A complete report on the damage and disastrous caused by chennai floods of 2015.

1. A Case study on
Chennai Flood 2015-Project Report

2. Abstract:
Nature, as everyone sees is a greatest gift to have ever
existed. Along with its beauties and flaws, all other creatures
admire it as an eternal entity. When all five sensed creatures
admire it, the only six sensed creature, the so called ‘Humans’
are known for their talent of adventuring into all the
admirations, which have led to something beyond just admiring.
One among such a chaos is the Chennai floods 2015.Though a
natural calamity, the most responsible ones for this are the
people. In this case study I’ve put forth my points in explaining
why this happened, and how people reacted. So on the whole
this case study gives you a detailed explanation of the actions
responsible and the reactions to this so called ‘Natural’ calamity.
Introduction:
Post Flood News (AIR): “Heavy rain in the beginning of
December 2015 caused severe flooding in Tamil Nadu and
Andhra Pradesh. A deep tropical depression came through the
Bay of Bengal and hit the southeastern coast of India and Sri
Lanka on 10-11 November 2015, causing heavy rain. Heavy rain
started during Nov 16-19, with 30-37 cm of rain accumulating
over a 9-day period 9. After pausing for several days, the rain
again resumed in early December and in some locations the rain
continued until December 10. Chennai received over 33 cm of
rain in a 24-hour period from December 1-2, causing widespread

3. flooding and damage. In Tamil Nadu, Chennai city, Cuddalore,
Kanchipuram, and Tiruvallur districts were worst affected.
Unfortunately, around 500 people have lost their lives in Tamil
Nadu as a result of this devastating flood”
Action of ‘then’ Government: In response to the
devasting floods of Tamil Nadu, the response of Former CM J
Jayalalithaa is quite frightening. As per the report of NDTV, she
says, “Losses are unavoidable when there’s very heavy rain,
swift rescue and relief alone are indicators of a good
government” These words are intended to normalize a human-
made disaster, and gloss over the pathology of urban
development under successive administrations. Furthermore the
government has taken actions by declaring Chennai as a Natural
disaster zone and Natural disaster response force carried out
rescue operations in the city.
The after effects are even worse; the rains along with
subsequent overflow of the Adyar River and Cooum River had
caused severe flooding and extensive evacuations in Chennai
and surrounding areas, as well as significant damage to homes
and surrounding farm fields. Many parts of the city got isolated
since road and rail access had been cut off, while failure of the
power and telecommunication system elevated the risk. The
runway at Chennai airport was flooded and got closed for 3 days
and 3,500 people got stranded there. For most people stranded in
rain hit Chennai, taking a flight to neighboring cities had been a
bleak option over those days. This was not just due to the fact

4. that the Chennai airport has been flooded, but also because
tickets were priced as high as Rs.50, 000 one way.
The Flow of the Report:
1. Observed Rainfall
2. Atmospheric condition during the rainfall
a. Impact of global warming
b. El-Nino
c. Tidal levels in Ocean
3. Why Chennai got affected?
a. Geology of Chennai
b. Devastation of Pallikaranai
c. Perungudi Dump yard
4. Sewage System of Chennai
a. Macro drainage System
b. Micro drainage system
c. Problems with drainage system
d. Reservoir releases
5. After effects of Flood
a. Loss of life and property
b. Effects in various sectors
i. Automobile and Petroleum industry
ii. IT and telecommunication industry
iii. Food supply chain
iv. Health Sector

5. 6. Response and Recovery
7. Ideas and recommendations
8. Conclusion
9. References
To begin, let’s start with analyzing the situation at that time.
Observed Rainfall:
The city of Chennai and its suburb areas recorded multiple
torrential rainfall events during November-December 2015 that
inundated the coastal districts of Chennai, Kanchipuram and
Thiruvallur. This affected more than 4 million people with
economic damages that cost around US$3 billion. There was
very heavy rainfall on November 8, 9, 12, 13, 15, 23, and
December 1. During the 24 hours ending 8:30 a.m. on December
2, 2015, “extremely heavy rainfall” was reported in Chennai.
According to statistics it is recorded as follows:
 49 cm at Tambaram in Kanchipuram district,
 47 cm at Chembarambakkam in Thiruvallur district,
 42 cm at Marakkanam in Thiruvallur district,
 39 cm at Chengalpattu in Kanchipuram district,
 39 cm at Ponneri in Thiruvallur district,
 38 cm at Sriperumbudur in Kanchipuram district,
 38 cm at Cheyyur in Kanchipuram district,
 35 cm at Chennai airport,

6.  34 cm in Mamallapuram, Poonamallee, Red Hills and
Chennai city.
 28 cm being the lowest rate is recorded in Taramani,
Cholavaram, Thamaraipakkam and Madurantakam.
According to the United States’ National Aeronautics and Space
Administration’s (NASA’s) Integrated Multi-Satellite Retrievals
for Global Precipitation Measurement or GPM (IMERG), from
November 29 to December 2 over 400 mm of rainfall fell over
areas south of Chennai.
The captured pic by NASA is shown below:

7. The hourly rainfall intensities for two IMD stations
Nungambakkam and Chembarambakkam for Dec.1 & 2, 2015
are shown below respectively
The Nungambakkam rainfall intensity is plotted on the Intensity
– Duration – Frequency plot derived for Chennai based on 30
years of hourly rainfall data.
From the IDF plot it is clear that the 24 hour rainfall that was
recorded in Nungambakkam on December 1, 2015 was more
like a 25-year storm whereas the rainfall that occurred in
Chembarambakkam could be higher than a 100-year storm.

8. From the IDF plot it is clear that the 24 hour rainfall that was
recorded in Nungambakkam on December 1, 2015 was more
like a 25-year storm whereas the rainfall that occurred in
Chembarambakkam could be higher than a 100-year storm.
Although the maximum 1-hr storm seems to be a storm of less
than 5-yr recurrence interval, it is the sustained rainfall over a
long duration that caused the heavy deluge.
Here the rainfall intensity is showcased in comparison with past
year analysis.
This helps us understand the impact of the rainfall better, as it
gives the comaparison with how it was and how it is.

9. Atmospheric Conditions during the Extreme
Rainfall Event:
The extreme high intensity rainfall event that occurred
over Chennai was an outcome of a depression generated over a
warm Bay of Bengal which brought huge moisture from BoB
and resulted in heavy precipitation over the South-East coast of
India. The spatial distribution of Mean Sea Level Pressure
(MSLP) till November, 27, 2015 shows a wide spread low
pressure over the South of BoB, which became concentrated
over Sri Lanka and brought huge moisture over Chennai region

10. on Dec. The high perceptible water (PW) over the same region
made the conditions favorable for heavy precipitation over
Chennai, which 7 continued till December 2, 2015. The low
MSLP remained concentrated over the same region during
Dec.4, 2015, but low perceptible water over Chennai did not
favor further extremes. The MSLP, PW and wind data are
obtained from European Reanalysis Interim (ERA-Interim).
Observed precipitation plotted in the bottom-most panel.
The series of depictions below are obtained from satellite
measurements as part of NASA’s Global Precipitation
Measurement (GPM).
Panel 1 gives the distribution of mean sea level pressure
Panel 2 gives the perceptible water and surface wind
Panel 3 gives satellite observed precipitation during the
extreme event over southern India and Bay of Bengal.

11. Impact of Global Warming:
Impact of Global Warming and Urbanization Scientific
theories and model studies suggest an increase in tropical
cyclones during recent decades, though these are not really very
evident from the recorded number of cyclones. However, the
potential destructiveness of cyclones, defined as the total
dissipation of power, integrated over the lifetime of the cyclone
has increased, is increasing and will increase in a warming
environment and this is primarily associated with the warming
of SST. It is true that the warming of Bay of Bengal is attributed
to the global warming, which is hypothesized to be a potential
cause of the extreme event over Chennai; however to confirm
this, it needs an event based attribution study. Urbanization is
another factor which is reported to intensify the extreme
precipitation, either through generation of convection due to
urban heat island (UHI) or through the uneven urban terrain
resulting in wake diffusion and turbulence. Extremes in
Southern and Central Region of India are observed to be
affected by urbanization during summer monsoon season;
though the specific impacts during winter monsoon and cyclones
have not yet been explored. Chennai is reported to have
significant urban heat island and there is a possibility of such
UHI-extremes link. However, it should be noted that the local
temperature variations do not have the capacity to organize such
a huge extreme events with high moisture flux, but can increase

12. the intensity of a severe extreme event. In order to minimize the
impacts of severe extreme events, there is a need for good
forecasting system.
The representation of observed sea temperature above Bay
of Bengal is depicted here:

13. Effect of El-Nino..?
The El-Nino of 2015 was one of the strongest
reported, which started developing in 2014. El-Nino is reported
to have impacts on North East Monsoon by modestly
intensifying it. A possible hypothesis would be that a stronger
El-Nino led to a strong easterly during Nov-Dec 2015 which
probably brought moisture to the East coast of India over
Chennai with a much intensified rainfall.
However, the scientific question remains if the easterlies
generated by El-Nino are the only reason or some other factors/
drivers have caused heavy precipitation over Chennai. This
hypothesis needs climate model based verification, which is yet
to be given.
Tidal Levels in Oceans:
It is quite obvious that draining of flood waters
through the three rivers in Chennai would depend upon the tidal
levels in the Bay of Bengal. Flooding would be exacerbated and
recession would be delayed if an intense rainfall event coincides
with the occurrence of high tidal levels. However, this issue has
not been focused in the mainstream discussions on Chennai
floods. Data on tidal levels for the months of November and
December are obtained from an organization which guides
fishing activities. These data are presented in graph below. From
this it is clear that, the tidal influence on the flooding event

14. appears to have been minimal as the heavy rainfall and flooding
is not found to coincide with the high tidal level.
Record of Chembarambakkam Rainfall
In these Graphs, the first graph shows the total rainfall.
While the second graph protrays the total inflow of water and
the last one shows the total outflow.
A comaprison of all three details shows that the outflow is
in a higher rate at the beginning, contributing to the flood while
later the water has been taken in, thus reducing the
consequences a bit.

15. Record of Pondi Rainfall

16. Why Chennai Got Affected?
Though major parts of Tami Nadu are affected, the
most affected region is Chennai. When we analyze why this is
so, the reason is because Chennai lies at the critical point of the
storm.
This image is the NASA map showing the rain intensity in
Chennai between NOV 28 and DEC 4 2015.
Geology of Chennai:
The geology of Chennai comprises mostly clay, shale
and sandstone. The city is classified into three regions based on
geology as:
 Sandy Areas- Areas along the banks and coasts. Some
of the areas are Thiruvanmiyur, Adyar, Kottivakkam, Santhome,

17. George Town, and Tondiarpet. The specialty of these areas is
that rainwater run-off percolates very quickly.
 Clayey Areas- These areas cover most parts of the city
which includes T.Nagar, West Mambalam, Anna Nagar,
Perumbalur and Virugambakkam.. In these areas, rain water
percolates very slowly and is held by the soil for a longer time.
 Hard-rock Areas- This category covers Guindy,
Velacherry, Adambakkam and a part of Saidapet. In these areas,
rain water percolates very slowly and is held by the soil for a
longer time.
Devastation of Pallikaranai (Flood sink of City):
The city has large marsh in the south (about 20 km south of
the city center), smaller satellite wetlands around it and large
tract of pasture land. The southern marshland called Pallikaranai
marshland is known as the flood sink area of the city as it
drained about 250 sq. km of the city in the eighties. The
marshland that was around 5,000 hectares (ha) during
independence got reduced to almost 600 ha around 2010-11. The
only reason for all this was rapid urbanization.
During the time of 2010-2011 along with the
marshland, all other wetlands of Chennai became sites of waste
disposal, housing, commercial and industrial purposes. As the
city expanded in the south, Pallikaranai marsh became
fragmented. As any other city, the state of Tamil Nadu only

18. valued the land and not the water body which came to be treated
as wasteland.
In 2002, a survey by the Tamil Nadu Pollution Control
Board showed that that the marsh lost around 90 per cent of its
original extent. This is also the year when the city observed a
big flood event. The most affected areas were the adjoining
areas around the marsh.
The notable change in the areas of this marsh is recorded
here. It is also mentioned that these changes took place between
the year 2003 to 2005.
This clearly gives the account of extra land annexed for
dumping.
Segment 2003 2005
Garbage Dump 50.25ha 57.24ha
Area taken for
dump and sewage
58.75ha 132.25ha
Northern Segment 227ha 150.56ha
Southern Segment 284ha 279.65ha
Apart from dumping, government and private sectors have
annexed lands even for their own purposes. Some of them are
mentioned below:
Building Area Occupies in hectares
MRTS 92.405
FEFSI 34.410

19. Ashram Latha Rajinikanth
trust
5
Tamil Nadu Agriculture
marketing board
12.150
Dr.Ambedhkar Law university 8.100
Judicial Academy 6.070
MMRD road 200” width 13.600
IIT Chennai 17.810
NIOT 20.250
Govt free Pattas 2
Land allotted for ex-
serviceman
61.675
Total 273.60
Perungudi Dump yard:
The most prominent Perungudi dump yard that spans
over 75.22 ha is located on the north-eastern part of the marsh.
The area of the dump yard has doubled over the last decade with
an increase from 32 ha in 2002-03 to about 75 ha in 2013,
according to Tamil Nadu State Land Use Research Board. It
shows that around 273.50 ha were allotted to different
institutions by 2010. Over and above this, there are other
allotments that made the total allotment area of 474 ha area
already allotted or occupied.
By 2014, about Rs.394 crores of that amounts had been
spent by the Tamil Nadu government but, as the Comptroller
and Auditor General noted, it hadn’t done much to protect

20. Chennai from flooding. Evidently, good money has been spent
down the drain.
Sewage System of Chennai:
Macro Drainage System:
The total area of the Chennai city is 1189𝑘𝑚2
, within
which there are three rivers flowing namely:
(i) Kosasthalaiyar,
(ii) Cooum and
(iii) Adyar flow
Kosasthalaiyar River originates near Kaveripakkam in
North Arcot district and flows in general eastward direction. It
bifurcates into Cooum River and Kosasthalaiyar main branch at
Keshavaram anicut. The main branch of Kosasthalaiyar River
then flows northwards and enters into Poondi Reservoir. Nagari
River, originating in Chittoor district, is a northern tributary, and
joins the Kosasthalaiyar River at Poondi reservoir. On the
downstream side of Poondi reservoir, Kosasthalaiyar River
flows through Thiruvallur district and CMA, and finally joins
the sea at Ennore.
Cooum River bifurcates from the main Kosasthalaiyar
River at the Keshavaram anicut and flows eastwards through
Kanchipuram district into CMA and finally joins the sea near
Napier Bridge. Surplus from about 75 tanks in the catchment
reaches the Cooum River.

21. Adyar River originates from two tank groups namely:
Pillapakkam and Kavanur, in Kanchipuram District and flows
through the CMA before it joins the sea at Adyar Mouth.
Surplus from about 450 tanks in the catchment, besides surplus
from Chembarambakkam tank, reaches the Adyar River.
Besides the above three rivers, the macro drainage system
of CMA consists of several canals. It is to be noted here that the
Buckingham canal has been constructed more than 200 years
ago, as a navigation channel. It originates close to Kakinada in
Andhra Pradesh and runs along the east coast for a total length
of 418 km. Its entry point into CMA is near Athipattu village
and the exit point is near Semmencheri village. While the three
rivers run west to east, Buckingham canal runs north to south
and connects all these three rivers. While Otteri Nullah,
Kodungaiyur drain and Captain Cotton Canal drain into the
Buckingham canal, Veerangalodai and Velachery drain
discharge into Pallikaranai marsh. Virugambakkam drain
discharges into Cooum River. Mambalam drain discharges into
Adyar River.
These macro drainage canals are mostly maintained by the
Public Works Department (PWD) of Chennai city. All these
details are perfectly demonstrated in the tabulation below:

22. There are major tanks in the CMA which cater to the
drinking water needs of the Chennai City. They are:
(i) Sholavaram Tank (25Mm3 ),
(ii) Red Hills Tank (93Mm3 ),
(iii) Chembarambakkam Tank (103 Mm3 ) and
(iv) Poondi Reservoir (91 Mm3 )
The Flow of Water: Sholavaram Tank receives water from
Poondi Reservoir and supplies the water to the Red Hills tank.
Surplus water from the Red Hills tank is released into
Kosasthalaiyar River during floods. Chembarambakkam Tank is
also a drinking water reservoir. It has its own catchment, and it
also receives water from the Poondi reservoir. Excess water

23. from this reservoir is released into the Adyar River. Besides
these three major tanks, several water bodies exist in CMA area,
although their number has come down significantly in the last
three decades due to urbanization and encroachment of lake
beds.
Thus it can be seen that the macro drainage of the CMA
during floods is carried out by a complex web of these rivers and
several major drains. These drinking water reservoirs double up
as flood control reservoirs in case of emergencies, and the
multitude of water bodies perform the detention function to
reduce the peak discharges.
Micro Drainage System:
The macro drainage is served by a network of 31
minor drainage canals (16 in old city and 15 in the expanded
areas) maintained by the Greater Chennai City Corporation for
storm water drainage within the CMA. In addition to this, a
network of storm drains to the length of about 1660 km
discharges storm water into the rivers and major / minor drains.
Eighty four percent of these micro-drains carry sewage while the
rest carry storm water. Efforts are underway through the
Jawaharlal Nehru National Urban Renewal Mission (JNNURM)
and aid from World Bank and Asian Development Bank to
further expand the network of storm drain to areas currently
lacking proper storm drainage connectivity to natural
waterways.

24. Problems with drainage system:
Chennai has experienced major floods during the last
three decades in the years 1976, 1985, 1996, 1998 and 2005 and
then the big one in 2015. The drainage system has been found
wanting because of several reasons. These include:
(i) Reduction in the vent way caused by the
construction of bridges,
(ii) Sand bar formation at the mouths of rivers,
(iii) Clogging of the drains due to indiscriminate
dumping of solid waste and construction debris,
(iv) Inadequate design capacity,
(v) Lack of connectivity of storm sewers with macro
drainage,
(vi) Encroachments.
While successive governments have focused on dredging of
rivers and desilting of major drains, maintenance of minor drains
is neglected due to scarcity of funds as well as public apathy. In
this context it is important to bring out the effect of bad solid
waste management on the condition of drainage channels, both
major and minor
Although a road network to the length of 6000 km (387 km
of bus route and 5623 km of interior roads) is maintained by the
Greater Chennai Corporation, only about 1660 km of storm
drains exist (about 205 km of these drains have a width of 0.6m

25. or more). Storm Water Drains are usually provided only for
roads with 12 m width or more. Earlier, storm water drains were
designed for a rainfall intensity of 31.39 mm/hr (storm duration
of 1hr with 2-yr return period). However, this was subsequently
revised in 2014 to 68 mm/hr based on recommendations from 17
World Bank, though it is not immediately clear as to which
return period this intensity corresponds.
Chennai city has been urbanizing very rapidly over the last
few decades. Population in Chennai city has increased from a
mere 500,000 in the year 1901 to more than 45 lakhs in the year
2011. It is estimated that the area covered by the high density
urban areas increased from 81.32 km2 in 1988 to 330.30 km2 in
2014. The area covered by low density urban areas increased
from 53.79 km2 in 1988 to 303.14 km2 in 2014. A major
consequence of this urbanization is the reduction in the
infiltration component of the hydrologic cycle, which would
increase the peak run-off discharge.
Another consequence of urbanization is the disappearance
of many minor and medium water bodies. These water bodies
served as detention basins and resulted in decrease in the peak
discharge. Urbanization has reduced the detention effect.
Inappropriate urbanization may also lead to the
encroachment of the waterways, which reduces their vent way.
A glaring example of this is the construction of Mass Rapid
Transit System (MRTS) along and in some locations in the
Buckingham canal. The new runway of the Chennai airport has

26. been built on the Adyar River. Similarly, culverts provided on
many of the new roads have inadequate capacity to pass the flow
from one side to the other.
Another effect of urbanization which is usually overlooked
is the “compound wall effect”. Compound walls are built around
almost all institutions, commercial and industrial organizations
and large residential complexes, in order to prevent
encroachment. These compound walls alter the local overland
flow paths and sometimes even block the local channels because
of inadequate provision of culverts. This in turn changes the
local flooding pattern, protecting some areas while flooding the
others. During major rainfall events many of these compound
walls collapse because they are not usually designed to take
water pressure from one side. In several cases, the compound
wall and roads have affected the natural flow and the lack of
adequate cross drainage has led to much of localized flooding
and water logging. In some cases, people who are affected by
flood, damaged these walls and roads in order to drain flood
waters from their locality
Aggradation of roads due to constant resurfacing without
adequate milling is also one of the major reasons for localized
flooding and water logging during the recent floods. Localized
flooding and water logging is quite common and widely
prevalent across the CMA every year, even during normal
showers, due to aggradation of roads and lack of adequate cross
drainage infrastructure. As per Indian Road Congress codes

27. (IRC: 120-2015), the roads have to be milled before resurfacing.
Although this is mandated by the corporation, this norm is
usually flouted by the contractors and not strictly enforced.
Reservoir Releases:
Chembarambakkam tank receives water from its own
catchment as well as some surplus water from Poondi through
the Krishna water link canal. Before discharging at
Chembarambakkam, Krishna water link canal crosses/joins
Cooum at Aranvoil anicut and gathers some water from Cooum
as well before taking off to Chembarambakkam.
Chembarambakkam tank can hold water up to a maximum level
of 7.315 metre, with a full capacity of 3645 million cubic feet
(103.214 million cubic metres). When the Chembarambakkam
tank is full, excess water is released into the Adyar River.
On Nov. 17, 2015, 18,000 cusecs (509.7 cusecs) was
released from the reservoir in Chembarambakkam, causing
massive flooding in areas such as Mudichur, West Tambaram,
and Manapakkam among others. On Dec. 1, 2015, the
Chembarambakkam reservoir was at 93% capacity with storage
of 3396 million cubic feet due to a rainfall of 47.5 cm. This led
to the release of 29,000 cusecs (821.2 cusecs) over 12 hours into
the Adyar River (The Hindu 2015a). The outflow from Poondi
reservoir (which empties into the Cooum River) was at 8,552
cusecs (242.2 cusecs) on Dec. 1, 2015. On Dec. 2, the outflow
was at 30,200 cusecs (855.2 cusecs) – more than that of

28. Chembarambakkam. On Dec. 3, Poondi discharged 36,484
cusecs (1033.1 cusecs), while the release from
Chembarambakkam on the same day came down to 11,000
cusecs (311.5 cusecs).
The daily average inflow and outflow of water in the
Chembarambakkam reservoir is shown below,
There are strong opinions from various parts that the
authorities should have released the water from the
Chembarambakkam reservoir gradually well ahead of the heavy
rainfall since Chennai had been warned by IMD in mid-October
of 2015 says the news from NDTV, 2015. The situation would
have been better if the authorities had released controlled
quantities of water from Chembarambakkam and other

29. reservoirs throughout November 2015. However, these are
conservation reservoirs and not flood control reservoirs.
Therefore, they are regulated differently. Being conservation
reservoirs, without a reliable weather forecast (forecasts with
~70-80% false alarms) and a reservoir inflow forecast, decisions
on timely release of flood waters are rather difficult. Further, all
water bodies were completely full from the above-normal
November rainfall and the catchment was completely saturated,
resulting in heavy runoff.
Hence, the reservoir release alone cannot be blamed for the
huge deluge in Chennai. Nonetheless, it is high time to have a
comprehensive flood forecast system in place for assisting the
authorities in making informed decisions about operating the
reservoirs for managing floods in addition to making sure that
the storage for drinking water supply is not compromised.
The After Effects:
It is not an overstatement to say that the December
2015 floods in Chennai have been mammoth although there
have been varying reports on the number of casualties, areal
extent of flooding and the magnitude of economic loss. They
affected the Coromandel Coast region of the South Indian states
of Tamil Nadu and Andhra Pradesh, and the union territory of
Puducherry, with Tamil Nadu and the city of Chennai
particularly hard-hit. More than 400 people were killed and over

30. 18 lakh people were displaced. With estimates of damages and
losses ranging from ₹50000 crore (US$7 billion) to ₹100000
crore (US$15 billion), the floods are the costliest to have
occurred in 2015.
As early as December 3, 2016, the Home Minister of India
informed the Lok Sabha that rains and floods have claimed 269
lives in Chennai alone until that time. Probably the most
shocking news was that of death of 18 patients in MIOT
International Hospital, reported on December 5, 2015. The
hospital is located close to the Adyar River and the flood waters
damaged the power units supplying power to the ventilators. The
death toll further mounted to 347 by December 25, 2015, as per
the official release from the State Government. The Chief
Minister of state asserted that a total of 470 lives have been lost
in the state of Tamil Nadu during the North East monsoon. Over
18 lakh (1.8 million) people were displaced because of the
flooding event. About 30.42 lakh (3.042 million) families had
suffered total or partial damage to their dwellings; 3,82,768 lakh
hectares of crops had been lost due to flooding, including over
3.47 lakh hectares of agricultural crops and 35,471 hectares of
horticultural crops; roughly 98,000 livestock animals and
poultry had died. It is reported that more than 100,000 structures
were damaged as a result of the floods. Almost 30% of Chennai
households have each faced losses between Rs.2 lakh and Rs.20
lakh.

31. Effects In various Sectors:
Other than loss of life and property of people, even the
economic and industrial sectors suffered a lot. The most affected
sectors and the companies that suffered a lot of economic loss
are mentioned below. Let’s see these under each sector.
Automobile and Petroleum Sector:
The automotive industry is one of the key drivers of
India’s economy, accounting for around 4 percent of India’s
GDP and over 200,000 jobs. Gujarat and Chennai-Bangalore
corridor are the two major areas where Indian automobile
manufacturing is concentrated. Subsequently, Chennai is
renowned as the Detroit of India. In fact, Chennai hosts
country’s largest auto manufacturing hub with Ford, Daimler,
Nissan, TVS, Hyundai, Renault-Nissan, Royal Enfield and
Ashok Leyland having their factories there. Out of the $38
billion annual production of auto components in India, almost 25
percent, or $9.5 billion comes from Chennai and its surrounding
automotive belt.
South Korean carmaker Hyundai, has the largest car
manufacturing plant around 45 km from Chennai having daily
production of 2,200 cars whereas the annual capacity is 6,80,000
units. In view of the heavy rain and floods, the company had to
call off the third shift on December 1 and all shifts on December
2, 3 and 4. The company did not share the exact production loss.
However, going by its daily production capacity and the number

32. of shifts and days suspended, production loss could be around
7,300 units. The damages to roads because of the floods have
caused logistics challenges, despite this, they are also facing
issues like supply uncertainty since most of their vendors was
located close by. However, later they worked closely with their
vendors and supply chain partners to ensure supply of parts is
not impacted. The IIIE Industrial Engineering Journal, Vol. IX,
Issue No. 8, August 2016 company then had to work all shifts
and its production teams worked towards resolving the shortfall.
Even though, the waiting period of some models impacted by a
week to 10 days
Royal Enfield’s production facilities at Thiruvottiyur
and Oragadam were shut on December 1 and the company
resumed production of motorcycles on December 7. However,
owing to low turnout of employees and some issues with its
local suppliers, the facilities had to run at their 50 per cent
capacity in December second week. The firm has reported
production loss of 11,200 vehicles owing to the closure of both
the facilities (The Hindu, 2016). Finally, Indian two-wheeler
manufacturer TVS Motor claimed that the company suffered
sales loss of approximately 15,000 units due to the inclement
weather.
Apollo Tyres has informed the exchange that its
factory at Oragadam, near Chennai, was flooded and production
disrupted till December 2 due to heavy rains in Chennai. The
production loss due to this natural calamity was 450 tones but it

33. was adequately covered under the insurance policy of the
company. The shutdowns and production losses have affected
shares of some Chennai-based companies on domestic stock
exchanges. Shares of Ashok Leyland—whose Ennore plant in
Chennai accounts for 40% of its production—closed down over
1% on the Bombay Stock Exchange (BSE) on Dec. 3. Shares of
Chennai Petroleum Corporation (CPCL) ended down over 5%
while TVS Motors closed over 2% lower on the BSE.
When coming to the petroleum industry, Supreme
Petrochem Limited informed the BSE that the operations of the
company's EPS plant at Chennai had disrupted due to heavy
rains and floods. Even though they did not produced exact loss
statements, they claimed, that the plant was adequately insured.
In addition, they served their customers from the company's EPS
plant at Maharashtra. Reuters reported that the state-run Chennai
Petroleum Corp (CPCL) had to shut its 210,000 barrels per day
refinery in the city’s industrial zone of Manali. Finally, the flood
has made The Indian Oil Corporation’s large Manali refinery in
Chennai to close down, disrupting the fuel supply chains in and
around the city (Press Trust of India, 2015). This also affected
the transportation facilities in the state.
IT and telecommunication Industry:
Chennai is also a hub for several Indian and
multinational IT companies, such as Infosys, Cognizant, along

34. with Tata and IBM. Around 400,000 people in the city work in
the IT sector. Most of the IT companies are located in Porur, an
area west of Chennai that was widely inundated. However,
given the nature of their business, IT companies say they have
successfully managed to get the work executed from other
locations.
Telecom operators have suffered Rs. 300 crore of
losses amid the unprecedented rainfall in Chennai and its
surrounding areas. The calamity has also compelled Finnish
network gear maker Nokia to stop production of 3G and 4G gear
at its nearby factory. China's biggest telecoms gear maker
Huawei also got hit by the flood situation that affected its
Chennai factory, which purely caters to export markets such as
China, Asia Pacific and the Middle East. Even under the
circumstances, most of the telecom operators offered their
customers free calls and internet data to facilitate
communication that was crucial even in the relief work.
Companies like Airtel, Vodafone, BSNL, MTS etc. offered free
10 minutes talk and 50-100 Mb of data for prepaid customers in
Chennai.
Food Supply Chain:
The floods severely impacted the food availability for
initial days but the community was supported by government
and other agencies. Across the three districts Cuddalore,

35. Kanchipuram and Chennai, the food and security issue was
much common since many household had lost their food items
in the flood and was unable to restart cooking as there was
muck, wet floor and no dry ration available. People depended on
the food been supplied by the philanthropists. Cuddalore district
was the most affected.
Essential household items like milk and vegetables
were sold at more than double the normal price in some places
in Chennai. As the state electricity board had suspended power
as a precautionary measure, most of the residents of the city and
its neighborhoods, who had stocked milk and vegetables, were
unable to preserve them for long. Large queues were seen in
places where milk was being sold. Despite this, famous
Koyambedu vegetable market was cut off from the city, leading
to the spiraling vegetable prices. In addition, the price of mineral
water also hit the roof with a 20-litre bottle normally available
for Rs 30 being sold for Rs 150 per bottle. Most of the
supermarkets and hotels across the city were either shut or had
run out of stocks. Adding to this vulnerability, over 1.5 lakh
(150,000) street vendors sustained losses of over 300 crores.
Health Sector:
When rains ravaged the city, a well-known MIOT
International hospital on the banks of the Adyar river in
Manapakkam was hit by flood in parts of its premises and
according to the government 18 people were declared dead

36. within the initial two to three days of the. As there was no
electricity, the hospital was put to run on the generator.
Unfortunately, flooding of generator room and resultant snap of
ventilator and oxygen support resulted in loss of human life.
Speaking to reporters, some relatives of those dead alleged that
those on life support like ventilator and oxygen could not be
continuously given such backup as the generator room was
flooded. Out of 75 ICU patients in that hospital, 57 ventilator
patients were moved out. To avoid similar situations seven
emergency ambulances were deployed to transport patients from
MIOT hospital to private and a government hospital. Also, out
of the 18 dead, 14 were taken to the Government Royapettah
Hospital as there was no power in the mortuary of MIOT
Hospital.
Summary of estimated Economic Loss:
Descripti
on
Amount(
in
crores)
Source
Chennai
real
estate
30, 000 http://www.dnaindia.com/india/report-
chennairealty-market-faces-rs-30000-
crore-loss-postfloods-2160122
Small
and
medium
14, 000 http://www.newindianexpress.com/cities
/henna i/Flood-hit-Industrial-Belts-

37. scale
industries
Clamour-
forAid/2015/12/27/article3198021.ece
Insurance
Compani
es
4, 800 http://indianexpress.com/article/india/in
dia-
news-india/chennai-floods-insurance-
cos-get-rs-
4800-cr-claims/
Street
Vendors
225 http://www.thehindu.com/news/cities/ch
ennai/
over-15-lakh-street-vendors-
affected/article8023454.ece
Response and Recovery:
In the aftermath of the flooding event, there was good
coordination between the government and the defense agencies
during the rescue phase. After the crisis phase passed, there was
no direction from the State administration to the Army which led
them to figure out as what they were required to do.
Many volunteers came up with their helping hand during
initial stages of the rescue operations. Also, many organizations
and youths, split into different groups, joined hands in rescuing
people which blurred the cultural differences amongst
communities. All the mosques, churches and temples were
opened to the flood victims who were also served food even
after the flood water drained out from the arterial roads, many of
the low-lying areas continued to be flooded with sewage due to
silting and blockage of drains with plastic, mattresses and
sundry material. Authorities gathered nearly 25,000 sanitary
workers to clean the stinking garbage piled up over the

38. preceding several days to prevent the spreading of diseases.
After the floods, piled up garbage piled amounted to 8,000 to
10,000 tones. In normal times, it is about 650 tones
Ideas and Recommendations:
Many lessons can be learnt from an event of this magnitude
to aid better preparedness to face such events in future, not just
in Chennai but also in other urban areas in India and elsewhere
in developing countries. Herein, some ideas are proposed as
recommendations on which attention needs to be focused by the
policy makers, administrators and academicians. These
recommendations should be considered in conjunction with the
guidelines for Urban Flooding prepared by National Disaster
Management Authority.
Following some of these may help us the next time in case of
any future calamities.
Better Understanding of the Weather: It is obvious that flood
risk can be minimized if one can predict the occurrence of major
precipitation events well in advance. This is especially so for
cities like Chennai, where major reservoirs are drinking water
reservoirs, and one tends to store as much water as possible
when the rains come, and little storage is left for flood
mitigation. If the reliability of prediction of precipitation
magnitude can be improved, especially for an impending high
intensity event, it will help operators of drinking water
reservoirs to take timely actions and operate them for flood
mitigation.

39. Water Wiring of Cities: One of the major issues with regard to
management of urban floods in India is the lack of information
on them. It is absolutely essential to deploy sensors at all key
locations in the major drainage networks in the Cities and record
on-line the temporal variation in water levels and also the flow
rates. Sufficient number of telemetric rain gauge stations should
be installed. The water level sensors should be not only
deployed in channels, but also at key locations in the flood plain
and at all major and medium water bodies. All the data should
be transmitted to centralized control rooms to provide real time
information, flood hazard mapping etc.
Development of Urban Flood Models: Many mathematical
models are presently available worldwide for studying urban
floods. However, extensive and proper usage of these models in
India is hampered by lack of data for their calibration and
validation. There is an urgent need to bridge this gap, and to
keep ready calibrated urban flooding models for all the cities
which get flooded frequently. Such models can be used for
designing flood warning systems, on-line control of urban floods
and planning water sensitive urban development.
System Operation: Although the Chennai floods 2015 could
not have been prevented simply by appropriate operation of
reservoirs in the city, there was a possibility of lessening the
magnitude of the effect. Therefore, one should revisit the
reservoir operation guidelines, and formulate more rational rules
for the operation. In any urban area, major natural drainage
channels, the storm water drains, the water bodies such as lakes
and ponds and the roads (as water conveyance structures for
overland flow) act as a single unit during major storm events.

40. Therefore, system dynamics methods should be employed to
find out how best to utilize each of these components of the
system for minimizing the damage.
Stricter Norms on Roads and Compound Walls: In the
discourse on the effect of urbanization on the floods, major
emphasis is usually laid on,
(i) How the run-off and the peak flow magnitude increases
due to decrease in the infiltration component,
(ii) How the disappearance of water bodies, small and large,
due to land use change, decreases the detention effect of
the catchment,
(iii) How encroachment of water ways reduces their flood
carrying capacity and
(iv) How poor solid waste management clogs the storm
water drainage system.
Well-planned Peri-Urban Development: The core parts of
most of the cities such as Chennai are already fully developed
and in a very unsustainable way. Retrofitting these parts of the
city for a water sensitive urban development is almost
impossible because of social, political and economic
considerations, besides technical reasons. However, peri-urban
areas are amenable to policy interventions. Policies must be
introduced such that the development is water sensitive and is
based on the principles of sustainability [Sustainable Urban
Drainage (SusDrain) / Low Impact Development (LID)].
Urban Flooding Study Group: Although urban flooding in the
scale of Chennai Floods 2015 occurs rarely, the effect of such
floods is enormous in terms of loss of life and property. Even

41. the trauma caused by such floods is long lasting. However,
coordinated efforts are not being made to collect data on these
floods as they unfold, make rapid assessment of events and
finally learn from them to make the urban systems resilient to
such events.
Maintenance of Drainage System: One cannot over-emphasize
the need for keeping all the storm water drains free from
blockages due to indiscriminate dumping of solid waste into
them. While keeping the major drains clean could be the
responsibility of the urban local body, keeping the minor drains
clean should be the responsibility of local population. It is not
possible to make the entire drainage system work effectively,
unless part of the ownership of the drainage system is taken by
the local users. It may be worthwhile to encourage the formation
of citizen groups which work in close coordination with
government.
Assessment of Climate Change Impacts: Uncertainties
introduced by climate change need to be addressed in the storm
water drainage designs. It is very likely that the short duration,
high intensity rainfalls that cause urban floods will continue to
increase in future. The design storm used in the hydrologic
designs must therefore be reassessed to account for climate
change. It must however be noted that the climate models are
currently not reliable for simulation of monsoon precipitation
even at daily scale, and therefore disaggregating the climate
model outputs to sub-daily scales are burdened with a large
uncertainty. The disaggregated outputs must therefore be used
with caution.

42. Co-ordinated flood relief operations: Many flood relief
workers who come from outside of the area may lack
appropriate knowledge of local geography and conditions. This
may lead to inefficiencies and inequities in the relief work, as
we discuss earlier in this report. Therefore, local government
officials should ensure effective coordination between different
agencies involved in flood relief operations. Also, proper safety
measures should be taken for the health of flood relief workers
themselves, especially the sanitation workers.
Conclusion:
The 2015 floods in Chennai city and surrounding areas in
Tamil Nadu have brought to the fore the need for developing a
scientific understanding of urban floods to help enhance the
engineering, administrative and societal resilience. Therefore, an
attempt is made in this report to present issues that contributed
to the devastating floods in Chennai city during November-
December 2015. Brief discussions on the after-effects of the
floods and the responses are also provided. Although much of
the material presented in the report is collated from information
available in public domain, results from a few preliminary
analyses carried out by the authors - especially on estimation of
the return period of the rainfall recorded during the period,
inferences on the atmospheric drivers and the hydrologic
responses - are also included.
Questions related to the influence of global climatic events
such as the El Nino on the high intensity rainfall recorded during
the event and increasing frequencies of such high intensity
rainfall because of climate change and urban heat island effect
remain unresolved and require

43. further observations and model-based investigations. However,
it is possible to estimate the hydrologic response in terms of the
flood inundation in the City for a given intensity of rainfall, if
appropriate data is made available to the scientific community.
Such estimates will be useful for improving disaster
preparedness and management. It is also possible to estimate the
impact of urbanization on the occurrence of floods in future so
that further development in the City can be made sustainable.
Further efforts on improved forecasting of extreme weather
events and associated hydrological responses can also aid water
management decisions such that the contribution of human
regulations (such as reservoir operation) on aggravating the
floods can be avoided.
We having an immense growth and advancement in
technology yet suffer from such devastating disasters due to the
lack of awareness and knowledge. We still can save our mother
earth from these disasters by using the technical advancements
in the most straight forward way to lessen the extremeness of the
natural disasters. Let’s learn more and save more.
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