lascurain esconference
TRANSCRIPT
Constructed ecosystem services:
the case of hybrid dunes at Barcelona
1-Mimicking natural processes on urban dunes
Last mobile dunes 1980
1992 the first maritime promenade in Spain with dunes as core element of the landscape treatment
Transformations due to urbanization & modification of coastal dynamics
1956
Anthropocene!
2015
1990
2004
2007-16
Disruption of natural longshore sand transport processes
Increasing flood prone beach areas extending more than 3km
Marram grass decay after less than 10 years
Something worrying when is the most relevant dune constructor. We have not found any photograph of dunes without marram grass
Literature describes competition processes and soil patogens as most relevant factor
Probably mechanical sieving impedes the natural sand aeolian transport, but is only one of the relevant factors
The accumulation of dog excreta can also be a problem for a plant which requires oligotrophic soils
Without marram grass and aeolian sand transport, dune relief disappears. No more bare sand and its biodiversity
Pine tree encroachment is another factor of dune habitat reduction
Altered ecosystem but biodiversity still remaining. Still on time to react!
An European project + the Metropolitan Administration of Barcelona
Goals: 1. Learn how to construct urban dunes2. Learn how to manage the huge demand of cultural ecosystem
services of the urban dunes.
Socio-cultural and economic processes
Cartographies of intensity of use along the year
Dune construction from beach sand
Wind is no more constructing dunes, but …
.. still keeps its ability to erode dunes and uproot marram grass
In just 8 weeks marram grass uprooted and invasive species stablished
Determination of prevailing constructing/eroding winds from historic flights and fieldwork
Erosion risk can be mapped along dune structures.
We have developed a new system to transform marram grass plantings in to efficient sand-trapping systems
Marram grass as natural capital (dune builder)
Marram grass as natural capital and core element of a nature based solution
2-Coastal dynamics & decision chain
No dunes, no beach!!
When beach width is not enough to provide a comfort strip
The only official way to protect the coastline is beach nourishment (100,000m3/yr). No long-term strategy
Sand nourishment has not modified the emerged beach profile which keeps vulnerable to flooding
Beach nourishment hasn’t stopped erosion processes
The need of a policy analysis
A decision environment which is not evidence-based
A highly hierarchical, authoritative and unchecked decision process
The most dependent stakeholders without capacity to intervene on the decision-making
process
Time to think on improving the governance environment
3- Ecosystem services concept as an explicit management tool
LIDAR and satellite images has become very precise
A retraslocation of only 6.000m3 of emerged sand has proved to be much more efficient & effective
And a previous project done at Calafell (50km south) beach will work at Castelldefels.
Efficient storm water retention basins
Beautiful landscapes
Biodiversity
There’s a big chance for a management plan of the emerged sand budget, combining precise LIDAR information, dune construction, beach profile reconstruction and coastal lagoon excavation
A nature-based solution for coastal defence and climate change adaptation.
An evidence-based management plan that includes a strong social component
We are modelling scenarios for RCP 2.6 (57cm SLR and 25 m of beach regression, yr 2.100) for the different factors: wahsover risk, erosion, flood events,...
But adapting fast to much more near ones! (this is Emilia Romagna on Italy last year)
A nature-based solution to get resilient beaches
With reliable data from LIDAR yearly flights
http://maps.croma.org.es/geoserver/www/cr004_visor-ampliat.html
With a Web Map service
Nature-based solution involving policy analysis, governance, and participated coastal engineering
[email protected]@volemduneshttp://www.operas-project.eu/