Consulting

The SISKA develops methods and applies tools for the study of the vulnerability of groundwaterthe delimitation of protection zonesand the search for sources of pollution.

In collaboration with other specialist partners, the SISKA offers solutions for prospecting and exploiting groundwater, including analysis of spring flows and simulation of flows under different scenarios (meteorological, anthropogenic impacts, exploitation strategies).

The SISKA proposes specific approaches for assessing the hazards posed by karst for various constructions and activities.

Civil engineering and karst

When building, particularly underground (tunnels, galleries, reservoirs, etc.) the karstic environment can represent a problem for the structure (unexpected vacuum, water under pressure and in large quantities, presence of poorly consolidated sediments). Thanks to the Karst ALEAthe SISKA can predict potential hazardsand propose protective measures to minimise them, and recommendations to manage them in the event of a problem.

Wind turbines and karst

The SISKA develops methods for assessing and supporting the siting of wind farms in karst regions. The aim is to minimise the dangers of karst for the stability of infrastructures. An information brochure on this issue has been published by the SSS.

Infiltrations

In an urban karstic environment, the federal recommendation to infiltrate grey water (roof and road water) is problematic insofar as this infiltration tends to cause collapses. The SISKA can draw up collapse hazard maps and assessments at plot level. In the event of a collapse, targeted recommendations can be issued.

If infiltration sites are selected, the SISKA can issue recommendations on the conditions and flow rates of infiltrable water.

Collapse hazards

The karstic subsoil contains numerous cavities, sometimes covered by a thin layer of soil. Collapses are therefore not uncommon. The SISKA can draw up collapse hazard maps and assessments at plot level.

Geothermal

The specific characteristics of karst can lead to poor dimensioning of geothermal projects. Indeed, due to the significant circulation of air and water, karstic massifs are colder than other types of environment. However, karstic springs drain geothermal heat and represent interesting resources. The SISKA has unique expertise that enables it toassess energy potential and the strategy for geothermal exploitation in carbonate regions.

The SISKA can draw up prescription maps for the installation of geothermal probes based on groundwater vulnerability criteria.

The construction of structures and various human activities (tunnels, galleries, roads, wind turbines, geothermal energy, infiltration of grey water, etc.) can have an impact on the karstic environment. The SISKA is specialised in assessing and minimising these impacts, in accordance with the Ordinance on Environmental Impact Assessment (OEIE).

The SISKA has developed a series of tools and methods for such assessments (Visual KARSYS, Karst ALEA and others).

Impact on groundwater

In karstic environments, almost all rainwater infiltrates the subsoil and travels in a few days to a few weeks to the springs that feed the rivers. Developments and structures can modify the water regime, flow and quality. These changes can be critical for drinking water catchments, rivers and underground aquatic fauna. The SISKA can assess these impacts and seek solutions to minimise them.

Impact on underground fauna

The underground environment is home to a specific and varied fauna, including several endemic species. Underground habitats are very stable because they are little affected by external variations (climate, urbanisation, etc.). However, their inhabitants are very sensitive to change. The SISKA can assess the fauna present, the sensitivity of the habitats and the potential or actual influences of a development or construction project.

Impact on the underground climate

The temperature underground is almost constant and the air is humid (>98%) all year round. Any disruption to these weather conditions will have an impact on the cave, the fauna and any archaeological objects found there. The underground atmosphere is often enriched with CO₂ and radon, which can pose problems if the area is occupied for long periods (e.g. archaeological excavations, tourist visits). The SISKA knows and measures the characteristics of the underground climate and can therefore assess the impact of a development or construction project.

Impact on the karstic landscape

The karst landscape is a heritage recognised throughout the world (18 sites listed on the World Heritage List). UNESCO World Heritage Site and many sites listed in the federal landscape inventory). In Switzerland, sinkholes, potholes and caves are often not explicitly inventoried, even though they form part of the country's natural heritage. The SISKA can identify these objects, assess them and seek solutions to minimise potential impacts.

The Karst ALEA method has been developed to predict the position and characteristics of karstic cavities in a limestone massif. It is useful for assessing the problems that the karstic environment may pose during the construction of a structure, as well as for evaluating the impact of the project on the environment.

It also serves as a basis for drawing up collapse hazard maps.

Link to applied methods Karst ALEA