In the Dutch river system, measures are taken to keep the river system sustainable for the future. One way of doing this, is by replacing transverse groynes in the inner river bend by so-called longitudinal training dams (LTDs). As a pilot project, LTDs are constructed over a ten-kilometre stretch in the Waal River. LTDs are expected to reduce long-term subsidence, increase the lowest water levels, increase the discharge capacity during floods and create ecologically more favourable conditions. However, existing knowledge about the effects of LTDs on erosion/deposition and regional flow patterns is highly limited.
Management phase: Implementation & Monitoring |
Management goals: Morphological understanding |
The main aims of this research are to understand:
- the effect of the intake geometry of an LTD on the morphological patterns and associated flow structures in the inflow region,
- the morphodynamic evolution of the bed in both the main channel and the side channel after construction of an LTD,
- the dynamic behaviour of subaqueous dunes in the Waal River, and the influence of the LTD construction thereon and,
- the physical mechanisms governing exchange processes in LTD openings.
To achieve these goals, both physical scale model experiments and field measurements will be used.
Temporal scale: Seasonal measurements |
(a) Picture of the line laser scanner measuring a profile. The red light on the profile is the line emitted by the laser. (b) Overview of the experimental set‐up. c) Physical scale model of the upstream section of a longitudinal training dam (1:60) in a 2.5-metre-wide flume. Arrow indicates flow direction. (Source: Adapted from Figure 1; de Ruijsscher et al. 2018; https://doi.org/10.1002/2017WR021646)
- In order to prepare the experiments, a 1:60 physical scale model is built. In this scale model, polystyrene lightweight granules will be used as substitute sediment.
- A so-called line laser scanner is used to reconstruct the bed profile. A red laser line is projected on the bottom of the flume, which reflection is recorded by a 3D camera (top right in the Figure).
- Problems that occur using this method are data scatter and missing data. Both are reasonably resolved by using an interpolation and smoothing algorithm, which also appears to be a useful tool for filtering bed forms of different spatial scales.
Data-collection methods: Field survey measurements | Physical and laboratory experiments | Remote sensing |
Main progress and next steps
- Implementation and analysis of a line laser scanner as a new non-intrusive measurement method for measuring sub-aqueous bed forms in flume experiments.
- The scale model experiments are ongoing. Analysis will follow during spring and summer 2018.
- Two Horizontal Acoustic Doppler Current Profilers (H-ADCPs) and Optical BackScatter (OBS) devices were mounted at a traffic pole at the upstream side of the most downstream LTD to measure horizontal flow velocities and turbidity at two different heights from end of May 2017 onward. These measurements are daily accessible and still continuing.
- First data gathered by Rijkswaterstaat is accessible, which allows for analysis of the morphological data.
Key study areas: Waal River (Netherlands)
Last modified: 10/06/2018
dr. ir. Ton Hoitink
dr. ir. Bart Vermeulen
dr. ir. Erik Mosselman
Prof. dr. ir. Wim Uijttewaal
Application of a line laser scanner for bed form tracking in a laboratory flume
08/03/2018 by Timo de Ruijsscher et al.
Contains: Data repository access Journal publication Modeling tool access
- de Ruijsscher, T. V., Naqshband, S., & Hoitink, A. J. F. (2018). Flow Bifurcation at a Longitudinal Training Dam: a Physical Scale Model. In: Huismans, Y., Berends, K.D., Niesten, I., Mosselman, E (Eds.). The future river: NCR DAYS 2018 Proceedings. Netherland Centre for River Studies publication 42-2018, 8-9 February 2018, Deltares, Delft, pp. 148-149.
- Poelman., J.Y. (2018), de Ruijsscher, T. V., & Hoitink, A. J. F. (2018). Response of flow and bed morphology to the introduction of large wood for sediment management. In: Huismans, Y., Berends, K.D., Niesten, I., Mosselman, E (Eds.). The future river: NCR DAYS 2018 Proceedings. Netherland Centre for River Studies publication 42-2018, 8-9 February 2018, Deltares, Delft, pp. 150-151.
- de Ruijsscher, T. V., Naqshband, S., & Hoitink, A. J. F. (2017). Interaction of dunes and bars in lowland rivers . In: S. Lanzoni, M. Redolfi, G. Zolezzi (Eds.), RCEM 2017 – Back to Italy, 15-22 September, 2017, Padova, Italy, p. 48.
- de Ruijsscher, T.V., Dinnissen, S., Vermeulen, B., Hazenberg, P. Hoitink, A.J.F. (2017). Application of a line laser scanner for bed form tracking in a laboratory flume. In: A.J.F. Hoitink, T.V. de Ruijsscher, T.J. Geertsema, B. Makaske, J. Wallinga, J.H.J. Candel, J. Poelman (Eds.), Book of abstracts NCR days 2017, NCR Publication 41-2017, 1-3 February 2017, Wageningen University & Research, pp. 94-95.
- Jammers, S.M.M., Paarlberg, A.J., Mosselman, E. & Uijttewaal, W.S.J. (2017). Sediment transport over sills at longitudinal training dams with unaligned main flow. Book of abstracts NCR days, Wageningen, 1-3 February, 2017. pp. 86-87. (student project at HKV)
- van Linge, B.W., Mosselman, E., van Vuren, S., Rongen, G.W.F. & Uijttewaal, W.S.J. (2017) Flow patterns around longitudinal training dams. Book of abstracts NCR days, Wageningen, 1-3 February, 2017. pp. 42-43. (student project at HKV)
- de Ruijsscher, T.V., Dinnissen, S., Vermeulen, B., Hazenberg, P. Hoitink, A.J.F. (2016). Dune and alternate bar detection in a laboratory flume using a 3D laser scanner. In: G. Constantinescu, M. Garcia, D. Hanes (Eds.), Proceedings of the International Conference on Fluvial Hydraulics (River Flow 2016), 11-14 July, 2016, St. Louis, USA, pp. 379-380.