Kerala floods: Assess damage before moving back to your home

Architects and structural engineers warn that people should assess the damage caused to their properties, check if the structure is safe for them to move in. Experts say that reinforced concrete structures be built henceforth, preferably on stilts. What is surprising is that most houses in Kerala are load bearing structures – built with bricks and laterite without any frame and that too with large tiled roofs. During the floods it was the tiles on the roof and the pavements that compounded the problem. While the tiles on the roofs added to the weight of the structure, the tiled pavements left no room for the water to be absorbed by the soil.

Any crack which is larger than a match box stick is a cause of concern Dr Anil Joseph of Association of Structural and Geotechnical Engineers from Kochi and his team of volunteers that includes engineering students, have been involved in inspecting thousands of homes in and around Kochi and monitoring relief measures. He suggests that before moving in, people should check for cracks. Any crack which is larger than a match box stick is a cause of concern, he says.

Most load bearing structures that use bricks or laterite lose strength by almost 30 percent when subjected to water. Before entering, conduct a crude test of knocking on the walls with a hammer and check for noticeable cracks on the walls. If there are cracks, there is a possibility of the building collapsing at any point, he warns.

Soil in Kerala is formed by deposition of marine clay. It is because of this reason that foundations are not strong, he says, adding that structures need to be constructed in such a way that scoring or the process by which the river water takes away or washes away the soil does not happen. Minimum depth of foundation considering the scouring should be 5 feet (1.5 meters) and it should be deeper in areas where water damage by river waters is likely to be more.

Have a reinforced belt running across at the plinth level above the basement or above the level of the windows for additional protection from floods and earthquake. As far as possible, go in for stilt constructions so that the bottom area is free. Stilts can be made of steel or concrete columns, he says.

Check for differential settlement by pouring water on the floor and see if the water collects at a point and whether there is a difference in the level of the floor. If the water leaks it means the titles have cracked and the slab has got deflected. Check if windows and doors close easily. If the building has tilted, they won’t close properly.

If soil erosion has occurred near the structure due to the flooding, it needs to be inspected by experts. All electrical and plumbing lines also need to be checked for leakage, he adds.

Besides standalone houses, over 20,000 people had to be evacuated from high-rise buildings that have come up close to the riverfront. As water reached above three levels/floors all utilities located at the basement level became non-functional – there was no water to drink, generators went off and there was no electricity, cars parked in basements were submerged. All these issues need to be considered before coming up with a strategy to deal with a similar calamity in the future, he says.

A new architectural vocabulary is the need of the hour
George Mathai, chairman, Terrafirm Global Academy of Design & Innovation, says that the government has to come up with new set of environmental controls. There needs to be fine balance between construction and policy change. The need of the hour is a new architectural vocabulary for Kerala that takes into account plans for evacuation. There needs to be a clear demarcation of low, medium and high danger zones and a synchronized informational management system for disaster management.

Roy Antony, architect from Kochi, also suggests that henceforth, buildings should be constructed in column framed structures. “Proper layouts need to be prepared to ensure that rescue work can be executed. In these floods, we had no idea where people were stranded as there were no plans in place,” he says.

Avoid paving yards with tiles. It may be easy to maintain but it prevents the soil from naturally absorbing excess water, he says.

Presently, there is no flood line mapping for the state. Authorities need to map all the areas along the river, he adds.

A fine balance between urbanization and environment is a must Urbanisation has been a major culprit behind these floods. “It has been haphazard (to use a mild term). Land's monetary value seems to have been the only criterion to build over it or not. Thus wetlands and low lying areas (which act as cushion during floods) have been the worst victims of misuse often as a result of acts of commission and omission by the regulatory authorities. The classic case is the raising of Kochi Airport over a distributary of river Periyar and in its active flood plains. The result is for all to see," explains Misra.

“We hope that now at least one thing would come to the fore. That river's flood plains should not be built upon, no matter there is a dam upstream. On the contrary if there is such a dam then a 100-year flood plain must be respected as a no development zone with a further buffer to account for higher than normal floods in view of the climate change uncertainties,” says Misra.

As people move back into their properties, it shall be important that they assess (or ask experts to assess) the vulnerability of their properties to risk from extreme natural events (floods, landslides, etc) and decide to take steps (may not immediately) that reduces the vulnerability. Such a step could even include voluntary relocation to safer locales. In any case if for whatever reason, the natural drainage lines in their surround have been obstructed or realigned, it shall always remain a threat feature. It must be restored to natural setting, he says.

Chetan Agarwal, environment analyst, is of the opinion that a backward analysis and mapping of all catchment areas is a must. Correlate which areas were the most impacted and which were less impacted. Execute a scientific study to figure out reasons for the areas that were less impacted.  A similar analysis of areas affected by the Orissa cyclone a few years ago showed that not all areas were impacted even though they were on the path of the cyclone. The villages that were not affected were those that had a strong buffer of mangrove trees, he says.

What caused the floods?

Several environmental experts have pointed out that the flood damage would have been much reduced had the dams and reservoirs released the water gradually. Also, had the state had advanced warning systems in place, many lives and destruction would have been averted. Kerala is one state that has not yet established any flood forecasting stations.

Also, the destruction would have been much less severe had the state taken upon itself to implement the recommendations made by the Gadgil Committee way back in 2011. The Gadgil Committee had suggested that 140,000 sq km out of the 160,000 sq km of the Western Ghats, which includes Kerala and five other states, be categorised into three zones as per their ecological sensitivity and the requirement of environmental protection. In some areas, the committee had recommended restrictions on mining and quarrying, use of land for non-forest purposes and construction of high rises.

But, those warnings were ignored. In the end, the Centre decided to implement the report of a high-level working group headed by K Kasturirangan, which, according to many, is a watered-down version.

The Kasturirangan Committee report termed only around 37 per cent of Western Ghats (60,000 sq km) as ecologically sensitive and recommended to environment ministry to notify it. Finally, in 2017, the environment ministry notified about 57,000 sq km of the Western Ghats as an ecologically-sensitive area where  mining activities, large constructions and  polluting industries were banned. This led to the opening up a huge area of the Western Ghats to activities such as mining and building dams.

Gadgil was recently quoted by the media as saying that it was not just floods but disregard for the environment that had unleashed destruction in Kerala. Mindless scramble for infrastructure development has compromised the state’s ability to deal with the floods.  “These are not just natural events. There are unjustified human interventions in natural processes which need to be stopped,” he had said.

Vandana.ramnani@nw18.com