Research at the Vallcebre catchments started in 1989, with the objective of better understanding the hydrological functioning of Mediterranean mountain catchments. Along with the monitoring of weather, precipitation and stream flow variables, several state variables (soil moisture, water table,...) and processes (rainfall interception, tree transpiration,...) are measured all the time or for periods lasting several years.
The Vallcebre catchments are located at the headwaters of the Llobregat river, on the southern margin of the Pyrenees (Catalonia, North-east Spain) at latitude 42º 12’ N and longitude 1º 49’ E, at an altitude of 1,100 to 1,700 m a.s.l. The research area consists of two catchment clusters, whose centers are 2.5 km apart. The main cluster (Cal Rodó catchment, 4.17 km2) was sub-divided into three sub-catchments, whereas the smaller cluster (Cal Parisa catchment, 0.32 km2) consists of two catchments of similar size.
The catchments are covered by pasture and forest, resulting from spontaneous forestation by Pinus sylvestris after land abandonment. Some small, intensely eroded areas of badlands topography are also present in the catchments.
Climate is humid Mediterranean, with a marked water deficit in summer. Mean annual temperature is 9.1ºC and long-term mean annual precipitation is 862 ± 206 mm. Long-term mean annual reference evapotranspiration is 823 ± 26 mm. Mean annual runoff in the Vallcebre catchments is around 302 ± 222 mm (equivalent to 37% of rainfall). Stream-flow is highly seasonal: the stream dries out in summer every 2 years on average, for a period ranging from 15 to 40 days. Stream-flow is rather flashy in the catchments, with a response time of around one hour.