Site description

The Alptal-valley (canton Schwyz) in a subalpine region in central Switzerland has been a hydrological test site of the WSL for several decades. Precipitation, runoff, sediment transport, snow cover development and other hydro-meteorological variables have been measured. The Alptal is situated in the pre-alpine flysch region south of Einsiedeln. The majority of the soils are rich in clays, with small permeability and low thickness. The bedrock, flysch, is basically impermeable. At an average yearly precipitation of ~2200 mm floods are common. Three catchments with different landuse and different fraction of forested areas have been monitored over several decades. They have drainage areas between 0.75 and 1.5 km2 and lie at elevation between 1000 and 1600 m a.s.l. The forest consists of sub-alpine spruce, with maple and beech common at lower elevation. In two of the catchments the grassy areas are used as pastures, while in the third catchment they are left to natural reforestation.

The weekly hydrochemical measurements from the three small torrents are a part of the National River Monitoring and Survey Programme (NADUF).

The facilities of WSL are also used for student excursions where hydrological measurement techniques are demonstrated and the complex hydrological processes of a sub-alpine area are illustrated. For the coming years we plan to extend the installation towards a user lab for students and the general public.

Map of the catchments

Table with catchment characteristics