For doubting Thomases & Georges: Here is why landslides happen in forests

The great deluge, it was felt, might teach people to leave the environment alone. So absolute was the catastrophe that it was thought that development junkies would lie low at least for a while.

This was why the triumphalism exhibited by a handful of MLAs during the special Assembly session on August 30 was unsettling. It was as if they treated the greatest disaster the land has faced in a century as a moment of triumph, as a vindication of sorts. “We cannot overcome the force of nature by issuing stop memos to hotels like Plum Judy,” said CPM's Devikulam MLA S Rajendran. This was audacious given that nearly 60 foreign tourists were trapped inside Plum Judy Resort in Pallivasal (Idukki) by a massive landslide just a few days ago on August 10.

Rajendran had more to say. “Hundreds in Devikulam were swept away by the floods in 1924. Then, it happened not because the dams were opened. There were no concrete buildings either,” he said. Kuttanad MLA Thomas Chandy wanted unrestricted mining of Vembanad Lake. “Pamba, Achenkovil, Meenachil, and Manimala rivers have carried all the silt and slush along the way and deposited them in Vembanad Lake. The lake has lost its depth. In certain areas of the lake, the bottom of the boats scrape mounds of deposited silt. If permission is granted to mine the sand from the lake without any restriction, it would increase the depth of the lake,” he said.

Nilambur's MLA, CPM independent P V Anwar, who had allegedly violated rules to construct a water theme park, hurled a rhetorical poser. “Why have landslides and landslips occurred in deep forests that have not been touched for centuries by even a shovel, leave alone JCBs.” P C George, too, said he could not take scientists like Madhav Gadgil seriously because landslides had occurred even inside forests.

If Rajendran's comments were outrageous, K M Mani's observation that it would be impractical to ban constructions in landslide-prone areas in Idukki needs to be countered pragmatically. Certain other statements like Anwar's and Chandy's, which might seem logical on the surface, have to be rubbished scientifically.

Onmanorama, by talking to the scientific community, has attempted to put in perspective the three major claims made by the pro-development MLAs.

Such a large calamity has no relation whatsoever to unbridled development. If so, how did landslides occur inside pristine forests.

Professor Madhav Gadgil brushed aside the forest analogy saying it was too simplistic. “You cannot have a 'one cause one effect' understanding of landslides. It is an interplay of factors that causes the event,” Gadgil said. “Rampant constructions, done without a thought for the environment, increases the probability of landslides.”

The landslide that killed 20 in Kuracheri village in Thrissur, for instance. A stand-alone hillock fell over five houses, killing 20 people during the recent floods. “There is not a river or a lake near the place. No hills either. So it is clear that deforestation, illegal construction and quarrying had caused the damage,” said noted ecologist S Faizi.

Landslides inside forest areas are nothing to be surprised about. “It is a natural phenomenon,” said environment scientist K Soman. “As part of a natural weathering process, crevices in rocks get saturated with water. And when the pressure of the accumulated water and other debris gets the better of the soil and root system that binds the terrain, water will burst out with hellish force,” Soman said. The only difference is, in non-forest areas, thanks to senseless human intervention, it happens regularly.

Landslides inside the forests can also be man-made. Activities in non-forest areas can remote-control devastation inside the forest. “The consequences of quarry operations are felt not just in the immediate vicinity of a quarry,” said T V Sajeev, scientist at Kerala Forest Research Institute (KFRI). “When each explosion takes place, the vibrations would travel through the rocks 17 times faster than the speed of sound. Such fast-moving subterranean vibrations will unsettle the interiors of hills situated far deep in the forest, leaving it loose and vulnerable for a heavy rain to wash it all down in a mighty torrent,” Sajeev said

This is why it has always been said that quarries should be at least 500 metres from the edge of a forest. The LDF government had last year reduced the distance to 50 metres. Dr Sajeev said forest fires, which are mostly man-made, too could lead to landslides. “A burnt tree loses its capacity to bind the soil, the rocks and sand. So the soil in vast stretches burnt black and dry by forest fires will be vulnerable to intense and ceaseless rainfall,” he said.

Sridhar Radhakrishnan, an engineer who runs the NGO Thanal, said the state's forests have lost their intactness, stability and integrity. “Proper soil conservation measures are not being implemented, especially in plantation areas, and the forest department itself has planted foreign varieties like teak and acacia in vast swathes of evergreen forests,” Sridhar said. “All of these interventions, cumulatively, have led to the forests losing its original nature,” he added.

Sridhar said massive constructions, say a reservoir like in the Sabarigiri project, inside forest areas would also alter the topography and structural stability of the forest terrain. “We have no idea how such an altered ecosystem would respond to unusual rains. When water seeps through this distorted system a landslide perhaps could be triggered,” Sridhar said.

Sand mining should be permitted in a big way in Vembanad Lake. The floods had deposited massive quantities of slush and silt in the lake, reducing its depth considerably.

Madhav Gadgil just said that an in-depth study of Vembanad ecosystem was the need of the hour. KFRI's Sajeev also said more studies were required. “We still do not have any data. This immediate call for sand mining is nothing but an opportunistic attempt to exploit a tragedy,” he said. “It is not as simple as Thomas Chandy has made it out to be. In some areas there are heavy deposits but in other areas the depth has increased considerably,” Sajeev said.

Sridhar said it was true that Vembanad is now filled to the brim. “But it is not just sand or silt. There could be rich minerals and other things of ecological value. Any blanket permission for mining will spell disaster,” he said. Any decision, he said, should be taken only after carrying out a scientific assessment. He also said Vembanad lake had shrunk over the years. “We need to find ways to bring it back to its original self. For this, encroachments have to be removed,” he said.

Soman said it was slush, and not silt, that had now been deposited in the lake. “Dredging should be allowed only to clear the path for water transport. This call for indiscriminate mining is nothing but an attempt to reclaim more paddy lands and water bodies, and this will lead to nothing but more disaster,” Soman said.

Hundreds of landslides and landslips have been reported from Idukki. If construction activities are banned in landslide-prone areas, it would be anti-farmer and impractical.

Gadgil, after the kind of indignation his report had caused in the state, said he would not comment on the issue. The Gadgil report prohibits all manner of constructions on hill slopes, a terrain the report had classified as ecologically sensitive zone one (ESZ-I).

KFRI's Sajeev recommended an adaptive approach. “It is not as if people don't live in disaster-prone areas. It is just that they are sensible enough to adapt to the topography of these areas,” he said. Take Maldives, for instance. The maximum elevation from sea level is four metres, which means the island is in trouble if a four-metre wave sweeps the shore. Or take Nepal, which regularly witnesses this phenomenon called 'mountain building' or upheaval of mountains. Mountains just lift themselves up, tip, and shower a cascade of rocks and boulders to the plains below.

“People survive in these regions because they have evolved architecture suitable to the terrain,” Sajeev said. “In the high ranges of Idukki we have constructions suitable for midlands and coastal areas. The settlers have still not adapted to the peculiarities of high ranges,” he said.

Ecologist Soman, too, felt so. “They don't have multi-storeyed building along the slopes of the Alps mountains in Europe. The architecture should blend with the terrain,” he said. He was also critical of politicians who were against prohibiting unbridled constructions in Idukki.

Sridhar said there was no need to rehabilitate people on a mass scale. “But a new development strategy has to be evolved through a participatory process,” he said. Precisely what the Gadgil report had recommended.