The recent devastating landslides in Kerala’s Wayanad district, resulting in at least 193 deaths and numerous individuals being trapped, underscore the urgent need for immediate micro-level mapping of landslip hazard zones throughout the state. This proactive measure is crucial for disaster preparedness and response.
Additionally, it underscores the extreme importance of relocating and rehabilitating people residing in environmentally vulnerable danger zones, as failure to do so could lead to further loss of life and property.
The state government has repeatedly ignored this crucial issue since the devastating floods in 2018 caused numerous landslides in hill districts like Wayanad and Idukki.
Despite extreme weather events becoming an annual reality in the state for the last six years, this pressing issue has consistently been relegated to the back burner.
The Western Ghats, which run throughout Kerala, are prone to frequent landslides during the biannual monsoon seasons—the South West monsoon and the North East monsoon. Unlike other natural hazards, landslides can be triggered by various factors, such as slope failure, heavy rainfall, soil depth, earthquakes, thunder, and human activities.
Read more: Wayanad landslides: 160 bodies recovered, rescue operations underway | 10 points
Anthropogenic factors include loading the slope’s crest, excavation at the toe of the slope, deforestation, quarrying, mining, and land use patterns, which also aggravate it.
However, the principal triggering factor is the heavy, aggressive rainfall that is short.
The first officially recorded flood in Kerala occurred in 1881, and the oldest known landslide in Kerala happened on October 4, 1882, at Meladukkam, Kottayam.
Residents of Kodiyathoor, near Kottayam, came up with the word “Urulpottal” (debris flow) in 1949 after a landslide in the hilly area.
Landslides occur when a part of a hill moves down. Experts say that in Wayanad’s Chooralmala and Mundakkai, the phenomenon of Soil Piping played an important role in inducing the landslides.
They say the surface soil in the area is unconsolidated and unsorted. In such soil, rainwater causes underground flow, removing the clay content and causing interconnected tunnels. These interconnected tunnels act as paths for massive water discharge and soil erosion, and they are called piping.
In the case of Wayanad, environmental experts, including those in the Madhav Gadgil committee, had called for the rehabilitation of people residing on vulnerable hill slopes with an incline of over 22 degrees, given the possibility of widespread landslips and landslides. Those experts found the areas vulnerable, including where the landslides occurred on Tuesday.
In recent years, the state disaster management authority divided the hill district into three based on landslide susceptibility risk and has also come.
With a landslide susceptibility map for the district. However, rehabilitation was not initiated despite repeated warnings of lurking extreme weather events.
A professional study that the state government commissioned suggested setting up separate disaster management systems.
Action plans for panchayats classified under the district’s high, medium, and low categories for landslide susceptibility.
A study by the Kerala Sasthra Sahitya Parishad, a popular science forum, found that the district’s hill slopes have become unstable. Following the constructions carried out on the slopes by unscientifically levelling the slopes, many areas have become landslide-prone after digging rainwater harvesting pits and changes in land use patterns like monocropping and deforestation, which have continued for decades.
According to the authority, Meppadi, Muppainad, Vythiri, Pozhuthana, Vellamunda, Thondernad, Mananthavady, Thirunelly, Muttil, and Kottathara are listed as places at high risk of landslides. Chooralmala and Mundakkai have a long history of massive landslides, and the crop tea plantations have significantly contributed to the tragedies unfolding over the years.
CK Vishnudas, the executive director of the Hume Centre for Ecology, emphasised the need for immediate attention to rehabilitating individuals residing in high-risk regions.
As stated in the Gadgil Committee report, Kavalappara in Malappuram district and Puthumala in Wayanad district, which witnessed multiple fatalities due to landslides in 2020, are included in the Ecologically Fragile Land (EFL) category.
A catastrophe occurred again in the areas designated as Ecologically Fragile Land (EFL) in the report Gadgil gave to the then-Union forest-environment minister, Jairam Ramesh. By the way, the distance between Puthumala, Chooralmala, and Mundakkai is just under two kilometres.
In 2011, the Western Ghats Ecology Expert Panel (WGEEP) officially identified this area as having the greatest ecological sensitivity and named it Ecologically Sensitive Zone (ESZ) 1.
Quarrying, the process of extracting materials from the earth, the destruction of hills for construction purposes, the construction of large-scale roads, the expansion of land in hilly areas, and the cultivation of a single crop over a vast area all contribute to the occurrence of landslides. Climate change makes these landslides worse by intensifying the continuous, heavy rainfall.
These demonstrate the lack of a national policy addressing the vulnerability of people living in ecologically vulnerable areas to annual landslides and floods.
T V Sajeev, a principal scientist at the Kerala Forest Research Institute, states that quarrying, the destruction of hills for construction purposes, extensive road construction and expansion in hilly areas, and the cultivation of single crops are significant factors contributing to landslides caused by heavy and continuous rainfall.
CP Rajendran, a geoscientist and professor at the Jawaharlal Nehru Centre for Advanced Scientific Research in Bengaluru, asserts that Kerala urgently needs to establish unambiguous land management and water usage regulations.
In addition, it is imperative to develop enduring measures to mitigate the impact of yearly floods and landslides, particularly affecting impoverished individuals residing in environmentally vulnerable areas.
He emphasises the need to pay greater attention to altering land use patterns and implementing large-scale initiatives with significant environmental consequences.
Rajendran states that the state must implement land use zoning restrictions, including data on landslip susceptibility. Kerala encompasses approximately 19,000 square km of hilly terrain with slopes above 10 degrees. “These regions exhibit sparse vegetation cover and have experienced significant disruption due to human activities,” he stated.
Additionally, he believes that a map indicating the susceptibility of landslides can help the state comprehend the type and extent of potential landslides in various regions.
Hydrogeologist V R Haridas states that landslips and similar phenomena have recently occurred in Kerala. Therefore, the state must develop long-term measures to deal with this issue effectively. Having conducted a thorough investigation of the Kavalappara and Puthumala landslides as part of the National Bank for Agriculture and Rural Development’s (NABARD) Climate Adaptive Project, this expert believes that the soil composition in Kerala has seen significant and dramatic changes.
“The altered soil composition appears unable to endure intense rainfall.” The changes that have taken place in the past three years have been consistent. “Without comprehensive and scientific approaches, landslides resulting in significant casualties would occur yearly,” he stated.
He suggests that monocropping may have contributed to the situation in Pettimudi, whereas indiscriminate granite quarrying is the primary cause in other areas, such as Wayanad, Pathanamthitta, and Malappuram.
Das reports that Wayanad is currently experiencing a situation where the slopes of the hills have been saturated due to exceptionally heavy rainfall in the past week.
“If the rainfall continues, there is a genuine danger that it could cause lateral displacement and raise the likelihood of the overburden slipping,” he states.
According to the Kerala Disaster Management Authority, the occurrence of landslides should not have been unexpected. In the last week, there has been a significant increase in rainfall in the high-range districts of Kerala, which include Wayanad, Idukki, Malappuram, and Kottayam.
Frequent tectonic activity, coupled with fluctuating weather patterns resulting from global warming, are identified as causative factors for natural disasters, such as landslides, in the Himalayan region. “We must conduct scientific research on tectonic activities in Kerala, particularly in the higher elevations of Idukki,” Mohan stated.
According to a recent study by the Kerala University of Fisheries and Ocean Sciences (KUFOS) in partnership with Michigan Technological University and the Indian Institute of Tropical Meteorology, Pune, approximately 13% of Kerala’s land is highly susceptible to landslides.
