Airport & Rain

Friends, recently Kerala state has been devastated by rains, and the flooding which took place was really bad, with thousands of homes submerged in waters, and one of the  the worst affected area is Kochi airport and its surroundings, with the result that  the airport is temporarily out of operations till 28th of Aug. This submerging of the airport is the last example of the vulnerability of the major Indian Airports that have sprung up in the flood plains of the rivers.

The prolonged closure   of Kochi airport reminds me of closure of Mumbai airport after the heavy downpour on 25th July 2005, and Chennai airport in 2015, when both these cities were hit by floods due to unprecedented floods. In both the cases the airports were affected, and it took more than a week to normalise operations. The problem with all these airports are , they are not only built near rivers but had expanded their runways into the nearby rivers.

Kochi airport is also built in the flood plains of Periyar river, is relatively new , due to the reason that the existing airport at that time was incapable of handling additional traffic. Out of necessity, the new airport was built on field and land that used to be a part of canal.

In the case of Mumbai, the airport is built on Mithi river, when the runways were extended into river by bending its course. Similarly Chennai airport is built near Adyar river, and in this case also runways extends into river. There is one more airport located at Vizag, that is also in low lying coastal area. This airport was also flooded in 2014 cyclone due to poor drainage system.

News is that the airport which is being built in Navi Mumbai, this area is also near 2 rivers and both are being diverted. officials say that mouth of Ulwe river will be widened and the airport will be located above the flood level.

Now Mumbai has seen the altering of river course can be disastrous, when at Mumbai 2nd runway was built in 1970s , created a right angle bend in the river.So when the unprecedented rain happened in July 2015, the airport was totally flooded. Airport authorities have since sought to mitigate the problem by doubling the width of Mithi river, as well as dredging the river bed to make it deeper.

Now case of Chennai- here also when second runway was extended in 2011 across Adyar river on a bridge supported by closely placed pillars which blocked the water flow. Although the airport had flood retaining wall and a raised runway, this arrangement failed when in 2015 water was released after the heavy downpour from Chembaramkkam Dam.  Here also authorities have widened the river and regularly desilt the channel near the bridge.

Now the million dollar question is why would any designer place a critical and expensive piece of infrastructure near  a river ? The answer is probably because of plain topography, as atleast 4 Km of  flat land is needed  for a runway apart from what is needed for other facilities.

The fact is that when Mumbai and Chennai airports were built, the population of these cities were not even 30% of the present population, and  at that time they were far off from the rivers but as air traffic increased due to population growth and plane also became bigger and bigger, then these airports had no other choice and they expanded towards rivers .

If planned, nor every airport near a water body is vulnerable. Classic example is airport at Goa, which is coastal one but it is built on a plateau with cliffs on both sides, deep storm water drains and runways have water spill off channels.

There is also a National Disaster Management Authority guidelines on urban flooding-

-keeping airport operational under conditions of excessive flooding can be very crucial for rushing emergency supplies.

-Even in the case of arterial roads being flooded, helicopters can be rushed to deliver the essential supplies received at the airports.

-Therefore,very important that the airports to be made flood proof by providing efficient drainage for a much higher rain fall intensity and using best management practices like holding ponds.

These types of holding ponds are there in certain airports in USA and Europe.

With new 100 airports being proposed in the country, it becomes vital that they are designed and planned well,ideally the airport should not be in flood plain of any water body, bit if it is a must to have it in that area, then one should build the infrastructure to last for 100 year, with floods.

Friends, what is your say on this matter, please post your views/comments/feed backs on this blog.