2. Faculty of Geosciences
Beach-dune interaction
Urgency:
โข nature restoration
โข long-term coastal safety
No sand sharing: (1) loss in geomorphological dynamics
(2) loss in biodiversity
(3) no vertical growth with sea-level rise
Dune erosion Dune growth
4. Faculty of Geosciences
Building with Nature: Sand Engine
Beach-dune interaction:
โข Short gradients (new embryo dunes)
โข Foredune growth ~ 15 m3/m/year
โข No dune erosion
8. Faculty of Geosciences
Questions
โข How much sand is actually blown toward the dunes?
โข Which factors affect this amount?
โข What to expect from dune remobilization?
โข Are present-day large-scale measures effective?
โข Can nourishments and dune remobilization be combined?
โข โฆ
9. Faculty of Geosciences
Needs
โข Experiments: Learning by doing
โข Long-term (years) monitoring with high resolution (seasons)
โข Close co-operation between stakeholders and scientists
โข Models with different complexity
โข โฆ
11. Faculty of Geosciences
My projectBeach-dune interaction: models
Need
Accurate predictive
model of aeolian sand
supply
Challenges
Supply limitation
1. How wet?
2. When?
3. How much?
4. Upscaling
12. Faculty of Geosciences
Timing of aeolian events
Potential transport
โข Events (4 hrs > 8 m/s)
โข Hsu (1974)
Observed transport
โข Sand-strip activity
13. Faculty of Geosciences
Timing of aeolian events
Mismatch between potential and actual events:
โข Moderate wind speeds: considerable aeolian activity
โข Large speeds are large: no aeolian activity
15. Faculty of Geosciences
Timing of aeolian events
No aeolian activity under strong shore-normal
/ oblique winds because of surge
16. Faculty of Geosciences
Summary
โข From preventing dune-erosion to beach-dune interaction
โข Building with and for Nature
โข Practice-inspired questions and scientific ideas
โข Pilot experiments: โLearning by doingโ with long-term
monitoring to eventually predictively understand
Only then ready for the challenges of the decades to come
20. Faculty of Geosciences
Mismatch between potential and actual events:
โข Moderate wind speeds: considerable aeolian activity
โข Large speeds are large: no aeolian activity
Timing of aeolian events