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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Long-term effects of longitudinal training walls: a numerical study
Long-term effects of longitudinal training walls: a numerical study
Author : T.B. LE (*1, 2), A. CROSATO (1, 3), W.S.J. UIJTTEWAAL (1)
ABSTRACT
Recently, engineers propose building longitudinal training walls instead of traditional transverse groynes to enhance river
navigation or free water inlets at low flow conditions and at the same time maintain the channel conveyance during high
flows. For example, the main low-flow stream of the Tra Khuc River in the middle of Vietnam, does not follow the same
route year after year causing problems to the inlets of irrigation channel systems along this river. Engineers would like to
build longitudinal training walls to stabilize the main stream during low flows without affecting the flood conveyance on
rainy season. Another example is along the well-trained Waal River, Dutch authorities are considering substituting the
old groynes with longitudinal training walls to obtain an improved navigation channel, while preserving the river
conveyance capacity during floods. However, whether longitudinal training walls are indeed effective in achieving the
goals and whether they may also produce some undesirable effects is still not clear. This investigation analyses the
stability of a system of parallel channels that is formed after the construction of a longitudinal training wall. The analysis
is based on the application of a numerical model (Delft3D). The model is applied to a river channel with alternate bars or
point bars (as most rivers do). The results show that with a single training wall along one side or two training walls along
both sides of the river the parallel channel(s) may become unstable. In addition, starting with a flat bed (to consider the
case in which all bars dredged before side wall construction) does not change the unstable character of the channel
system. In general, the position of the training wall with respect to a bar plays an important role for the subsequent
morphological developments.
File Size : 722,401 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 27/08/2015
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