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Tordera Delta

Case study sites

Site description

Keywords: Deltaic sandy shoreline

The Case Study site of the Tordera Delta area is located at the Tordera river’s mouth (Punta de la Tordera), covering an area of approximately 1.4km2. It is a low-lying, coastal plain and as so, a large part of the delta, mainly south of the mouth, has a low relative height, with respect to the Mean Sea Level (1–1.5m). This configuration is creating increased vulnerability to flooding of coastal and river origin, during storm events.

The delta affects two contiguous municipalities, separated by the river, a natural border between them: Malgrat de Mar, southward of the river, covering an area of 8.8km2 (Maresme county) and Blanes, northward of the river, covering an area of 17.7km2 (La Selva county). The total population of the area has increased from 10,942 in the 1940’s to 58,089 in 2013. According to municipal data, there is approximately 18% increase of the population during the summer due to the tourist character of the region.

Why was this area selected?

The Tordera Delta Case Study site is a profound example of an area where the adequate protective mechanisms of the local ecosystem were significantly weaken due to poorly designed human interventions, thus resulting in increased vulnerability and risk from extreme events. 

Land, coastal and marine uses

Keywords: Nature, Residential use, Tourism

The main land and coastal uses in the municipalities comprising the Case Study site are related to the tertiary and services sector, in particular commerce and tourism. In the deltaic coast, the hinterland is essentially occupied by campsites which provide accommodation and services for seasonal tourism. Some parts of the coast are also occupied by residential areas. In the delta, agriculture is also present (landward of campsites). The lower part of the Tordera river is of high environmental value and part of the Natura 2000 network.

Hazards

Keywords: Marine flood, Erosion, Flash flood, Sea level rise

The Tordera Delta is a highly dynamic zone currently in retreat due to the unbalance between the southeast directed net longshore sediment transport and the decrease of the Tordera river sediment supplies. As a result of this, beaches surrounding the river mouth, that have traditionally been stable or accreting, are being significantly eroded. Up to recent decades (1970s) the coastal zone was fed with river sediment supplies, delivered during river flooding episodes. As a result, the coast presented an equilibrated- accretive behaviour. From the end of the 70s until present the evolution trend changed due to human action. The sharp decrease in river sediment supplies changed the balance between sediment supply and removal due to littoral dynamics which caused the delta to be reshaped and eroded with rates reaching a maximum value of 3m per year in some areas. This has resulted in a significant beach width reduction in such a way that the natural protection function originally provided by the beach has significantly decreased. As a result of this, the hinterland is becoming more frequently exposed to direct wave action during storms, which induce, damage in infrastructures and inundation events. Moreover, since this is a low-lying coastal stretch, it is also a sensitive area to climate change connected sea level rise and flash flooding events.

Socio-Economic losses & Environmental Impacts

Keywords: Loss of beach & habitat, Property damage

The main environmental impacts in the area of the Tordera Delta are associated with the increased erosion rate and the loss of beach surface providing protection to the hinterland and space for recreation. In this sense, beach erosion has affected to existing infrastructure by increasing their exposure to wave action during storms. These infrastructures have been severely affected in such a way that the existing promenade has suffered significant damages many times during the last decade. Also, campsite installations have been severely affected as well as the auxiliary installations of the desalination plan. Economic losses are also utterly connected to this situation as the tourist activity is at constant risk of losing space and infrastructure. Additional costs are created from the unorganised efforts to partially confront the occurring problems, either by the administration or the stakeholders. Solemnly in the social sector, the lack of a coherent plan for the prevention and management of the area (up to today) downgrades any effort for stakeholder engagement.

Partner in charge

Universitat Politècnica de Catalunya

Members of the project’s end-users and stakeholders board

Spanish Ministry of Environment: Land & Sustainability Department (Gov. of Catalonia), Catalan Water Agency

 

For further information please download the factsheet (.pdf in Spanish)

 

Photo Gallery

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 Tordera 1

Fig. 1: S’Abanell beach during the impact of an extreme storm in December 2008 (source: PubliBlanes.net).

Tordera 2

Fig.2: State of the s'Abanell beach, northwards the Tordera river mouth. Metallic fence is the limit between the beach and the campsite in the hinterland and, the building is a pumping station of the desalination plant (nolonger operative) (October 2007).

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