DISTRIBUTED RAINFALL RUNOFF e-mail : todini@geomin.unibo.it MODELS APPLIED TO THE DARGLE Prof. Eng. Ezio TODINI e-mail : todini@geomin.unibo.it

DISTRIBUTED RAINFALL-RUNOFF MODELLING Rainfall Runoff Models Black Box M. Semi Distributed M. Distributed M. Advantages of Distributed Models Physical meaning of model parameters Distributed representation of phenomena Limited calibration requirements Possibility of internal analysis

Model 1: AFFDEF Main model characteristics: Mass Balance in each cell Main model characteristics: Modified CN for estimating infiltration Radiation method for evapotranspiration Muskingum-Cunge for ovrland and channel flow

Main model characteristics Vertical lumping of hydraulic conductivity Model 2: TOPKAPI Main model characteristics Vertical lumping of hydraulic conductivity Dunne infiltration Soil horizontal flow, overland and channel flows represented using a kinematic equation Horizontal lumping of kinematic equations Model for the single cell

TOPKAPI Distributed approach The model for the single cell SOIL COMPONENT mass conservation moment conservation ODE

TOPKAPI Distributed approach The model for the single cell SURFACE COMPONENT mass conservation moment conservation … ODE

TOPKAPI Distributed approach The model for the single cell CHANNEL COMPONENT mass conservation moment conservation … ODE

TOPKAPI Distributed approach Parameters

Model 3: MIKE SHE Main model characteristics: 1D Richards equations for unsaturated zone 3D Boussinesq equation for greoundwater Parabolic approximation for overland flow

Case study The Dargle Republic of Eireland County of Wicklow

Elevation from 20 m to 713 m a.s.l. Sandy and sandy loam for about Case study - Surface Area circa 122 km2 Elevation from 20 m to 713 m a.s.l. Sandy and sandy loam for about 1.5 m

Saturation mechanism Dunne Horton The “unrealistic” profile used in MIKE SHE to meet the observations

Results: AFFDEF Efficiency Coefficients Variance of obs. = 17.85 Variance of errors= 6.97 Nash Sutcliffe= 0.59 Explained Variance= 0.61 Coefficient of correlation =0.91 Volume Control = 0.74 Willmott= 0.93 Efficiency Coefficients

Uniform value for curve number: 20 Risults: AFFDEF 5 [Km2 ] Areal threshold Average computer time = 5 min Saturated Hydraulic Conductivity 0.01 [ms-1] Variance of obs. = 17.85 Variance of errors= 6.97 Nash Sutcliffe= 0.59 Explained Variance= 0.61 Coefficient of correlation =0.91 Volume Control = 0.74 Willmott= 0.93 Efficiency Coefficients Infiltration Res. Const 4320000[s] Infiltration constant 0.7 Infiltration Capacity 0.1 Uniform value for curve number: 20

Results: TOPKAPI Efficiency Coefficients Variance of obs. = 17.85 Variance of errors= 4.01 Nash Sutcliffe= 0.77 Explained Variance= 0.77 Coefficient of correlation =0.91 Volume Control = 0.90 Willmott= 0.95 Efficiency Coefficients

Results: TOPKAPI Average comp. time = 5 min Permeability [m3s-1] θS θR α L [m] Soil Type 9.1E-04 0.453 0.041 2.5 0.9 Sandy Loam 0.7 3.1E-05 1.5 0.463 0.020 1.0 Loam 4.1E-05 Average comp. time = 5 min Variance of obs. = 17.85 Variance of errors= 4.01 Nash Sutcliffe= 0.77 Explained Variance= 0.77 Coefficient of correlation =0.91 Volume Control = 0.90 Willmott= 0.95 Efficiency Coefficients

Results: MIKE SHE Efficiency Coefficients Variance of obs. = 17.85 Variance of errors= 8.32 Nash Sutcliffe= 0.52 Explained Variance= 0.54 Coefficient of correlation =0.85 Volume Control = 0.80 Willmott= 0.90 Efficiency Coefficients

Results: MIKE SHE Average computer time = 2.5 h Variance of obs. = 17.85 Variance of errors= 8.32 Nash Sutcliffe= 0.52 Explained Variance= 0.54 Coefficient of correlation =0.85 Volume Control = 0.80 Willmott= 0.90 Efficiency Coefficients Thickness of soil layer -1.3 [m] Horizontal hydraulic conductivity 5*10-4 [m s-1] Vertical hydraulic conductivity 1*10-5 [m s-1] Storativity coefficient 0.2 [m-1]

Distributed soil moisture Saturation percentage

TOPKAPI CALIBRATION TOOL

Example of link ECMWF -TOPKAPI on the Po Basin The basin closed at Ponte Spessa (Surface area 36,900 km2 ) Ponte Spessa

The Soil Types The Land Uses The DEM The Land Uses

Reproduction of the 1994 event in the Po river

ECMWF: deterministic run

ECMWF: deterministic run

ECMWF: deterministic run

ECMWF: deterministic run

ECMWF: deterministic run