HydroEurope Final Presentation Pranav DHAWAN, Wooseok JANG, Kalpesh MALANI, Pablo SANCHEZ HERNANDEZ Clément LUCAS, Anna MSIGWA, Hakim OUERTANI, Malo LAMBERT 1

Table of Contents 1.Project Overview 2.MIKE 11 3.HEC-RAS 4.IBER 5.IBER - Effect of New Roads 6.Conclusion 7.Evaluation of urban flood resilience 8.Results City Scale 9.Conclusion and Recommendation 2

Project Overview Hydraulic Modelling Software used: This week’s question 1.Modeling of structures (weir formulas, comparison with recorded values) 2.Effects of reduction of channel width by new road (50 m & same as levees elevation) 3 2-D Models 1. Iber 1-D Models 1. MIKE HEC-RAS VS Input Data: ●Flood event of 1994 Validation Data: ●Measured maximum levels at weirs

MIKE 11 Weir Formula - Discharge through the structure can be modelled Q = discharge through structure W = Width C1 = first weir coefficient Hus = upstream water level Hds = downstream water level Hw = is weir level is the second weir coefficient 4 Villemonte Formula Honma’s Formula

MIKE 11 5 C 1 ≈ Weir 10Weir 8Weir 4 Water level 3.96 m3.39 m 1.09 m

MIKE 11 6

Effects of New Roads MIKE 11 7

HEC-RAS Input data - 62 cross sections  8 weirs  Manning's coefficient : RB = LB = 0.06  MC = 0.03  Simulation time : 4 November 1994, 12 : 00 to 7 November 1994, 00 : 00 Weir Formula  C = Weir Flow coefficient - L = Length of the spillway crest - H = Upstream Energy Head above the spillway crest 8

HEC-RAS 9

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HEC-RAS 11

IBER Weir Formula -Discharge through the structure can be modelled -In that case it has been directly implemented in the mesh 12

IBER - Effects of New Roads 13 IBER permit the simulation of free surface flow in natural and artificial channels by the resolution of 2D Shallow Water Equations Inputs: -Manning coefficients (0.03, 0.04 and 0.02) -Cell size discretization: (10m, 75m and 300m) -Initial condition: 0.3 in the river bed -Inflow: 04/11/ : /11/ :00 -Weirs and road implemented directly on the mesh

IBER - Effects of New Roads 14 Results: No road Road

IBER - Effects of New Roads 15 Level Time

IBER - Effects of New Roads 16 No roadRoad

IBER - Effects of New Roads 17 Points to consider: ●The coarse cell size of the DEM and the mesh does not permit the properly representation of structures (weirs, roads,...) ○The resolution of the dem and mesh size should be at least the same or smaller than the dimension of the structures. ●There is insufficient data for the calibration of the 2D model ○Example: extent of the flood area, time-series of water level/discharge in several point of the domain,...)

Weirs 1D : - Easy to calibrate - Several possibilities of formulas - Time of the simulation quick 2D : - Difficulties to calibrate (need accurate data) - Not many possibilities to represent the weirs - Time of simulation very long Better to use 1D 18 Conclusions Road 1D : Time consuming in changing all the cross section 2D : Easier to select a bigger area and increase it Better to use 2D, still need accurate data Effect of the road : Difficulties to make an accurate analysis but first impression with our model is that it could have a huge impact on the possible flooding

Evaluation of urban flood resilience ●Introduction - Flood resilience index (FRI) represent level of flood resilience assessment in analysing area and for certain flood characteristic ●Methodology - Parcel scale - City scale ●Results 19

Evaluation of urban flood resilience 20 FRI map and Urban Functions on part of Nice city

Results City Scale 21

Conclusion and Recommendation 22 ● The assessment shows that the city of Nice is aware of the flood and motivated to address it. However, capacity building of human resources remains limited. Interventions are more numerous and long term. Development and implementation of solutions. Recommendation -Traditionally, flood education only focus on raising awareness. It should also focus on how to improve the response knowledge of the public.

Thank you for your attention