A practical solution to ground water recharge by rain water harvesting system

International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308

(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

132

A PRACTICAL SOLUTION TO GROUND WATER RECHARGE BY

RAIN WATER HARVESTING SYSTEM IN PUDUKKOTTAI DIST,

TAMILNADU

R.Greesan

Dept. of Civil Engg. Chendhuran College of Engg & Tech.,Pudukkottai,TN

ABSTRACT

The world was surrounded by water. Even though we are in the planet of earth which

has 97% of water, we are facing our maximum of trouble regarding water. Some of the

sources are saying that, Water scarcity will be the major reason to cause third world war. This

case study was done in the district of Pudukkottai, which is not having any perennial resource

of water and the dist was mostly depends on rain water for domestic and agri purposes. In this

project we are tried to give better solution to the ground water and ground water recharge.

This paper prescribed the technique of Roof Top Harvesting for storing and utilizing the

rainwater and also for recharging the ground water. In the trend of urbanisation, the roof top

harvesting is the effective, trouble-free system to implement with less expense. This will

result in effective utilisation of water, ground water recharge, sustain our natural resources

and automatically the environment will come under the greenish envelope without any doubt

and drought. That’s the solution was very near to us to build a green city.

WATER

Water is a prime natural resource, a basic human need and a precious national asset,

which is one of the most critical elements in Development Planning according to Indian

National Water Policy. Planning and Development of Water Resources and their Use need to

be governed by National Interest. It has been estimated that out of the Total precipitation

around 4000 billion cubic metre in the country, Surface Water availability is about 1780

billion cubic metre. Out of this, only about 50% can be put to beneficial use because of

topographical and other constraints.

In addition, there is a Ground Water Potential of about 420 billion cubic metre. The

availability of water is highly uneven in space and time. Precipitation is confined to only

about 3 to 4 months with 20 – 40 significant Rainy days within a year. Hence, there is an

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133

imperative need for effective collection of Rain Water for storing in appropriate places like

Reservoir, Lakhs, Tanks, Ponds and Aquifers etc. In order to use the stored water efficiently

for Economical and Social Purposes.

Current Water Usage

Usage (%) World Europe Africa India

Agriculture 69 33 88 83

Industry 23 54 5 12

Domestic 8 13 7 5

Future Water Usage

Year Agriculture Industry Domestic Total Per Capita

India Billion Lit/Day Lit/Day

2000 1658 115 93 1866 88.9

2050 1745 441 227 2413 167.0

China

2000 1024 392 105 1521 82.7

2050 1151 822 219 2192 155.4

USA

2000 542 605 166 1313 582.7

2050 315 665 187 1167 484.6

Agriculture is the dominant section in Indian Economy. Tamil Nadu has poor ground

water potential, depends mainly on the Surface Water Irrigation, as well as Ground Water

Irrigation. The Surface Water Potential largely depends on the storage of water in Reservoirs,

Dams and Tanks only.

The state has used the Surface and Ground Water Potentials to maximum limit and

hence the future development and expansion depends only on the efficient and economical

use of Water Potential and Resources.

To achieve the Water Use Efficiency, it is necessary to improve and upgrade the

existing Conveyance and Storage System and also to introduce Modern Irrigation methods.

Per Capita Water Use

Continents Per Capita Water Use

(m3/yr)

Africa 245

Asia 519

North and C. America 1861

South America 478

Europe 1280

USSR (Former) 713



134

Per capita water availability in India

Year Population (Million) Per capita water

availability (m3/year)

1951 361 5177

1955 395 4732

1991 846 2209

2001 1027 1820

2025 1394 1341

2050 1640 1140

Study Area

Pudukkottai district area profile

PUDUKKOTTAI

Pudukkottai district is bound on the North and North West by Trichirapalli district,

Sivagangai district on the West and South West, on the East and North East by Thanjavur district

and on the South East by Bay of Bengal.

The district is formed in January 1974 out of certain pockets of the then Trichy and

Thanjavur districts, has an area of 4663 sq.km with a coastal line of 39 km.

Pudukkottai district is divided into two revenue divisions with 9 taluks. There are 7 Agricultural

Divisions which is headed by the respective Assistant Director of Agriculture and 13 blocks

headed by Agricultural Development Officer. Moreover, there are two municipalities and 8 town

panchayats covering 757 revenue villages and 498 village panchayats.

The average rainfall of the district is 923 mm per year. The frequency of rainfall is also uncertain.

Even though the district has more number of tanks, most of the tanks are silted in nature. So the

water holding capacity of the tanks is very poor. This often leads to water scarcity for irrigation

during the critical stages of the crop, especially during maturity. The major crops of Pudukkottai

district are Paddy, Groundnut, Cashew, Sugarcane, Pulses, Fruits,Coconut.

Geology The district is mainly covered with crystalline metamorphic rock period predominantly

occupying the western part of the district ; the sedimentary formations comprising cretaceous,

tertiary and quaternary periods occupy the eastern and south-eastern part of the district. The stage

of ground water development in all the thirteen blocks is less than 65% of utilizable recharge.

Genocide Pudukkottai District is a coastal covered district and lies between 9 51’ 0’’ & 10 45, 0’

North latitude and 78 25’ 30’’ and 79 16’ 30’’ East longitude covering a geographical area of

about 4661 sq.km in the South Eastern part of Tamil Nadu.

Agro Ecological Region Generally Hot and dry with moderate moisture availability, but the coastal plain including

Cauvery delta has moderately large moisture availability.

International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976

(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March

Agro climatic zone: Cauvery delta zone and southern zone.

Physiographic and Drainage Pudukkottai district has an undulating topography with a gen

towards Southeast. Small hillocks are seen in the Northern, Western and Southern part of the

district. Alluvial plains of Agniar, Ambuliar and

Avudaiyarkoil and Manamelkudi blocks in the Southeastern

Rainfall Details

Climate of Tamil Nadu Tamil Nadu is largely dependent on the monsoon rains, the failing of which

sometimes leads to droughts in the country. The climate Tamil Nadu varies from dry sub

humid to semi-arid. There are 3 distinct times of rainfall in Tamil Nadu, namely the South

West monsoon from the months of June to September characterized by heavy southwest

winds; the North East monsoons

northeast winds; and the dry season from the months of January to May. The annual rainfall

of the state is approximately 945 mm (37.2 in), of which 32% is the South West monsoon and

48% is the North East monsoon. The state can be divided into 7 agro

west, north-east, southern, west, high altitude hilly, high rainfall, and Cauvery Delta.

Rainfall Details On Pudukkottai Dist

Climate and Rainfall

• Climate is mainly tropical in nature with a cooler period from

February.

• Maximum average temperature is

• Rainfall is variable both annually and seasonally. The annual rainfall ranges from

496.4mm to 1032 mm in the last 10 years period.

• The season wise rainfall pattern of the district is as below:

1. Winter period 52.2 mm

2. Summer period 123.6 mm

3. South West monsoon period

4. Northeast monsoon period

392.1


6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

135

Cauvery delta zone and southern zone.

Pudukkottai district has an undulating topography with a general genital slope


district. Alluvial plains of Agniar, Ambuliar and coastal plains occupy the Aranthangi,

Avudaiyarkoil and Manamelkudi blocks in the Southeastern part of the district.

Tamil Nadu is largely dependent on the monsoon rains, the failing of which

sometimes leads to droughts in the country. The climate Tamil Nadu varies from dry sub

d. There are 3 distinct times of rainfall in Tamil Nadu, namely the South


winds; the North East monsoons from the months of October to December, characterized by

inds; and the dry season from the months of January to May. The annual rainfall


48% is the North East monsoon. The state can be divided into 7 agro- climatic zones:

east, southern, west, high altitude hilly, high rainfall, and Cauvery Delta.

Rainfall Details On Pudukkottai Dist

Climate is mainly tropical in nature with a cooler period from December to

emperature is 24C- 43C.

Rainfall is variable both annually and seasonally. The annual rainfall ranges from

mm in the last 10 years period.

The season wise rainfall pattern of the district is as below:

123.6 mm

South West monsoon period 350.0 mm

Northeast monsoon period 392.1 mm

52.2123.6

350

392.1WINTER

SUMMER

SW MONSOON

NW MONSOON


April (2013), © IAEME

eral genital slope


plains occupy the Aranthangi,

Tamil Nadu is largely dependent on the monsoon rains, the failing of which

sometimes leads to droughts in the country. The climate Tamil Nadu varies from dry sub-

d. There are 3 distinct times of rainfall in Tamil Nadu, namely the South


from the months of October to December, characterized by

inds; and the dry season from the months of January to May. The annual rainfall


climatic zones: north-

east, southern, west, high altitude hilly, high rainfall, and Cauvery Delta.

December to

Rainfall is variable both annually and seasonally. The annual rainfall ranges from



136

Rainwater Harvesting

A Glance of RWH

Figure shows the State wise Rainwater Harvesting

The principle of collecting and using precipitation from a catchments surface.

An old technology is gaining popularity in a new way. Rain water harvesting is

enjoying a renaissance of sorts in the world, but it traces its history to biblical times.

Rainwater harvesting provides an independent water supply during regional water

restrictions and in developed countries is often used to supplement the mains supply.

Rainwater harvesting systems are appealing as they are easy to understand, install and

operate. They are effective in 'green droughts' as water is captured from rainfall where runoff

is insufficient to flow into dam storages. The quality of captured rainwater is usually

sufficient for most household needs, reducing the need for detergents because rainwater is

soft. Financial benefits to the users include that rain is 'renewable' at acceptable volumes

despite climate change forecasts, and rainwater harvesting systems generally have low

running costs, providing water at the point of consumption.

History In ancient Tamil Nadu (India), rainwater harvesting was done by Chola

kings. Rainwater from the Brihadeeswarar temple was collected in Sivaganga tank. During

the later Chola period, the Vīrānam tank was built (1011 to 1037 CE) in Cuddalore district

of Tamil Nadu to store water for drinking and irrigation purposes. Vīrānam is a 16-kilometre

(9.9 mi) long tank with a storage capacity of 1,465,000,000 cubic feet (41,500,000 m3).

At Present

India

• In India, rain water harvesting was first introduced by Andhra Pradesh ex-Chief

Minister N. Chandrababu Naidu. He made a rule that every house which is going to built

in cities of that state must have a percolation pit/rainwater harvesting system. This rule

increased the ground water level in good phase.



137

• In the state of Tamil Nadu, rainwater harvesting was made compulsory for every building

to avoid ground water depletion. It proved excellent results within five years, and every

other state took it as role model. Since its implementation, Chennai saw a 50 percent rise

in water level in five years and the water quality significantly improved.

• In Rajasthan, rainwater harvesting has traditionally been practiced by the people of

the Thar Desert. There are many ancient water harvesting systems in Rajasthan, which

have now been revived

Need Of Rwh Rain water harvesting is essential because:

• Surface water is inadequate to meet our demand and we have to depend on

ground water

• Due to rapid urbanization, infiltration of rain water into the sub-soil has

decreased drastically and recharging of ground water has diminished.

Rainwater Harvesting Techniques The two main techniques of rainwater harvesting are:

• Storage of Rainwater on surface for future use.

• Recharge of Ground water

The storage of rain water on surface is a traditional techniques and structures

used were underground tanks, ponds, check dams, weirs etc.

Components Of A Rainwater Harvesting System

A rainwater harvesting system comprises components of various stages -

transporting rainwater through pipes or drains, filtration, and storage in tanks for reuse or

recharge.

The common components of a rainwater harvesting system involved in these stages

are illustrated here.

1.Catchments The catchment of a water harvesting system is the surface which directly receives the

rainfall and provides water to the system. It can be a paved area like a terrace or courtyard of

a building, or an unpaved area like a lawn or open ground. A roof made of reinforced cement

concrete (RCC), galvanised iron or corrugated sheets can also be used for water harvesting.

2.Coarse mesh at the roof to prevent the passage of debris

3.Gutters

Channels all around the edge of a sloping roof to collect and transport rainwater to the

storage tank. Gutters can be semi-circular or rectangular and could be made using

4.Conduits Conduits are pipelines or drains that carry rainwater from the catchment or rooftop area

to the harvesting system. Conduits can be of any material like polyvinyl chloride (PVC) or

galvanized iron (GI), materials that are commonly available. 5.First-flushing A first flush device is a valve that ensures that runoff from the first spell of rain is

flushed out and does not enter the system. This needs to be done since the first spell of rain

carries a relatively larger amount of pollutants from the air and catchment surface.



138

6.Filter

The filter is used to remove suspended pollutants from rainwater collected over roof.

A filter unit is a chamber filled with filtering media such as fibre, coarse sand and gravel

layers to remove debris and dirt from water before it enters the storage tank or recharges

structure. Charcoal can be added for additional filtration. In a simple sand filter that

can be constructed domestically, the top layer comprises coarse sand followed by a 5-10 mm

layer of gravel followed by another 5-25 cm layer of gravel and boulders.

i) Charcoal water filter A simple charcoal filter can be made in a drum or an earthen pot. The filter is made of

gravel, sand and charcoal, all of which are easily available.

(ii)Sand Filters Sand filters have commonly available sand as filter media. Sand filters are easy and

inexpensive to construct. These filters can be employed for treatment of water to effectively

remove turbidity (suspended particles like silt and clay), colour and microorganisms.

In a simple sand filter that can be constructed domestically, the top layer comprises

coarse sand followed by a 5-10 mm layer of gravel followed by another 5-25 cm layer of

gravel and boulders.

Artificial Recharge To Ground Water Artificial recharge to ground water is a process by which the ground water reservoir is

augmented at a rate exceeding that obtaining under natural conditions or replenishment. At

man-made scheme or facility that adds water to an aquifer may be considered to be an

artificial recharge system.

Source: A water harvesting manual for urban

areas



Urbanisation Effects On Groundwater Hydrology

• Increase in water demand

• More dependence on ground water use

• Over exploitation of ground water

• Increase in run-off, decline in well yields and fall in water levels

• Reduction in open soil surface area

• Reduction in infiltration and deterioration in water quality

Methods Of Artificial Recharge In Urban Areas

• Water spreading

• Recharge through pits,trenches,wells,shafts

• Roof top collection of rainwater

• Roadtop collection of rainwater

• Induced recharge from surface water bodies

Artificial recharge methods can be classified into tw

(i) direct methods, and (ii) indirect methods.

Direct Methods

(a) Surface Spreading Techniques

The most widely practised methods of artificial recharge of groundwater employ

different techniques of increasing the contact area and resident

soil so that maximum quantity of water can infiltrate and augment the groundwater storage.

Areas with gently sloping land without gullies or ridges are most suited for surface

spreading techniques.

Flooding The technique of flooding is very useful in selected areas where a favourable hydro

geological situation exists for recharging the unconfined aquifer by spreading the surplus

surface-water from canals / streams over large area for sufficiently long period so that it

recharges the groundwater body. This technique can be used for gently sloping land with

slope around 1 to 3 percentage points without gullies and ridges.



139

Urbanisation Effects On Groundwater Hydrology

r demand

More dependence on ground water use

Over exploitation of ground water

off, decline in well yields and fall in water levels

Reduction in open soil surface area

Reduction in infiltration and deterioration in water quality

Artificial Recharge In Urban Areas

Recharge through pits,trenches,wells,shafts

Roof top collection of rainwater

Roadtop collection of rainwater

Induced recharge from surface water bodies

Artificial recharge methods can be classified into two broad groups

(i) direct methods, and (ii) indirect methods.

Surface Spreading Techniques The most widely practised methods of artificial recharge of groundwater employ

different techniques of increasing the contact area and resident time of surface-water with the


Areas with gently sloping land without gullies or ridges are most suited for surface

que of flooding is very useful in selected areas where a favourable hydro


water from canals / streams over large area for sufficiently long period so that it


slope around 1 to 3 percentage points without gullies and ridges.



The most widely practised methods of artificial recharge of groundwater employ

water with the


Areas with gently sloping land without gullies or ridges are most suited for surface-water

que of flooding is very useful in selected areas where a favourable hydro-


water from canals / streams over large area for sufficiently long period so that it




140

Ditches and Furrows In areas with irregular topography, shallow, flat-bottomed and closely spaced ditches

and furrows provide maximum water contact area for recharging water from the source

stream or canal. This technique requires less soil preparation than the recharge basin

technique and is less sensitive to silting.

Recharge Basins Artificial recharge basins are either excavated or enclosed by dykes or levees. They

are commonly built parallel to ephemeral or intermittent stream-channels. The water contact

area in this method is quite high which typically ranges from 75 to 90 percentage points of

the total recharge area. In this method, efficient use of space is made and the shape of basins

can be adjusted to suite the terrain condition and the available space.

(b) Sub-Surface Techniques When impervious layers overlie deeper aquifers, the infiltration from surface cannot

recharge the sub-surface aquifer under natural conditions. The techniques adopted to recharge

the confined aquifers directly from surface-water source are grouped under sub-surface

recharge techniques.

Injection Wells Injection wells are structures similar to a tube well but with the purpose of

augmenting the groundwater storage of a confined aquifer by “pumping in” treated surface-

water under pressure. The aquifer to be replenished is generally one that is already over

exploited by tube well pumping and the declining trend of water levels in the aquifer has set

in.

Gravity-Head Recharge Wells

In addition to specially designed injection wells, ordinary bore wells and dug wells

used for pumping may also be alternatively used as recharge wells, whenever source water

becomes available. In certain situations, such wells may also be constructed for effecting

recharge by gravity inflow. In areas where water levels are currently declining due to over-

development, using available structures for inducing recharge may be the immediately

available economic option.

Connector Wells Connector wells are special type of recharge wells where, due to difference in

potentiometer head in different aquifers, water can be made to flow from one aquifer to other

without any pumping. The aquifer horizons having higher heads start recharging aquifer

having lower heads.

Recharge pits Recharge pits are structures that overcome the difficulty of artificial recharge of

phreatic aquifer from surface-water sources. Recharge pits are excavated of variable

dimensions that are sufficiently deep to penetrate less permeable strata. A canal trench is a

special case of recharge pit dug across a canal bed. An ideal site for canal trench is influent

stretch of a stream that shows up as dry patch. One variation of recharge pit is a contour

trench extending over long distances across the slope and following topographical contour.

This measure is more suitable in piedmont regions and in areas with higher surface gradients.

Recharge Shafts

In case, poorly permeable strata overlie the water table aquifer located deep below

land surface, a shaft is used for causing artificial recharge. A recharge shaft is similar to a

recharge pit but much smaller in cross-section.



141

Indirect Methods

(a) Induced Recharge It is an indirect method of artificial recharge involving pumping from aquifer

hydraulically connected with surface water, to induce recharge to the groundwater reservoir.

In hard rock areas, the abandoned channels often provide good sites for induced recharge.

The greatest advantage of this method is that under favourable hydro-geological situations,

the quality of surface-water generally improves due to its path through the aquifer materials

before it is discharged from the pumping well.

Pumping Wells Induced recharge system is installed near perennial streams that are hydraulically

connected to an aquifer through the permeable rock material of the stream-channel. The outer

edge of a bend in the stream is favourable for location of well site. The chemical quality of

surface-water source is one of the most important considerations during induced recharge.

Collector Wells For obtaining very large water supplies from river-bed, lake-bed deposits or

waterlogged areas, collector wells are constructed. The large discharges and lower lift heads

make these wells economical even if initial capital cost is higher as compared to tube well. In

areas where the phreatic aquifer adjacent to the river is of limited thickness, horizontal wells

may be more appropriate than vertical wells. Collector well with horizontal laterals and

infiltration galleries can get more induced recharge from the stream.

Infiltration Gallery

Infiltration galleries are other structures used for tapping groundwater reservoir below

river-bed strata. The gallery is a horizontal perforated or porous structure (pipe) with open

joints, surrounded by a gravel filter envelope laid in permeable saturated strata having

shallow water table and a perennial source of recharge. The galleries are usually laid at

depths between 3 to 6 metres to collect water under gravity flow. The galleries can also be

constructed across the river-bed if the river-bed is not too wide. The collector well is more

sophisticated and expensive but has higher capacities than the infiltration gallery. Hence,

choice should be made by the required yield followed by economic aspects.

(b) Aquifer Modification

These techniques modify the aquifer characteristics to increase its capacity to store

and transmit water. With such modifications, the aquifer, at least locally, becomes capable of

receiving more natural as well as artificial recharge. Hence, in a sense these techniques are

artificial yield augmentation measures rather than artificial recharge measures.

(c) Groundwater Conservation Structures The water artificially recharged into an aquifer is immediately governed by natural

groundwater flow regime. It is necessary to adopt groundwater conservation measures so that

the recharged water remains available when needed.

Groundwater Dams / Underground Barriers A groundwater dam is a sub-surface barrier across stream that retards the natural

groundwater flow of the system and stores water below ground surface to meet the demands

during the period of greatest need. The main purpose of groundwater dam is to arrest the flow



of groundwater out of the sub-basin and increase the storage within the aquifer. The sub

surface barriers need not be only across the canal bed. In some micro watersheds, sub

dykes can be put to conserve the groundwater flow in larger area in a valley. Sites have to be

located in areas where there is a great scarcity of water during the summer months or there is

a need for additional water for irrigation.

Data Collection And Analysis

To study about the rainwater harvesting system and ground water recharge the

following data’s are collected from the respective department in the district of pudukkottai.

Annual Rainfall Details

0

1000

2000

3000

2005 2006 2007

Month NORMAL 2005

January 3.95

FEBRAURY 32.3

WINTER 36.25

March 24.7

APRIL 29.1 76.6

MAY 69.9 61.5

SUMMER 123.7 145

June 39.2 14.8

JULY 46 66.6

AUGUST 102.3 85.3

SEPTEMBER 98.2 112.9

S.W.MONSOON 285.7 279.6

OCTOBER 192.3 197.2

NOVEMBER 239.8 453.9

DECEMBER 96.1 161.1

N.E.MONSOON 528.2 812.2



142

basin and increase the storage within the aquifer. The sub

surface barriers need not be only across the canal bed. In some micro watersheds, sub

erve the groundwater flow in larger area in a valley. Sites have to be


a need for additional water for irrigation.

the rainwater harvesting system and ground water recharge the


Seasonal Rainfall

2008 2009 2010 2011 2012

Grand Total

N.E.Monsoon

S.W.Monsoon

Summer

Winter

2005 2006 2007 2008 2009 2010 2011

1 5.3 1.25 6.2 9.9 1.4 14.36

23 0 1.95 38 0 0

24 5.3 3.2 44.2 9.9 1.4

6.9 42 0 185.3 3.9 0

76.6 39.2 19.7 19 46.6 6.6 54.05

61.5 32.3 21.2 15.7 36.3 103.2

145 113.5 40.9 220 86.8 109.8 94.91

14.8 74.1 46.6 23.2 32 52.4

66.6 10.5 50.6 58.2 27.1 44.9

85.3 74.8 167.6 158.5 54.2 106.3 116.08

112.9 66 49.8 27.8 113.7 171.5 109.6

279.6 225.4 314.6 267.7 227 375.1 317.88

197.2 213.4 195.3 196.5 36.9 123.2 213.2

453.9 239.8 51.8 343.7 324.9 257.4 283.7

161.1 24.2 284.7 63.8 163.9 131.3

812.2 477.4 531.8 604 525.7 511.9 534.6



basin and increase the storage within the aquifer. The sub-

surface barriers need not be only across the canal bed. In some micro watersheds, sub-surface

erve the groundwater flow in larger area in a valley. Sites have to be


the rainwater harvesting system and ground water recharge the


Grand Total

N.E.Monsoon

S.W.Monsoon

Summer

Winter

2011 2012

14.36 2.01

7.14 0

21.5 2.01

3.66 0

54.05 22.12

37.2 28.94

94.91 51.06

35.7 9.44

56.5 29.51

116.08 95.98

109.6 128.1

317.88 263.03

213.2 262.2

283.7 51.6

37.7 9.8

534.6 323.6



• Annual Rainfall Details

COMPUTATION OF GROUNDWATER RECHARGE BY ROOFTOP

The computation was carried out in Individual Buildings

follows:

1. Average Roof Top Area for Individual Buildings

2. Average Rainfall of Pudukkottai Dist

3. Effective Annual Rainfall contributing to Recharge :70%

4. Considering Losses:30%

5. Total rainfall collected in the year = 0.923 x 100 = 92.3 cum

6. Quantity available for recharge per Annum : 92.3 x 0.7 = 64.6cum/yr

7. Average family size:4Nos

8. Zone: Residential Zone

9. Per capita stipulated for domestic use

10. Per capita availability of rainwater:64.6/4 = 16.15cum/yr

SL.NO

1

2

3

4

5

6

7

8

1260.8

821.6

0

200

400

600

800

1000

1200

1400

2005 2006



143

COMPUTATION OF GROUNDWATER RECHARGE BY ROOFTOP HARVESTING

The computation was carried out in Individual Buildings and Multistoried Buildings

for Individual Buildings:100Sqm

of Pudukkottai Dist: 923mm

Effective Annual Rainfall contributing to Recharge :70%

Total rainfall collected in the year = 0.923 x 100 = 92.3 cum

Quantity available for recharge per Annum : 92.3 x 0.7 = 64.6cum/yr

ly size:4Nos

stipulated for domestic use :135lpcd

Per capita availability of rainwater:64.6/4 = 16.15cum/yr

YEAR RAINFALL IN MM

2005 1260.8

2006 821.6

2007 890.5

2008 1135.9

2009 849.4

2010 998.2

2011 969.1

2012 639.7

821.6890.5

1135.9

849.4

998.2 969.1

2007 2008 2009 2010 2011 2012

RAIN FALL



HARVESTING

and Multistoried Buildings as

639.7

2012



SL.NO DESCRIPTION

01 Roof top area

02

Total Quantity

available for

recharge per

Annum

03

Per Capita

Demand per

Annum

The computation was carried out in Multistoried Buildings as follows:

1. Average Roof Top Area for In

2. Average Rainfall of Pudukkottai Dist: 923mm

3. Effective Annual Rainfall contributing to Recharge :70%

4. Considering Losses:30%

5. Total rainfall collected in the year = 0.923 x 500 = 461.5cum/year

6. Quantity available for recharge per Annu

7. Average family size:4Nos

8. Zone: Residential Zone

9. Per capita stipulated for domestic use :135lpcd

10. Per capita availability of rainwater:323.05/4 = 80.76

Figure shows the Quantity

0

100

200

300

100200

64.6

Qty of Water for Recharge

323.05

80.760

200

400

600

800

1000

1200

1400

500 1000



144

INDIVIDUAL HOUSES MULTISTORIED BUILDINGS

100 sq.m 200 sq.m 500 Sq.m 1000Sq.m

64.6 cu.m 129.2

cu.m 323.05 646.1

16.15 cu.m 32.30

cu.m 80.76 161.525

The computation was carried out in Multistoried Buildings as follows:

Average Roof Top Area for Individual Buildings:500Sqm

Average Rainfall of Pudukkottai Dist: 923mm

Effective Annual Rainfall contributing to Recharge :70%

Total rainfall collected in the year = 0.923 x 500 = 461.5cum/year

Quantity available for recharge per Annum : 461.5 x 0.7 = 323.05cum/yr

Average family size:4Nos

Per capita stipulated for domestic use :135lpcd

lity of rainwater:323.05/4 = 80.76cum/yr

Figure shows the Quantity of Harvested Water for Recharging Ground

200300

400

129.2 193.8258.4

Qty of Water for Recharge

Qty of Water for

Recharge

646.1

969.15

1292.2

161.52242.28

323.04

1000 1500 2000

Ground Water

Recharge Qty

Per Capita Availability



MULTISTORIED BUILDINGS

1000Sq.m

646.1

161.525

m : 461.5 x 0.7 = 323.05cum/yr

d water

Qty of Water for

Per Capita Availability



Benefits Of Artificial Recharge In Urban Areas

• Improvement in infiltration and reduction in run

• Improvement in groundwater levels and yields.

• Reduces strain on Special Village Panchayats/ Municipal / Municipal

Corporation water supply

• Improvement in groundwater quality

• Estimated quantity of additional recharge from 100 sq. m. and 500sq.m

roof top area is64.600 and 323.050 litres.

ROOF TOP AREA(Sq.m) VS ANNUAL RAINFALL(mm)

0

50

100

150

2005 2006 2007

132.38

86.27

Roof Top Area/ Annual Year (i)

Roof Top

Area/

Annual

Year

2005

(1260.8)

2006

(821.6)

2007

(8

50 44.13 28.76 31.17

100

88.26 57.51 62.34

150

132.38 86.27 93.50

200

176.51 115.02 124.67

250

220.64 143.78 155.84

300

264.77 172.54 187.01

350 308.90 201.29 218.17

400

353.02 230.05 249.34

450 397.15 258.80 280.51

500

441.28 287.56 311.68

1000

882.56 575.12 623.35



145

Benefits Of Artificial Recharge In Urban Areas

Improvement in infiltration and reduction in run-off.

Improvement in groundwater levels and yields.

Reduces strain on Special Village Panchayats/ Municipal / Municipal

Corporation water supply

Improvement in groundwater quality

Estimated quantity of additional recharge from 100 sq. m. and 500sq.m

roof top area is64.600 and 323.050 litres.

ROOF TOP AREA(Sq.m) VS ANNUAL RAINFALL(mm)

2007 2008 2009 2010 2011 2012

86.27 93.5

119.27

89.19104.81101.75

67.16

Roof Top Area/ Annual Year (i)

50

100

150

2007

(890.5)

2008

(1135.9)

2009

(849.4)

2010

(998.2

)

2011

(969.02)

2012

(639.65)

31.17 39.76 29.73 34.94 33.92 22.39

62.34 79.51 59.46 69.87 67.83 44.78

93.50 119.27 89.19 104.81 101.75 67.16

124.67 159.03 118.92 139.75 135.66 89.55

155.84 198.78 148.65 174.69 169.58 111.94

187.01 238.54 178.37 209.62 203.49 134.33

218.17 278.30 208.10 244.56 237.41 156.71

249.34 318.05 237.83 279.50 271.33 179.10

280.51 357.81 267.56 314.43 305.24 201.49

311.68 397.57 297.29 349.37 339.16 223.88

623.35 795.13 594.58 698.74 678.31 447.76



2012

(639.65)

22.39

44.78

67.16

89.55

111.94

134.33

156.71

179.10

201.49

223.88

447.76



Cost Analysis

Typical investment cost for rooftop harvesting systems are in range of Rs.4000/

Rs.8000/- A completely new structure exclusively for rainwater harvesting would have a cost

involvement as follows:

0

100

200

300

2005 2006 2007

Roof Top Area/ Annual Year (ii)

32.30564.61

96.915129.22

161.525193.83

10

100

200

300

400

500

600

700

50

10

0

15

0

20

0

25

0

30

0

35

0

Avg. Rainfall



146

Typical investment cost for rooftop harvesting systems are in range of Rs.4000/

A completely new structure exclusively for rainwater harvesting would have a cost

2007 2008 2009 2010 2011 2012

Roof Top Area/ Annual Year (ii)

150

250

300

193.83226.135

258.44290.754

323.05

646.1

40

0

45

0

50

0

10

00

Avg. Rainfall

Series 1

For Avg. Rainfall of

923mm

50

100

150

200

250

300

350

400

450

500

1000



Typical investment cost for rooftop harvesting systems are in range of Rs.4000/- to

A completely new structure exclusively for rainwater harvesting would have a cost

Avg. Rainfall of

923mm

32.305

64.61

96.915

129.22

161.525

193.83

226.135

258.44

290.745

323.05

646.1



147

Abstract Estimate

S.NO QTY DESCRI PTION OF WORK RATE UNIT AMOUNT

01 12.60

Earth work excavation for foundation

in all soils including initial lead and lift

etc., and refilling the sides of

foundation in the excavated earth etc.,

complete.

200.00 M3

2520.00

02 0.62 Filling the foundation and basement in

the clean river sand watering and

ramming to consolidation etc.,

complete.

1000 M3

700.00

03 0.62 Cement concrete 1:5:10, using 40mm

ISS HBG metal for foundation and

flooring concrete etc.,

1800 M3

1200.00

04 5.78 Brick work in cement mortar 1:5, using

chamber bricks size is standard etc.,

including materials and labour charges

etc., complete.

3700 M3

21300.00

05 23.00 Plastering in cm 1:5, 12mm thick etc.,

including materials and labour charges

etc., complete.

150 M2

3450.00

06 Sand layer L.S 1000.00

07 Pebbles & charcoal L.S 4000.00

08 Water supply arrangements L.S 1000.00

09 Contingencies & other unforeseen

items.

L.S 530.00

TOTAL 37000.00

CONCLUSION

From the Project we can conclude that

• Rainwater Harvesting plays a vital role in urbanisation to prevail over the demand of

water.

• Ground water recharge is the major result of Rainwater harvesting

• In the Dist of Pudukkottai which was not having any perennial resource of river, the

storage of rainwater is the only backbone for agriculture and production.

• The sample of study shows that , For 100Sq.m we can recharge ground water with

64.6cu.m of rainfall per year

• Without having any demand, up to 100days we can utilise the harvested rainwater for

our own use.

• The cost of instalment is also worthable to implement such valuable system.

• With the rain harvesting and optimum usage of water, we can able to rebuild our

environment as green city.



148

REFERENCES

1. Kawsal Kishore (2004) “ Rain Water Harvesting “. Journal of Civil Engineering &

Construction Review ,may 2004,P42-P48.

2. Hand book for planning water shed management works” Govt of India, Ministry of

Water Resource CWC, December 2008.

3. WRO _ Pudukkottai.

4. Kumar, M. Dinesh. 2003. Paper: “Roof Water Harvesting for Domestic Water

Security”: Who gains and who loses?

5. Michael Nicklas, “Rainwater, High Performance Buildings”, Summer 2008.

6. “Gawai A.A. and Aswar D.S (2006) “Towards Self Reliance for Water Needs through

Rain Water Harvesting”.

7. “Rain Water Harvesting Technology “ Dr.K.A.Patil & G.K.Patil National Seminar on

8. Rain Water harvesting & Management 11-12, November 2006.

9. IS 10500:1991 :Drinking Water Standards”

10. Rain water Harvesting & Ground Water Recharge “Madharao Bhajirao Deshmukh”.

11. Nadia Khelif, Imed Ben Slimène and M.Moncef Chalbaoui, “Intrinsic Vulnerability

Analysis to Nitrate Contamination: Implications From Recharge in Fate and Transport in

Shallow Groundwater (Case of Moulares-Redayef Mining Basin)”, International Journal

of Civil Engineering & Technology (IJCIET), Volume 3, Issue 2, 2012, pp. 465 - 476,

ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.

12. Neeraj D. Sharma and Dr. J. N. Patel, “Experimental Study of Groundwater Quality

Improvement by Recharging With Rainwater”, International Journal of Civil

Engineering & Technology (IJCIET), Volume 2, Issue 1, 2011, pp. 10 - 16,

ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.