Reducing the risk of landslides and erosion

Signs to look out for

• Trees and poles on a slope start to lean in the same direction.
• Chunks of earth begin to slide. Small landslides (initial landslides) can be a sign that a larger landslide may occur.
• Erosion damage to watercourses.
• New or growing cracks in the ground.
• Subsidence in buildings, doors and windows that cannot be opened.
• Ruptured pipes or broken cables in the ground.
• A sudden interruption of flow, increased flow or higher turbidity in a watercourse may indicate a landslide or avalanche upstream.
• In the case of rockfalls, loose boulders on the slope

Activities that can trigger landslides and avalanches

These activities can trigger landslides and avalanches.

Increased load on the crest of a slope

• Heavy objects, such as parked cars, scrap metal, excavated materialor piles of timber weighing down the slope.
• Garden waste dumped on the slope increases the load on the slope and can smother vegetation.
• Piles of snow dumped on the slope increases the pressure on it, and meltwater from the snow can erode the soil.
• Heavy rainfall or leaking water and sewer pipes that leads to water accumulating in the soil.

Reduced counterweight in slope base

• Excavation at the bottom of a slope increases the risk of landslide.
• Rain and meltwater from roofs and streets, and drainage water that is channelled on to a slope, can excavate and wash away the soil. The soil around the outlet of a pipeline should therefore be protected from erosion using gravel.
• Fills, jetties, piers and erosion protection can change the flow of a watercourse A and new part of a slope may be exposed to water erosion, resulting in a landslide. If you construct something that causes damage downstream you may be liable to pay compensation. To carry out works in the water, you may need a permit under the Environmental Code.
• Severe disturbance, such as an explosion or vibration in the ground.

Repairing the ground

A slope or hillside damaged by erosion can be repaired by planting cuttings or tree seedlings where the soil is damaged. Use tree species that are naturally found in the area. The roots of the trees hold the soil together, thus preventing erosion, and should be left on the slope.

However, you can cut down large, individual trees that begin to lean. Like trees, plants are important because they absorb water and bind the soil together.

Contacting municipalities

You can always contact the local planning office in your municipality, or the municipal rescue services, if you have any questions about landslides.