Catchment Name and Location: Catchment “La Tordera”, located in Catalonia, Spain, in the region of ‘Valles Oriental’ and ‘La Selva’.
With an area of 864 km2, it goes from the mountain range called Montseny (Catalan Pre-Coastal Range) with a maximum altitude of 1712 m, to the Mediterranean coast in the city of Blanes. The main river in the catchment has a 60km length. The first part is located in the upper catchment (mountain area) and the last part is extended over the delta of the Tordera river between the cities of Blanes and Malgrat de Mar. The main land use is forest (80%) with 10% of land used as agriculture and the rest considered as urban areas. The main concentration of agriculture lands is located in the lower part of the delta due to favourable conditions of the soil and availability of water (aquifers).
The catchment of La Tordera has geographical characteristics that make it very interesting to study. It goes from high altitudes to the Mediterranean coast, and it is affected mostly by the influence of the Mediterranean Sea in terms of weather. The zone is normally affected with high intensity rainfalls mostly in autumn and spring, causing flash floods that can affect the delta area (agriculture) and damage urban settlements located in the lower part of the catchment (mouth). The dynamic of the catchment and its response to the occurrence of high intensity rainfall events it is also influenced by its topographic conditions and the high slope presented in the upper part of the catchment with low concentration times and a high capacity to produce steeped hydrographs.
Beside the fact that the catchment is located in a specific place of Spain, and it is affected particularly by high intensity rainfall events, it is also exposed to the possible effect of the Climate Change in terms of water availability and natural disasters. As an added point, it suffers from constant pressure from the establishment of new settlements and the increment of population that will probably produce changes in the land use composition of the area. At the same time, the medium zone of the river and delta has a high pressure of occupation from agriculture, industry and urbanization making it more susceptible to develop problem at social scale in the occurrence of high intensity rainfall events.
Damage generate by the Gloria storm flood event at the mouth of the Tordera river.
