1. INTRODUCTION

1.1 GENERAL

In ancient times, dams were built for the single purpose of water supply or irrigation.

As civilizations developed, there was a greater need for water supply, irrigation, flood

control, navigation, water quality, sediment control and energy. Therefore, dams are

constructed for a specific purpose such as water supply, flood control, irrigation,

navigation, sedimentation control, and hydropower. A dam is the cornerstone in the

development and management of water resources development of a river basin. The

multipurpose dam is a very important project for developing countries, because the

population receives domestic and economic benefits from a single investment.

Demand for water is steadily increasing throughout the world. There is no life on

earth without water, our most important resource apart from air and land. During the

past three centuries, the amount of water withdrawn from freshwater resources has

increased by a factor of 35, world population by a factor of 8. With the present world

population of 5.6 billion still growing at a rate of about 90 million per year, and with

their legitimate expectations of higher standards of living, global water demand is

expected to rise by a further 2-3 percent annually in the decades ahead. But

freshwater resources are limited and unevenly distributed. In the high-consumption

countries with rich resources and a highly developed technical infrastructure, the

many ways of conserving, recycling and re-using water may more or less suffice to

curb further growth in supply. In many other regions, however, water availability is

critical to any further development above the present unsatisfactorily low level, and

even to the mere survival of existing communities or to meet the continuously

growing demand originating from the rapid increase of their population. In these

regions man cannot forego the contribution to be made by dams and reservoirs to the

harnessing of water resources.

Seasonal variations and climatic irregularities in flow impede the efficient use

of river runoff, with flooding and drought causing problems of catastrophic

proportions. For almost 5 000 years dams have served to ensure an adequate supply of

water by storing water in times of surplus and releasing it in times of scarcity, thus

also preventing or mitigating floods With their present aggregate storage capacity of

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about 6 000 km3, dams clearly make a significant contribution to the efficient

management of finite water resources that are unevenly distributed and subject to

large seasonal fluctuations. Most of the dams are single-purpose dams, but there is

now a growing number of multipurpose dams. Using the most recent publication of

the World Register of Dams, irrigation is by far the most common purpose of dams.

Among the single purpose dams, 48 % are for irrigation, 17% for hydropower

(production of electricity), 13% for water supply , 10% for flood control, 5% for

recreation and less than 1% for navigation and fish farming.

Presently, irrigated land covers about 277 million hectares i.e. about 18% of

world's arable land but is responsible for around 40% of crop output and employs

nearly 30% of population spread over rural areas. With the large population growth

expected for the next decades, irrigation must be expanded to increase the food

capacity production. It is estimated that 80% of additional food production by the

year 2025 will need to come from irrigated land. Even with the widespread measures

to conserve water by improvements in irrigation technology, the construction of more

reservoir projects will be required. Electricity generated from dams is by very far the

largest renewable energy source in the world. More than 90% of the world's

renewable electricity comes from dams. Hydropower also offers unique possibilities

to manage the power network by its ability to quickly respond to peak demands.

Pumping-storage plants, using power produced during the night, while the demand is

low, is used to pump water up to the higher reservoir. That water is then used during

the peak demand period to produce electricity. This system today constitutes the only

economic mass storage available for electricity. It has been stressed how essential

water is for our civilization. It is important to remember that of the total rainfall

falling on the earth, most falls on the sea and a large portion of that which falls on

earth ends up as runoff. Only 2% of the total is infiltrated to replenish the

groundwater. Properly planned, designed and constructed and maintained dams to

store water contribute significantly toward fulfilling our water supply requirements.

To accommodate the variations in the hydrologic cycle, dams and reservoirs are

needed to store water and then provide more consistent supplies during shortages.

Natural river conditions, such as changes in the flow rate and river level, ice and

changing river channels due to erosion and sedimentation, create major problems and

obstacles for inland navigation. The advantages of inland navigation, however, when

compared with highway and rail are the large load carrying capacity of each barge,

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the ability to handle cargo with large-dimensions and fuel savings. Enhanced inland

navigation is a result of comprehensive basin planning and development utilizing

dams, locks and reservoirs which are regulated to provide a vital role in realizing

regional and national economic benefits. The below Fig 1.1 shows the different

purposes of dams.

  Fig 1.1: Different applications of dams

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2. MULLAPERIYAR DAM

The Mullaperiyar Dam is a masonry gravity dam on the Periyar River in the Indian

state of Kerala.  It is located 881 m (2,890 ft) above mean sea level, on the Cardamom

Hills of the Western Ghats in Thekkady, Idukki District of Kerala, South India. It was

constructed between 1887 and 1895 by John Pennycuick to divert water eastwards to

the Madras Presidency area (present-day Tamil Nadu). It has a height of 53.6 m

(176 ft) from the foundation, and a length of 365.7 m (1,200 ft). The Periyar National

Park in Thekkady is located around the dam's reservoir. The dam is located in Kerala

on the river Periyar, but is operated and maintained by Tamil Nadu state. Although

the Periyar River has a total catchment area of 5398 km2 with 114 km2 in Tamil

Nadu, the catchment area of the Mullaperiyar Dam itself lies entirely in Kerala. By

reports on November 21, 2014, Mullaperiyar water level touches 142 feet for first

time in 35 years.

The Periyar river which flows westward of Kerala Arabian sea was diverted

eastwards to flow towards the Bay of Bengal to provide water to the arid rain

shadow region of Madurai in Madras Presidency which was in dire need of a greater

supply of water than the small Vaigai River could provide.[ The dam created the

Periyar Thekkady reservoir, from which water was diverted eastwards via a tunnel to

augment the small flow of the Vaigai River. The Vaigai was dammed by the Vaigai

Dam to provide a source for irrigating large tracts around Madurai. Initially the dam

waters were used only for the irrigation of 68,558 ha (169,411 acres).

Currently, the water from the Periyar (Thekkady) Lake created by the dam, is

diverted through the water shed cutting and a subterranean tunnel to Forebay

Dam near Kumily (Errachipalam) in Tamil Nadu. From the Forebay dam, hydel pipe

lines carry the water to the Periyar Power Station in Lower Periyar, Tamil Nadu. This

is used for power generation (175 MW capacity) in the Periyar Power Station.From

the Periyar Power Station, the water is let out into Vairavanar river and then to

Suruliyar and from Suruliyar to Vaigai Dam. The below Fig 2.1 shows the

Mullaperiyar dam.

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Fig 2.1: Mullaperiyar dam

2.1 CONSTRUCTION

In May 1887, construction of the dam began. As per "The Military Engineers in

India" Vol II by Sandes (1935), the dam was constructed from lime stone and

"surkhi" (burnt brick powder and a mixture of sugar and calcium oxide) at a cost of   

104 lakhs, was 173 feet high and 1241 feet in length along the top and enclosed more

than 15 thousand million cubic feet of water. Another source states that the dam was

constructed of concrete and gives a figure of 152 feet height of the full water level of

the reservoir, with impounding capacity of 10.56 thousand million cubic feet along-

with a total estimated cost of   84.71 lakhs. The construction involved the use of

troops from the 1st and 4th battalions of the Madras Pioneers as well

as Portuguese carpenters from Cochin who were employed in the construction of the

coffer-dams and other structures. The greatest challenge was the diversion of the river

so that lower portions of the great dam could be built. The temporary embankments

and coffer-dams used to restrain the river waters were regularly swept away by floods

and rains. Due to the coffer dam failures, the British stopped funding the project.

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Officer Pennycuick raised funds by selling his wife's jewelry to continue the work.

In Madurai, Major Pennycuick statue has been installed at the state PWD office and

his photographs are found adorning walls in people homes and shops. In 2002, his

great grandson was honoured in Madurai, a function that was attended by thousands

of people.

The dam created a reservoir in a remote gorge of the Periyar river situated

3,000 feet above the sea in dense and malarial jungle, and from the northerly arm of

this manmade water body, the water flowed first through a deep cutting for about a

mile and then through a tunnel, 5704 feet in length and later through another cutting

on the other side of the watershed and into a natural ravine and so onto the Vaigai

River which has been partly built up for a length of 86 miles, finally discharging 2000

cusecs of water for the arid rain shadow regions of present-day Theni, Madurai

District, Sivaganga District and Ramanathapuram districts of Tamil Nadu, then under

British rule as part of Madras Province (Sandes, 1935).

The Periyar project, as it was then known, was widely considered well into the

20th Century as "one of the most extraordinary feats of engineering ever performed

by man".A large amount of manual labour was involved and worker mortality

from malaria was high. It was claimed that had it not been for "the medicinal effects

of the native spirit called arrack, the dam might never have been finished". 483 people

died of diseases during the construction of this dam and were buried on-site in a

cemetery just north of the dam. In 2012, it was announced that a memorial dedicated

to dam engineer Pennycuick would be erected at the dam site.

2.2 LEASE AGREEMENT

On 29 October 1886, a lease indenture for 999 years was made between the Maharaja

of Travancore, Visakham Thirunal Rama Varma and the British Secretary of State for

India for Periyar Irrigation Works. The lease agreement was signed by Dewan of

Travancore V Ram Iyengar and State Secretary of Madras State J C Hannington. This

lease was made after 24 years negotiation between the Maharaja and the British. The

lease indenture granted full right, power and liberty to the Secretary of State for India

to construct make and carry out on the leased land and to use exclusively when

constructed, made and carried out, all such irrigation works and other works ancillary

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thereto. The agreement gave 8000 acres of land for the reservoir and another 100

acres to construct the dam. The tax for each acre was   5 per year. The lease provided

the British the rights over "all the waters" of the Mullaperiyar and its catchment basin,

for an annual rent of   40,000.

In 1947, after Indian Independence, after British India was partitioned in 1947

into India and Pakistan, Travancore and Cochin joined the Union of India and on 1

July 1949 were merged to form Travancore-Cochin. On 1 January 1950 (Republic

Day), Travancore-Cochin was recognized as a state. The Madras Presidency was

organized to form Madras State in 1947.

On 1 November 1956, the state of Kerala was formed by the States

Reorganization Act merging the Malabar district, Travancore-Cochin (excluding four

southern taluks, which were merged with Tamil Nadu), and the taluk

of Kasargod, South Kanara. The Kerala state government announced that the earlier

agreement which had been signed between British Raj and Travancore agreement was

invalid and needed to be renewed.

After several failed attempts to renew the agreement in 1958, 1960, and 1969,

the agreement was renewed in 1970 when C Achutha Menon was Kerala Chief

Minister. According to the renewed agreement, the tax per acre was increased to   30,

and for the electricity generated in Lower Camp using Mullaperiyar water, the charge

was   12 per kilo Watt per hour. Tamil Nadu uses the water and the land, and the

Tamil Nadu government has been paying to the Kerala government for the past 50

years   2.5 lakhs as tax per year for the whole land and   7.5 lakhs per year as

surcharge for the total amount of electricity generated. The validity of this agreement

is under dispute between the States of Kerala and Tamil Nadu. As of 2013 the matter

is pending before a Division Bench of the Supreme Court. The dispute puts into

question the power of the federal government of India to make valid orders respecting

Indian States, in this case regarding a watershed and dam within one state that is used

exclusively in another. The below Fig 2.2 shows construction stages of Mullaperiyar

dam.

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Fig 2.2 Construction stages of Mullaperiyar dam.

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3. DAM SAFETY ISSUES

After the 1979 Morvi Dam failure which killed up to 15,000 people,[safety concerns

of the aging Mullaperiyar dam's and alleged leaks and cracks in the structure were

raised by the Kerala Government. A Kerala government institution, Centre for Earth

Science Studies (CESS), Thiruvananthapuram, had reported that the structure would

not withstand an earthquake above magnitude 6 on the scale. The dam was also

inspected by the Chairman, CWC (Central Water Commission). On the orders of the

CWC, the Tamil Nadu government lowered the storage level from 152 feet to 142.2

feet then to 136 feet, conducted safety repairs and strengthened the dam.

Strengthening measures adopted by Tamil Nadu PWD from 1979 onwards include

cable anchoring of the dam's structure and RCC backing for the front slope. During a

recent scanning of the Mullaperiyar dam using a remotely operated vehicle by the

Central Soil and Materials Research Station on directions from the Empowered

Committee of the Supreme Court, the Kerala Government observer opined that

"mistakes in the strengthening works carried out by Tamil Nadu" in 1979 damaged

the masonry of the dam.

Current safety concerns hinge around several issues. Since the dam was

constructed using stone rubble masonry with lime mortar grouting following

prevailing 19th century construction techniques that have now become archaic,

seepage and leaks from the dam have caused concern. Moreover, the dam is situated

in a seismically active zone. An earthquake measuring 4.5 on the Richter scale

occurred on 7 June 1988 with maximum damage in Nedumkandam and Kallar (within

20 km of the dam). Consequently several tremors have occurred in the area in recent

times. These could be reservoir-induced seismicity, requiring further studies

according to experts. A 2009 report by IIT Roorkee stated that the dam "was likely to

face damage if an earthquake of the magnitude of 6.5 on the Richter scale struck its

vicinity when the water level is at 136 feet". The important concern is that for

constructing a new dam it will nearly require 8 years of construction, during that

period tamilnadu will not get water for cultivation around 4 districts, which will

seriously affect the economy of that nation. If dam collapse then .there will be no live

and livelihood of people in Idukki, kuttanad etc will be under flood.The below Fig

3.1, 3.2 shows the cracks in the Mullaperiyar dam.

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Fig 3.1: Shows cracks in the Mullaperiyar dam

Fig 3.2 : Largest crack in the Mullaperiyar dam

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4. DAM BREAK ANALYSIS

There are serious violations on the safety aspects of the dam in terms of seismological

safety, hydrological safety and environmental safety as discussed in detail under the

above sites. The dam has been under-designed because at the time of its construction

cement was not available and hence neither a masonry dam in cement mortar nor a

concrete dam with cement mortar could be built to ensure better safety standards. The

old methods of construction followed about a century ago enabled the engineers to

use only surkhi mortar with lime, sand and rubble stone was used for the construction

of the dam. Since the dam was under designed with poor materials of construction, it

is bound to collapse due to aging also. Moreover the magnitude of peak floods to be

used for the spillway design was based upon rough estimates which do not confirm to

the modern estimates of extreme floods as recommended by experts of the

International committee on large dams Even the seismic potential was under-

estimated Hence there are abundant chances for the dam to collapse and such an

accident will result in economic bankruptcy to the states that depend upon Periyar

river water. Consequently the people of Kerala living downstream of the dam are

vociferously demanding for the implementation of dam review policies followed for

evaluation of safety of the existing dams and take remedial actions to protect the lives

of the people and their properties. But there is no unanimous agreement on this

subject of dam safety between Kerala, Tamil Nadu and the Union Government and

this has resulted in a controversy on the safety of the dam. A serious controversy on

the safety of Mullaperiyar dam is raised by the people in Tamil Nadu and Kerala.

While Kerala is demanding for the removal of the existing aged and decaying dam on

the plea that its inevitable collapse within the near future will result in an avoidable

manmade disaster like the Bhopal tragedy in India and the Fukushima nuclear

accident in Japan. Due to this disaster waiting in the wings more than a lakh of people

between the dam and the Idukki reservoir 40km below the dam more than 35 lakhs of

people in the lower reaches of Periyar river upto Ernakulum-Cochin belt will be

drowned causing not only loss of millions of lives of human and animal population

but also precious housing properties and agriculture fields placing a total loss

amounting to more than one lakh crores of rupees. This economic burden will have to

be borne directly or indirectly by all the people of various states in the country. Tamil

Nadu Government is insisting that the existing dam is safe and that it should not be

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decommissioned at any rate because the Tamilians may lose their rights over

irrigation water transfer from Periyar river in Kerala to Vaigai river in Tamil Nadu.

This problem can be simply solved if Kerala state is genuinely concerned about

saving the lives of 35 lakhs of Keralites by constructing 2 or 3 smaller dams in

between the Mullaperiyar dam and Iddukki dams. But the urge to construct these

dams cannot be perceived by the people of Kerala and its elected representatives in

the state legislature unless they are presented with a Mullaperiyar dam break scenario

with its damaging impacts on hundreds of villages, towns and cities in the Idukki,

Ernakulam and Kottayam districts. For this purpose a dam break analysis for

Mullaperiyar dam is carried out by using the popular national weather service dam

break flood forecasting model (NWS DAMBRK) for assessing the likely maximum

flood discharge and elevation to be attained by the flood inundation for several

habitations down steam in the eventuality of a dam failure.

4.1 NATIONAL WEATHER SCHEME DAM BREAK MODEL

The U. S National Weather Service (NWS) initially developed DAMBRK program

(Fread, 1984) in 1977. Research has been ongoing in developing improvements in the

DAMBRK model allowing it to have an increasing range of application (Fread,

1989). The model has wide applicability, it can function with various levels of input

data ranging from rough estimates to complete data specification, the required data is

readily accessible and it is economically feasible to use with minimal computational

effort on microcomputers. DAMBRK model can be used to develop the outflow

hydrograph from a dam breach and hypothetically route the flood through the

downstream valley. The governing equations of the model are the complete one-

dimensional Saint-Venant equations of unsteady flow which are coupled with internal

boundary equations representing the rapidly varied flow through structures such as

dams and embankments which may develop a time dependent breach. Also,

appropriate external boundary equations at the upstream and downstream ends of the

routing reach are utilized. The system of equations is solved by a nonlinear weighted

four-point implicit finite difference method. The flow may be either subcritical or

supercritical. The hydrograph to be routed may be specified as an input time series or

it can be developed by model using specified breach parameters (size, shape, time of

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development). The possible presence of downstream dams which may be breached by

the flood, bridge or embankment flow constrictions, tributary inflows, river sinuosity,

levees located along the downstream river, and tidal effects are each properly

considered during the downstream propagation of the flood. DAMBRK may also be

used to route mud and debris flows using specified upstream hydrographs. High water

profiles along the downstream valley, flood arrival times, and hydrographs at user

selected locations are the standard DAMBRK model output.

4.2 DATA REQUIREMNTS FOR NWS – DAMBRK MODEL

The DAMBRK model was developed by National Weather Service (NWS) so as to

require data that was accessible to the forecaster. The input data requirement are

flexible in so far as much of the data may be ignored (left blank on the input data

cards or omitted altogether) where a detailed analysis of a dam break flood inundation

event is not feasible due to lack of data or insufficient data preparation time.

Nonetheless the resulting approximate analysis is more accurate and convenient to

obtain than that which could be computed by other techniques. The input can be

categorized into two groups. The first data group pertains to the dam: (the breach,

spillways, and reservoir storage volume). The breach data consists of the following

parameters: T (failure time of breach, in hours), b (final bottom width of breach), Z

(side slope of breach), hbm (final elevation of breach bottom), ho (initial elevation of

water in reservoir), hf (elevation of water when breach begins to form), and hd

(elevation of dam). The spillway data consists of the following : hs (elevation of

uncontrolled spillway), Cg (coefficient of discharge of gated spillway), Cd

(coefficient of discharge of crest of dam), Qt (constant head independent discharge

from dam). The storage parameters consists of the following: a table of surface area

(As) in acres or volume in acre-ft. and the corresponding elevations within the

reservoir. The forecaster must estimate the values of T,B,Z,Hbm , and Hf . The

remaining values are obtained from the physical description of the dam, spillways,

and reservoir. In some cases Hs, Cs, Hg and Cg and Cd maybe ignored and Qt used in

their place. The second group pertains to the routing of the outflow hydrograph

through the downstream valley. This consists of a description of the cross-sections,

hydraulic resistance coefficients, and expansion coefficients. The cross-sections are

specified by location mileage, and tables of top widths (active and inactive) and

corresponding elevation. The active top widths may be total widths as for a composite

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section, or they may be left floodplain, right flood plain, and channel widths. The

channel widths are usually not as significant for an accurate analysis as the over bank

widths. The number of cross-sections used to describe the downstream valley depends

on the variability of the valley widths. They also depend on the availability of

crosssection measurements. However, a minimum of two must be used. Additional

cross-sectional data to be input by the forecaster according to such criteria as data

availability, variation, preparation time etc. The number of interpolated cross-sections

created by the model is controlled by the parameter DXM which is input for each

reach between specified crosssections. The expansion-contraction coefficients (FKC)

are specified as non-zero values at sections where significant expansion of

contradictions occur. But they may be left blank in most analyses. In the present case

of Mullaperiyar dam due to non availability of detailed topographical sheets of the

Periyar river basin the Google Earth satellite pictures have been used for

measurement of distances, bed level elevations, location of dams and reservoirs and

human habitations upto Cochin. It is found that the river slope for different river

stretches with several waterfalls vary from an average of 10m per km, 5m per km and

1m per km. Since the super critical flows below the water falls are some extent to

modified by a few dams and reservoirs in lower Periyar basin and Bhutantankkettu

reservoirs a gradient 1m per km has been considered and the input data has been

incorporated in the DAMBRK computer model to obtain the flood depth elevations

and the human habitations that will be submerged under a wall of flood arising due to

the Mullaperiyar dam burst under the worst conditions of cloud burst which results in

overtopping of the dam including the Earth dam on the left side. The details of the

output data on bed levels flood elevation levels and flood depths are presented in the

tables and graphs furnished below. Dam break analysis will give an idea about the

flow of water along with the failure. By the frequent study of the dam using this kind

of software will help to realize the impact of the failure. This type of softwares are

manufactured by info work an it wing of the NWS. . Fig 4.1 , 4.2 ,4.3 ,4.4 shows the

pictorial representation of dam break analysis. The below table 4.1 shows the dam

break analysis

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Fig 4.1: Stage 1

Fig 4.2: Stage 2

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Fig 4.3: Stage 3

Fig 4.4: stage

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Table 4.1 Mullaperiyar dam: Dam breaks analysis

Distance from dam

(km)

Bed levels

(m)

Flood elevation

(m)

Flood depth

(m)

0 827 850 23

10 804 826 22

30 768 785 17

40 750 763 13

50 720 730 10

70 252 264 12

100 70 82 12

120 36 48 12

140 20 32 12

170 9 21 12

180 7 19 12

5. SAFETY MEASURES OF MULLAPERIYAR DAM

5.1 CONSTRUCTING A NEW DAM

The one and only perfect method to this problem is to construct a new dam. Kerala

enacted the Kerala Irrigation and Water Conservation (Amendment) Act, 2006 to

ensure safety of all 'endangered' dams in the State, listed in the second schedule to the

Act. Section 62A of the Act provides for listing in the schedule, "details of the dams

which are endangered on account of their age, degeneration, degradation, structural or

other impediments as are specified". The second schedule to the Act lists

Mullaperiyar (dam) constructed in 1895 and fixes 136 feet as its maximum water

level. The Act empowers Kerala Dam Safety Authority (Authority specified in the

Act) to oversee safety of dams in the State and sec 62(e) empowers the Authority to

direct the custodian (of a dam) "to suspend the functioning of any dam, to

decommission any dam or restrict the functioning of any dam if public safety or threat

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to human life or property, so require". The Authority can conduct periodical

inspection of any dam listed in the schedule.

In pursuance of Kerala's dam safety law declaring Mullaperiyar dam as an

endangered dam, in September 2009, the Ministry of Environment and Forests of

Government of India granted environmental clearance to Kerala for conducting

survey for new dam downstream. Tamil Nadu approached Supreme Court for a stay

order against the clearance; however, the plea was rejected. Consequently, the survey

was started in October 2009. On 9 September 2009 Govt. of Tamil Nadu stated that

there is no need for construction of a new dam by the Kerala Government, as the

existing dam after it is strengthened, functions like a new dam. The overall cost of the

construction would be around 55 crores. The kerala government was ready to pay half

the amount for the construction of the new dam but tamilnadu state government was

no interested in it.

For Tamil Nadu, Mullaperiyar dam and the diverted Periyar waters act as a

lifeline for Theni, Madurai, Sivaganga and Ramnad Districts, providing water for

irrigation, drinking and also for generation of power in Lower Periyar Power Station.

Tamil Nadu has insisted on exercising its unfettered rights to control the dam and its

waters, based on the 1866 lease agreement. Kerala has pointed out the unfairness in

the 1886 lease agreement and has challenged the validity of this agreement. However

safety concerns posed by the 116 year old dam to the safety of the people of Kerala in

the event of a dam collapse, have been the focus of disputes from 2009 onward.

Kerala's proposal for decommissioning the dam and construction of a new dam has

been challenged by Tamil Nadu. Tamil Nadu has insisted on raising the water level in

the dam to 142 feet, pointing out crop failures. One estimate states that "the crop

losses to Tamil Nadu, because of the reduction in the height of the dam, between

1980 and 2005 are a whopping   40,000 crores. In the process the farmers of the

erstwhile rain shadow areas in Tamil Nadu who had started a thrice yearly cropping

pattern had to go back to the bi-annual cropping."The Kerala Government maintains

that this is not true. During the year 1979–80 the gross area cultivated in Periyar

command area was 171,307 acres (693.25 km2). After the lowering of the level to

136 ft (41 m), the gross irrigated area increased and in 1994–95 it reached 229,718

acres (929.64 km2). The Tamil Nadu government had increased its withdrawal from

the reservoir, with additional facilities to cater to the increased demand from newly

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irrigated areas. In 2006, the Supreme Court of India by its decision by a three member

division bench, allowed for the storage level to be raised to 142 feet (43 m) pending

completion of the proposed strengthening measures, provision of other additional

vents and implementation of other suggestions.

However, the Kerala Government promulgated a new "Dam Safety Act"

against increasing the storage level of the dam, which has not been objected by the

Supreme Court. Tamil Nadu challenged it on various grounds. The Supreme Court

issued notice to Kerala to respond, however did not stay the operation of the Act even

as an interim measure. The Court then advised the States to settle the matter

amicably, and adjourned hearing in order to enable them to do so. The Supreme Court

of India termed the act as not unconstitutional. Meanwhile, the Supreme Court

constituted a Constitution bench to hear the case considering its wide ramifications.

Kerala did not object giving water to Tamil Nadu. Their main cause of objection is

the dams safety as it is as old as 110 years. Increasing the level would add more

pressure to be handled by already leaking dam. Tamil Nadu wants the 2006 order of

Supreme Court be implemented so as to increase the water level to 142 feet (43 m).In

2000 Frontline one author stated thus: "For every argument raised by Tamil Nadu in

support of its claims, there is counter-argument in Kerala that appears equally

plausible. Yet, each time the controversy gets embroiled in extraneous issues, two

things stand out: One is Kerala's refusal to acknowledge the genuine need of the

farmers in the otherwise drought-prone regions of Tamil Nadu for the waters of the

Mullaperiyar; the other is Tamil Nadu's refusal to see that it cannot rely on or

continue to expect more and more from the resources of another State to satisfy its

own requirements to the detriment of the other State. A solution perhaps lies in

acknowledging the two truths, but neither government can afford the political

repercussions of such a confession".

On 18 February 2010, the Supreme Court decided to constitute a five-member

empowered committee to study all the issues of Mullaperiyar Dam and seek a report

from it within six months. The Bench in its draft order said Tamil Nadu and Kerala

would have the option to nominate a member each, who could be either a retired

judge or a technical expert. The five-member committee will be headed by former

Chief Justice of India A. S. Anand to go into all issues relating to the dam's safety and

the storage level. However, the then ruling party of Tamil Nadu, DMK, passed a

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resolution that it not only oppose the apex court's decision to form the five-member

committee, but also said that the state government will not nominate any member to

it.The then Tamil Nadu Chief Minister M. Karunanidhi said that immediately after

the Supreme Court announced its decision to set up a committee, he had written to

Congress president asking the Centre to mediate between Kerala and Tamil Nadu on

Mullaperiyar issue. However, the then Leader of Opposition i.e., the Ex Chief

Minister of Tamil Nadu J. Jayalalithaa objected to the TN Government move. She

said that this would give advantage to Kerala in the issue. Meanwhile, Kerala Water

Resources Minister N. K. Premachandran told the state Assembly that the State

should have the right of construction, ownership, operation and maintenance of the

new dam, while giving water to Tamil Nadu on the basis of a clear cut agreement. He

also informed the media that Former Supreme Court Judge Mr. K. T. Thomas will

represent Kerala on the expert panel constituted by Supreme Court.

On 8 March 2010, Tamil Nadu told the Supreme Court that it was not

interested in adjudicating the dispute with Kerala before the special “empowered”

committee appointed by the apex court for settling the inter-State issue. However,

Supreme Court refused to accept Tamil Nadu's request to scrap the decision to form

the empowered committee. The Supreme Court also criticized the Union Government

on its reluctance in funding the empowered committee. Implementing directions of

the Supreme Court, the Central Government extended the terms of Empowered

Committee for a further period of six months, namely till April 30, 2012.

5.2 STRENGTHENING OF MULLAPERIYAR DAM

From dam break analysis it is clear that if water level rises above 136ft, the chance of

collapse of the dam will increase by 45%.The strengthening of the dam was mainly

carried out in two stages.

Mainly 45-60 minor and major cracks are seen in the dam. Around 8-10

cracks have a size of more than 3-6 mm. From this analysis it is clear that if a small

earth quake occurs the dam will collapse and further deterioration will occur due to

the presence of these cracks. Since a concrete structure usually has a very long life, it

is quite common that the demands on the structure change with time. The structures

may have to carry larger loads at a later date or full fill new standards. In extreme

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cases, a structure may need to be repaired due to an accident. Another reason can be

that errors have been made during the design or construction phase so that the

structure needs to be strengthened before it can be used. If any of these situations

should arise it needs to be determined whether it is more economical to strengthen the

structure or to replace it. Fig 5.1 represents the performance characteristics of the dam

with aging.

Fig 5.1: Performance Characteristics of the dam

5.2.1 Stage 1: Protection with cfrp

Carbon fibers have a high modulus of elasticity, 200-800 GPa The ultimate

elongation is 0.3-2.5 % where the lower elongation corresponds to the higher stiffness

and vice versa. Carbon fibers do not absorb water and are resistant to many chemical

solutions. They with stand fatigue excellently, does not stress corrode and do not

show any creep or relaxation, having less relaxation compared to low relaxation high

tensile pre stressing steel strands. Carbon fiber is electrically conductive and,

therefore might give galvanic corrosion in direct contact with steel.

The main impetus for development of carbon fibers has come from the

aerospace industry with its need for a material with combination of high strength,

high stiffness and low weight. Recently, civil engineers and construction industry

have begun to realize that his material (CFRP) have potential to provide remedies for

many problems associated with the deterioration and strengthening of infrastructure.

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Effective use of carbon fiber reinforced polymer could significantly increase the life

of structures, minimizing the maintenance requirements. Carbon fiber reinforced

polymer is a type of fiber composite material in which carbon fibers constitutes the

fiber phase. Carbon fiber is a group of fibrous materials comprising essentially

elemental carbon. This is prepared by pyrolysis of organic fibers. PAN-based (PAN-

poly acrylonitrile) carbon fibers contains 93-95 percentage carbons, and it is produced

at 1315°C (2400° F) Carbon fibers have been used as reinforcement for ablative

plastics and for reinforcements for lightweight, high strength and high stiffness

structures. Carbon fibers are also produced by growing single crystals carbon electric

arc under high-pressure inert gas or by growth from a vapor state by thermal

decomposition of hydrocarbon gas.

CFRP materials possess good rigidity, high strength, low density, corrosion

resistance, vibration resistance, high ultimate strain, high fatigue resistance, and low

thermal conductivity. They are bad conductors of electricity and are non-magnetic.

Carbon fiber reinforced polymer (CFRP) is currently used worldwide to retrofit and

repair structurally deficient infrastructures such as bridges and buildings. Using CFR

Reinforcing bars in new concrete can eliminate potential corrosion problems and

substantially increase a member’s structural strength. When reinforced concrete (RC)

members are strengthened with externally bonded CFRP, the bond between the CFRP

and RC substrate significantly affects the members load carrying capacity. Fig 5.2

represents CFRP. Fig 5.3 represents placing of cfrp in dam.

Fig 5.2: Carbon fiber reinforced polymer

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Fig 5.3: Front view of dam after placing cfrp

By providing cfrp with in the cracks and guiding it along to the base we can avoid the

seepage of water and this cfrp will provide a greater resistance against overturning.

Most modern methods are used for placing the cfrp along the dam. Thus overturning

pressure and seepage can be avoided by providing cfrp. The main disadvantage of this

method is it requires skill full workers. The cost of cfrp /m was very much considered

to normal bars so for implementing of this method requires a government with have

high priority to the life of people is required. The cfrp is covered with line X coating.

5.2.2 Stage 2: Concreting with ECC

In terms of material constituents, ECC utilizes similar ingredients as fiber reinforced

concrete (FRC). It contains water, cement, sand, fiber, and some common chemical

additives. Coarse aggregates are not used as they tend to adversely affect the unique

ductile behavior of the composite. A typical composition employs w/c ratio and sand

and cement ratio of 0.5 or lower. Unlike some high performance FRC, ECC does not

utilize large amounts of fiber. In general 2% or less by volume of discontinuous fiber

is adequate, even though the composite is designed for structural applications because

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of the relatively small amount of fibers, and its chopped nature, the mixing process of

ECC is similar to those employed in mixing normal concrete. Also by deliberately

limiting the amount of fibers, a number of proprietary studies have concluded

economic feasibility of ECC in specific structural applications. Various fiber types

can be used in ECC, but the detail composition must obey certain rules imposed by

micromechanics considerations. This means that the fiber, cementitious matrix, and

the interface (mechanical and geometric) properties must be of a correct combination

in order to attain the unique behavior of ECCs. Thus ECC designs are guided by

micromechanical principles. Most data so far has been collected on PVA-ECC

(reinforced with PolyVinylAlcohol fibers) and PE-ECC (reinforced with high

modulus polyethylene fibers).

The most fundamental mechanical property difference between ECC and FRC

is that ECC strain-hardens rather than tension-softens after first cracking. In FRC or

fiber reinforced high strength concrete, the first crack continues to open up as fibers

are pulled out or ruptured and the stress-carrying capacity decreases. This post-peak

tension softening deformation is typically represented by a softening stress-crack

opening relationship. In ECC, first cracking is followed by a rising stress

accompanied by increasing strain. This strain-hardening response gives way to the

common FRC tension softening response only after several percent of straining has

been attained, thus achieving a stress-strain curve with shape similar to that of a

ductile metal. Closely associated with the strain-hardening behavior is the high

fracture toughness of ECC, reaching around 30 kJ/m2, similar to those of aluminum

alloys. In addition, the material is extremely damage tolerant and remains ductile

even in severe shear loading conditions.

The Characteristics of Engineered Cementitious Composite would be

pointless without the very specific qualities and strengths that it exhibits. These

special qualities are based upon its material make up and the interactions with the

surrounding environment it experiences. The characteristics break down into the

physical strength and interactions that Engineered Cementitious Composite

undergoes, along with the chemical reactions and properties that allow the process of

self-healing to occur. These physical properties include remarkable tensile (or

bending) strength and ductility, which allow for one of the more important

interactions in the concrete itself: micro-cracking. The process of micro-cracking

exponentially increases the tensile strength and remains within a low degree of

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permeability. This low permeability reduces the effects associated with the absorption

of chemicals which include the weakening of any underlying support structures and

erosion of the concrete itself. This increases the lifespan and repair cycle of the

concrete and the structure as a whole, while also creating the conditions that allow

specific chemical reactions to occur that help to fill in the cracks of the concrete.

Engineered Cementitious Composite concrete exhibits many natural, physical

qualities that allow it to be applied in place of standard fiber reinforced concrete as a

more dependable, long-term replacement. These characteristics include its low

permeability along with high tensile strength, flexibility, and resistance to corrosion

or the fragmentation of the concrete under stress. When stress is introduced to a

sample of Engineered Cementitious Composite, the major transfer of this stress is

through the formation of micro-cracks in response to a tensile strain. The nature of

these cracks is different from that of the cracks seen on other fiber reinforced

concretes due to the fact that flat steady state micro-cracks are formed as opposed to

localized Griffith crack propagation. The former of the stress responses is ideal

because when this type of micro-cracking occurs, it forms multiple, uniform cracks

over a small area, whereas Griffith crack propagation forms large jagged cracks that

are localized and harmful to the strength and permeability of the concrete. Under the

conditions of steady state flat crack propagation, a process known as plasticity occurs

where the material strength is higher after the first crack is formed and increases

linearly to the final tensile strength factor. These cracks in Engineered Cementitious

Composite then follow simple formulae of crack potential and width that allows

Engineered Cementitious Composite to form smaller crack widths. These equations

used to predict things such as crack width, strength, length, and flexibility can be

found below.

2.1) P=(εsh-(εe+εcp+εi)

This equation demonstrates that as the sum of the elastic tensile strain capacity (εe),

tensile creep strain (εcp), and strain capacity (εi) increase or decrease relative to the

shrinkage strain (εsh), the cracking potential (P) will increase or decrease

respectively.

2.2) Lch=EGf /σt2

This equation demonstrates that as the tensile strength (σt) increases or decreases

relative to the product of the Young’s modulus (E) and the fracture energy (Gf), the

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Hillerborg’s material characteristic length (Lch) will decrease or increase

respectively.

2.3) W=L(P/(1-L/2Lch)

In equation 3, crack width (W) is proportional to the product of the crack length (L)

and the crack potential divided by the crack length minus one divided by the

Hillerborg’s material characteristic length. This relates that a larger cracking potential

will result in a greater crack width which is shown to be the opposite for Engineered

Cementitious Composites. These equations also show that when cracking potential

(P) is greater than or equal to zero, a single crack forms in the concrete with a

proportional width (W) and the material will have a larger strain capacity as the

number of cracks increases until the strain capacity value reaches an ultimate tensile

strength. Engineered Cementitious Composite has a large strain capacity of about five

percent (500 times that of standard concrete), and an extremely low chance of the

formation of localized fracture damage.

The formation of these micro-cracks creates a unique resistance to the

absorption of water and chloride ions which pose the greatest threat to the underlying

structure of any reinforced concrete. Through experimentation and analysis, it was

determined that Engineered Cementitious Composite exhibits crack width well under

the threshold of permeability for water and chloride ions under accelerated corrosion

testing. When compared to that of normal concrete over a 14 week freeze thaw cycle,

the traditional concrete was deteriorated at such a rapid rate, that it was removed from

testing after five weeks. The next application of ECC is self-healing of micro cracks

in ECC can occur in a natural environment despite a high level of damage caused by

preloading tensile deformations of 0.5% and 1.0% and wide swings in temperature

and precipitation in Michigan climate. Self-healing is not limited to a controlled

laboratory environment. Studies have shown that cracked concrete has the ability to

heal itself over time when exposed to water. It has been found that there is a gradual

reduction in permeability of damaged concrete as water is allowed to flow through the

cracks.

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5.3 Overview of the process

27

Fig 5.4: Overview of the process

6. CONCLUSION

The construction of the new dam is the only option for the betterment of the people.

Another solution put forward by the government was constructing some dams in

between Mullaperiyar and Idukki dam but the construction of the new dams requires

large amount of money. Kerala government is willing to contribute major share of

this new project but tamilnadu government is neglecting all the positive sides and

they are saying that the existing dam is capable of withstanding any hazardous

situation. The strengthening of the existing dam was not up to the mark as that of

construction of a new dam. The strengthening of the existing dam will also cost

around 50% of the amount required for the construction of a new dam and the

construction of a new dam requires around 55 crores. If the life has more concern

than money the Government should go for a new dam. If the construction of new dam

is not possible, then strengthening of the Mullaperiyar dam is the only option.

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REFERENCE

1.  Frye, Albert Irvin (1918). Civil engineers' pocket book: a reference-book for

engineers, contractors, and students, containing rules, data, methods,

formulas and tables (2nd (corrected) ed.). D. Van Nostrand Company. p. 859.

Retrieved 30 November 2011.

2. Firas Al-Mahmoud, Arnaud Castel, Raoul Francois and Christian Tourneur,

(2010),”RC beams strengthened with NSM CFRP rods and modelling of

peeling-off failure”, Composite Structures Journal, Vol.92, pp.1920-1930.

3.  "National Register for Large Dams". India: Central Water Commission.

2009. pp. 194–197. Retrieved30 November 2011.

4.  "Mullaperiyar Environmental Protection Forum v. Union of India (UOI) and

Ors" . Supreme Courth of India. pp. 1–2. Retrieved30 November 2011.

5. "Four dams - Mullaperiyar Dam, Parambikulam Dam, Thunakadavu Dam and

Peruvaripallam Dam - are owned, operated and maintained by Tamil Nadu

whereas they were situated in the territory of Kerala - Tamil Nadu Chief

Minister Jayalalithaa."

6. Sandeep S. Pendhari, Tarun Kant, Yogesh M. Desai, (2008), “Application of

polymer composites in civil construction: A general review”, composite

structures journal, Vol.8, pp.114-124

7. Uang CM, Elgamal A, Li WS, Chou CC. Ji-Ji Taiwan Earthquake of

September 21,1999: A brief reconnaissance report. Department of Structural

Engineering,University of California, San Diego; 1999.

 

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