Data analysis

GLUE analysis

Model analysis

Rating Curve analysis based on

hydraulic model

Formulation of different Rating Curve

models

Pappenberger et al., 2006

Coarse selection of parameter sets

Sampling of parameter sets

Stringent selection of behavioural

parameter sets

Evaluation of behaviour of different

RC models

Delimitation of consistent periods in the data points

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ASSESSMENT OF THE BENEFITS OF RATING CURVE MODELS WITH INCREASED COMPLEXITIES.

Katrien Van Eerdenbrugh1, Niko Verhoest (1), Tom De Mulder2

1Laboratory of Hydrology and Water Management, Ghent University, Ghent, Belgium (katrien.vaneerdenbrugh@ugent.be), 2 Hydraulics Laboratory, Ghent University, Ghent, Belgium (tomfo.demulder@ugent.be)

Pappenberger F. et al., Influence of uncertain boundary conditions and model structure on flood inundation predictions. Advances in Water Resources, 29(10), 1430–1449, 2006.

6. REFERENCES

3. HYDRAULIC MODEL

5. RESULTS (sequel)4. METHODOLOGY

For the hydrodynamic analysis, a MIKE11 model of the river Demer that covers the entire study site is used. This model is constructed by the Flemish Government for operational water management purposes and the structure (model setup, geometry) was only slightly adapted for this research. The MIKE11 software solves the continuity equation and momentum equation of de Saint Venant using a finite difference numerical scheme. In the model of the river Demer, floodplains are modelled as a network of fictitious river branches. This network is connected to the river by spillways, representing river dikes.

RC0: Mean membership values of all data points (parameter sets after coarse selection)

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5. RESULTS

RC0: Mean membership values for a consistent period of data points (behavioural parameter sets after stringent selection)

RC2: Empirical CDF of the parameters (behavioural parameter sets after stringent selection vs. original samples)

Performance of the different models

RC0RC1RC2

Model analysis

Model analysis

Data analysis

Discharge assessment through rating curves is a widespread technique in the field of hydrologic monitoring. In practical applications, this technique often is based on rather stringent assumptions concerning the nature of the prevailing flow conditions. In this poster, the results of a hydrodynamic model are used for evaluation of rating curve formulations accounting for the influences of hysteresis and backwater effects. Subsequently, the performance of three different rating curve models and the identifiability of their parameters are assessed based on available stage-discharge measurements and their accompanying uncertainties. The mean membership value of a coarse selection of parameter sets for each data point is used as an indication for the delimitation of consistent periods in the data points.

1. INTRODUCTION

This research focusses on a 31 km reach of the river Demer, a part of the Scheldt river basin in Belgium. The regime of the river is nearly fully determined by runoff due to rainfall. • Two discharge stations based on rating curves inside the study area

(more than 30 years of measurements).• Low velocities and backwater effects in nearly all flow situations.• No influence of movable infrastructure.

2. STUDY AREA & DATA