Hydrology of the Bernese Fens

HUB BERN | Project LANAT-5

Our goal:

Our aim is to support the creation and application of hydrological bases for the long-term conservation and rehabilitation of fens.

Intact fens, such as that pictured here on Engstligenalp, are important water reservoirs. They are central to protection of biodiversity and the climate. Photo: Hintermann & Weber

In a nutshell:

Fen habitats are biotopes with highly specialized flora and fauna, historically used as pastures or meadows. Intact fens play a crucial role in CO2 storage and act as valuable water reservoirs. With proper guidance, they can also serve as appealing recreational areas for visitors. Fens heavily rely on water and are vulnerable to climate change. According to the federal Fens Ordinance, adequate ecological buffer zones must be established around them, to allow proper water balance and long-term protection. A detailed analysis of the hydrological conditions in the vicinity of a fen is used to determine the areas from which the water balance of the fen is influenced by inflow or outflow; the so-called hydrological precautionary perimeter. For the 106 Bernese raised bogs, the hydrological precautionary perimeter was ruled out by an expert. Up until now, this important basis for the restoration and preservation of the fens has been lacking.

Thus, in a first step, an impact model was created as part of this project. It displayed robust results for fens in areas with impermeable subsoil. However, the model needs to be improved to be applied in areas influenced by groundwater near lakes and rivers. In a second step, the impact model will be tested in practice using topographic, geological, and vegetation data. The model will then be applied to all Bernese fens of national or regional importance. The precautionary perimeter enables the leading authorities and specialist agencies to adequately take into account the hydrological conditions in specific planning and projects. To facilitate the implementation of the precautionary perimeter, a working guide is being developed for the authorities.

The Hohgant-Seefeld nature reserve: karren fields and sinkholes are typical of karstic areas. Modelling the water balance is challenging because waterflows mainly occur underground. Photo: Dominique Hindermann (Archive ANF)

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In collaboration with:

Amt für Landwirtschaft und Natur des Kantons Bern LANAT (Office for Agriculture and Nature of the Canton of Bern)