La playa emergida como fuente de información para gestionar la adaptación de las playas mediterraneas al cambio climático

1. La playa emergida como fuente de información
para gestionar la adaptación de las playas
mediterráneas al cambio climático
sgm.es
José Lascurain

8. Mean difference and total error
topo1k 2008 2012 2014 2017
topo1k
2008 0,15
2012 0,14 0,08
2014 0,16 0,12 0,08
2017 0,13 0,09 0,08 0,11
We explored the potential of LIDAR technology with a new method.
RMS to define vertical accuracy

9. Shoreline established at 0,7 m
height in order to avoid wave
interference.
Coastline defined by the
software, not digitised. So its
resolution is the same as the
provided DEM (1m).

10. Dune and backshore
differentiated.
So, each 100m cell is transformed
in a point containing information
of area, volume, slope, azimuth,..

11. Backshore Total
Lack of correlation of beach width and sand volume.

12. Total emerged sandBackshore
Recognizable patterns at backshore level between cell volume and
average slope. A relationship with sand grain diameter.

13. When outliers suggest dysfunctions

14. Strong winter
winds parallel to
the beach
Human-induced wind scour process
Mechanical
sieving to get sand
cleaned impedes
vegetation
growth, thus
allowing wind
scour.

15. It can be a “non linear” process. Probably a sea level rise of only 20 cm
could made this beach stretch disappear

19. A very relevant question: how much sand is enough?

20. )
2
)004.0563.0(
35.0()(10.1
5.02
5,0
00%2
+
+=
β
βLHR
L’impacte dels temporals proveeix més informació
més ràpidament que els models predictius pel 2100
R2% = run-up overpassed by 2%
A2% = màximum wave reach
ηmax= set-up
RT
2% = total wave height for a T retorn period
Overwash risk gives a similar value for a T return period of 16,5 yrs.

21. So, it is possible to get a glimpse of the overall backshore sand budget, and
how it changes with time.
Transfers between beach stretches easily identified, but transfers to the
submerged part or neat losses from the beach cell not so easy to be identified

22. But always keeping in mind of the obligation to provide every summer with
the needed amount of dry and clean sand to as much as 500 sunbathers for
each 100 m long cell.

23. A sand budget with a clear geographic expression

24. Also useful to detect risk areas
and prevent storm impacts.

25. 2010
Summer 2016
Storm 20-21 januray 2017

26. 0
500000
1000000
1500000
2000000
2500000
2010 2017
Emerged sand volume (m3)
Backshore Dune
Mapping vulnerability and the role of the “declining” dune reserve”

28. The dune system will provide the needed barriers to prevent wave
overwash

30. The need to learn how to construct and maintain mobile and semi-mobile dunes.

31. 6,3 m
3,2 m
..it is the most visited landscape on most of the
Mediterranean basin, provides huge flows of
ecosystem services, and sustains a relevant
part of the economy.
The emerged beach is just the “tip of the iceberg” of the system, but …
This sand is just gold, because . . .

32. The knowledge of sand budget
has been mostly provided by
numerical models
They need sustained
bathymetric surveys and > 10
yrs of wave environment data.
So, creating large information
gaps along the med coast.

36. Climate change is making med beaches to shrink. Some beaches are starting to be
unable to provide enough space to cope with the social demand of sunbathers

37. The loss of beach quality and quantity will have a huge cultural and
economic impact. And those scenarios are probably much closer than
previously thought.
It is also about brandscape ecology.

38. This is why we need an efficient and reliable
accounting system
• LIDAR information can fill the gap (cheap, fast and with
increasing accuracy).
• A reliable method to manage the emerged sand budget for:
• Fast identification of outliers(dysfunctions).
• Provision of short term scenarios.
• Inform daily beach management.
• Assess existing management strategies,.
• The need of a new governance to adapt to the pace of climate
change.

39. Thanks for your attention.
info@sgm.es