Summer School 2005 Rainfall Runoff Model KALYPSO-NA Exercise 3. Longterm Calibration

Transcription

1 Summer School 2005 Rainfall Runoff Model KALYPSO-NA Exercise 3 Longterm Calibration Montenegro, September 2005

2 In this exercise the long lasting processes of the hydrological cycle shall be calibrated with measured discharge data. Proceeding Import the model from the server into Kalypso user interface. This model is already calibrated. Only some parameters, which are responsible for the longterm processes, are wrong. Your task for this exercise is the calibration of this parameters within the given range. Table 1: Parameter range parameter range for the exercise model parameter description table label min max RetGw [h] Retentionconstant groundwater k QGw RetBas [h] Retentionconstant baseflow k Qbasis PorsGW [-] Porosity groundwater Porosity GW hgo [m] hgu [m] Thickness of the aquifer from the bottom of the aquifer up to the highest point of the river in a subcatchment max h GW 6 15 Thickness of the aquifer from the bottom of the aquifer up to the lowest point of the river in a subcatchment min h GW 2 10 The timestep for the simulation is 24 hours (1440 minutes), the simulation period lasts from to Calibrate the model for the gauging station Tungendorf (it is node 1906). 1

3 How to calibrate: Figure 1: Parameter interaction Run the model with the given wrong parameters and visualise the results and the time series of the gauge. In which respect do both hydrographs not match? If you don t have enough baseflow, check the result files of the groundwater for some subcatchments which are important for the discharge at gauging station Tungendorf. 1) baseflow: Do you have baseflow in any catchment? 2) Groundwaterlevel: Are the levels below or above hgu? If the groundwater levels are below hgu, think about which parameter could be responsible for that. Hints: What will happen, if you reduce/enhance the retention constant of the groundwater. What will happen, if you reduce/enhance the porosity of the groundwater? Carry out changes of the parameters and calculate again. This process can require some trials. If you managed to have baseflow at all, check the dynamic of the baseflow, by comparing the lower parts of the measured and the simulated hydrograph. Another possibility is to check the dynamic of the groundwater levels for each subcatchment. Does the dynamic not match, change the retention constants of groundwater and baseflow. Carry out changes of the parameters and calculate again. This process again can require some trials. 2

4 Workflow 1) Start Kalypso (doubleclick the link on the desktop). Import the existing projekt / model from the server. Make a new calculation case. 2) Have a look at the parameters in the table Subcatchments.gtt (Calculations\ \Tables\Model). Here you can change the parameters that are described above. If the parameters are not available in the table you can add them from the list you get by a right mouse click in the table. If you change the values it is important to save your changes! 3) Run the calculation a. Mark the calculation folder. b. Run the calculation (Menu Calculation Case -> run calculation(s)) c. Choose the calculation case you want to calculate. 4) Have a look at the results You can find the results in the folder Calculations\ \Ergebnisse Output Timeseries Description Abfluss_Node_xy.zml Discharge at one Node qgg Discharge of a catchment qbs Baseflow of a catchment qgw Groundwater Discharge of a catchment gws Groundwater table in a catchment 5) Open the results in a diagram view You can open all the results (*.zml) by doubleklick on it. With drag and drop you add more timeseries to the diagram view. The measured timeseries of the gauging station is in the folder Calculations\ \Pegel\Pegel_Tungendorft.zml. With this information you are able to check your calibration at the node Tungendorf (1906). 6) Open the results in the special grafik tool a. Open all timeseries which interests you to the diagram view (max. 10). b. Open the GraficTool (GraficToolButton in the Menubar). 3

5 Translation Pegel Gauging station Niederschlag Precipitation Klima Climate Ergebnisse Result Berechnet Calculated Abfluss Discharge 4