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Construction : Special Report | February 2016 | Source : CW-India

Chennai Challenge

As the city prepares to rebuild itself in the aftermath of the worst-ever rains in a decade that led to massive destruction of property, infrastructure and other assets, CW looks at the constraints and challenges ahead.

Roads inundated with flood and sewage water, homes and streets plunged into darkness, breakdown of rail, road, air traffic and telecommunication, essentials in short supply - Chennai had come to a grinding halt in the two-week deluge last November/December. With hundreds of lives lost, thousands rendered homeless and many infrastructure facilities damaged, the city is a long way from regaining its footing.

Deluge decoding
Was the devastation a natural calamity, manmade disaster or a combination of both? The government and its agencies are largely laying the blame on the rains. ¨The major reason was the unprecedented heavy rains in Chennai and outside, owing to which all the 1,000 odd lakes and reservoirs ´surplussed´, resulting in the three major rivers in Chennai and its major canals like Buckingham Canal witnessing unprecedented floods,¨ avers *Vikram Kapur, Commissoner, Corporation of Chennai. ¨Further, only one-third of the roads in Chennai have storm-water drains (SWDs), which were de-silted twice before the monsoons. However, these SWDs are micro drains, not designed for handling floods of the intensity experienced. In addition, most of the newly added areas in Chennai, which were earlier under local town or village panchayats, do not have any integrated SWDs and, hence, these areas are more vulnerable to flooding even during normal rains.¨

However, experts, industry pundits and NGOs maintain that several other factors like mindless urban planning involving illegal construction, choking of water exits, a poor drainage system and inadequate de-silting of SWDs exacerbated the situation. ¨The situation was made worse by several other factors like poor SWD design and management, lack of SWD systems in large parts of the city, lack of dredging of major and minor drainage channels all year round, poor networking of roadside ditches with major SWD channels by underground storm sewers, and inadequate cross-drainage structures in roads and highways on embankments causing islands of localised flooding. The capacities of the roadside ditches are low and chocked with solid wastes,¨ states Dr Balaji Narasimhan, Associate Professor, Civil Engineering Department, Indian Institute of Technology (IIT)-Madras. ¨During major floods, the roads should also serve as a flood carrier to facilitate quick drainage. For this, the level of the road pavement should be well below the adjoining plots. However, most of our roads are elevated above the adjoining plots, causing widespread localised inundation with no scope for drainage.¨

In addition, Chennai has not paid sufficient attention to natural water bodies and natural flood discharge channels that could drain a spill-over, according to Sunita Narain, Director General, Centre for Science and Environment. ¨The city has unfortunately turned its back on its water system,¨ she says. ¨Constructions have come up over many of the water bodies, blocking the smooth flow of water, the catchments have been encroached and drainage systems destroyed. This is why I maintain that the flood of 2015 is also manmade and the heavy rainfall was not the only reason.¨ According to a report submitted by Chennai Metropolitan Development Authority to Madras High Court last year, 1.5 lakh illegal constructions have come up on 300 water bodies in the city.

Encroachment of inlet, outlet and surplus channels of water bodies is a major problem, confirms Dr Narasimhan. ¨During a monsoon that was normal or below normal, the tanks would store water and aid in groundwater recharge,¨ he says. ¨But during rainfall that is above normal, if the tanks are already full (which was the case in December 2015), they may not reduce the magnitude of runoff. And if the inlet, outlet and surplus channels of these tanks are either encroached or choked with solid wastes, there would be severe water-logging.

As the water line starts to rise, the encroachers on the tank bed will breach the bund, resulting in water-logging in the downstream side as well. This is what happened at several places across Chennai in areas adjacent to ´Eris´ (encroachment of water spread area of tanks).¨ Even the swelling of Adyar River is partly attributed to encroachments that reduced its flow capacity, in addition to the release of water from Chembarambakkam, resulting in flooding of the airport and adjacent areas. Surprisingly, the Chennai International Airport is built on the flood basin of the Adyar!

Action ahead
Evidently, the restoration of Chennai involves a gamut of activities, from rebuilding homes and other damaged structures, relocation of population to safer zones and revamping the drainage systems, roads and bridges, to developing new infrastructure facilities, creating effective waste management, clearing illegal encroachments on water bodies and floodplains and preventing them in the future.

Several suggestions and proposals are being put forward by industry pundits, NGOs, developers, urban planners and engineers, such as mapping flood-prone areas, constructing buildings in flood-prone areas on stilts, retrofitting old buildings that could have become weak owing to retention of moisture for a long time, dredging of drainage channels all around the year instead of just before the monsoons, and developing a master plan that takes into account the drainage system as well as natural drainage channels, ponds and lakes.

¨There is a need to undertake a detailed survey of the wetlands and then bring every water body and its catchment under legal protection,¨ says Narain. ¨The city development rules should include a comprehensive list of water bodies and their catchments in its classification. The Central Government should provide funds for water supply to only those cities that have brought their own water sources under protection.¨

For his part, Dr Narasimhan lists some suggestions: ¨In addition to roadside ditches, storm-water sewers (parallel to underground wastewater sewers) should be well networked to major drainage channels. Resurfacing of roads should be done without increasing original height. Inlet, outlet and surplus channels of the tanks (Eris) should be kept free of encroachments, debris and solid waste. In a cascading system, the outlet drain from one tank should be maintained to the inlet to the downstream tank or another major drainage way, thus, ensuring longitudinal connectivity in drainage.¨ He further adds that to prevent transferring the flooding problem from upstream to downstream, new developments should be mandated to incorporate low-impact development (LID) and sustainable drainage system (SuDS) techniques to reduce the rate of runoff generation at the source or site (during normal monsoon rainfall) to levels equal to those of pre-development levels.

The government and the corporation, are already on the move to implement many of the above. A major integrated storm-water drain project for the newly added areas of Chennai at a cost of Rs 4,500 crore is in its first phase of implementation. ¨Tenders have been finalised for 35 of the 39 packages and work orders have been issued,¨ shares Kapur. ¨The first phase of the project in the Adyar and Cooum sub-basins started in January 2016 at a cost of Rs 1,100 crore with funding from the World Bank. For the balance four packages comprising canal works, the resettlement action plan has been submitted to the World Bank for clearance. Scheduled to be completed by January 2018, the project is bound to provide better drainage of rainwater in the newly added areas.¨

However, Kapur issues a caveat:
¨These micro drains however well designed and executed cannot prevent flooding, if the city´s macro drains, maintained by the PWD, receive extraordinarily heavy quantity of water from outside the city and are flowing at levels much higher than the micro drains maintained by the corporation. This was exactly what happened during the flood of December 2015.¨

The Chennai Corporation and other government agencies like the Chennai Metropolitan and Water Supply and Sewerage Board and the Tamil Nadu Slum Clearance Board (TNSCB) are now focusing on the restoration of damaged infrastructure, including roads, water and sewerage systems, storm-water drains, bridges and culverts. ¨Over Rs 1,000 crore worth of road works are now in progress and nearly 10,000 families on the banks of the Adyar are being shifted to newly built slum tenements,¨ reports Kapur. ¨An unprecedented 2.19 lakh metric tonne of solid waste generated during and after the floods was cleared in record time by pressing into service over 35,000 workers, 675 vehicles and 120 JCB machines mobilised from within the city and various parts of the state.¨

For effective rebuilding of Chennai, a committee of experts with powers to approve and monitor is a must, believe many. Other suggestions have also been put forward. ¨For effective implementation, projects should be executed through a SPV (state, central and investor), in a transparent process with integration of ICT in infrastructure development and involving citizens in the implementation as well as decision-making process,¨ says Sarita Hunt, Managing Director-Chennai and Coimbatore, JLL.

Smart swing
Interestingly, Chennai is on the list of the Central Government´s 100 smart cities programme, which may give a fillip to its resurrection plans. While the Centre is yet to approve the list of cities, the city is hopeful of being selected. Under the smart cities mission, each selected city will get an assistance of Rs 100 crore for development through ´smart´ solutions. Chennai Corporation in association with JLL has formulated ideas for smart city development.

Hunt reveals the key highlights of the proposal. ¨Under pan-city solutions, non-motorised transport, parking management, cycle sharing, video surveillance, smart water (monitoring billing, complaints, issues) and pedestrian footpaths will be addressed,¨ she says. ¨Under area-based development, smart water meters, sensors at critical locations (storm-water drains), sensor dustbins for better and efficient solid waste management and multi-level car parking are on the cards.¨

Opportunities and challenges
With several housing and infrastructure projects in the offing, a world of opportunities is likely to open up for developers. ¨As far as direct participation in rebuilding Chennai is concerned, we are looking at the government to come up with schemes,¨ affirms T Chitty Babu, Chairman - Best Practices, CREDAI National, and Chairman and CEO, Akshaya Pvt Ltd. ¨As of today, the government is trying to procure houses from ready stock with various sources, including private developers. When the need for private participation comes up, the developer community will be pitching and joining the government in a PPP kind of association.¨

That said, several challenges face the government and other stakeholders involved in Chennai´s development - from formulating a concrete holistic plan to executing it in a time-bound manner. One major challenge would be to rebuild homes that were washed away and damaged. ¨The affected population largely lived in encroachments,¨ points out Babu. ¨Today, land within the city in these locations may not be available even with the government. So, the government has to look at land parcels closer to the existing locations and build the homes there. Identifying the land parcels and getting the affected families to move will be the biggest challenge.¨ According to Kapur, the government has already initiated several measures in this regard. It has estimated that there are nearly 50,000 slum families living on the banks of rivers or canals, particularly the Adyar and Cooum rivers as well as the Buckingham Canal, who are vulnerable to flooding every year. Several hundreds of them lost their houses in the recent floods. In the initial phase, 10,000 such families are being relocated to TNSCB tenements in Southern Chennai, where necessary infrastructure is being provided, along with the measures to safeguard their livelihood and their children´s education. ¨During the next one year or so,¨ he says, ¨TNSCB will build additional tenements to accommodate all such vulnerable families and the Chennai Corporation, in coordination with the TNSCB and PWD, will relocate such families, while simultaneously protecting rivers or canals from future encroachments.¨

It is no doubt a long, rough road ahead for Chennai.

*Vikram Kapur, Commissioner, Corporation of Chennai, has taken charge as Managing Director Chennai Metropolitan Water Supply and Sewerage Board on January 22, 2016.

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