A contaminated landslide runout deposit will thus act as a source of contamination to the downstream water system until all the contaminated deposit has been eroded away and the contaminants have been transported from the deposit to the river, and further to the river mouth – diluted but not necessarily negligible.

The impact of a landslide can be extensive, including loss of life, destruction of infrastructure, damage to land and loss of natural resources. Landslide material can also block rivers and increase the risk of floods.

Water can trigger landslides and mudslides because it alters the pressure within the slope, which leads to slope instability. Consequently, the heavy water-laden slope materials (soil, rock, etc.) will succumb to the forces of gravity. Excessive water is thought to be one of the most common triggers for landslides.

Floods cause erosion because the amount of power that the flow of water brings is often sufficient enough to completely tear away top layers of soil. …

Water erosion. This includes the splashing of soil particles by raindrop impact; sheet erosion whereby a layer of topsoil is removed by flowing water; and gully erosion where a channel is formed. Gullies are often perceived as the most serious form of water erosion because they are obvious features in the landscape.

Below are the common water erosion types that can affect soil if not prevented promptly.

• Splash Erosion. This is the first stage in the erosion process that is caused by rain.
• Sheet Erosion.
• Rill Erosion.
• Gully Erosion.
• Tunnel Erosion.
• Impact On Flora.
• Impact On Fauna.
• Flooding.