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Team 10 Presentation Vol. II 18th February 2011 Sophia Antipolis, France. Improvement by calibration or with geometry?. Introduction. Hydrological Analysis Spatial rainfall distribution Relation between rain gauges HEC-HMS Model Setup - Methods and Parameters Output HEC-RAS Setup
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Team 10 Presentation Vol. II 18th February 2011 Sophia Antipolis, France Improvement by calibration or with geometry?
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
Hydrological Analysis • Thiessen Polygon • Why no interpolation?
Hydrological Analysis • Thiessen Polygon • Table: partial contribution of gages on the subcatchments • Strongest influence St. Martin Vesubie • Smallest influence Roquesteron
Hydrological Analysis • Correlation between the stations • A strong correlation between the ones that are close to each other
Hydrological Analysis • Correlation of Rainfall and Elevation • Weak correlation distance between rain gauges, rainfall caused by frontal depression
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
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
River Network of Lower Var :Q Total Length : Approx. 24 Km Branches: 10 Weirs : 9 X-sec: 120 :WL
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
MIKE SHE • Setup and parameters • Strickler coefficient • Extreme values • Net effective rainfall • What is the effect of changing these values on the hydrograph?
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
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
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
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
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)
References Guinot, V. and Gourbesville, P. (2003). Calibration of physically based models: back to basics?Journal of Hydroinformatics, 5(4): 233-244