Dynamic Dunes Congress 2015 Workshop: Research and monitoring - Bas Arens

1. Monitoring dynamic dunes
state of the art
geomorphology

2. White dunes

3. Grey dunes

4. Grey dunes
Grey dunes

5. What to measure?
interest parameter
Sand transport (process) Events
Gradients
Sand transport (result) Height changes: deflation, accumulation
Sediment budget
Landscape dynamics Areas bare sand, colonized, sand burial
Geomorphic features Blowouts, Carves, mobile dunes, dune
building

6. Measuring landscape form
Method Accuracy Reliability Costs Advantage Disadvantage
Air
photographs
+/- High High Retrospective Expensive
Problems with
data gathering
Recording date
Field
mapping
+/- Medium-
high
Medium-high Recording
date

7. • Air photo
– Bare-vegetated
– Shapes
– Evolution in time

8. • Landscape
dynamics

9. Measuring Process
sand transport indirectly
Method Accuracy Reliability Costs Advantage Disadvantage
Erosion pins + Low Low Easy, 1D Risk for data loss
1D
Augering +/- High Low Easy, 1D
Retrospective
Accuracy?
Profile GPS ++ High Medium Easy, 2D 2D
Lidar +/- High High 3D Accuracy
Photogram.
Drone
+/- high Medium-high 3D No data in
vegetation

10. • Erosion pins
– Spot
measurements
– Risk of data loss
-10
-5
0
5
10
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
heightchange(cm)
pin number
Kraansvlak transect 1
24/9 to 1/10/99 1/10 to 12/11/99 12/11 to 3/12/99

11. • Augering
– Spot
measurements
– Accuracy

12. • Transects
– Accurate
– 2D

13. • LIDAR
– Not accurate in
vegetation
– Not usable for
small changes

14. Measuring Process
sand transport directly
Method Accuracy Reliability Costs Advantage Disadvantage
Sand
catchers 1
knik
? +/- Low – high easy Splash
erosion
Sand
catchers 2
? +/- Low-high easy Data loss
Electronic
device
+/- +/- high High
resolution
data
Complicated
expensive

15. Sand traps
horizontal vertical

16. • Sand traps
– Spot
measurements
– Transport
direction
– Accuracy??
– Difficult to
translate to
deposition or
erosion