After what seemed like more than a week of rains, and more rains, the people of Chennai and Tamil Nadu woke up to a clear sky on 17th Nov. Unlike its previous experiences, this time it was media-hyped ‘more rains coming’; ‘another depression in the bay’; ‘NASA puts Chennai on high alert’ – and added was each individual’s alert on what likely to be breach of canals, escape of water, inundating places putting more hardship !
The troubles of common man cannot be brushed aside as mere manipulation of media and individuals on social media, though at times, it was too exaggerated. Water-logged roads and subways, sewerage lines mixing with the drinking water and lakes breaching their banks are just a few of the problems that Chennai faces every rainy season, and it just got worst last week. There has been big disruption to normalcy and the master plan did reveal its lack exposure to hydrology.
Chennai received its highest rainfall in the last 10 years, recording 246.5mm rainfall in 24 hours on Monday, breaking the November 2005 record of 142.4mm, the Meteorological department said. The city had the highest rainfall of 452.4mm in November 1976. Cuddalore, Kanchipuram, Thiruvallur and Vellore are among the districts that received heavy rainfall. However, Chennai is no stranger to heavy rains. An interesting report in Indian Express reveals more aspects - India receives more than 75% of its annual precipitation from June to September. The rest is spread out through the rest of the year, but mainly in the months of October, November and December.June-September is the season of the southwest monsoon. After the first week of September, the monsoon begins to “retreat”, and the process continues until around October 15, even though the southwest monsoon season is officially declared over on September 30.Tamil Nadu and parts of Kerala, Andhra Pradesh, Telangana and Karnataka, however, see a second period of rainfall — in October, November and December. This is the northeast monsoon, also known as “winter monsoon” — which is nothing but the ‘retreat’ of the monsoon from the northeastern part of India, in the northeast-southwesterly direction. This ‘retreat’ is delayed compared to the retreat from north and northwest India, and produces rain until December in Tamil Nadu and parts of peninsular India.The northeast monsoon accounts for as much as 48% of Tamil Nadu’s annual rain. Some coastal areas get about 60% of their annual rain during this season. Together, the five meteorological subdivisions of Tamil Nadu, coastal Andhra Pradesh, Rayalaseema, Kerala and south interior Karnataka receive 30% of their annual rainfall during the northeast monsoon season.
The state has received 39.3 cm rain (area weighted) since November 1; Chennai alone has received 92.2 cm (area weighted). In the 24 hours between November 15 and 16, Chennai got 24.6 cm rain — the most it has got over any 24-hour period in the last 10 years. The November 15-16 rain beat the November 2005 24-hour rain of 14.2 cm by a long way, according to Meteorological Department, Chennai. In November 1976, Chennai recorded 45.2 cm rainfall in a 24-hour period. In 1985, it got 25 cm over two days.
El Nino effect, which has a negative impact on the southwest monsoon, has often been associated with good rainfall in the northeast monsoon. Ironically, therefore, while Chennai has gone under water and the Test match in Bengaluru has had to be abandoned after four continuous days of washouts, farmers in large parts of the country are battling drought. Heavy rainfall was brought by a low pressure system, whose formation over the Bay of Bengal was first sighted in the last week of October. This was also associated with an upper air cyclonic circulation extending up to 3.6 km above mean sea level. According to police, 178 people have been killed across Tamil Nadu since October 28.
Way back in 1977 there was the devastating diviseema cyclone killing thousands of people in Andhra Pradesh. Chennai too was badly affected – Kotturpuram was much talked about as it was inundated and people were facing untold sufferings. INES article states that now, at least 300 water bodies have been converted into residential areas. Most waterways, tanks and reservoirs are choked with silt, and their flow channels and banks have been encroached upon.Some 16 channels and 43 minor drains in the city need to be redesigned, and a grid of stormwater drains joining the Buckingham Canal and Cooumriver needs to be built as a longterm solution to flooding, an expert at the Chennai Metropolitan Development Authority said.
As Critics would happily say, people do not learn from past mistakes. Rains, floods and sufferings are not new. Many decades ago, there was one in 1943 occurring in the month of October during NE monsoon, causing immense damage. There reportedly were rains for six continuous days – the Coovum and the Adyar rivers overflowed inundating the surrounding residential areas. Wikipedia reports that thedamage caused by the Adyar river was minimal because the surrounding areas were well-planned and constructed. The brunt of the damage was borne by the slums that lay on the banks of the Coovum. Slums in Lock Cheri,Choolaimedu, Perambur, Kosapet, Kondithope and Chintadripet were washed out and people sought refuge in the Ripon Building. The police used boats and catamarans to row people to safety !
There have always been jokes of boats in Chennai – for its dry and hot summer and lack of rains. This time, again there were some boat operations in areas inundated by water. Some reports state that Taxi operator Ola too deployed boats along with professional rowers to rescue people in the waterlogged areas to safer places."Ola deployed boats in waterlogged and partially submerged areas on the basis of information from the Fire and Rescue department", Ola said in a statement.The boats were manned by professional rowers and also fishermen to rescue people and to provide food and drinking water free-of-cost. The boats were equipped with two rowers, sufficient umbrellas capable of ferrying between five to nine people in a trip.
With regards – S. Sampathkumar
19th Nov. 2015.