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C2) Lowland backwater effects

Start: 09/2014
End: 09/2018
Status: Active

Contact details

Tjitske Geertsema

Wageningen University & Research

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.

Project output

Local and regional effects in the discharge and water levels due to stream restoration.

Challenge

Fast flowing rivers may negatively affect the biodiversity and increase the high water levels in case of floods. In addition, fast flows may not allow to sufficiently recharge the groundwater levels which can ultimately cause more prolonged droughts. Therefore, river managers are considering to restore a more natural flow regime in the river tributaries or streams to increase their water storage capacity and/or infiltration to the ground water. Typical restoration measures in the Netherlands include the re-construction of the natural bends or the location of woody patches in the stream (see right photo). However, their effects are not clear regarding the discharge and water level changes particularly when generating an opposite stream course also known as back water effect. Moreover, streams are typically assessed in isolation of their river system which is necessary to better plan these interventions on a regional scale.

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Key goals: Fundamental understanding Innovative monitoring

Effects in the flow patterns and water levels due to typical stream restoration interventions and the coincidence in the discharge and rainfall patterns between a tributary and its river.

Innovative components

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 woody patches. We compared these measurements with calculations from the simplified representation of the woody obstruction (top right of the image). We also looked the flow pattern effects of two example locations with very sharp stream bends (top left of the image) by collecting discharge and water level data during low and high water levels.
  • At the regional level, we looked at historical records (1999 to 2015) to understand the correlation of rainfall patterns and the coincidence of peaks in the discharge between a tributary and the river itself (bottom side of the image).

For whom and where?

River managers planning stream restoration projects in the Netherlands or abroad could take into account either the regional or local approach to decide about the strategic location of these type of interventions.

Data-collection methods: Field survey measurements Historical approach Numerical modeling

Temporal scale: 1-10years Daily series Hourly series

Application development and findings

Findings at local level confirm that the geometry of the wood patch and the stream affect the relation between discharge and water level drop over the wood patches. Instead, medium and high discharge events in sharp bends show similarities in water level profiles (little changes in space and time), but differences in flow patterns due to backwater effects (i.e. opposite stream course). At regiolal level became evident that when a peak in the discharge coincides at the confluence between a tributary and its river, the backwater effect can increase. These findings were deduced from the following locations:

  • The comparison of field measurements in four streams in the Netherlands (Tongelreep, Ramsbeek,. Leerinkbeek and Tungelroysebeek) and the outputs of a simplified representation.
  • Measurements collected during the winter season of 2017-2018 for two sharp bends in the river Dommel.
  • The coincidence at regional level between nine highest discharge peaks in the Meuse River and its tributaries, Dommel and Aa River.

Status for day-to-day practice

Water managers can take into account these insights to define the strategic location of a river restoration intervention. For example, backwater effects can be reduced by placing the wood patches at a strategic cross section. Our simplified representation was useful to predict these backwater effects but its limitations include the non-physical representation of the roughness coefficients due to the difficulties to measure this parameter in the field.

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)

Next steps

This section will be available as soon as possible.

Last modified: 20/05/2019

Explore the contact details to get to know more about the researchers, the supervisory team and the organizations that contribute to this project.

Main researchers

Tjitske Geertsema

Wageningen University & Research

Supervisory team

dr. ir. Ton Hoitink

Wageningen University & Research

Wageningen University & Research

Contributing partners

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.

Other outputs

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Abstract

2018

  • 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.

2017

  • K. Kästner, A.J.F. Hoitink, T.J. Geertsema, B. Vermeulen. Do distributaries in a delta plain resemble an ideal estuary? Results from the Kapuas Delta, Indonesia. 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. 16-17.
  • 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.
  • T.J. Geertsema, P.J.J.F. Torfs, A.J. Teuling, A.J.F. Hoitink. Backwater development by woody debris. European Geosciences Union (EGU) General Assembly 2017, Geophysical Research Abstracts, Vol. 19, EGU2017-15820,17 – 22 April 2016, Vienna, Austria.

 2016

 2015

Take a look to the dissemination efforts and application experiences which are available in the news items and blogs.

Events

15/09/2017

Symposium on River, Coastal and Estuarine Morphodynamics 2017 in Padova (Italy)

Seven intrepid researchers took part on one of the most important conferences on the field.

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Videos

Rivercare floodplain

01/11/2017

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Anything to ask or share?

About us

We would like to learn from your experiences and questions to take our knowledge further into practice in the Netherlands and abroad. Your feedback will help us to find out about your interests and how useful the information provided was to you.