How safe are lives in colonies on floodplains and riverbeds? When thousands of lives have been feared lost and hundreds of homes and hotels have been washed away in the recent floods in Uttarakhand, experts are raising questions about the safety of buildings on floodplains - especially in Delhi. One major cause of worry is the massive unauthorised construction work that has taken place here in blatant disregard of building rules and norms.
Take a round of one of these unauthorised colonies and it doesn’t take long to find out how safety measures have been compromised with for more space and floors at the cheapest cost. The Tibetan Colony along the Ring Road in North Delhi is a case in point. Started as a refugee colony during the ‘60s with make-shift structures, today it has multi-storeyed hotels and restaurants and has virtually turning into a commercial hub.
“Nowhere in Delhi have unauthorised constructions mushroomed as rapidly as in the Tibetan Colony. Now the government has regularised it without assessing the structural safety of the buildings. But that’s just one example. Out of the about 9700 hectare riverbed area, 61 unauthorised colonies have come up on 981 hectares of land - Batla House, Teeba Colony etc being a few. Some have been regularised, others have not. There has, however, been no study yet on the structural aspect and impact of frequent flooding in the areas so far,” says a senior Delhi Development Authority official.
Real estate experts, civil engineers, environmentalists and even legal experts feel the government should show a great sense of urgency in putting in place safety measures for the buildings and check the expansion of construction activities to preserve the river bed and floodplains.
According to Chandan Ghosh, professor and head, geohazards division of the National Institute of Disaster Management, who had conducted a study on the structural safety on 10,000 buildings in east Delhi after the Lalita Park building collapse tragedy in which about 71 lives were lost, “I can talk about vulnerability of riverbed structures because there is commonality between construction activities in unauthorised areas all over Delhi. Poor construction material is used, there is irregular plan and elevation and no raft or pile foundation. Also, construction material disintegrates when there’s water logging and the water contains chemicals such as chlorine and sulphate.”
In his report, Ghosh has recommended that most of the structures in east Delhi should be pulled down and new constructions done as there is no way to make the existing buildings safe.
“The situation can be worse in case of buildings on the floodplains as you never know what kind of damage is being done to the foundation by the frequent flooding of the river. I think the condition of these buildings must be assessed before there’s any tragedy to wake up the government,” says Ghosh.
Supratic Sen, a civil engineer from IIT-Delhi agrees when he says, “Riverbed soils are sand or sandy-silt or silty-sand which requires detailed soil investigation before any construction work is carried out. Soil erosion due to flow of water could lead to either complete collapse of a structure or its displacement. In addition, during earthquakes, this soil deposit mixed with water is susceptible to liquefaction which causes sinking/tilting of buildings.”
He adds, “River bed construction also has the problems of water pressure on building elements. Hence, any construction, legal or illegal, should be done only on either raft foundations or pile foundations and super structure should be designed to withstand water pressure or earthquakes.”
Manoj Misra, convener, Yamuna Jiye Abhiyan, questions the futility of the Prime Minister-appointed Yamuna River Development Authority (YRDA) and the Lieutenant Governor’s moratorium on construction activities on the river bed and floodplains. “Despite a moratorium, large-scale construction activities are going on with the connivance of the government officials.”
Sanjay Parikh, a Supreme Court lawyer, who has filed several public interest litigation for environmental causes, points at the legal loopholes and says “While allowing a Commonwealth Games Village on the riverbed, the Supreme Court has ruled that if an embankment has been constructed on the riverbed, the area on the other side of the river ceases to be a riverbed. This order has been manipulated by the land mafias and rampant construction - legal and illegal - is being carried out on the floodplains all over the country. So what has happened in Uttarakhand will happen elsewhere.”