Since the onset of the south-west monsoon on May 29, Wayanad district in Kerala has experienced 247 landslides, landslips and land subsidence or cave-ins. A large number of these occurred on August 9. This is quite unusual as the hilly district – part of the ecologically fragile Western Ghats – did not register a single landslide or landslip in the last three years while the last reported case of land subsidence dates back to 2008.
This has raised concerns about the changing nature of Wayanad’s land and the increasing vulnerability of one of the most ecologically sensitive regions in the world.
“There were 47 landslides, 155 landslips and 45 [instances of] land subsidence from June 1 to August 30 this year,” said district soil conservation officer PU Das. “The geological incidents left a trail of destruction in the district. This is a record of sorts.”
Landslides and landslips are defined as the mass movement of rock, debris or earth down a slope. During landslides, the earth breaks as it cannot withstand the pressure exerted by rain water while landslips usually occur when layers of soil disintegrate under pressure. Land subsidence is any downward movement of soil that causes the land to sink or collapse. Deep cracks or fissures in the land are signs of subsidence.
Natural phenomenon like heavy rain and human activities such as deforestation and quarrying are usually the factors behind these geological processes. According to a preliminary examination by experts in Wayanad, the marshy nature of its land may have caused the subsidence.
As Kerala experienced its worst floods in a century that left 483 people dead, Wayanad received an average 2,944 mm of rainfall between June 1 and August 29 – 24% higher than the normal precipitation for this period. The catchment area of the Banasura Sagar dam, 20 km northwest of district headquarters Kalpetta, received the highest rainfall of 4,824 mm, causing floods. Later, landslides, landslips and land subsidence virtually cut off the district from the rest of the state for many days.
Vulnerable Western Ghats
Kerala accounts for 18% of the 1,600-km-long Western Ghats, a mountainous stretch that runs through five other states – Maharashtra, Gujarat, Goa, Karnataka and Tamil Nadu. The Western Ghats are said to be one of the eight “hottest hotspots” of biological diversity in the world.
Yet, attempts to conserve this ecologically sensitive mountain range and bring it under strict development rules have been met with stiff resistance from all six states.
In 2011, a panel headed by ecologist Madhav Gadgil studied widespread ecological devastation in the Western Ghats and divided 64% of the region into three zones: highest sensitive, high sensitive and moderate sensitive. It recommended a stop to mining, polluting industries and large-scale development activities in the highest sensitive and high sensitive zones. But all six states opposed these recommendations.
A year later, the Central government formed another committee, headed by scientist K Kasturirangan. This committee watered down many of the Gadgil panel’s recommendations. It divided the Western Ghats into cultural lands (areas with human settlements) and natural lands and recommended that 60,000 square km or 37% of the total area of the Western Ghats be declared ecologically sensitive.
By 2017, the Centre had notified 56,285 square km of the land as sensitive. The Kasturirangan panel had recommended that 13,108 square km of the area in Kerala be declared sensitive but under pressure from the state, the Centre brought down the notified area to less than 10,000 square km.
Citing the floods in Kerala, the National Green Tribunal on August 24 restrained the six states from giving environmental clearance to activities that may hurt the region’s ecology and warned against reducing the sensitive area notified by the Centre.
Linking the lack of conservation effort to the landslides, landslips and cave-ins in Wayanad, soil conservation officer PU Das said, “This year’s geological incidents showed Wayanad is indeed an ecologically sensitive area. We need to take urgent measures to protect the Western Ghats.”
‘I saw trees, debris and water sliding towards us’
At around 4 am on August 9, a landslide swept through Makkimala in Tavinhal gram panchayat. There are 27 homes in the neighbourhood. All residents save two – Zeenath and her husband Razak, who lived close to the mountain – managed to escape to safety.
“Everyone was running for their lives and we thought they had left their home with us,” said 55-year-old Suhara, a neighbour of the deceased couple. “Unfortunately, earth fell on them before they could get up from their sleep. Their three children ran to safety.”
Krishnankutty, a 62-year-old daily wage labourer, said Makkimala had never experienced such a landslide before. “It has remained intact even during heavy rainfall,” he said. “I don’t know what is happening to our surroundings.”
All 27 families remain in a relief camp with the district administration having advised them to stay put. This advisory has caused confusion among the villagers. “Will we lose our land and homes?” asked Suhara “I pray that the government does not relocate us from here. Makkimala will not let us down.”
In Kurichiarmala, 50 km south of Makkimala and one of the highest points in Wayanad, around 300 villagers had a miraculous escape the same day as a landslide narrowly missed their homes. But it destroyed 100 acres of tea plantations.
Unlike the landslide in Makkimala that struck without warning, villagers in Kurichiarmala quickly moved to a relief camp after 60-year-old Cheku, a retired plantation worker and trade union leader, sounded an alarm. “I heard a loud noise at around 10 am on August 9,” he recalled. “When I looked at the forest, I saw huge trees, debris and water sliding towards us. We were lucky the debris flow diverted just 20 metres away from our neighbourhood.”
In Vythiri gram panchayat, landslide debris washed into the police station on the night of August 9. There were no casualties as all personnel were busy with flood and landslide relief efforts in the police station limits. The police station is now functioning out of the circle inspector’s home.
According to Das, the northern, northwestern and western parts of Wayanad bore the brunt of the landslides. He blamed these on rampant construction that has blocked primary and secondary water streams. The small stream where a river originates is called a primary stream while a secondary stream is formed by the joining of primary streams. “Buildings have come up in the way of first and second order streams,” said Das. “The earth gets saturated with water and this causes landslides.”
Another factor behind the landslides is soil dissociation, according to Das. “During heavy rain, earth dissociates into gravel, clay and fine particles,” he explained. “This disintegration weakens the earth.”
When entire buildings sank
Land subsidence is relatively rare in Wayanad. The last reported instance in 2008 was limited to one region, geologists say.
But this year is different. They reported a 50-km-long crack running from Thirunelli to Boys’ Town in Manathavady taluk.
In Priyadarshini Housing Colony in Boys Town, 30 families have had to move out of their homes. “The foundation of my house sank to a depth of 30 cm,” said Cleetus, a resident. “The house developed cracks because of the sudden movement. I am living in a rented facility now.”
He said his neighbour Vettom John’s home continues to sink even now. “A tiny portion of the land subsided on August 9 but more land sunk in with each passing day,” he said. The land in front of John’s house has sunk by a metre.
According to the soil conservation department, fissures, some as deep as 6 metres, have also been spotted in the land.
In perhaps the most dramatic collapse, a two-storey shopping complex in Vythiri gram panchayat sank to the ground. The ground floor sank on August 9 and the first floor became invisible the following day. “The shopping complex had four popular stores and an ATM counter,” said KM Sashidharan, a policeman at the Vythiri police station. “It was a popular destination. Casualties were avoided as the building caved in at night.”
According to the United States Geological Survey, land subsidence occurs when aquifer systems (underground layers of water-bearing rock) compact or as a result of drainage, subsequent oxidation of organic soils, dissolution and collapse of rocks.
But Das had another explanation for the subsidence in Wayanad. “We have noticed that all cases of land subsidence were reported near paddy fields,” he said. “Studies have proven that the plains in Wayand were marshy before they were converted into paddy fields. The excessive rain revived the marshy nature of the land and it resulted in subsidence.”
Das said the soil conservation department has written to the state government to set up a team comprising a senior geologist, environmental engineer and soil conservation expert to study the geological phenomena in Wayanad. “We can find out whether the district is still susceptible to landslides, landslips and land subsidence only after a detailed scientific study,” he added.
All photographs by TA Ameerudheen