University of Twente Student Theses


Evaluating and improving a two-dimensional hydraulic model of the Oberrhein

Berg, M.C. van den (2018) Evaluating and improving a two-dimensional hydraulic model of the Oberrhein.

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Abstract:This paper improves and evaluates a two-dimensional model of the Oberrhein. The reason why the output data of the previous developed model (PD-model) of the Oberrhein seemed to overestimate the inundation extent was mainly a software issue. Some bugs in the GUI (graphic user interface) of the D-HYDRO software package caused the primary flood defences to be excluded from the calculation. Because of the exclusion of the weirs, the water in the model was only confined by the elevation of the landscape. Using an alternate module of the D-HYDRO package called DIMR, this problem was resolved. This study also found that adding a warm-up period to the PD-model resulted in a smoother transition to a high discharge event. By validating the model, the correctness and reliability of the improved model was assessed. The improved model simulated discharge accurately. The model had a RMSE value of 34.2 m3/s, this is less than half the standard deviation of the observed data and thus was deemed acceptable. The NSE had a value of 0.85, this value lies between 0 and 1 and therefore was deemed acceptable. Also the improved model simulated the inundation extent better, the FAR and CSI tests both improved although the PD-model did score better on the POD test. This suggested that instead of a overestimation now an slight under estimation of the inundation extent occurred at some locations throughout the model. A sensitivity analysis revealed that the simulated discharge of the model was not very responsive in respect to changes to parameters like the surface roughness and eddy viscosity. Therefore the model was very robust in respect to these parameters To examine which modelling technique was most appropriate in the area of interest a literature review was conducted. The revelations found were backed up with experiments using the improved model. Using the review and the experiments it was established that two-dimensional computations are vital to simulate the Oberrhein regardless of using average or high discharge.
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
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