The Impact of Land Use and Land Cover Change on Landslides and Floods in Wayanad: Causes and Mitigation

Wayanad, a picturesque district in Kerala, India, is renowned for its lush greenery, wildlife sanctuaries, and rich cultural heritage. However, this scenic region has been increasingly plagued by landslides and floods, particularly during the monsoon season. A critical factor contributing to these disasters is the rapid and often unplanned land use and land cover (LULC) changes, especially due to quarrying and deforestation. The following sections delve into the various aspects of how LULC changes lead to landslides and floods in Wayanad, and explore potential mitigation measures.

Understanding Land Use and Land Cover Changes

"Land Use" refers to the human utilization of the land for various purposes such as agriculture, urban development, forestry, and mining. "Land Cover" represents the physical material at the surface of the earth, such as vegetation, water bodies, bare soil, and artificial structures.

In Wayanad, significant LULC changes have occurred over the years:

• Deforestation for agriculture and plantations.
• Quarrying activities for granite and other minerals.
• Urbanization and infrastructure development.

Causes of Landslides and Floods

1. Deforestation and Vegetation Loss:

Root Structure Removal: Trees and vegetation stabilize the soil with their root systems. Deforestation weakens this natural support, making the soil more prone to erosion and landslides.

Increased Runoff: Vegetation intercepts rainfall, reducing the volume and speed of runoff. The removal of trees and plants leads to higher runoff, contributing to both landslides and floods.

2. Quarrying:

Terrain Instability: Quarrying involves the removal of large amounts of earth and rock, destabilizing slopes and making them susceptible to landslides.

Water Infiltration: Quarries can alter the natural drainage patterns, increasing water infiltration into the ground, which can trigger landslides.

Dust and Debris: Quarrying generates dust and debris that can block natural drainage channels, exacerbating flood risks.

3. Urbanization:

Impervious Surfaces : Urban development creates impervious surfaces like roads and buildings, which prevent water from infiltrating the soil, leading to increased surface runoff and potential flooding.

Poor Planning: Rapid and unplanned urbanization often ignores the natural topography and drainage patterns, aggravating flood risks.

Case Studies

1. Puthumala Landslide (2019): In August 2019, a devastating landslide struck Puthumala in Wayanad, resulting in 12 deaths and extensive property damage. The incident was attributed to deforestation and unregulated quarrying activities that destabilized the soil and slopes.

2. Meppadi Landslide (2019): The same monsoon season saw another significant landslide in Meppadi, Wayanad, where several people lost their lives, and many were displaced. The continuous heavy rains coupled with deforestation for cardamom plantations were identified as the primary causes of this disaster.

3. Malappuram Landslides (2020): In the neighboring district of Malappuram, multiple landslides occurred in August 2020, killing 52 people. The landslides were exacerbated by heavy monsoon rains and the deforestation for rubber and other plantations, which weakened the soil structure and increased runoff.

4. Uttarakhand Floods and Landslides (2013): Beyond Kerala, the 2013 Uttarakhand disaster serves as a stark reminder of the dangers of unregulated land use. Excessive deforestation, rampant construction, and unplanned tourism development along with the glacial lake outburst floods (GLOFs) triggered devastating landslides and floods, resulting in thousands of deaths and significant destruction.

Triggering Factors

Landslides are caused by a combination of conditioning factors (related to soil, topography, rocks, geomorphology, and slope angles) and triggering factors (intense rainfall and human activities).

1. Conditioning Factors:

Soil and Geology: The soil's composition and the underlying geology significantly influence landslide susceptibility. Regions with loose, unconsolidated soils are more prone to landslides.

Topography: Steep slopes and rugged terrain are naturally more susceptible to landslides.

2. Triggering Factors:

Heavy Rainfall: Intense and prolonged rainfall can saturate the soil, increasing its weight and reducing its cohesion, leading to landslides.

Deforestation and Land Use Changes: Removing vegetation for agriculture, plantations, or construction destabilizes the soil.

Quarrying and Mining: These activities disturb the natural stability of slopes.

Urbanization: Unplanned development increases surface runoff and disrupts natural drainage systems.

Mitigation Measures

1. Afforestation and Reforestation:

Planting Trees: Reforestation and afforestation can help stabilize the soil and reduce runoff. Native species should be prioritized for better ecological balance.

Protecting Existing Forests: Implementing strict regulations to prevent further deforestation and degradation of existing forests.

2. Regulating Quarrying Activities:

Zoning and Planning: Quarrying should be restricted to areas less prone to landslides. A detailed geological survey should precede the approval of new quarries.

Sustainable Practices: Implementing sustainable quarrying practices, such as controlled blasting and proper waste management, to minimize environmental impact.

3. Improving Urban Planning:

Flood-Resistant Infrastructure: Designing urban infrastructure to accommodate natural drainage patterns and including green spaces that allow water infiltration.

Regulating Construction: Enforcing building codes and regulations that consider the topography and potential flood risks.

4. Early Warning Systems and Community Awareness:

Monitoring and Alerts: Installing early warning systems for landslides and floods, leveraging technology to provide timely alerts to residents.

Education and Training: Conducting awareness programs for communities on disaster preparedness and response.

5. Soil and Water Conservation:

Terracing and Contour Plowing: Implementing agricultural practices that reduce soil erosion and runoff.

Rainwater Harvesting: Encouraging the collection and storage of rainwater to reduce surface runoff and replenish groundwater.

6. Geotextiles for Slope Stabilization:

Erosion Control: Geotextiles, which are permeable fabrics, are used to prevent soil erosion by stabilizing the soil. They act as a barrier that holds the soil in place while allowing water to pass through.

Soil Reinforcement: By reinforcing the soil, geotextiles enhance its shear strength, which is critical for slope stability. This reduces the likelihood of landslides in vulnerable areas.

Drainage Improvement: Geotextiles help improve drainage by facilitating the removal of excess water from the soil, thereby reducing pore water pressure and the risk of soil slippage.

Vegetation Support: These fabrics support vegetation growth by maintaining soil structure, which further stabilizes the slopes through root reinforcement.

Conclusion

The frequent landslides and floods in Wayanad underscore the urgent need for sustainable land use and land cover management. By adopting a multi-faceted approach that includes afforestation, regulated quarrying, improved urban planning, the use of geotextiles for slope stabilization, and community awareness, Wayanad can mitigate the adverse impacts of these natural disasters. It is imperative for policymakers, local authorities, and the community to work together to protect Wayanad’s fragile ecosystem and ensure a safer and more resilient future for its residents.