Team 10 Presentation Vol. II 18th February 2011 Sophia Antipolis, France

1. Team 10 Presentation Vol. II 18th February 2011 Sophia Antipolis, France Improvement by calibration or with geometry?

2. Introduction • Hydrological Analysis • Spatial rainfall distribution • Relation between rain gauges • HEC-HMS • Model Setup - Methods and Parameters • Output • HEC-RAS • Setup • MIKE 11 • Setup • MIKE SHE • Setup and Parameters • Calibration • Geometry

3. Hydrological Analysis • Thiessen Polygon • Why no interpolation?

4. Hydrological Analysis • Thiessen Polygon • Table: partial contribution of gages on the subcatchments • Strongest influence  St. Martin Vesubie • Smallest influence  Roquesteron

5. Hydrological Analysis

6. Hydrological Analysis • Correlation between the stations • A strong correlation between the ones that are close to each other

7. Hydrological Analysis • Correlation of Rainfall and Elevation • Weak correlation  distance between rain gauges, rainfall caused by frontal depression

8. Hydrological Analysis – HEC HMS Model

9. HEC HMS SETUP Lumped Model Setup – Finished Distributed Model setup – Not Ready Jet (Difficult Grid Generation) Lumped (Semi-distributed)  • Transformation Method: Clark UH • Simple, Fast, Risky! • Loss Method: SCS Curve Number • Good Approximations, Simple, Risky too! • Routing: Muskingum • Event, Lumped, Empirical • Baseflowmodel: Constant Monthly • Averaged time series data

10. Parameter Setup

11. Sensitivity

12. Sensitivity

13. HEC RAS • Goal : comparison with Mike11 data obtained. • Realized : • Install network • Create cross-sections • Integrate Hydrological results • Problems met: • To run the unsteady simulation • To install the weirs 02/18/2011 13

14. River Network of Lower Var :Q Total Length : Approx. 24 Km Branches: 10 Weirs : 9 X-sec: 120 :WL

15. Model Inputs • Network • X-section • Weir formula: Weir formula 2 (Honma) • Hydrodynamic Parameter • Resistance : roughnesscoefficient • Initial Condition : • Water Depth (1m) and • Discharge (10 cumec) • Boundary Condition: • Upstream Bnd: Q from hydrological analysis • Downstream: WL • Simulation Mode: Unsteady • Simulation Period: 05/11/1994 to 6/11/1994

16. Model Output: Maximum Longitudinal Water Profile

17. MIKE SHE • Setup and parameters • Strickler coefficient • Extreme values • Net effective rainfall • What is the effect of changing these values on the hydrograph?

18. MIKE SHE – Strickler coeffieient • Strickler coeffieient – numerical representation of the catchment and river bed roughness • Extreme values of Strickler coeffieient used • 10 – flood plain covered in trees • 60 – tarmac

19. MIKE SHE – Net Effective Rainfall • Proportion of rainfall that forms runoff • Losses due to infiltration • Reduction in hydrograph peaks with decreasing net effective rainfall • Less runoff volume represented by the area under the hydrograph • 0.9 is a suitable value due to antecedent catchment conditions

20. MIKE SHE – Parameter Calibration • Parameters make little difference to the simulation. • In this case calibration is not required and can be detrimental to the model results

21. ...and the geometry

22. Grid resolution 1000m grid – 2 820 data points 600m grid – 7833 data points 300m grid – 31 333 data points 75m grid – 50 133 321 data points

23. Event of 5 November 1994 modelled using a DEM with a resolution of 300 m for a river geometry based on 300 m (Model 300a) and 75 m (Model 300d) DEM resolutions. The time is counted from 0000 hours on 5 November 1994. (Guinot, V. And Gourbesville P. 2003)

24. Resolution is important!!!

25. Thank You For Your Attention

26. References Guinot, V. and Gourbesville, P. (2003). Calibration of physically based models: back to basics?Journal of Hydroinformatics, 5(4): 233-244