KOCHI: The massive landslide that swept away two hamlets causing death and devastation at Mundakkai and Chooralmala in Wayanad once again highlights the need to have a long-term strategy to avoid loss of life and property. Kerala has been witnessing landslides every monsoon since 2018 which has spread fear and anxiety among the people in the high ranges.
With climate change increasing the possibility of extreme precipitation in critical zones, the state needs to adopt mitigation strategies that can reduce the impact of extreme events. Climate resilience will be key to lessen the impacts and we need innovative solutions to avoid human casualty.
Though conservationists demand the evacuation of people from critical zones and complete termination of development activities in the high ranges, this seems impractical considering the density of population and the livelihood of the farmers. This underscores the need to strike a balance between development and conservation and steps to secure the lives of the people living on the slopes. The state needs to regulate construction activities and to implement building technologies that reduce the impact on the terrain.
The peaks with steep slopes are vulnerable to failure in case of extreme rainfall. Removal of deep-rooted trees that bind the soil together is another factor contributing to landslides. According to earth scientists, any peak with a slope of more than 20 degrees is vulnerable in case of extreme rainfall. If the area receives more than 12 cm of rainfall in 24 hours, the slopes can fail due to the heavy flow and piping phenomenon.
According to elders, nature has an early-warning system that gives indications of landslides in advance. The trees will start leaning and new springs will appear on the slope. The water in the stream will turn muddy ahead of the landslide.
Slope and change in land-use pattern critical
There are many factors that trigger a landslide, including extreme rainfall, steepness of the slope, the height and shape of hills, thicknesses and permeability of soil, the width of the valley, the change in land-use pattern, construction activities, destruction of natural vegetation, blockage of first-order streams, said earth scientist and former director of water resources department V Subhash Chandra Bose.
“There are many peaks in Wayanad with steep slopes where the disturbance of soil stability for cultivation and construction of buildings has increased landslide susceptibility. In view of the IMD forecast about heavy rainfall in September, the authorities should initiate precautionary measures immediately,” he told TNIE.
Kurichiarmala is the highest of all peaks and has a slope of 90 degrees. “The risk of landslides is high in this area due to high human intervention, including agriculture and construction activities. Amboottimala of Ambalavayal-Nenmeni, Manikonnamala of Thariyodu-Vellamunda area, the hills adjacent to Banasurasagar and Kurumbalakottamala of Kottathara panchayat are the other peaks that have steep slopes of more than 80 degrees. These areas are landslide hot spots,” said Bose.
“The government should implement the concept of seasonal rehabilitation of people living in vulnerable areas to avoid loss of human lives. There are hundreds of resorts in the area and the authorities should make it mandatory for them to give free accommodation to people evacuated from vulnerable areas while issuing the licence. Wayanad district should have a master plan for rehabilitation of people from the valleys which could be implemented over the next 25 years. We should develop townships in safe zones,” he said.
Kerala needs landslide hazard regulatory framework
Landslides can potentially become more common in Kerala due to the climate change scenario resulting in the intensity of precipitation events, said scientist and consultant of the National Centre for Earth Science Studies (NCESS), K K Ramachandran.
“The foremost importance is for the identification of landslide-susceptible locations through a micro-mapping campaign incorporating cadastral parcels. Finalisation of such high-risk locations should be done based on the slope, geology, soil, land use, and local traditional knowledge incorporating historic landslides. It should be participatory for wider awareness and acceptability. This should lead to a Landslide Hazard Regulatory Framework having an implementation jurisdiction from local self-government to the state level,” he said.
“Mitigation strategies need to be two-fold in the sense that the landslide as a hazard needs to be addressed first, followed by the hazard turning into a disaster with the loss of lives and properties. Depending on the relative potential of contributing factors, mitigation strategies also can vary. For example, potential land-use modification solutions for risk reduction as enumerated in the Gadgil report can be adopted. Towards this, land-use regulatory codes need to be adopted for effective mitigation including restrictions and moratoriums for constructions,” said Ramachandran.
Localised planning to evolve development model
The Kerala State Disaster Management Authority (KSDMA) will consider certain changes in the standard operation procedure for orange alert in the backdrop of the lessons learnt from the Mundakkai disaster, said member secretary Sekhar Kuriakose.
“Presently, forceful evacuation is linked to Red Alert. But Mundakkai has taught us that we should consider Orange alerts also for forceful evacuation. There was no laxity in Mundakkai and Punchirimattom areas as the district panchayat president, who is also the co-chairman of the District Disaster Management Authority, had visited the area and requested the residents to evacuate on July 29. Those who took the alert seriously were saved,” he said.
“We should have a localised consultative process for development. We should evolve a strategy through consultation at the local-level and the Town and Country Planning department (Local Self-Government Engineering department). The development strategy has to be terrain-specific and we should consider various factors like socio-economic stature, land suitability and land availability,” said Kuriakose.
“The strategy for the slopes of Mundakkai and Punchirimattom has to be different from Chooralmala which is a valley. This granularity is something you cannot capture by data collection alone. That is the spirit of preparing local self-government disaster management plans and risk-informed development plans. There are already orders issued, and the government has provided funds to facilitate the process,” he said.
Factors triggering landslide
Extreme rainfall
Steepness of the slope
Height of hills
Shape of hills
Thicknesses and permeability of soil
Width of the valley
Change in land use pattern
Construction activities
Destruction of natural vegetation
Blockage of first-order streams
Solutions
Avoid agriculture practice and human intervention above slopes of 22 degrees
Protect forests
Plant deep-rooted plants
Maintain slope in construction
Promote land water and biomass activities
Protect the side wall of roads with bio fencing using vetiver, bamboo, etc.
Construction material should be eco-friendly and disaster-responding
Ensure proper drainage systems for rainwater flow
Proper village-level database and warning system
Rehabilitation facilities
‘CARE’ RECOMMENDED
Kerala needs a four-pronged approach to mitigate tragedies, says Thomas Oommen, Chair and Professor, Department of Geology and Geological Engineering, The University of Mississippi, USA.
In recent years, Kerala has experienced an alarming increase in landslides, with the devastating incident in Wayanad serving as a stark reminder of the urgent need for a mitigation strategy. This tragedy has prompted a critical question: Should we continue to respond to these disasters in the same way, or should we adopt a more strategic approach to prevent future tragedies like the one in Wayanad? Kerala needs better identification, monitoring, and mitigation efforts.
To achieve this, four strategic initiatives—CARE (Coordinate, Assess, Respond, Empower)—are recommended:
Coordinate: There must be collaboration among government agencies, non-profits, academic institutions, and citizens to develop a unified strategy and best practices for landslide hazard identification, mitigation, monitoring, response, and recovery.
Assess: Accurate assessment of landslide hazards and risks at the appropriate scale is essential for providing decision-makers with the information needed for effective policy and decision-making.
Respond: Landslide monitoring and warning systems should be data-driven, ensuring they are efficient, effective, and beneficial for communities in protecting lives and property.
Empower: Vulnerable communities must have open access to data on landslide risk information, empowering them to take proactive measures to protect themselves.
Forecasting landslides is inherently difficult, but the lack of real-time monitoring and comprehensive data collection compounds the situation. This shortfall makes it nearly impossible to issue adequate early warnings to at-risk communities. By embracing these strategies, Kerala can move towards a safer future, where the risk of landslides is managed more effectively, and tragedies become a thing of the past.
(To be concluded)