Hydro Europe 2016 Team L Influence of the various model parameters (Hec HMS + Mike SHE) 1

2 I.Brief softwares presentation II.Hec HMS 1.Model 2.Parameters 3.Results III.Mike SHE 1.Model 2.Parameters 3.Results IV.Conclusion Summary:

3 I.Brief softwares presentation Hec HMS: Lumped model Based on various model Free software Mike SHE: Distributed model Based on Saint Venant equation Paid software

4 II. Hec HMS A.Model Kinematic waves SCS Unit Hydrograph Tc, Tlag CN SCS Curve Number 3 2

5 B. Parameters Curve Number - % of imperviousness - Manning’s n Model calibration: Volume error < 5%- Peak error < 1,5% - Tpeak error = 30 min

6 C. Results CN increases Peak discharge becomes higher Percentage of completely impervious area increases the discharge peak becomes higher A certain percentage of variation in the CN doubles the relative error in the output, while the same variation in the percentage of impervious area only deviates a quarter in the peak discharge.

7 Manning roughness does not influence significantly the peak discharge. But, when decreasing the roughness, the peak discharge increases and appears earlier.

8 III. Mike SHE A. Model Basic model setup used in the tutorial  75 x 75 m grid  Rainfall data from the flood event  04/11/ :00 until 06/11/ :00  Only Overland Flow and Rivers and Lakes Modules used Focus on parameters with physical meaning  Computational parameters unchanged  Ignored parameters considered negligible for the flood event or without enough data to investigate (in the modules Evapotranspiration, Unsaturated Flow, Saturated Flow)

9 NRFIWD DS Manning

10 B. Parameters Net Rainfall Fraction:  Fraction of rainfall available for infiltration and overland flow  Reference model: constant value of 0.9 in the entire domain Manning (Strickler) value:  Reference values from landuse file given in the tutorial Detention Storage:  Used to limit the amount of water that can flow over the ground surface  Reference value 0 Initial Water Depth:  Typically 0m  If a non-zero initial condition is prescribed, water will flow into the model as long as the internal water level is lower than the set value (the boundary will act as a source of water)

11 C. Results NRF:

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14 Detention Storage:

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17 Conclusion As steeper the curve, the parameter has more influence in the HEC HMS model. Hec HMS:

18 Mike SHE: No linear dependence among parameters. Most influential: Net Rainfall Fraction and Strickler on River Bed

19 Thank you for listening !