Hydraulic Analysis of a Meander on the Danube River Using a 2d Flow Model

Abstract

This paper presents the development, calibration and verification of a two-dimensional modelfor a Danube reach and its old cutoff meander. Theconsidered meander was at one point separated fromthe main reach with a levee, which caused a seriesof unwanted environmental consequences. Aiming tostop the ongoing degradation of the meander, the validated model was engaged to investigate the effectsdifferent river works would have on its current state.The considered river works involved dredging in certain parts of the meander, while keeping in mind thenegative effects these works can have on the environment, as well as possible widening of the existingopening in the levee. Numerical simulations showedhat all the considered scenarios would result in a general increase of velocities, which is important from theaspect of sediment deposition. After a thorough evaluation of the results, it was found that by carefullyselecting the locations where dredging should be conducted, no other interference is needed to put an endto the increasingly deteriorating situation in the meander. Computations confirmed that the suggested riverworks would increase the unit discharge in the entiremeander, especially in its upstream part. The redistribution of flow around the island downstream of thelevee (that formed during past years as a result of sediment deposition) was also predicted, where the flowwould once again favor the left side of the island. Thisis a more natural path of flow that would aid the flushing of previously deposited sediment in this part of themeander.