chapter 5 formulation of water management strategies...

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CHAPTER 5

FORMULATION OF WATER MANAGEMENT

STRATEGIES AND ANALYSIS

5.1 INTRODUCTION

Water demand management-controlling and influencing the amount

of water used by consumers in areas where there is a scarcity of water

resources-raises issues for communities, water providers and regulators for

which there is rarely a simple solution. It has become an important element in

integrated policies of water resources development. Multilateral and bilateral

funding agencies involved in the water sector recognize the need for better

understanding of the implications of introducing water demand management

measures and in particular, the impact on the livelihoods of the poor. Thus the

water demand management can be broadly viewed as an interactive approach

that addresses competing community demands placed on a region's water

resources so as to meet defined water quantity and quality objectives.

The principle infrastructure components required to satisfy water

demand management include

• drinkable water supply

• sewage collection, treatment and disposal

• stormwater collection and disposal

• recycled water collection, storage, treatment and re-use.

The various management options that can be adopted include

increasing the urban water use efficiency, conjunctive management of surface

water and groundwater, recycling the municipal waste water, increasing the

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agricultural water use efficiency, desalination, increasing the conveyance

efficiency etc.

5.2 FUTURE WATER REQUIREMENTS FOR CMA

Increasing urban population and urban needs would put more

pressure in future for water. But the current supply position from the surface

sources is nowhere near the need. The solutions to water crisis are quite

closely associated with integrated view of water governance-which

encompasses issues such as long-term perspective and planning and a broad

based partnership and dialogue among all key stakeholders. The present

project strives to work towards contributing to this goal.

The census data for the years 1981, 1991 and 2001 were collected

and the Chennai Metropolitan Area’s future population is forecasted using

geometrical increase method. It is found to be 137.5 lakhs for the year 2025.

Figure 5.1 shows the growth of population in the Chennai Metropolitan Area

for a period of 2001 to 2025. The increase of water demand for the respective

years are showed in Figure 5.2

0

20

40

60

80

100

120

140

160

2001 2005 2010 2015 2025

YEAR

PO

PU

LA

TIO

N (

LA

KH

S)

Populat ion in Lakhs

Figure 5.1 Population Growth in CMA

85

0

200

400

600

800

1000

1200

1400

2001 2005 2010 2015 2025

YEAR

DE

MA

ND

(M

LD

)

Demand in MLD

Figure 5.2 Water Demand in CMA

In CMA, for the year 2025, for the population of 137.5 lakhs, the

total requirement of water will be of the order of 1292 MLD. If the existing

system of water supply is continued, the demand for the growing population

in the Chennai Metropolitan Area cannot be met satisfactorily. Apart from

that, there will be head to tail losses and pressure variations in the distribution

pipelines, difficulty in transporting water from distant sources and

administrative difficulties. To overcome the above problems, the Chennai

Metropolitan Area can be classified into different sectors. Water can be drawn

from the nearby sources, treated and distributed in the sector itself in an

effective manner.

5.3 SECTORIAL CLASSIFICATION OF CHENNAI

METROPOLITAN AREA

For the present study, the Chennai Metropolitan Area is divided into

4 interconnected and independent sectors. They are north sector, central

sector, south sector and west sector. An autonomous body has to be set up in

each sector that manages all the activities including the acquisition, storage,

treatment, quality maintenance and distribution of water for that sector. Thus

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each sector can be made self sufficient to meet its own water demand. This

will help in the equitable distribution of water throughout the sectors.

5.4 AREA CATEGORIZATION IN EACH SECTOR

The categorization of the study area is listed below.

5.4.1 North Sector

The north sector is primarily an industrial area having an areal

extent of 355.94 sq.km. The places that comes under the north sector are

Minjur, Athipattu, Padianallur, Kattivakkam, Ponneri, Polichur,

Chinnasekkadu, Puzhal, Naravarikuppam, Manali, Madhavaram, Tiruvottiyur,

Washermanpet, Fort, Tondiarpet, Royapuram, Harbour, Perambur (Kolathur,

Vyasarpadi), Sembium and Park Town.

5.4.2 Central Sector

Central sector is the commercial heart of the city and the downtown

area. Egmore, Chindadripet, Nungambakkam, Metha Nagar, Mylapore,

Chepauk, Triplicane, Purasawalkam (Villivakkam, Ayanavaram, Aminjikarai,

Kellys), T.Nagar, Teynampet, Ambattur, Avadi, Poonamallee,

Thiruverkadu,Thirunindravur, Nerkundram, Maduravoyal, Anna Nagar,

Mugappair, Thousand Lights and Thirumazhisai are the places coming under

the central sector. The central sector occupies an area of 362.66 sq.km.

5.4.3 South Sector

South sector, a previously predominantly residential area is fast

turning into a commercial area, hosting a large number of IT and financial

companies. Tambaram, Perungalathur, Chitlapakkam, Sembakkam,

Peerkankaranai, Moovarasampettai, Vandalur, Madambakkam,

Meenambakkam, Tirusulam, Pallavaram, Pammal, Anakaputhur,

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Thiruneermalai, Kundrathur, Oggaiyamduraipakkam, Perungudi, Taramani,

Velachery, Thiruvanmiyur, Adayar, Kottivakkam, Palavakkam, Neelankarai,

Karapakkam, Sholinganallur, Kelambakkam, Injambakkam, Alandur,

Madipakkam, Puzhithivakkam, Jalladiampet and Pallikaranai are included in

the south sector having an areal extend of 316.10 sq.km.

5.4.4 West Sector

The west sector is similar to the south sector having mixed land

uses, with inter- mixture of urban and non-urban uses. The west sector also

adjoins the Chennai Municipal Corporation limits and comprises residential

areas that are fastly developing. In addition, it has got several large industrial

and business establishments and has high metropolitan level of health and

higher educational institutions. This sector comprises of middle income, low

income and poor income residents.

The places included in this sector are Guindy, Porur, Ramapuram,

Manapakkam, Nandampakkam, Sikkarayapuram, Valasaravakkam,

Karambakkam, Mangadu, Ekkattuthangal, Kodambakkam, M.G.R. Nagar,

K.K.Nagar, Vadapalani, Nesapakkam and Virugambakkam occupying an area

of 137.30 sq.km. The sectorial classification of Chennai Metropolitan Area is

shown in the Figure 5.3.

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Figure 5.3 Sectorial Classification of CMA

SCALE 1:50000

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5.5 WATER MANAGEMENT STRATEGIES FOR NORTH

SECTOR

The north sector is primarily an industrial area. The Araniar and

Kosasthalaiyar rivers originate in Andhra Pradesh and join the sea near

Chennai. The river basins covers an area of about 1000 sq.km and is situated

about 30 km north to Chennai city. Groundwater is the major source of water

supply in this sector. There are plenty of well fields available in this area. The

major source of the north sector is the Araniar Kosasthalaiyar Basin. This

basin contains enormous amount of water that itself will be sufficient to cater

the water requirements of this sector. During the monsoon period, huge

quantity of water drains to the sea. This enormous source has to be properly

managed by adopting strategies separately for both pre monsoon and post

monsoon periods.

From the population data, the future population for the north sector

is forecasted for the years 2005, 2010, 2015 and 2025 and the demand is

assessed using the TWAD Board norms. The forecasted population and water

demand for the north sector is shown in Table 5.1.

Table 5.1 Population and Demand for North Sector

Year Population

(Lakhs)

Demand

(MLD)

2001 17 177

2005 19 191

2010 20 208

2015 23 229

2025 28 278

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For the year 2025, the population is forecasted as 28 lakhs and the

water demand is 278 MLD. The management strategies to improve the water

supply for the north sector are as follows.

5.5.1 Construction of Reservoir in Araniar Kosasthalaiyar Basin

Generally flood occurs during north east monsoon when there is

heavy rainfall coupled with cyclonic storms formed in the Bay of Bengal

which inundates the basins of Araniar, Kosasthalaiyar and its tributaries.

During monsoon large quantity of water is draining through the Araniar and

Kosasthalaiyar Rivers to Bay of Bengal.

The combined average surplus of the Araniar River at

A.N. Kuppam and Lakshmipuram anicuts was 143 Mm3 (390 MLD) during

the year 1976-2000. It is inferred that at 50% dependability, the surplus

amount of water is 50 Mm3 (136 MLD) and at 75% dependability the surplus

is 28 Mm3 (76 MLD). The average surplus of Kosasthalaiyar River at Vallur

anicut was 202.5 Mm3 (552 MLD) for the period of 1976-2000 and the

surplus amount of water at 50% dependability is 23 Mm3 (62 MLD) and there

is no surplus water at 75% dependability (Institute for Water Studies).

The surplus at 75% dependability of the A-K basin, nearly 28 Mm3

(76 MLD), can be utilized by saving it properly. This can be achieved by

constructing a reservoir of 36.63 Mm3 (100 MLD) near the Araniar

Kosasthalaiyar basin that will improve the water potential of this sector. The

reservoir also serves the adjacent areas by recharging the groundwater thereby

maintaining the ecological balance. Also check dams has to be constructed

across the Araniar and Kosasthalaiyar Rivers to recharge the groundwater.

Already proposals for reservoirs namely Ramanjeri and Thirukandalam across

river Kosasthalaiyar have been made by the government department. Due to

peoples agitation in that area it was given up.

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5.5.2 Stormwater Runoff

In the present study, due importance is given to develop a

stormwater management plan for each sector, that addresses the existing

problems of wastage of water and provides guidance for conservation for the

future. In CMA, the rainwater drained as runoff can be managed and

consumed appropriately, to meet the water scarcity of the growing population.

The north sector has an areal extent of 355.94 sq.km where the

water bodies occupy 45.5 sq.km. Considering the average annual rainfall for

the north sector as 1081 mm, the runoff accounts to 50.35 Mm3 (137 MLD)

for an areal extent of 310.44 sq.km. Measures can be adopted to the store this

runoff generated during the monsoon and can be supplied during the non

monsoon period. The storage can be done by collecting the stormwater

through stormwater drains and storing it in storage structures constructed at

vacant lands of Manali and Palavoyal (Landuse Map and Toposheets) each

with a storage capacity of 21.97 Mm3 (60 MLD). A detailed study has to be

conducted for implementing the recommendation given above.

In addition to the storage structures, the tanks and lakes can also be

used to store the excess runoff. In this sector, apart from Cholavarm and

Redhills Lake that supplies water to Chennai city, Erattai eri having a storage

capacity of 0.98 Mm3 (2.67 MLD) (CMWSSB) can be deepened and

converted to a recharge structure that improves the groundwater status of the

sector.

5.5.3 Additional Well Fields

The Araniar-Kosasthalaiyar basin has a groundwater potential of

690.48 Mm3 (1885 MLD) (Source: Chennai Metro Water Supply and

Sewarage Board) and hence usage of the aquifers to augment the water supply

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to Chennai are huge. Presently about 37.36 Mm3 (102 MLD) is drawn from

the A-K well fields to the Kilpauk water works. This shows that there is

653.12 Mm3 (1783 MLD) of water available in this basin. Additional well

fields has to be drilled to extract the required groundwater during drought.

Self yield should be worked out for each area and accordingly the pumping of

water from the well fields should be limited so as to prevent execess

withdrawal of groundwater. This will also prevent the seawater intrusion.

This can be implemented in an efficient manner by conducting appropriate

hydrogeological investigations.

5.5.4 Water Treatment Plant at Ponneri

The water potential in the north sector is so high that if provisions

are made to store and treat the water in this sector itself, the difficulties in

transporting water can be eliminated. Considering the factors like the

accessibility from various sources, availability of vacant land and easiness to

distribute water, Ponneri is chosen for constructing the water treatment plant.

The provision of a water treatment plant in this sector will also serve the

increasing demand due to the industrial development in the northern parts of

Chennai Metropolitan Area.

A water treatment plant of capacity 300 MLD is recommended to be

constructed at Ponneri against a total water requirement of 278 MLD in the

year 2025. The surplus water of 28 Mm3 (76 MLD) stored in the proposed

reservoir in the Araniar Kosasthalaiyar Basin, the stored surface runoff of

43.95 Mm3 (120 MLD) and wellfields providing 30 Mm

3 (82 MLD) will be

able to meet the requirement. This water can be brought to the water treatment

plant at Ponneri, where it is treated and distributed to various parts of the

north sector. This will improve the existing infrastructure of water supply

system in the north sector.

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5.5.5 Overall Management

For the north sector, 278 MLD of water is required for a forecasted

population of 2774311 during the year 2025. The management strategies

recommended to meet the demand satisfactorily in the north sector includes

usage of surplus water by constructing a reservoir in Araniar-Kosasthalaiyar

Basin, storing the runoff water in storage structures as well as in tanks and

lakes, drilling additional well fields and constructing a water treatment plant

at Ponneri.

During monsoon periods, the groundwater will increase and the

people will mostly depend on their own individual wells. As the groundwater

usage is more, the quantity of water that has to be supplied by the water

supply boards will be less. The surface water can be stored for non monsoon

period. Even if the extraction of groundwater is more, it will be recharged by

the monsoon showers as well as by the check dams constructed across the

river courses.

During non monsoon period, the water availability in the individual

wells will be less. So the water requirements have to be met by the water

supply boards. The conjunctive use of surface water and groundwater can be

adopted for this period. The surplus water stored during monsoon and the

stored stormwater runoff can be supplied in addition to the groundwater from

the well fields. A detailed study has to be done to decide on the frequency of

water supply that has to be adopted for the monsoon and non monsoon

periods. This can be achieved by analyzing the present water supply strategy

adopted by the water supply boards.

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5.6 WATER MANAGEMENT STRATEGIES FOR CENTRAL

SECTOR

Central sector is the commercial heart of the city. At present, the

water supply for the Chennai city and the near by areas is given from the

Kilpauk water works. The water to the Kilpauk water works is drawn from

various surface water sources such as Redhills, Poondi and Cholavaram and

the groundwater is extracted from the well fields such as Poondi,

Tamaraipakkam, Panjetty, Minjur, Kannigaiper, Southern coastal aquifers and

Porur infiltration wells. Also the external sources of water like Telugu Ganga

water and New Veeranam water contributes to Kilpauk water works.

To solve the water crisis, by sectorial classification, some of the

places which comes under the Kilpauk water works were excluded and some

new areas were included to form the central sector. Those places that were

excluded are Perambur, Washermanpet, Vyasarpadi, Patel Nagar, Harbour,

Tiruvottiyur, Royapuram, Tondiarpet, Manali and George Town in the north,

Adayar, Thiruvanmiyur and Velachery in the south, Kodambakkam,

M.G.R.Nagar, K.K. Nagar, Nesappakam, Vadapalani, Virugambakkam,

Saligramam, West Mambalam, Saidapet, Ashok Nagar, Ekkaduthanal,

Guindy and Saint Thomas Mount in the west. These places were added

respectively to the other sectors.

From the population data, the future population for the central sector


assessed. The forecasted population and water demand for the central sector

are shown in Table 5.2.

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Table 5.2 Population and Demand for Central Sector

Year Population

(Lakhs)

Demand

(MLD)

2001 31 325

2005 34 357

2010 39 397

2015 45 457

2025 60 595

In the central sector, for the year 2025, the population is forecasted

as 60 lakhs and the water demand is 595 MLD. The management measures

that are recommended for the central sector are as follows.

5.6.1 Kilpauk Water Works

According to the sectorial classification, the water from Kilpauk

water works is to be used for the central sector alone. The present capacity of

Kilpauk water works is 327 MLD. According to 2001 census the city’s

population is 43 lakhs and the water demand is 477 MLD. As per the sectorial

classification, population to be served by the Kilpauk water works for the year

2001 is revised to 31 lakhs and the corresponding demand is 325 MLD.

Hence the stress on the Kilpauk water works to serve more population is

reduced.

By analyzing the present water supply carried out by the metro

water supply board, a quantity of 78 Mm3 (213 MLD) of the surface water is

supplied from the Poondi, Cholavaram and Redhills. The groundwater from

the well fields accounts to 37.36 Mm3 (102 MLD).

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The central sector has an areal extent of 362.66 sq.km where the

water bodies occupy 34.5 sq.km. Considering the average annual rainfall for

the central sector as 1108 mm, the runoff accounts to 54.57 Mm3 (149 MLD)

for an areal extent of 328.16 sq.km. In the central sector, 88.23 sq.km. is

occupied by the Chennai city.

The stormwater runoff that is generated outside the Chennai city

accounts to 39.90 Mm3 (109 MLD) that can be conserved for central sector.

This can be achieved by designing a proper stormwater drain network and

diverting it to the storage structures that can be constructed in the vacant lands

available outside the city limits of this sector. A detailed study has to be

conducted for the design of stomwater network. Kovilpadugai near Redhills

lake (Landuse Map and Toposheets), that has a larger extent of vacant land, is

identified for constructing a storage structure having a capacity of 36.63 Mm3

(100 MLD).

In addition, a number of lakes and tanks are available in the western

side of the central sector. The surface water sources that comes in the central

sector are Ambattur Tank, Korattur Lake, Maduravoyal Lake,

Ayyanambakkam Lake, Nadukuthagai Lake, Sundara Cholapuram Lake,

Koladi Lake, Paleripattu Lake and Arapeth Eri with a combined approximate

storage of 25.18 Mm3 (68.74 MLD). In addition to the storage structures, the

lakes and tanks of the central sector can be deepened and used as recharge

structures to store the excess runoff from the adjacent areas. A provision can

be made to draw about 10.98 Mm3 (30 MLD) of water from the tanks and

lakes.

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The tanks and lakes are in the grip of encroachment by city

dwellers on its banks. It is the only means that can conserve the ecological

balance of Chennai. At present, all these tanks and lakes are in the stage of

vanishing. The encroachment on the approach channels have to be removed

and the proper measures have to be adopted for free flowing of water during

monsoon. Government have to initiate actions to clear the encroachments and

rehabilitate them. They should also enact laws to prevent further

encroachments. The lakes and tanks should also be standardized to bring it

back to its original condition. The system of tanks have to be rejunuvated so

that the surplus of the upstream tank will directly flow by gravity to the

downstream tanks. This will also improve the of groundwater status of this

sector.


In this sector, both the surface and groundwater comprises

315 MLD. Apart from these, nearly 100 MLD of water comes from the

stormwater runoff can be stored in recharge structures. About 30 MLD can be

taken from the tanks and lakes. To meet out the gap, a system to abstract,

harness and supply the groundwater from the A-K basin well fields that has

an availability of 1783 MLD can be planned. This can be achieved by drilling

additional well fields in the Araniar-Kosasthalaiyar Basin by conducting

appropriate hydrogeological investigations. Therefore, additional water of

80 MLD can be tapped from newly proposed wellfields in Araniar

Kosasthalayar Basin so as to meet the demand satisfactorily.

This shows that the water from the existing internal surface and

groundwater sources are enough to cater the needs of the central sector. The

external sources like Telugu Ganga and Veeranam water are recommended to

be diverted to cater the needs of other sectors.

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For the central sector, 595 MLD of water is required for a predicted

population of 5993775 for the year 2025. The management strategies thus

recommended to meet the demand satisfactorily includes improved

distribution of water by reallocating areas to be served by Kilpauk water

works, storing the runoff water in storage structures as well as in tanks and

lakes and drilling additional well fields in A-K Basin. A detailed study has to

be conducted for each of the above management strategies recommended to

implement it in action.

During drought period, if the internal sources were not able to meet

the requirements, suitable arrangements should be made to distribute the

external water sources to the sectors. To meet out this requirement, a partial

amount of the Veeranam water and Telugu Ganga water has to be taken to the

central sector through the existing pipelines.

5.7 WATER MANAGEMENT STRATEGIES FOR SOUTH

SECTOR

The south sector has mixed land uses, with inter-mixture of urban

and non-urban uses and is yet to become fully urbanized. These areas have

developed as overspill of city development. This sector also have a large

number of small and medium manufacturing and business enterprises,

specialty restaurants and recreation places. The water requirement for the

institutional and the industrial needs are more compared to the domestic needs

of this sector. This can be met with proper planning and allocation of the

water resources, for which identification of new water sources is essential.

The places under this sector namely Kottivakkam, Palavakkam,

Neelangarai and Injambakkam are located along the coast and bisected by the

East Coast Road, a major highway leading to the southern coastal areas of the

state. It is bound on the west by a manmade canal (viz. The Buckingham

canal once used for navigation), which follows low-lying flats having

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connection with the sea at a few points. This area gets its water supply from

the southern coastal aquifers, individual wells and public wells.

From the population data, the future population for the south sector


assessed. The forecasted population and water demand for the south sector are

shown in Table 5.3.

Table 5.3 Population and Demand for South Sector

Year Population

(Lakhs)

Demand

(MLD)

2001 10 89

2005 12 105

2010 15 126

2015 19 159

2025 32 258

The population forecasted for the south sector for 2025 is 32 lakhs

and the corresponding water demand is 258 MLD. In order to meet the

demand of the south sector, the following suggestions are given.

5.7.1 Water from River Palar

River Palar is the major water source 60 km south of Chennai city

that supplies water to few areas of south sector. It mainly caters water during

the monsoon, as flash floods are common during the northeast monsoon.

Presently, a number of infiltration wells sunk in the river at Palayaseevaram,

Vengudi, Kullambakam etc. together supplement 9.16 Mm3 (25 MLD) of

water to the peri urban areas like Alandur, Pallavaram, Tambaram, Pammal

and Chitlapakkam.

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To increase the subsurface water availability in the River Palar

region, sand mining has to be reduced. Also constructing check dams across

the river in the downstream of Palayaseevaram will help to recharge the

groundwater in the surrounding regions, thereby the infiltration wells gets

boosted up and this water can be used to satisfy the growing demand in the

south sector.

5.7.2 Water from Veeranam Project

Apart from this, water from the Veeranam Project can be taken to

the south sector. The amount of water that is supplied through this project to

Chennai is 66 Mm3 (180 MLD). As of now, the Veeranam water enters the

Chennai Metropolitan Area at Tambaram and it is transported to Porur Lake.

Instead the water can be stored by deepening and desilting the Thiruneermalai

tank near Tambaram. As a result, the transportation difficulties for a longer

distance can be minimized and the water can be effectively used by the

consumers of the south sector.


The south sector has an areal extent of 316.10 sq.km where the

water bodies occupy 12.2 sq.km. Considering the average annual rainfall of

this sector as 1198 mm, the runoff accounts to 54.65 Mm3 (150 MLD) for an

areal exent of 303.90 sq.km. This runoff that is generated can be stored to

augment the water supply of this sector. This can be achieved by collecting

the stormwater by laying stormwater drains and storing it in structures

constructed at vacant lands of Oggiyamduraipakkam, Nemilicheri and

Pallikaranai (Landuse Map and Toposheets) each with a storage capacity of

14.65 Mm3 (40 MLD).

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The surface water sources for the south sector of Chennai

Metropolitan Area has to be improved. The details of the water sources which

are available and presently not in use in the south sector are Peerkankaranai

Lake, Tambaram Puduthangal Lake, Tambaram Periya Eri, Kadaperi Lake,

Pallavaram Lake, Nemilicheri Lake, Pallikaranai Anai Eri, Kovilambakkam

Periya Eri, Perungudi Lake, Pallikaranai Narayanapuram Lake and Velachery

Lake with an approximate storage of 2.43 Mm3 (6.6 MLD) (CMWSSB). In

addition to the storage structures, measures can be taken to deepen the tanks

and lakes. The excess runoff from the adjacent areas of the tanks and lakes

can be diverted to it that will improve the groundwater status of this sector.

5.7.4 Water Treatment Plants

To meet the basic needs of the people in the south sector and to

provide an improved water supply, nearly 258 MLD is required. With all the

surface sources, groundwater sources and the external water sources, water

can be supplied to the south sector by constructing two water treatment plants

each of capacity 100 MLD. One water treatment plant can be placed at

Oggiyamduraipakkam and another at Tambaram where provisions can be

made to collect, store, treat and distribute water to cater the needs of the south

sector.

The water treatment plant constructed at Oggiyamduraipakkam will

serve water to the south east coastal areas like Oggiyamduraipakkam,

Sholinganallur, Kelambakkam, Kottivakkam, Palavakkam, Neelangarai,

Injambakkam, Perungudi, Adayar, Velachery and Pallikaranai. The treatment

plant at Tambaram can provide water to the areas like Tambaram, Tambaram

Sanatoruim, Perungalathur, Chitlapakkam, Sembakkam, Peerkankaranai,

Moovarasampettai, Madampakkam, Vandalur, Chrompet, Pallavaram,

Pammal, Anakaputtur, Kundrathur, Thiruneermalai, Trisulam,

Meenambakkam, Alandur, Puzhithivakkam, Madipakkam and Jalladiampet.

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For the south sector, 258 MLD of water is required for a predicted

population of 3248235 for the year 2025. The management strategies

recommended to meet the demand satisfactorily includes water from River

Palar, New Veeranam water, stormwater runoff and construction of water

treatment plants at Oggiyamduraipakkam and Tambaram. A detailed study

has to be conducted for each of the above management strategies

recommended to implement it in action.

During normal and above normal rainfall years, people will be

depending more on their own individual wells. In the non-monsoon season,

the water from the external sources can be supplied as per the management

strategies recommended for the south sector. And in the monsoon periods, the

demand of the south sector can be met mostly with the available internal

surface and groundwater sources along with a considerable amount of

Veeranam water. At times of excess rainfall the Veeranam water can be

stopped temporarily as it lies within Tamil Nadu.

During drought, suitable arrangements have to be made to supply a

part of the Veeranam water to both south sector and central sector. A part of

Veeranam water can be taken to the Porur Lake through the existing pipelines

and can be used for central sector.

5.8 WATER MANAGEMENT STRATEGIES FOR WEST

SECTOR

The west sector is similar to the south sector having mixed land

uses, with inter- mixture of urban and non-urban uses. The west sector also

adjoins the Chennai Municipal Corporation limits and comprises residential

areas which are fastly developing. In addition, it has got several large

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industrial and business establishments and has high metropolitan level of

health and higher educational institutions.

At present the public water supply systems are operated by the local

bodies. The systems were installed by the Tamil Nadu Water Supply and

Drainage Board under the State Rural/Urban Water Supply Programme. The

system consists of local wells, from which water is pumped to overhead tanks

and distributed through pipelines. The consumers are supplied either through

individual house connections or street taps. Most of the poor draw their water

from street taps. A large number of better off population, commercial,

institutional and industrial establishments which are not covered by the above

system draw their water requirements from insitu open or bore wells.

From the population data, the future population for the west sector is

forecasted for the years 2005, 2010, 2015 and 2025 and the demand is

assessed. The forecasted population and water demand for the west sector are

shown in Table 5.4.

Table 5.4 Population and Demand for West Sector

Year Population

(Lakhs)

Demand

(MLD)

2001 8 77

2005 9 86

2010 10 98

2015 12 115

2025 17 161

In the west sector, for the year 2025, the population is forecasted as

17 lakhs and the water demand is 161 MLD. In order to meet the demand of

the west sector, the following suggestions are given.

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5.8.1 Telugu Ganga Project

Telugu Ganga Project has been recently implemented, primarily to

meet the pressing need of water supply to Chennai Metropolitan Area. By

mutual agreement, 336 Mm3 (12 TMC) of water has to be delivered to Poondi

reservoir in Tamil Nadu. Presently only 84 Mm3 (3TMC) of water is given

that augments the water supply to Chennai.

At present, the entire amount of water coming from this project is

distributed to the Chennai city alone. But for the present study, the entire

amount of water received in Poondi reservoir by Telugu Ganga Project can be

directly diverted to the Chembarambakkam Lake and stored. This water can

be taken to the Porur Lake through the Thanthi channel and can be treated at

the Porur water treatment plant from which the water can be supplied to the

west sector alone. Policy decisions has to be taken by the concerned

authorities.

5.8.2 Water from Chembarambakkam Lake

The Chembarambakkam Lake is one of the major lakes in Tamil

Nadu having a water spread area of 165 sq.km and a storage capacity of

103.2 Mm3 (282 MLD). This lake lies in the west sector of Chennai

Metropolitan Area. The water from the Telugu Ganga Project and the local

catchment area can be stored in Chembarambakkam Lake, which can also be

diverted through the Thanthi channel as an additional source for the Porur

Lake to cater the needs of the west sector. The quantity of water that can be

stored and diverted can be determined through modelling and this is beyond

the scope of this study.

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The west sector has an areal extent of 137.30 sq.km where the water

bodies occupy 14.06 sq.km. Considering the average annual rainfall of the

west sector as 1264 mm, the runoff accounts to 23.36 Mm3 (64 MLD) for an

areal extent of 123.24 sq.km. This excess water can be stored to augment the

water supply to this sector that can be achieved by collecting the stormwater

through stormwater drains and diverting it to a storage structure constructed at

vacant lands of Irungattukottai near Chembarambakkam Lake (Landuse Map

and Toposheets) with a storage capacity of 21.97 Mm3

(60 MLD). The rest of

the water can be diveted to the tanks and lakes.

The present capacity of the Porur Lake is 1.83 Mm3 (5 MLD). The

Porur Lake can be deepened to increase its capacity. This will aid in storing

more water during monsoon and will aslo help in storing the surplus water

from Chembarambakkam Lake instead of draining to River Adyar. In addition

to all these measures, there are a number of infiltration wells in the

surroundings of Porur. Provisions can be made to improve the existing

groundwater level by saving the stormwater runoff of that sector.

5.8.4 Water Treatment Plant at Porur

For the present study, a water treament plant of capacity 180 MLD

can be installed at Porur for the west sector. The groundwater potential in this

area is high that if provisions are made to store this water in this sector itself,

the difficulties in transporting the water from the water bodies to the Kilpauk

water treatment plant can be eliminated. The provision of a water treatment

plant will also help in meeting the increasing demand. Thus introducing a

water distribution station at Porur will improve the existing infrastructure of

water supply system in the west sector.

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For the west sector, 161 MLD of water is required for a predicted

population of 1733637 for the year 2025. The management strategies

recommended to meet the demand satisfactorily includes water from Telugu

Ganga Project, Chembarambakkam Lake, storage of stormwater runoff and

construction of water treatment plant at Porur. A detailed study has to be

conducted for each of the above management strategies recommended to

implement it.

Thus by adopting the sectorial classification of water distribution

system, the present water supply for Chennai Metropolitan Area can be

managed effectively and successfully. A rough estimate is prepared for the

management strategies of each sector by analyzing the works and proposals of

the concerned departments as well as conducting survey with the officials.

The cost estimate is presented in the Appendix. The summary of the features

of the four sectors are given in the Table 5.5.

Table 5. 5 Features of identified sectors of Chennai Metropolitan Area

Description Sectors

North Central South West

Areal extent (sq.km) 355.94 362.66 316.10 137.30

Average annual rainfall (mm) 1081 1108 1198 1264

Projected population for the year

2025 (Lakhs) 28 60 32 17

Forecasted water demand for the

year 2025 (MLD) 278 595 258 161

Proposed surface storage (Mm3) 80.57 36.63 14.65 21.97

Existing treatment plant

capacity (MLD) - 327 - -

Proposed treatment plant

capacity (MLD) 300 - 200 180

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The figures provided in all the four sectors are initial values and are

to be arrived at through detailed technical analysis.

5.9 ADDITIONAL WATER MANAGEMENT STRATEGIES

Apart from the management strategies adopted sector wise, some

overall measures can be taken for the water management in Chennai

Metropolitan Area. They are river conservation measures, wastewater reuse,

desalination and creating awareness to the public about the importance of

water conservation and management.

5.9.1 Conservation of Water Bodies in CMA

Most of the lakes in the Chennai Metropolitan Area are polluted

with sewage and garbage and are environmentally degraded. The suburban

areas of Chennai had numerous lakes and now the water bodies in

Adambakkam, Ambattur, Chitlapakkam, Nanganallur, Perungudi,

Tiruneermalai, Velachery, Villivakkam and Vyasarpadi have been encroached

upon to accommodate the growing population. Also, the remaining portion of

the lakes are used as dumping ground for industrial and municipal wastes thus

making it unfit for any level of human consumption. This further deteriorates

the quality of groundwater and pollutes the aquifer in the neighbourhood,

causing water-borne diseases.

Chennai being a water scarce city, the eco-restoration of these lakes

will go a long way in augmenting the water requirements of the city and also

will be recharging the dwindling groundwater table. During the monsoon

season the residential areas around these lake areas get inundated due to

blockages in the natural drains to the lakes. In order to alleviate these

problems, a comprehensive eco-restoration plan for the lakes should be

formulated.

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To check this visible human encroachment, there is a need to

monitor the water bodies. Haphazard human habitation often makes it

difficult to delineate the original extent of the lake. A comprehensive water

management plan has to be formulated not only to revive the vanishing water

bodies but also to put an end to poor urban planning leading to unsustainable

growth in the long run. Such a proactive approach will help when the

monsoon fails or becomes erratic.

It is necessary to catalogue and restore all the tanks in and around

the city to capture the runoff. Presently all the temple tanks are polluted with

weeds. They need improvement and restoration. They are to be cleaned from

slush and silt. The inlets to the temple tanks have to be widened and cleaned.

The steps to the tanks have to be made of cement mortar to prevent seepage

on sides. This improves storage. Cut stone steps and retaining walls on all the

four sides is to be provided to prevent deposition of silt due to erosion. PVC

pipes should be provided for draining rainwater into the tanks. Stoneware

pipes have to be laid at the compound walls to drain street water into temple

tanks during monsoon. The tanks should be protected all around by fences.

The encroachment problems around the tanks are to be prevented through

public participation and NGO action. Private organizations and firms can

carry out the rehabilitation of the temple tanks. Further maintenance and

operation of these tanks must be handed over to the public.

5.9.2 Wastewater Reuse

Drinking water is a limited resource. Rapid growth and development

in Chennai Metropolitan Area has put extreme demands on the sources of

high quality water. In order to increase the access to water, the following

three elements are especially important.

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1. Development of new water sources

2. Prevention of water resource degradation

3. Improvement in efficiency of water consumption.

Wastewater reuse contributes to all of above three elements.

Wastewater reuse can serve as an alternative source of water and can reduce

the pollution load to water environment by less discharged wastewater. The

wastewater reuse in agriculture and industry can enable more water to be used

in an efficient manner. By the reuse of wastewater, the amount of nutrients

discharged to our rivers will get considerably reduced, thereby protecting the

environment. Also the reuse water often cost less to the consumers than the

drinking water.

Some of the areas in the Chennai Metropolitan Area where the

recycled water can be used are irrigation of lawns, golf courses, cemeteries,

parks, school grounds, industrial and commercial landscapes, highway

medians and to recharge the groundwater. The recycled water can also be

used in industry and manufacturing processes such as cooling water and

boiler blow down, at construction sites, in decorative ponds and fountains,

vehicle washing, toilet flushing, in sprinkler systems located at the

commercial or industrial buildings and fire protection. The main goal of the

reuse of the wastewater in the Chennai Metropolitan Area is to improve the

health of humans, increased access to water supply and to improve the

sanitation.

5.9.2.1 Reuse of Household Wastewater

The wastewater generated in households can be classified as grey

water and black water. The grey water is defined as untreated household

wastewater that has not come in contact with toilet waste and includes

wastewater from bathtubs, showers, washbasins, washing machines and

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laundry tubs, but does not include wastewater from kitchen sinks or

dishwashers or laundry water from washing of materials soiled with human

excreta. The various sources of grey water and black water are shown in the

Figure 5.4.

Figure 5.4 Sources of Household Wastewater

In the prevailing sewerage system of Chennai, the grey water is not

reused as it is discharged into sewer system along with the black water. This

grey water can be utilized if it is separated from black water, thereby reducing

the fresh water consumption. It can be reused without pre-treatment for

agricultural or landscape irrigation in household scale or in larger scale. This

can be further increased to 60 percent by reusing wastewater after in situ

treatment. Some recommendations for reuse of the household wastewater are

as follows:

• For recharging the groundwater in Chennai Metropolitan

Area, the grey water obtained from the households can be

Toilet Dish washer Cloth washer

Bath shower Miscellaneous

Grey water Black water

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diverted towards a specially prepared soil bed, in which semi-

aquatic plants can be grown. If the water is to be recycled, the

bottom of the bed should be made permeable to allow

percolation.

• From each multi-storied complex, a network of two different

pipes can be laid to separate the black water and grey water at

the initial stage itself. Such projects require moderate capital

investment as well as minimal maintenance. An example for

such a complex network is at Tambaram, an 80-flat apartment

constructed by Alacrity foundation, where the system is now

three years old. Here, the quality of drinking water has

remained stable and a dry bore well has begun yielding. The

system operates on the principle of gravity with no related

problems of chemicals, smell or mosquito breeding. Hence if

this measure can be implemented in a micro level in

individual houses, it will lead to efficient reuse of wastewater

generated from the households and ultimately improve the

water access and the sanitation of the Chennai Metropolitan

Area.

• Grey water use greatly extends the useful life and capacity of

septic systems. For municipal treatment systems, decreased

wastewater flow means higher treatment effectiveness and

lower costs.

• In Chennai Metropolitan Area, the places like Anna Nagar,

Mogappair, Korattur, Padi, Thandarai, Palleripattu, Puzhal,

Villivoyal, Ponneri and Thirumullaivoyal have clayey soil

which has a slow water percolation. The grey water can be

recycled by constructing oxidation ponds in these areas, which

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can serve as a partial or complete substitute instead of having

a very costly over-engineered system.

• The nutrients present in the household wastewater are going

waste when it is let to the waterways. These nutrients can be

used in an effective manner if nutrients can be collected and

used as landfills to maintain the fertility of the land.

Apart from the reuse of household wastewater, the reuse of effluent

released from various industries in Chennai Metropolitan Area is also possible

in a wide range of categories from agricultural to potable purposes. The

sewerage effluent, in most cases the secondary effluent, is recycled with or

without treatment having specific water quality standards to meet the various

needs.

5.9.2.2 Effluent Reuse for Urban Applications

In urban cities like the Chennai Metropolitan Area, the recycling

system of effluent plays a great role for controlling water consumption and

reducing its pollutant load on the environment. There are big potentials for

introducing wastewater reuse in the city with high rate of water usage and

discharging wastewater everyday. Most of the water that are used for urban

activities need not have the quality as high as that of drinking water. In most

cases, the secondly treated domestic wastewater followed by sand filtration

treatment and disinfections can be used for non-potable purposes in urban

water reuse i.e., applications for toilet flushing in business or commercial

building, car washing, garden watering, park or other open space planting,

fire-fighting and so on. The schematic representation of reclaimed water use

in an urban area is shown in Figure 5.5.

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Figure 5.5 Schematic Diagram of Reclaimed Water Use

5.9.2.3 Effluent Reuse for Environmental Water Enhancement

Effluent reuse of the Chennai Metropolitan Area can also be applied

actively for the environmental enhancement such as augmentation of natural

and artificial stream, fountain and ponds in parks. Proper quality guideline has

to be considered on the assumption that human contact with the reused water

and sufficient disinfection has to be carried out by chlorination or UV

radiation. In addition to the hygienic aspect, the removal of the nutrients

which includes nitrogen or phosphorus should also be kept in view since it

may cause algal blooming which will deteriorate the quality and appearance

of the stream.

5.9.2.4 Effluent Reuse for Industry

The secondary effluent produced from the industries of the various

sectors in the Chennai Metropolitan Area can also be reused with or without

treatment and disinfection to meet intended purposes such as cooling

processes and boiler blow down. In addition to reduction in water

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consumption and pollution load to the environment, industrial water reuse in

Chennai Metropolitan Area can have the following specific benefits like

potential reduction in production costs from recovery of raw materials in the

wastewater, less permitting and administrative burden from the reduction in

wastewater toxicity as well as volume and heat recovery and reduced impacts

from high temperature effluent to the ecosystem.

5.9.2.5 Effluent Reuse for Groundwater Recharge

In Chennai Metropolitan Area, due to the rapid growth of

population, over exploitation of the groundwater is taking place without

knowing its consequences. The problems that may arise are seawater intrusion

in the coastal zones mainly in the north and south sectors, desertification and

degradation of land which occurs mainly due to reduction in the natural

potential of the land and depletion in surface and groundwater sources, drying

up of wetlands, reduction in pumping capacity and land subsidence.

In order to safeguard the groundwater table, percolation and

withdrawal of water from the aquifers should be properly balanced. Also there

is a frequent failure of monsoon. The groundwater potential is getting

degraded day by day and the water table has to be maintained. Effluent from

the industries can be reused for the recharge of groundwater. Compared to

conventional surface water storage, aquifer recharge has many advantages

such as negligible evaporation, little contamination by animals, no algae

blooming and less cost as construction of pipelines is not required. For other

benefits, it protects groundwater from saltwater intrusion by barrier formation

in coastal regions and control or prevents land subsidence.

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5.9.2.6 Potable Reuse of Effluent

Growing populations and increasing constraints on the development

of new water sources have spurred a variety of measures to conserve and

reuse water over the last two or three decades. Potable reuse of wastewater is

made possible by improved water treatment technologies and water analysis

techniques to detect the presence of microbial and chemical contaminants.

Even though the potable reuse of effluent is not generally recommended,

under worst conditions of water scarcity this option can be considered.

5.9.3 Desalination

Along with recommendations of water distribution by sectorial

division of each area, rehabilitation of tanks and rivers, construction of check

dams across the rivers, wastewater reuse etc., it is necessary to look for new

technologies which are viable and indigenous to match the increasing needs.

It has to be looked forward to solve the problem of water scarcity.

Desalination is such an attempt in this way. It is still in incipient stage

keeping cost involved. Technology has to march forward to bridge the gap

between the cost and demand and some recommendations are suggested

below:

• The yield of fresh water for every 100 litres of sea water

would be 1 to 1.5 litres. The water however would be so pure

that it would actually have to be ‘polluted’ with raw water to

make it potable and fit for consumption. As a means to

overcome the high cost involved in the desalinated water,

provisions can be arranged to supply this water to meet the

commercial water demands instead of providing it for the

domestic purposes. Desalinated water can be supplied to those

commercial places like high class hotels, hospitals and IT

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industries that can bear the high cost, so that the stress caused

by them to the normal water supply can be reduced to a

considerable level.

• By implementing desalination plants in many areas of the

CMA, the process will not only provide the people with fresh

water but also generates edible salt or caustic soda, that are

marketable that concludes desalination will no longer be an

expensive technology to get fresh water from sea water. The

market prices of these products eventually nullify the cost of

production of fresh water and tilt the scale towards profit.

• At present the drinking water requirement of the Chennai

Metropolitan Area is more which will further increase when

the commercial and industrial water needs are taken into

consideration. The implementation of the desalination plants

at several parts of the coastal areas will contribute

significantly to meet the Chennai Metropolitan Area’s water

requirement beneficially.

• Desalination technique cannot be used as a direct alternative

source but in a very high water crisis condition it can

considered as one of the various management strategies to

meet out the requirements.

5.9.4 Awareness to Society for Conservation of Water

For any management strategy to be successful, the cooperation of

public is vital. By providing awareness to the society about the water crisis,

importance of saving even a single drop of water and the efficient usage of

water, the water managers can bring remarkable changes in the water sector.

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Some of the measures that can be adopted by the pubic to save water indoor

and outdoor are recommended as follows

• People by themselves can adopt some protective measures to

reduce the leakage in pumps and pipelines at home. Leak

detection and maintenance in pumps and pipelines should be

done regularly. Each and every household should be verified

for water leakage, because many homes may have hidden

water leaks. The water meter should be read before and after a

two-hour period when no water is being used. If the meter

does not show exactly the same readings, it indicates there

exist leakage in pipelines. Report all significant water losses

to the local authorities.

• The flushing of the toilet often must be reduced. And care

should be taken that the toilet flush handle does not frequently

sticks in the flush position. If such a condition exists the water

will run constantly, then it has to be replaced immediately.

Minimum amount of water should be used for bath. The water

should not be wasted by opening the tap continuously, while

brushing the teeth, shaving or washing the face. Operate

automatic clothes washers only when they are fully loaded or

properly set the water level for the size of load required.

• The water must be used economically while gardening. The

lawns should be watered during early morning hours, when

temperature and wind speed are low. This will reduce the loss

due to evaporation.

• Micro and drip irrigation are examples of water-efficient

methods of irrigation. The sprinklers can be positioned so that

the water directly sprinkles on the lawns and shrubs, and not

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on the paved areas. The sprinkler systems and timing devices

must be checked regularly to make sure that they are in the

proper operating condition.

• Over fertilization of the lawns should be avoided. The

application of fertilizers will increase the need for water.

Apply fertilizers which contain slow release, water-insoluble

forms of nitrogen. Mulching can be practiced to retain

moisture in the soil. Mulching control weeds that otherwise

may compete with plants for water.

• All the water-conservation, water shortage rules and

restrictions must be strictly followed in all the places. All the

employers have to be encouraged to promote water

conservation at their workplace. It is also suggested that water

conservation can be put in the employee orientation manual

and training programs.

• The business that can promote water conservation must be

patronized. All the school system and local government

should be encouraged in developing and promoting a water

conservation ethic among children and adults. Also the public

has to support efforts and programs to create a concern for

water conservation among tourists and visitors to the state and

encourage the public to be part of a water conscious

community. The conservation of water can be promoted by

community newsletters and bulletin boards to ensure the

importance of water.

• The various Non-Governmental Organizations that work for

improving Chennai’s water condition are Akash Ganga,

Exnora, SUSTAIN etc. These organizations can contribute

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markedly in implementing the sectorial management of water

distribution by working with the respective institutions and by

creating public awareness on the subject of the precious water.

5.9.5 General Recommendations

• In the peri urban areas of CMA where development is

extensive, area around the proposed buildings should be left

unpaved. The storm water will infiltrate through the unpaved

areas and will recharge the groundwater. Similarly space can

be left around the open wells also. In order to implement this,

the government has to pass an act that should be strictly

followed by the public. Also the government can give

incentives to those people who leave more unpaved areas

around their built-up place than the regulations specified by

the government.

• The city can be planned in such a way that separate pipe lines

can be laid to carry sewage and sullage water from house

holds. This helps in the economical treatment of sullage water.

The sewage from the individual houses should be connected to

a public sewerage system and treated in a common oxidation

pond. This will reduce the groundwater contamination that

may arise after years due to leakage of individual septic tanks.

The sewage water after treatment can be supplied to meet the

secondary uses like cooling of Air Conditioning ducts, ice

plants, boilers, etc. Also the biogas generated from solid waste

treatment can be used effectively for household purposes.

• In flats, the usage of water can be estimated as a whole and

pipes can be laid to cater the needs of all the houses within it.

This can be achieved by increasing the diameter of the

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existing pipes. To satisfy the needs of institutions, IT

industries, star hotels, high commercial buildings, the amount

of water supplied can be metered and can be charged

separately.

• The city star hotels needs between 1.2 lakh litres to 3 lakh

litres a day. They are depending on private tankers at the time

of acute water shortage. Hence sewage conversion and sea

water desalination can be adopted. The reclaimed water can be

sold at the same charge as that of the metro water.

• In the coastal areas new law has to be framed to prevent the

over extraction of groundwater. The government should insist

the public not to drill bore wells beyond a considerable depth.

This prevents the salt-water intrusion and safeguards CMA’s

coastal ecosystem.

chapter 5 formulation of water management strategies...

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