Sunday, July 25, 2021

Infratrack

Flood protection for construction The need of the hour in india

 

A 2 million sq ft office building with its two floors submerged. What is the use of getting a long drawn out insurance claim on this building? Perhaps the asset loss from the flood water destruction can be replaced, at a cost. But the loss of business during the downtime is unobtainable and in some instances the business itself has to be closed down or taken elsewhere.

 

Why take the trouble, when irrespective of the business value of the building (daily income generating business, high value income generating office space, living space of residents, manufacturing centre, educational complexes, hospital, hotel, other income generating uses), flood protection for the building can be done at an infinitesimally small miniscule cost to the building owner or the house owner in comparison to the value of the building.

 

What I heard and observed from the recent Chennai floods is that many buildings especially those still in construction are sealing of basements with concrete and re-drafting the building plan. Considering that the real estate cost is optimised by having one or two basements it would be cost effective to have basement. But this basement has to be equipped with flood protection which can be easily done.

 

Flood protection as a technology and integral part of building construction is not known in India.

 

With flooding in India on the increase and climatologists predicting a further escalation of flood instances, it's clear that India faces a problem and there needs to be serious discussion and debate to identify the most effective solutions.

 

Valuable assets such as hospitals, power company sites, industry and commercial zones need protecting as an immediate priority that cannot wait until larger city or region wide schemes are adopted.

 

LIST OF RECENT FLOODS IN INDIA

2005 Gujarat flood

Maharashtra floods of 2005

2005 Chennai floods

2007 South Asian floods

2008 Indian floods

2009 India floods

2010 Ladakh floods

2012 Brahmaputra floods

2012 Himalayan flash floods 

2013 Assam floods

2013 North India floods

2014 India–Pakistan floods

Indian Armed Forces and the Jammu and Kashmir Floods, 2014

2015 Gujarat cyclone

July 2015 Gujarat flood

2015 Assam floods

2015 Gujarat flood

2015 Chennai floods

Flood in Thamirabarani River in 2015

 

FLOOD PROTECTION SOLUTIONS

Globally, major floods that used to happen only once every 100 years now take place every 10 or 20 years. Additionally there is increasing flood risk in coastal areas as sea levels are expected to rise up to 1.3 metres if greenhouse gas pollution continues at its current pace.

The estimate of the cost of the damage from the recent 2015 Chennai floods by an industry body and an international insurance company stood at Rs 15,000 Crore. (USD 2.5 billion)

Given the above list of floods, another flood in Tamilnadu and Chennai or other parts of India is unpredictable with any certainty but very much likely.

The history of prior forecast of rains has often failed even for monsoonal rains. There is no history of prior forecast of floods. Even if forecasts come about in future, the time before a flood event and the actual forecast being delivered would be few hours to few days at best. Hence the speed of erection of a flood protection solution becomes paramount in choosing a flood protection solution.

While the larger solution to the issue like creating a wide rain water drainage network throughout the city, creating a large storage system are long term solutions which take many years in the making, the economic feasibility of doing that in Chennai or Mumbai city does not arise.

In this scenario the solutions available for flood protection are the following.

  • Don’t build in an area of flood risk
  • Permanent static defences
  • Wide area protection through upstream storage / banks or barriers / overflow channels
  • Building or local area protection
  • Flood Resilience in construction

What can people do to protect their homes, offices, business establishments to brace themselves from incoming flood waters. This can be achieved by using appropriate equipment especially for entry gates of houses and buildings, car shed, basements of buildings and if there are critical electricity, water connection, costly equipments these can be protected as well. This can be done for very large areas too.

The key criteria in choosing a flood protection solution are given below.

The main solutions are the following

  • Fully temporary portable barriers
  • Temporary Demountable Barriers
  • Glass Floodwalls
  • Swing Floodgates
  • Sliding Floodgates
  • Other Gate Types
  • In-ground barriers
  • Flood Doors

 

For the purposes of this article we look at the following.

 

DEMOUNTABLE BARRIERS

One of the most cost effective flood control solutions is the demountable barrier system that can be fully removed when not required, but quickly erected in advance of any flooding. This versatile system can either fit to the walls either side of openings, or just into the pavement slab. When not in use there is little evidence of its presence, and the system can work with high quality finished surfaces such as marble paving as well as with bare concrete. The demountable flood control system is as suitable for a corporate headquarters as it is for a manufacturing plant or alongside a river. Heights of up to 3 metres have been protected and the system can be over hundreds of metres long. Sometimes these are used to build long continuous flood walls around existing grilled compound walls as seen in most new age buildings in India.

 

SWING FLOOD GATES

They are put in place so that they can be operated by anyone as soon as a flood is expected without any tedious procedures. Unlike demountable barriers these are always visible but can be finished to the colour of the surroundings. They can be used in place of a regular gate for regular use as well.

 

SLIDING FLOOD GATES

In buildings and premises where the existing gate is sliding type and the elevation and inclination of the ground is such that swing flood gates are not possible, sliding flood gates would be an ideal solution. This can be automated as well if required.

 

OTHER FLOOD GATE TYPES

These can be of various types to include pivot gates, heavy duty gates, drop down gates, chemical containment gates to prevent leakage of chemicals during floods.

 

IN-GROUND BARRIERS

They are fully recessed into the ground when not in use and will not become an obstruction in areas where additional structures are not suitable for aesthetic reasons or functionality. They are generally used in public spaces and can be automated. Cars or vehicles can move on top of it without getting damaged. The colour and texture can be customized to that of the surroundings even to a marble finish.

 

FLOOD DOORS

If permanent full time flood protection is required, then flood doors can be used that are fully flood tight whenever they are shut. The design of various types of flood control doors has been developed over many years, from original door designs for submarines, ships or oil platforms. Many of these doors are now installed in power company substations and plants which are not normally manned. High security locks and frames mean that the doors are suitable for protecting valuable assets against not just flooding.

"There are many designs such that when they are not in use they are not visible at all. One such design is the ‘Flip Up’ flood control barrier that normally sits level with ground level, and can be walked over or driven over with nobody knowing it is there. The barrier can be manually raised or automatically when the floodwaters rise. Other similar solutions include sliding gates that run on level ground across an opening but disappear into the wall at the side when not in use, or ‘drop down’ barriers that usually sit above an opening in the building structure above, that lower when required. Automatic solutions can vary in size from protection to a single doorway, up to a whole loading dock 40metres wide and 3.6 metres high. “ said Mr Andy Couch, Director, Flood Control International UK

 

CONCLUSION

The increase in flood events in India will necessitate the widespread usage of flood defence products other than sandbags. This would also be fruitful for construction companies, developers and occupants.

The only other option seems to be to raise the ground, close off basements and move away to a less flooded city. These steps drastically reduce the real estate value and potential of the land and thereby the economy, jobs and value generation it supports.

The limited knowledge about available flood defence systems and even more limited experience of using it is resulting in building owners, facility management companies and occupants themselves in ignoring flood risk until the next flood event.

The need of the hour is for this sector to create a flood protection system in existing buildings, premises and localities and to plan this for in-construction and upcoming real estate projects.

 

Dr Joseph Paul, 

A marine scientist presently practicing in the marine and maritime space from the hill tops to the deepest trenches in the ocean building bridges between science and business in sectors as diverse as building an airport runway into the sea, putting up an offshore wind farm, putting up marine leisure real estate.

In view of recent flood events he has been trying to bring in flood protection to India. This article is a first step in that direction. Previously he was an awardee of three international governments and lived in multiple countries abroad working to bring in new technology, businesses, investments into India.




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