Monitoring dynamic dunesstate of the art

geomorphology

White dunes

Grey dunes

Grey dunes

Grey dunes

What to measure?

interest parameter

Sand transport (process) EventsGradients

Sand transport (result) Height changes: deflation, accumulationSediment budget

Landscape dynamics Areas bare sand, colonized, sand burial

Geomorphic features Blowouts, Carves, mobile dunes, dune building

Measuring landscape form

Method Accuracy Reliability Costs Advantage Disadvantage

Air photographs

+/- High High Retrospective ExpensiveProblems with data gatheringRecording date

Field mapping

+/- Medium-high

Medium-high Recording date

• Air photo

– Bare-vegetated

– Shapes

– Evolution in time

• Landscape dynamics

Measuring Processsand transport indirectly

Method Accuracy Reliability Costs Advantage Disadvantage

Erosion pins + Low Low Easy, 1D Risk for data loss1D

Augering +/- High Low Easy, 1DRetrospective

Accuracy?

Profile GPS ++ High Medium Easy, 2D 2D

Lidar +/- High High 3D Accuracy

Photogram.Drone

+/- high Medium-high 3D No data in vegetation

• 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

he

igh

t c

ha

ng

e (

cm

)

pin number

Kraansvlak transect 1

24/9 to 1/10/99 1/10 to 12/11/99 12/11 to 3/12/99

• Augering

– Spot measurements

– Accuracy

• Transects

– Accurate

– 2D

• LIDAR

– Not accurate in vegetation

– Not usable for small changes

Measuring Processsand 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

Complicatedexpensive

Sand traps

horizontal vertical

• Sand traps

– Spot measurements

– Transport direction

– Accuracy??

– Difficult to translate to deposition or erosion