'Friendly ' Control of SOIL INSTABILITY

Example of landslide in ilustration version

Landslides cause bilions of dollars in property damage and thousands of deaths and injuries each year. In Malaysia, 460 landslides were reported since 1975. Of these, 30 cases were classified as major landslides.

• Landforming to increase the benefits of grass and woody slope covers with respect to erosion and stabililisation


• Optimise slope drainage


• Improve slope maintenance

Slope instability or landslide is typically associated with periods of heavy rainfall. In Malaysia, the higher grounds receive an annual rainfall as high as 4500 mm. The combination of high rainfall and high temperature all-year round causes intense chemical weathering and formation of thick soil profiles. In certain locations, the soil profile can reach 100 m in depth. The combination of a hot tropical climate, geological conditions, and other factors worsen slope instability. Slope instability is very destructive. Thos problem is likely to get worse due to extreme weather or global warming unless preventive measures are taken.

Preventive measure to reduce slope instability:

• Bio-engineering (veegetation) approach to design slope covers

Bio-engineering relies on a combination of structural components and plant materials to produce a dense crop of vegetation that serve as a "living system" to stabilise the hill slope, thereby, taming soil erosion.

The bio-engineering approach for slope cover has the following benefit:

1. Environment: Increase carbon sequestration to counter rising carbon dioxide level in the atmosphere.
2. Mechanical: Reinforcement of rooted soil, thus, preventing soil surface erosion and slope failure.
3. Hydrological: Reducing runoffs by intercepting rain water. Water entering the slope will weaken the slope. By keepong the slope dry, soil suction is maintained keeping the slope strong.