Landslides occur when the earth at a higher elevation of a hill or a mountain becomes unstable, due to rain or other seismic phenomena, and causes an impactful slide of the soil, mud, and rocks down through the slopes to lower areas. Several regions in Kerala, especially in Western Ghats, are at risk of landslides, with soil piping being a major factor.
The massive landslide that occurred at Puthumala in Wayanad was attributed to soil piping. Meppady is a place located not so far from Puthumala and experts believe that the landslide in Mundakkai may be linked to it as well.
The clay soil found in landslide-prone areas tends to accumulate beneath rocks. This mud carries so much water but does not release it, making it ready to unleash landslips.
Arun P R, a senior scientist at the Centre for Water Resources Development and Management (CWRDM), explains the phenomenon in detail: "When large trees are cut down, their roots left there decay eventually, allowing water to seep into that void. Over a period, this causes the soil to slip down, a process known as soil piping. This underground phenomenon can lead to abrupt soil movement and trigger landslides."
When an area is marked as landslide-prone, it should also include its catchment area and the valley where stones and soil are deposited. Particular care should be taken if the slope exceeds 22.5 degrees. Planting local tree varieties with deep roots in such areas is recommended to help stabilize the soil and prevent landslides. These roots can grip the stones beneath the soil and hold the soil together.
Bamboos that grow in the catchment areas of landslide-prone locations can help regulate the flow of water to vulnerable zones. While the revival of grasslands is not generally recommended, grass varieties like Ramacham (Vetiver) can aid in water absorption into the soil. Each of these disasters serves as a reminder that all construction work in hilly areas should be conducted strictly in line with geographical and biodiversity guidelines.
