer overflows Further enhancements of groundwater sewer interactions are possible by implicit linking of the MOUSE Pipe model with DHPs distributed groundwater model MIKE SHE MOUSE is particularly useful when used with MOUSE LTS a specially developed modelling tool for long term network simulations and result statistics Software Implementation MOUSE is an add on module to MOUSE HD Pipe Flow Model The MOUSE capabilities can be accessed i e continuous hydrology simulations can be executed only after the MOUSE license has been extended to include MOUSE RDII MOUSE utilizes the standard MOUSE Menu System with on line HELP facility which has been extended to accommodate some specific actions related t
28. ibed in MOUSE User Guide Activation of the RDI component and definition of the RDI parameters DHI Software 15 gt MOUSE RDII 2 2 2 2151 Fast Query lose Catch ID Location Help Catch ID 520 11 Insert Location 520 E Selection cse Area 20 000 ha Load Inhabitants 300 PE Xeoo 345 000 Im SaveAs Add Flow 0 000 13 5 Yeoor 594000 Im Model Model B Model C UHM Impervious area 35 00 2 Parameter set DEFAU LT Use individual data Time of Concentration F min Initial Loss 0006 Reduction Factor 90 Time Area Curve No fi Time Area ADI RDIset DEFAULT Area 550 pa Errors B41520 1 1 B4 1520 B4 1500 2 2 B4 1500 lt Selected B4 1501_3_3 B4 1501 ES B4 1502 4 4 B4 1502 B4 1491 5 5 4 1491 Select List gt Figure 3 The Catchments data dialog with RDI section in the lower part Definition of the RDI data The RDII computation for a certain catchment is activated by checking the RDI checkbox on the Catchments Catchments dialog The essential additional information is the extension of the RDI area as percent of the total catchment area and the selection of the RDI parameter set If the RDI area is specified as 0 the resulting RDI flow will be equal to zero i e the simulated flow will be equivalent to the surface runoff alone If the fie
29. ld were left empty the system would issue a warning error A RDI parameter set contains all RDI model parameters and initial conditions MOUSE comes with the Default set which can be edited to fit the specific needs Furthermore an unlimited number of RDI parameter sets can be specified and associated with individual catchments within the model setup so that differences in hydrological characteristics catchment response time initial water contents etc can be accounted for RDI parameter sets can be edited under the Menu option Catchments RDI Data 16 DHI Software DATA INPUT 2 2 3 E RDI Set Name r Fast Query RDI Set N Close DEFAULT tan s Help t aa RDI Set Name eae Insert Surface Storage Umax fi 0 000 mm Time Constant CK 20 000 hr Root Storage Lmax 00 000 mm Interflow CKIF 500 000 hr Overland Coefficient CO of 0 300 TC Baseflow 2000 000 hr Groundwater Coeff Carea 00 Snowmelt Snowmelt coefficient mm C day IV Evaporation Threshold Parameters Overland Tof 0 000 4 Interflow Tif 0 000 d Groundwater Tg 0 000 4 Groundwater Parameters Max gw depth causin Specific yield Sy basefiow GWLBIO 1000 m in i 0 00 gw depth for unit 0 00 Min gw depth GWLmin 4 flux m Initial Conditions Surface Storage U 0 000 mm OverLand Flow OF 0 000 mm h
30. n The result files can be presented in MIKE View as any other MOUSE result files DHI Software 21 MOUSE RDII 22 DHI Software PART III MOUSE RDII VALIDATION DHI Software 23 MOUSE RDII 24 DHI Software Ss GENERAL DISCUSSION Some of the parameters in MOUSE RDII here meaning both for the rain dependent inflow and the infiltration part are related to actual physical data However the final choice of parameter values must be based upon a comparison with historical measured discharges since a number of the parameters have an empirical character The available period of the measured discharge data and its resolution in time are of major importance for the credibility of the obtained parameter values Ideally for a good accuracy a 3 5 years long time series of measured discharge data with daily values is required for the calibration of the RDH parameters see ref 4 Several months long time series with higher resolution i e minutes or hours depending on the size of the area are needed for the calibration of the surface runoff model Measured time series with shorter duration are also useful although not securing optimal parameter values see ref 4 In such case it is important that the time series represents different hydrological situations i e typical wet period or dry period An exact correspondence between simulations and measurements can however not be expected and for areas where pr
31. nse of the discharge e g te and TArype fot model A M Land S for model B a very high resolution in time is usually required minutes to hours DHI Software 29 MOUSE RDII 30 DHI Software Ss GENERAL HYDROLOGICAL MODEL RDII It is not possible to determine the RDII parameters from geophysical measurements since most of the parameters are of empirical nature It is therefore necessary that measured discharge from the studied area is available so that the RDI parameters can be determined by comparison between simulated and measured discharge through the calibration procedure The introductory calibration is performed visually by comparing simulated and measured discharge The final optimization of the parameters is thereafter performed preferably using different numeric and graphical criteria see above and ref 6 The effects of changing each particular parameter are discussed below Also the most suitable hydrological periods for calibrating certain parameters are identified which implies that a certain parameter affects the model behavior more during periods with specific hydrological conditions Usually effects will also be obtained during other periods why these should also be studied when adjusting a parameter The parameters are discussed in the preferable order of adjustment However it may be necessary to return to the previous calibration step as well as repeating the whole process several times It i
32. o MOUSE This implies that the MOUSE on line HELP system and documentation related to the standard versions of MOUSE ate essential as a support for work with this module ref 1 DHI Software 3 DHI Software 4 Ss ABOUT MOUSE RDII USER MANUAL This manual provides information related to the principles and techniques for the preparation and execution of continuous hydrological simulations in urban rural and mixed catchments It is assumed throughout this manual that the user is well acquainted with the standard MOUSE system Fundamental knowledge of hydrology also facilitates the successful use of MOUSE RDII The User Manual contains a detailed information for usage of the MOUSE specific instructions for input of the required data and calculation Additionally this general part is supported with description of the calibration process which is probably of essential interest of all users The information concerning fundamental principles and methods which form the frame of the MOUSE RDII concept is accessible in the associated MOUSE Reference Manual Usage of the standard MOUSE and its other add on modules is described in respective user manuals amp tutorials This manual is divided in three units Part I Introduction Some general information about MOUSE and about this document Part II MOUSE User Manual Basic information about MOUSE RDII simulation principles and technigues n
33. r Lower Zone Moisture L 0 000 mm Interflow IF 0 000 mm h Show gt GroundWater Depth GWL 0 000 m Select List Figure 4 RDI Parameter Set dialog A detailed description and significance of various RDI parameters is provided in MOUSE Technical Reference Evapo transpiration and snowmelt are also applied in the surface runoff computations Since the control of these processes is possible only through the RDI parameter sets this means that they can only be activated if MOUSE is installed Boundary Data Time Series Time series of boundary data for MOUSE RDII are stored to and manipulated by the same database system as any other time series data in MOUSE This implies that all standard MOUSE facilities for the data input and presentation are at the user s disposal The required time series for an simulation are precipitation m s temperature Deg C and potential evapo transpiration mm hour As to avoid significant errors it is important to consider the way in which the model interprets the data stored in the time series database i e how the values for intermediate times are determined For rain intensities and potential evapo transpiration the model assumes a constant value since the last entered value For other types of data the model interpolates linearly between the two neighboring values DHI Software 17 MOUSE RDII 18 DHI Software 3 3 1
34. s in the surface and root zone storage controls many of the other processes they should be studied continuously throughout the calibration procedure Figure 9 shows an example of the variation of water content in the surface storage toot zone storage and groundwater storage The example comes from the DHI Software 33 34 Ss MOUSE RDII catchment of Rya treatment plant G teborg Sweden It appears that the root zone storage is emptied only during the summer period because the evaporation during the rest of the year is almost non existent Discharge from the groundwater storage exists continuously all year around Drawing of the surface storage is faster during summer period since the evaporation is high and is therefore the dominating effect on the surface storage During periods with low evaporation drawing of the surface storage is controlled by the given time constant for interflow CKrr The example also shows that filling of the root zone and groundwater storage only occurs when the surface storage is completely filled i e when precipitation has filled up the surface storage A larger surface storage i e a larger Umax will therefore imply that this happens more rarely and at a smaller extent allowing a larger part of the precipitation to evaporate A smaller root zone storage i e a smaller Lmax would have led to an increased relative variation in the storage Furthermore the actual evaporation will decrease in case of smaller
35. s recommended especially for less experienced users that only one parameter is changed at a time i e for each calculation so that the effect of the adjustment will appear clearly Sometimes however the effect of changing one parameter is not sufficient Then several parameters controlling similar phenomena can be adjusted together In some other cases undesired secondary effects can be obtained when adjusting certain model parameter These effects can often be eliminated by simultaneously adjusting other parameters which do not influence the desired effects but reduce secondary effects induced by the first parameter The following sequence of action is recommended 1 The first step in the RDII calibration is usually to adjust the water balance in the system i e the accuracy between the calculated and measured total volume during the observed period This is done by correcting the proportion of area Asrc An increase of proportionally increases every flow component at each time step The total volume generally also contains the runoff from impervious areas Surface Runoff Model see Chapter 6 and comments about overflow under Chapter 8 2 Next the overland flow coefficient CQoris adjusted to obtain a correct distribution of volume between overland flow peak flows and baseflow This is done after wet periods and preferably for a period with low evaporation A reduction of CQorreduces the overland flow and increases th
36. ter volumes This will however only give a rough estimation why departure from this methodology may be necessary e g for areas where a large amount of freshwater is used for irrigation The amount of leaking sea water is preferably estimated through an iterative procedure between MOUSE RDII calculation and studies of the difference between the calculated and measured discharge Only a rough estimation can be achieved why less accurate calibration results may have to be accepted Specially during the calibration procedure it is very important that non hydrological errors generally are kept at the lowest level possible in the flow series used Otherwise there is a risk of hydrological interpretations of these errors the error transmitting in the model and increasing when simulating extreme hydrological situations A typical example is a rough resolution in time for the foul flow component The method described above should give a description sufficiently correct for most cases DHI Software 39 MOUSE RDII 40 DHI Software REFERENCES 1 3 4 5 6 T 8 DHI 2000 MOUSE User Manual and Tutorial Version 2000 DHI Horsholm Denmark DHI 1992 NAM User Manual and Reference Manual DHI Horsholm Denmark Eriksson B 1983 Data concerning the precipitation climate of Sweden Mean values for the period 1951 80 Rapport 1983 28 SMHI Norrk ping Sweden in Swedish Gustafsson A M
37. values were used EXAMPLE 1 Catchment area Rya treatment plant G teborg Sweden Aurb 212 0 km2 Afrc 10 4 5 Asrc 51 7 5 Surface runoff model RDI model Umax 0 6 mm Umax 5 0 mm Lmax 180 0 mm CKof 7 0 hours CQof 0 35 Csnow 5 0 mm C day CKof 18 0 hours CKif 150 0 hours CKbf 2000 0 hours Tof 15 0 of Lmax Tif 0 0 5 of Lmax Tg 0 0 of Lmax Csnow 3 0 mm C day DHI Software 43 Ss MOUSE RDII EXAMPLE 2 Catchment area Kalmar treatment plant Sweden Aurb 33 0 km2 Afrc 3 0 5 Asrc 23 0 5 Surface runoff model RDI model Umax 0 6 mm Umax 10 0 mm Lmax 150 0 mm CKof 1 5 hours CQof 0 05 Csnow 2 5 mm C day CKof 10 0 hours CKif 400 0 hours CKbf 800 0 hours Tof 27 0 of Lmax Tif 63 0 of Lmax Tg 23 0 of Lmax Csnow 2 5 mm C day 44 DHI Software APPENDIX 1 Ss EXAMPLE 3 Catchment area Halmstad treatment plant Sweden Aurb 26 0 km2 Afrc 7 7 5 Asrc 46 0 5 Surface runoff model RDI model Umax 0 6 mm Umax 5 0 mm Lmax200 0 mm CKof 1 5 hours CQof 0 10 Csnow mm C day CKof 30 0 hours Ckif 500 0 hours CKbf 2500 0 hours Tof 40 0 of Lmax Tif 20 0 of Lmax Tg 20 0 of Lmax Csnow mm C day DHI Software 45 S MOUSE RDII EXAMPLE 4 Catchment area Trollh ttan treatment plant Sweden Aurb 22 0 km2 Afrc 15 0 5 Asrc 77 0 5 Surface runoff model RDI model Umax 0 6 mm Umax 5 0 mm Lmax 200 0 mm CKof 6 0 hours Coof 0 45 Csnow 3 0 mm C day CKof 20 0 hours CKif

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