Scientific description of the area
The LIC area of the Banyoles lake has a surface area of 1031 ha, and the areas affected by the LIFE project cover approximately 408,7 ha.
The area is part of the Lake Basin of Banyoles and is the lower point of an outcrioop of a major hydrogeological system.
The waters of this lake area come from the Alta Garrotxa, 50 km to the north, where they seep through the calcareous terrain towards the aquifer. The lake, the small ponds and the emergences configure the lowest point of the extensive hydrogeological system where the waters flow underground towards the north-south and due to a fault ascend and dissolver the chalk and calcareous layers. This dissolution eventually causes the land to collapse (dolines) and gives rise to lakes and emergences.
The Banyoles lake is comprised of a set of 6 basins and 13 points of underground water emergence. The most immediate area of the lake boasts different permanent small ponds such as those of the Cendra, Montalt, Can Ordis and Can Cisó or the Nou, which was formed in 1978. Also frequent are temporary lakes such as the beach of Espolla, with a surface area of 3 ha, and the emergences from the plain of Usall.
The receiving basin of the Banyoles lake is about 12.1 km2 and provides about 20 % of all the water of the lake; 80 % correspond to underground feeds. Only 4 of the torrents that carry water to the lake are permanent, whereas the others depend on the rains. Five channels in the south-east collect the water from the lake.