The 7th Brunings Lecture was held on February 1, 2022. For those who missed it, or for those who’d like to see it again: please watch the video below.

The theme was sediment management for sustainable living in deltas: a cross-section of the Utrecht University Hub “Sediments matter”and related work by our alumni. After setting the stage, we moved from rivers to the coast, and from specific issues to systemic views.

Click the box below the programme for abstracts and links to relevant websites and papers. Programme (click on links for people pages):

• 13:15 Teams channel open for dropping in
• 13:30 Welcome: Maarten Kleinhans (UU)
  and Hub director Hans Middelkoop (UU)
• Jos van Alphen (Staf Deltacommissaris):
  Dikes or drown? Adaptation to sea level rise
• Eveline van der Deijl (Deltares):
  A reference bed level for the Rhine and Meuse?
• Jana Cox (UU):
  Past and future of the Rhine-Meuse delta
• 14:05 Your questions about rivers
• Timothy Price (UU):
  Sand nourishment on the wave-dominated coast
• Maarten van der Vegt (UU):
  Sand nourishments in the Wadden Sea area
• Renske de Winter (Deltares):
  Pathways for sandy solutions
• 14:30 Your questions about the coast
• Jaap Nienhuis (UU):
  Past and future of global deltas
• Maarten Kleinhans:
  What the delta wants? A preview
• 14:45 Your questions about systemic views, and famous last words

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Maarten Kleinhans (UU)
Welcome to the 7th Brunings Lecture at UU on the work done over past five years on sediment management strategies by researchers of Utrecht University and UU alumni.

Hans Middelkoop (UU)
Researchers at the Water, Climate and Future Deltas hub (WCFD) at UU have worked over the past years to understand sediment behaviour and look for sustainable strategies to manage sediment. The future development and vulnerability of deltas depend on changes in human and climate drivers and pressures which play on a global scale and are highly uncertain. It is increasingly urgent to understand the impact of these drivers to be able to develop effective, flexible and integrated strategies to mitigate and adapt to these changes in the short and long term. One such strategy is sediment management, which requires understanding of sediment dynamics in an integrated manner at the delta scale and beyond. Also see:

• Hub website Sediments matter

Jos van Alphen (Staf Deltacommissaris)
Dikes or drown? Adaptation to sea level rise
Accelerated sea level rise may become a serious threat for the Dutch delta. In the Sea Level Rise Knowledge Programme government authorities, research institutes, businesses, planners, and NGOs are pursuing new expertise on the potential rise in sea level: its pace and its scope; the consequences for flood defences systems, freshwater supply, and spatial planning; and long term options to anticipate such consequences in good time. Also see:

• Movie on knowledge programme of the Delta Committee

Eveline van der Deijl (Deltares)
A reference bed level for the Rhine and Meuse?
Significant human intervention has taken place in the Rivers Rhine and Meuse. Due to an imbalance by these past interventions, and by changes in the climate, important river-related functionalities as shipping, freshwater, nature, and flood risk management will sooner or later come under pressure.
In order to accommodate various, sometimes conflicting, functions of the rivers sustainably, system choices are necessary. Therefore, a signaling instrument to visualize and analyze the (conflicting) demands of river functions for the river bed is now being established in the project Reference River Bed Level (Basis Rivierbodemligging). Also see:

• pdf of presentation of this novel concept, and request for your input

Jana Cox (UU)
Past and future of the Rhine-Meuse delta
The Rhine-Meuse developed from a mid-Holocene estuary to an urban delta that is losing sediment due to dredging and shipping. Historic maps (1500s to 2020) show how significantly altered the system has become. The present sediment shows effects of past and present interventions that caused the present sediment deficit, and the future budget show what the implications are for continued increase of activities. Also see:

• paper (open access) with actualised data of the present sediment budget
• paper on first estimate of future sediment budget (with Jaap Nienhuis and others)
• 3 minute overview movie in the 2020 Brunings Lecture

Timothy Price (UU)
Sand nourishment on the wave-dominated coast
Sand nourishments are used to counteract a negative sand balance along the Dutch coast, although it is unclear how this sand is redistributed and becomes part of the coastal system. Sandy coasts are incredibly dynamic areas, where waves and wind continuously move sand back and forth between sea and land. Medium-term coastal morphodynamics provide clues as to where the sand is going on the long term. Also see:

• Movie of lecture (in Dutch: Universiteit van Nederland)
• more about the shoreward migrating accretionary waves in these proceedings
• Poster on the relation between subtidal bars, embryo dunes and dune erosion
• Paper about the laser scanning, including foredune growth
• Access to the Egmond beach data

Maarten van der Vegt (UU)
Sand nourishments in the Wadden Sea area
With accelerated sea level rise the Wadden Sea basins need more sediment to maintain the intertidal area. Nourishing the ebb-tidal delta might promote additional import of sediment into the Wadden Sea, but it is uncertain how such a nourishment behaves in this highly dynamic area. Model simulations suggest that the added sediment interacts with the natural cyclic channel-shoal dynamics of the ebb-tidal delta. Therefore the behavior depends on the exact location of the nourishment and on when it is added to the system. Also see:

Renske de Winter (Deltares)
Pathways for sandy solutions
It is expected that coastal nourishment volumes will increase in the future as a result of a.o. sea level rise. The presentation will elaborate how nourishments strategies can preserve a safe coast that also supports a range of other functions such as nature and recreation. Also see:

• background to these pathways (work in progress) presented at Coastal Dynamics in Delft, 2021

Jaap Nienhuis (UU)
Past and future of global deltas
Global deltas have gained land in the past decades but this is bound to change. Sea-level rise will force global delta land loss under most climate scenarios, up to 1,000 km2/yr for worst-case conditions. Also see:

• River Basin Delta tool on PBL website

Maarten Kleinhans (UU)
What the delta wants? A preview
The lowlands of the Netherlands will respond to sea level rise and increased river flood frequency and magnitude. Assuming no change in activities, we analysed what will happen under future conditions and here we present a draft map of the Netherlands that should never become true. The map and a report will appear later in 2022.

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