Example location of woody patches at the Leerinkbeek stream which is a tributary of the Ijssel river system in the Netherlands. Source: https://vliegvisverenigingheelweg.nl/beken.
An evaluation of local controls on and regional impacts of water level and discharge dynamics in human-affected lowland rivers.
Fast flowing rivers may negatively affect aquatic biodiversity and increase the high-water levels during floods. In addition, fast flowing rivers cause groundwater levels to decline, which result in prolonged droughts. River managers, therefore, consider retaining more water in river tributaries or upstream streams. Typical restoration measures include the (re)construction of the natural bends or the insertion of wood patches in the stream (see right photo). The water level and discharge effects of these measures are poorly understood. Moreover, streams are typically assessed in isolation of their river system. This research investigates the local controls on and the regional impacts of water level and discharge dynamics of water retention measures, which help in planning these interventions on local and regional scale.
Key goals: Fundamental understanding Innovative monitoring
Effects in the flow patterns and water levels due to typical stream restoration interventions and the coincidence of discharge peaks and rainfall patterns in two tributaries and its main river.
We analyzed intervention effects at the local and the regional level:
- At the local level, we first collected hourly data in four streams (water level and discharge) to look at the upstream and downstream effects of wood patches. We compared these measurements with calculations from the simplified representation of the wood obstruction (top right of the image). We additionally investigated the flow pattern effects of two sharp river bends (top left of the image) by collecting water level, velocity and bathymetry data during low and high-water levels.
- At the regional level, we studied an historical record (1999 to 2015) to understand the correlation of rainfall patterns and the simultaneous occurrence of discharge peaks at a two lowland tributaries and the main river (bottom side of the image). We additionally studied regionally storage of (large) rain events in the groundwater by pro-actively drain the groundwater before the rain event.
For whom and where?
River managers, who are planning stream restoration projects, can use these studies to investigate and plan the water level and discharge effects of the intervention on local and regional scale.
Data-collection methods: Field survey measurements Numerical modeling
Temporal scale: 1-10years Daily series Hourly series
Application development and findings
Findings at local scale show that the stream and the wood patches geometry affect the relation between discharge and water level drop over the wood patches. For sharp bends, no local backwater effects are found, however the flow patterns in bends can change drastically in time. At regional scale, we showed that significant backwater effects occur in the tributaries during simultaneous occurrence of discharge peaks in the tributary and the main river. These findings were studied at the following locations (see map):
- A simplified backwater model for wood in streams was compared with field measurements in four streams in the Netherlands (Tongelreep, Ramsbeek, Leerinkbeek and Tungelroysebeek).
- Measurements were collected during the winter season of 2017-2018 for two sharp bends in the Dommel and Essche Stroom rivers.
- The simultaneous occurrence of discharge peaks at regional scale was studied using the nine highest discharge peaks in the Meuse River and its tributaries, Dommel and Aa River.
Status for day-to-day practice
Water managers can use these insights to define the strategic location of a river restoration intervention. For example, backwater effects can be reduced by decreasing the width of the wood patch and river bends do not result in local backwater effects.
Key locations that we studied within this project from which two of them were part of the IJssel river system whereas the other were tributaries of the Maas river.
Spatial scale: Catchment Reach
Key locations: IJssel River (NL) Maas River (NL)
This section will be available as soon as possible.
Last updated: 10/02/2020
Explore the contact details to get to know more about the researchers, the supervisory team and the organizations that contribute to this project.
Wageningen University & Research
As soon as available, explore the storyline to get to know more about the main methods or prototype tools that were developed within this project.
Explore the output details for available publications to get a glance of the innovative components and implications to practice as well as the links to supporting datasets.
Research outputs are currently under review. Meanwhile, the following are the main conference proceedings for additional details about this project:
- Geertsema, T.J., Torfs, P.J.J.F., Teuling, R.J. , Eekhout, J.P.C., Hoitink, A.J.F. (2018). Parametric model of wood-induced backwater in lowland streams. 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. 82.
- T.J. Geertsema, P.J.J.F. Torfs, A.J. Teuling, A.J.F. Hoitink. Backwater development by woody debris in streams. 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. 28-29.
- Geertsema, T.J., Hoitink, A.J.F., Teuling, A.J., Torfs, P., Weerts, A.H., Uijlenhoet, R. (2015). Simultaneous occurrence of discharge peaks in a large river and its lowland tributaries. 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. 1626-1632.
Take a look to the dissemination efforts and application experiences which are available in the news items and blogs.
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