Rainwater Harvesting

A

PROJECT REPORT

“PLANNING FOR RAIN WATER HARVESTING:

INDUSTRIAL AREA”

SUBMITTED TO

S.T.B.S. COLLEGE OF DIPLOMA ENGINEERING

IN F U L F I L L M E N T FOR THE AWARD OF THE DEGREEOF

DIPLOMA OF ENGINEERING

IN

CIVIL

Submitted by

ENROLL. NO. NAME ENROLL. NO. NAME

096470306001 MANDANI JAYESH K. 096470306032 SAVALIYA ABHISHEK V.096470306012 VEKARIYA SANDIP R 096470306034 SHELADIYA PRATIK A.096470306013 PATEL VIVEK B. 096470306041 KATHIRIYA HARSHAD R096470306018 BUTANI PAYAL B. 096470306044 DESAI HIRAK H.096470306020 SUTARIYA ANKITA J. 096470306048 PATEL KAUSHAL A.096470306025 RAMOLIYA SHAILESH V. 086470306013 BHINGRADIYA MILAN J.096470306026 PATEL DIPEN J. 086470306021 CHAUHAN DARPIT K.096470306028 KAKADIYA GAURANG A. 086470306110 SUTARIYA PIYUSH H.

GUIDEMRS. HEMAXI G. KHALASI

S.T.B.S. COLLEGE OF DIPLOMA ENGINEERING, SURAT

Gujarat Technological University, AhmedabadJune, 2012

i

S.T.B.S. COLLEGE OF DIPLOMA ENGINEERING, SURAT

Civil Engineering Department

2012

CERTIFICATE

Date:

This is to certify that Mr. /Ms. _____________________________________ having

Enrolment No: _________________ has completed Part-II IDP Project work having title

“PLANNING FOR RAINWATER HARVESTING: INDUSTRIAL AREA.

She/he has undergone the process of Shodh Yatra, Literature Survey and Problem

definition under the IDP Part-II during Semester-VI. She/he has also completed the IDP

Part-II work successfully during Semester-VI for the final fulfillment of the Diploma

Engineering.

Guide Head of the Department(Hemaxi.G.Khalasi) (Mr. M. P. Jariwala)

External Examiner

ii

ACKNOWLEDGEMENT

I consider it a privilege to be associated with the S.T.B.S. College of Diploma

Engineering, Surat in this academic endeavor. I express my heartfelt thanks to my Guide

Mrs. Hemaxi G. Khalasi, Lecturer in Civil Engineering Department; for his invaluable

guidance, continued interest throughout the project work and encouragement towards the

successful completion of this preliminary study.

I would also like to thank Mr. M.P.Jariwala, Lecturer and Head, Civil Engineering

Department, for providing valuable ideas and suggestions in my work. I am very much

Thankful to Prof. Y. S. Choupare, Principal of S.T.B.S. College of Diploma Engineering,

Surat for providing all the necessary facilities during my course.

I want to express my gratitude towards Mr. Chirag Wakawala, Engineer in Surat

Municipal Corporation and Surat Municipal Corporation (Hydraulic department) for

providing me necessary data required in my project work with valuable suggestions.

I am also very much Thankful to all the faculty members for their valuable

suggestions and comments during my dissertation work. I would like to express my

appreciation towards all those who gave me the possibility to complete this work. I would

also like to thank my friends and classmates for generous encouragement in my life.

Last but not least, I would thank to my almighty GOD for giving his blessing which

were always encouraging me during my tough time.

Place: STBS collage, Surat

MANDANI JAYESH K. SAVALIYA ABHISHEK V.VEKARIYA SANDIP R SHELADIYA PRATIK A.PATEL VIVEK B. KATHIRIYA HARSHAD RBUTANI PAYAL B. DESAI HIRAK H.SUTARIYA ANKITA J. PATEL KAUSHAL A.RAMOLIYA SHAILESH V. BHINGRADIYA MILAN J.PATEL DIPEN J. CHAUHAN DARPIT K.KAKADIYA GAURANG A. SUTARIYA PIYUSH H.

iii

ABSTRACTRainwater harvesting (RWH) has thus regained its importance as a valuable

alternative or supplementary water resource, along with more conventional water supply

technologies. The process of rainwater harvesting would encompass catching rainwater,

directing it to an appropriate location, filtering it if required and storing it for use. Storage

could be in tanks, sumps, ponds or lakes wherever appropriate and conditions permitting

recharge of ground water would also qualify as storage. A proper definition for this term to

understand its spirit would, in effect, necessarily have to take into consideration the

difference in catchments. While previously catchments were typically far off from the urban

area they served, now the city itself is seen as a catchment for its water requirement.

Rooftops, paved areas and unpaved areas and the entire city itself are, therefore, to be

managed as a water provision area. Four types of catchment areas have been considered

namely; roof, rainwater platforms, watershed management and hill slopes.

Main source of water for Surat is the river Tapi flowing through the city. Surface

water is drawn by intake wells from perennial channel of the river throughout the year. Water

thus drawn is treated by the water treatment plants and then the same is supplied to the

citizens and industries after post‐chlorination.Industrial demand is concentrated in specific

locations, heavy withdrawals are done from available water resources. Industries require

water for processing, cooling, boiler feed and other miscellaneous uses such as washing,

maintenance of yards and domestic requirement in townships.

Surat Municipal Corporation has also been making efforts to promote Rain Water

Harvesting at household level and have devised a scheme to encourage the implementer by

offering a certain percentage of subsidies. Further, as a part of city water management

projects, 91 recharge wells across the city have been implemented through an NGO. The

impact of these Rain Water Harvesting measures adopted by Surat Municipal Corporation

especially with reference to recharge well program unfortunately couldn’t be ascertained in

absence of supporting date records.

Surat Municipal Corporation has not taken any plan regarding industrial area.

According to Suart land use pattern industrial area is second one having 17.7%. So by taking

this deficiency in mind in our project we are trying to meet the deficiency.

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TABLE OF CONTENTS

Certificate i

Acknowledgment ii

Abstract iii

Table of Contents iv

List of Figures viii

List of Tables x

List of Charts xi

Abbreviations xii

References R

1.0 INTRODUCTION

1.1 General 1

1.2 Research Definition and Objectives 2

1.3 Need for rain water harvesting 2

1.4 Identifying Problem 3

1.5 Expected Outcome 4

1.6 Research Methodology 6

2.0 LITERATURE REVIEW

2.1 General 7

2.2 Historical development of rainwater harvesting 9

2.3 From where we can harvest rainwater 10

2.3.1 Rooftops 10

2.3.2 Paved and unpaved areas 11

2.3.3 Water bodies 11

2.3.4 Storm water drains 11

v

2.4 Rainwater harvesting in the developed world 11

2.5 Rainwater harvesting around the world- case studies 13

2.5.1 Bangalore 13

2.5.2 Indore, Madhya Pradesh, Central India 14

2.5.3 Aizawl (North-East India) 16

2.5.4 South East Asia, Japan 17

2.5.5 Brazil 19

3.0 RAINWATER HARVESTING SYSTEM

3.1 General 20

3.2 Scale of operations 21

3.3 Elements of RWH System 21

3.3.1 Catchment Surface 23

3.3.2 Gutters and Downspouts/Conduits 24

3.3.3 Leaf Screens/Roof Washers 26

3.3.4 Storage Tanks/Cisterns 27

3.3.5 Conveying 30

3.4 Types and configurations of RWH systems 32

3.4.1 Indirectly pumped systems 33

3.4.2 Directly pumped systems 34

3.4.3 Gravity fed systems 35

4.0 STUDY AREA PROFILE

4.1 General 37

4.2 City profile 38

4.2.1 Locational importance 38

4.2.2 Evolution of Present Form 39

4.3 Demographic Features 40

4.4 Land use Pattern 41

4.5 Urban Economy and Industrial Growth 44

4.5.1 Textile Industries 44

4.5.2 Diamond Cutting and Polishing 45

vi

4.5.3 Major Industrial Estates 47

4.6 Sources of Water Supply 48

4.6.1 Surface Water Sources 48

4.6.2 Ground Water Sources 50

4.7 South Zone: Study Area 51

5.0 DATA COLLECTION AND ANALYSIS

5.1 General 52

5.2 Survey Method 52

5.2.1 Inventory Study 52

5.2.2 Field Survey 52

5.3 Study Parameters 53

5.3.1 Source of Water 53

5.3.2 Bore well 53

5.3.3 Storage Tank 53

5.3.4 Type of Roof & Roof Area 53

5.3.5 Types of Production 54

5.4 Questionnaires Design 54

5.4.1 Source of Water 54

5.4.2 Roof Type 55

5.4.3 Present Gain Water from SMC 55

5.4.4 Storage Tank 56

5.4.5 Present Capacity of Tank 57

5.4.6 Roof Area 57

5.4.7 Future Water Demand 58

6.0 RWH SYSTEM DESIGN

6.1 General 60

6.2 Main RWH Component 60

6.2.1 Catchment Area 60

6.2.2 Conveyance System 60

6.2.3 Storage Device 60

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6.2.4 Distribution System 61

6.3 The Catchment Area 61

6.4 The Conveyance System 63

6.4.1 Gutter 63

6.4.2 First Flush Device 64

6.4.3 Screens 66

6.4.4 Filter 67

6.5 The Storage Device 67

6.5.1 Sizing of The Storage Facility 68

6.5.2 Design of Tanks 70

6.5.3 Tank Inlet & Outlet Configuration 70

6.5.4 Tank Overflow Configuration 71

6.5.5 Artificial Recharge Well 72

7.0 CONCLUSION AND DESIGN SUMMARY

7.1 General 73

7.2 Design Summary 73

REFERENCES R

ANNEXURE A

viii

LIST OF FIGURES

Sr.

No.Description

Page

No.

2.1 Flowchart demonstrating fundamental Rainwater harvesting processes 08

2.2 Typical Rooftop rainwater Collection methods 10

2.3 Storm water drain pipe 11

2.4 Store rain water in pond 11

2.5 Elements of the Typical Water Harvesting System 15

2.6 Pile and Swales 16

2.7 Ferro cement and plastic tank 16

2.8 ‘Rajison’ a simple and unique rainwater utilization facility at thecommunity level in Tokyo, Japan.

18

2.9 Tanks made of pre-cast concrete plates & wire mesh concrete 19

3.1 Chart for elements of rain water harvesting system 21

3.2 Common RWH system elements 22

3.3 Elements of typical water harvesting system 23

3.4 Provision of mesh filters at the mouth of the drain pipe 26

3.5 First flush device installation 27

3.6 Different types of Storage tank 28

3.7 Daily basic need of water requirement 29

3.8 Gravity based filter 31

3.9 Sand filters 32

3.10 Schematic of an indirectly pumped RWH system. 34

3.11 Schematic of a directly pumped RWH system 35

3.12 Schematic of a gravity fed RWH system 36

ix

4.1 Geographical Location for Surat City 38

4.2 Land use Patten in SUDA (2004) 42

6.1 Roof Catchment Areas 61

6.2 Typical PVC guttering and downpipe 63

6.3 Simple first-flush diverter 64

6.4 First-flush diverter 65

6.5 First-Flush systems using float-ball mechanism 65

6.6 Screens to exclude entry of insects and other potential contaminants 66

6.7 Rapid Sand Filter Bed 67

6.8 Design configurations for (a) tank inflow and (b) outflow 71

6.9 Design configurations for tank overflows 72

6.10 Artificial Recharge Well 72

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LIST OF TABLE

Sr.

No.Description

Page

No.

1.1 Average rate of rainfall in mm per hour. 25

4.1 Area, population and growth Rate of Surat – 1951 to 2006 40

4.2 Land use Breakup 42

4.3 Estimated jobs in textile industry 45

4.4 Industrial Estates in Surat District 47

4.5 Average yield and installed capacity (2009) 49

4.6 Water Supply- Quantity (2009) 49

4.7 Water Supply- Indicators 49

5.1 Source of water 54

5.2 Type of roof 55

5.3 Present Water Demand 55

5.4 Type of Storage Tank 56

5.5 Capacity of Tank 57

5.6 Roof Area 58

5.7 Future Water Demand 58

6.1 Runoff Coefficients for various catchment types 62

6.2 Sizing gutters and down-pipes for RWH systems 64

xi

LIST OF CHARTS

Sr.

No.Description

Page

No.

4.1 Category Wise Land use Distribution in the SMC Zones (%) 43

4.2 Growth of the Diamond industry in Surat, 1950-2007 46

4.3 Daily average water supply in SMC 48

5.1 Source of Water 54

5.2 Type of roof 55

5.3 Present Water Demand 56

5.4 Type of Storage Tank 56

5.5 Capacity of Tank 57

5.6 Roof Area 58

5.7 Future Water Demand 59

xii

ABBRAVATIONS AND SYMBOLS

CGI- Corrugated Galvanized Iron

GDP – Gross Developed Product

GI - Galvanized Iron

GWT - Ground Water Table

IMC- Indore Municipal Corporation

Lpcd – Liter per Capita per Day

MLD - Million Liters per Day

NE India- North East India

NGO - Non Government Organization

NREGA - National Rural Employment Guarantee

PVC- Poly Vinyl Chloride

RCC- Reinforced Cement Concrete

RWH- Rainwater harvesting

SMC - Surat Municipal Corporation

sq.km – Square Kilometer

SSI - Small Scale Industries

STEM - Symbiosis of Technology, Environment and Management

SUDA – Surat Urban Development Authority

UK - United Kingdom

USA - United State of America

UV - Ultra Violet

WC – Water Closet

WHO – World Health Organization

Planning for Rain Water Harvesting: Industrial Area 1

CHAPTER: 1 INTRODUCTION

1.1. General

Millions of people throughout the world do not have access to clean water for

domestic purposes. In many parts of the world conventional piped water is either

absent, unreliable or too expensive. One of the biggest challenges of the 21st century

is to overcome the growing water shortage.

Rainwater harvesting (RWH) has thus regained its importance as a valuable

alternative or supplementary water resource, along with more conventional water

supply technologies. Much actual or potential water shortages can be relieved if

rainwater harvesting is practiced more widely.

People collect and store rainwater in buckets, tanks, ponds and wells. This is

commonly referred to as rainwater harvesting and has been practiced for centuries.

Rainwater can be used for multiple purposes ranging from irrigating crops to washing,

cooking and drinking.

Rainwater harvesting is a simple low-cost technique that requires minimum

specific expertise or knowledge and offers many benefits. Collected rainwater can

supplement other water sources when they become scarce or are of low quality like

brackish groundwater or polluted surface water in the rainy season. It also provides a

good alternative and replacement in times of drought or when the water table drops

and wells go dry. One should, however, realize that rainfall itself cannot be managed.

Particularly in arid or semi-arid areas, the prevailing climatic conditions make it of

crucial importance to use the limited amount of rainfall as efficiently as possible. The

collected rainwater is a valuable supplement that would otherwise be lost by surface

run-off or evaporation.

During the past decade, RWH has been actively reintroduced by local

organizations as an option for increasing access to water in currently underserved

areas (rural or urban). Unfortunately decision-makers, planners, engineers and

builders often overlook this action. The reason that RWH is rarely considered is often

simply due to lack of information on feasibility both technical and otherwise. During

the past decade the technology has, however, quickly regained popularity as users

realise the benefits of a relatively clean, reliable and affordable water source at home.


In many areas RWH has now been introduced as part of an integrated water

supply, where the town water supply is unreliable, or where local water sources dry

up for a part of the year. But RWH can also be introduced as the sole water source for

communities or households. The technology is flexible and adaptable to a very wide

variety of conditions. It is used in the richest and the poorest societies, as well as in

the wettest and the driest regions on our planet.

1.2. Research definition & Objectives

Water harvesting in its broadest sense can be defined as the collection of run-

off rainwater for domestic water supply, agriculture and environmental management.

Water harvesting systems, which harvest runoff from roofs or ground surfaces fall under

the term rainwater harvesting.

Following are the main objectives of the study.

To study the techniques of R.W.H. in developed & developing nation.

To conduct field survey in surat city , where R.W.H. techniques is introduced.

To study the bylaws of R.W.H.

To design proposals for the rise in Ground Water Table (GWT) and used rain

water in industrial area at Surat city.

1.3. Need for rainwater harvesting

Due to pollution of both groundwater and surface waters, and the overall

increased demand for water resources due to population growth, many communities

all over the world are approaching the limits of their traditional water resources.

Therefore they have to turn to alternative or ‘new’ resources like rainwater harvesting

(RWH). Rainwater harvesting has regained importance as a valuable alternative or

supplementary water resource. Utilization of rainwater is now an option along with

more ‘conventional’ water supply technologies, particularly in rural areas, but

increasingly in urban areas as well. RWH has proven to be of great value for arid and

semi-arid countries or regions, small coral and volcanic islands, and remote and

scattered human settlements.

Rainwater harvesting has been used for ages and examples can be found in all

the great civilizations throughout history. The technology can be very simple or

complex depending on the specific local circumstances. Traditionally, in Uganda and


in Sri Lanka rainwater is collected from trees, using banana leaves or stems as gutters;

up to 200 liters may be collected from a large tree in a single rain storm. With the

increasing availability of corrugated iron roofing in many developing countries,

people often place a small container under their eaves to collect rainwater. One 20-

litre container of clean water captured from the roof can save a walk of many

kilometers to the nearest clean water source. Besides small containers, larger sub-

surface and surface tanks are used for collecting larger amounts of rainwater.

1.4 Identifying Problem

To increase ground water level in and around Surat city, Surat Municipal

Corporation (SMC) has decided to dig bore wells to solve the water scarcity problem.

The civic body has fixed a target of digging 100 bore wells each year and the scheme

will continue for the next five years. A special grant of Rs5 crore has been allotted by

the state government for the purpose.

The initiative has been taken under the Swarnim Gujarat Celebrations, where

civic body will not only motivate people for rain water harvesting, but will also

follow it. It will dig bore wells in open plots, gardens and places suitable for it, so that

rain water can penetrate deep into ground. Each bore will cost Rs1 lakh to SMC.

"Ground water level in Surat is going down rapidly. According to an estimate,

every year the water level goes down by 5-6 meters, which is very alarming. Apart

from private bore wells, many industrial units also pump out water from ground rather

than seeking water connection from the SMC," a civic official requesting anonymity

said. State urban development department has already given Rs1 crore to the civic

body to accomplish the target of 100 bore wells.

Water is a basic need that every human on the earth needs in order to survive.

Sadly in many parts all over the world there is a lack in the availably of clean water.

The indigenous people here are put under great water strains on a daily basis. While

there are many local water problems, the need to protect our water is a global issue.

We as a species live on the same planet and how we treat our local area affects the

entire earth. Being responsible with water and its usages is part of being a global

citizen.

This semester the Rainwater Harvesting project main goal is to help educate

and raise awareness of rainwater harvesting in the Surat city area. While water is not


in direct need here in city, people still need to be responsible with the use of water.

The implications of continued over consumption and pollution of our water will have

serious consequences. Changes in the climate have already been seen because of

global warming and it will only be a matter of time until the availability of water

becomes a worldwide problem.

1.5 Expected Outcome

Surat Municipal Corporation considered being one of the most active and

resourceful corporation in the state has implemented a few projects related to water

management for checking sea water ingress. Also, almost entire city has been covered

with the network storm water drain lines, which finally drain into river Tapi.

Surat Municipal Corporation has also been making efforts to promote Rain

Water Harvesting at household level and have devised a scheme to encourage the

implementer by offering a certain percentage of subsidies. Further, as a part of city

water management projects, 91 recharge wells across the city have been implemented

through an NGO. The impact of these Rain Water Harvesting measures adopted by

Surat Municipal Corporation especially with reference to recharge well program

unfortunately couldn’t be ascertained in absence of supporting date records.

Panam consultants have devised a plan with the basic objectives of managing

the storm water runoff and recharging the same to underground tapping the potential

aquifers to help augment the depleting groundwater levels and also improve the water

quality in general.

As per the project agreement, Surat Municipal Corporation has desired to

utilize the part of the project grant gives by the Government of Gujarat under the

“Swarnim Gujarat” project scheme for the harvesting rain water in the city of Surat.

The proposed implementation plan has been formulated after taking into

account the following data.

Topography of the data

Depth to water and water level records

Water level elevation maps

Rain fall data of last five years

Water logging and flooding of the areas


Site surveys

Geology and hydrology of area

Lithology sections of the area

For the management and recharge of the storm water runoff, the consultants are

recommending basically two types of water harvesting structure: (1) Screen type

recharges well and (2) Furaat type recharge differentiating the areas on the basis of

anticipated silt load, space availability and volume quantity of runoff water and water

logging condition. Screen type recharge wells have a comparatively higher intake

water capacity and can also effectively filter the silt and other impurities where as the

FURAAT STRUCTURES can be easily accommodated where the space is constraint

and also runoff water is expected to be generated mainly from the paved surface.

These water harvesting structures have been design with the modification in the

existing traditional water harvesting structures addressing mainly the issue of rate of

intake flow, filtration capacity, ease of operation and maintenance and cleaning,

lifespan, durability of the system and performance consistency.

Consultant also recommends roof top rain water harvesting for independent

houses, apartments and shopping malls and complex. Which, in a way will reduce the

overall load on the proposed schemes? Moreover, it will also make the resident/

owners self-reliant for their daily water needs and less dependent on the corporation

water supply. This in a way will not on the reduce the burden of the corporation will

also helping in reducing the energy bill.


1.6 Research Methodology

IdentifyingProblems

Literature Survey

Study objectives & Scope

Industrial Survey

Field SurveyInventory Study

Data Analysis

RWH Proposals

Conclusions &Recommendation



CHAPTER: 2 LITURATURE REVIEW

2.1. GENERAL

Rainwater harvesting (RWH) primarily consists of the collection, storage and

subsequent use of captured rainwater as either the principal or as a supplementary source

of water. Both potable and non-potable applications are possible. Examples exist of

systems that provide water for domestic, commercial, institutional and industrial purposes

as well as agriculture, livestock, groundwater recharge, flood control, process water and

as an emergency supply for fire fighting. The concept of RWH is both simple and ancient

and systems can vary from small and basic, such as the attachment of a water butt to a

rainwater downspout, to large and complex, such as those that collect water from many

hectares and serve large numbers of people. Before the latter half of the twentieth

century, RWH systems were used predominantly in areas lacking alternative forms of

water supply, such as coral islands and remote, arid locations lacking suitable surface or

ground water resources.

In developing countries the main use of harvested water is for potable supply

whilst in developed countries examples of all three uses exist, with potable supplies being

more common in rural locations and non-potable supplies in urban areas.

Perhaps one of the most interesting aspects of rainwater harvesting is learning

about the methods of capture, storage, and use of this natural resource at the place it

occurs. This natural synergy excludes at least a portion of water use from the water

distribution infrastructure: the centralized treatment facility, storage structures, pumps,

mains, and laterals. Rainwater harvesting also includes land based systems with man-

made landscape features to channel and concentrate rainwater in either storage basins or

planted areas.

Some commercial and industrial buildings augment rainwater with condensate

from air conditioning systems. During hot, humid months, warm, moisture-laden air

passing over the cooling coils of a residential air conditioner can produce 10 or more


gallons per day of water. Industrial facilities produce thousands of gallons per day of

condensate. An advantage of condensate capture is that its maximum production occurs

during the hottest month of the year, when irrigation need is greatest. Most systems pipe

condensate into the rainwater cistern for storage. The depletion of groundwater sources,

the poor quality of some groundwater, high tap fees for isolated properties, the flexibility

of rainwater harvesting systems, and modern methods of treatment provide excellent

reasons to harvest rainwater for domestic use.

Figure: 2.1 Flowchart demonstrating fundamental rainwater harvesting processes


2.2. HISTORICAL DEVELOPMENT OF RAINWATER HARVESTING

Rainwater harvesting and utilization systems have been used since ancient times

and evidence of roof catchment systems date back to early Roman times. Roman villas

and even whole cities were designed to take advantage of rainwater as the principal water

source for drinking and domestic purposes since at least 2000 B.C. In the Negev desert in

Israel, tanks for storing runoff from hillsides for both domestic and agricultural purposes

have allowed habitation and cultivation in areas with as little as 100mm of rain per year.

Around 850 B.C., King Mesha of Moab was victorious in war and conquered a

considerable territory east of the Jordan. This he proudly commemorated in the famous

“Moabite Stone” text. One detail in King Mesha’s self praise is: I made two reservoirs in

the midst of (qerkhah). Now there was no cistern in the city, so I said to all the people,

“Make you every man a cistern in the house”.

This may be the first time that cisterns were mentioned in a text, but the device

itself must have been invented considerably earlier. A progression has been suggested

“from the primitive use or natural rock holes to the digging of open cisterns and finally

the construction of roofed-over cisterns excavated in rock”.

According to an Archaeological Encyclopedia “The first cisterns were dug in the

middle and late bronze age (2200-1200 B.C, LW). The rainwater that collected in them

during the short rainy season would be enough for at least one dry season. In some parts

of Palestine cisterns were the main (sometimes even the only) source of drinking water in

peacetime as well as in wartime. In the early Iron Age (1200 – 1000 B.C.; LW) the sides

of cisterns began to be covered with watertight plaster, which considerably prolonged the

time for which water could be stored. It was this important innovation that made it

possible to extend the areas of settlement into the mountainous parts of the country.”

The rainwater was generally collected from the roof and courtyard of the house, in

cities as well as in the countryside. A private cistern was seen as a necessary element in

the planning of a new house in Tunis in the fourteenth century. A 1921 census in

Jerusalem counted 7,000 cisterns collecting runoff water. One informant stated that even

today in Amman it is legally required to include a cistern in any new house, but that some

people fill them with piped water instead of rainwater.


The earliest known evidence of the use of the technology in Africa comes from

northern Egypt, where tanks ranging from 200-2000m3 have been used for at least 2000

years – many are still operational today. The technology also has a long history in Asia,

where rainwater collection practices have been traced back almost 2000 years in

Thailand. The small-scale collection of rainwater from the eaves of roofs or via simple

gutters into traditional jars and pots has been practiced in Africa and Asia for thousands

of years.

In many remote rural areas, this is still the method used today. The world’s largest

rainwater tank is probably the Yerebatan Sarayi in Istanbul, Turkey. This was constructed

during the rule of Caesar Justinian (A.D. 527- 565). It measures 140m by 70m and has a

capacity of 80,000 cubic meters.

Around the globe there is a need to revive the traditional technologies blending

them with modern methods to achieve the requirement present and future need of water.

This is practiced on a large scale in many Indian cities like Chennai, Bangalore and Delhi

where rainwater harvesting is a part of the state policy. Elsewhere, countries like

Germany, Japan, United States, and Singapore are also adopting rainwater harvesting

with modern methods.

2.3. FROM WHERE WE CAN HARVEST RAINWATER

Rainwater can be harvested from the following surfaces:

2.3.1 ROOFTOPS

If buildings with impervious roofs are already in place, the catchment area is

effectively available free of charge and they provide a supply at the point of

consumption.

Figure: 2.2 Typical Rooftop rainwater Collection methods


2.3.2 PAVED AND UNPAVED AREAS

i.e., landscapes, open fields, parks,

storm water drains, roads and pavements and

other open areas can be effectively used to

harvest the runoff. The main advantage in

using ground as a collecting surface is that

water can be collected from a larger area.

This is particularly advantageous in areas of

low rainfall.

Figure: 2. 3 Storm water drain pipe

2.3.3 WATER BODIES

The potential of water bodies

such as lakes, tanks and ponds to

store rainwater is immense. The

harvested rainwater can be used not

only to meet water requirements of

the city; it also recharges ground

water aquifers.

Figure: 2.4 Store rain water in pond

2.3.4 STORM WATER DRAINS

Most of the residential colonies have proper network of storm water drains. If

maintained neatly, these offer a simple and cost effective means for harvesting rainwater.

2.4 RAINWATER HARVESTING IN THE DEVELOPED WORLD

In the developed world the use of RWH to supply potable water is mostly limited

to rural locations, mainly because piping supplies from centralized water treatment

facilities to areas with low population densities is often uneconomic. The development of

appropriate groundwater resources can likewise be impractical for cost reasons (Fewkes,

2006). Perrens (1982) estimates that in Australia approximately one million people rely


on rainwater as their primary source of supply. The total number of Australians in both

rural and urban regions that rely on rainwater stored in tanks is believed to be about three

million. In the USA it is thought that there are over 200,000 rainwater cisterns in

existence that provide supplies to small communities and individual households.

Harvesting rainwater for potable use also occurs in rural areas of Canada and Bermuda.

The number of RWH systems installed varies from country to country. For

instance, in Germany during the 1990s the market leader alone installed over 100,000

systems, providing a total storage volume in excess of 600,000m. It has been estimated

that between 50,000 and 100,000 professionally designed systems are currently installed

in Germany each year (Konig, 2001; Environment Agency, 2004) and the total number of

built systems is believed to be approximately 600,000 (Leggett et al, 2001b). By

comparison, France has few installed systems. Those that do exist are often simple,

inefficient and used mainly for garden irrigation, with the domestic utilisation of

rainwater for flushing toilets and washing machines being virtually non-existent. This

low uptake is attributed primarily to the organization of the French water supply system

which is essentially a set of regional monopolies that have no incentive to introduce

rainwater harvesting techniques since it would reduce their profits (Konig, 2001).

In urban locations, rainwater catchment surfaces tend to be restricted to roofs

although runoff can also be collected from other impermeable areas such as pavements,

roads and car parks. Runoff from these areas can be more polluted than that from roof

surfaces and may require a higher degree of treatment to achieve an acceptable level of

water quality. Water storage and distribution elements generally consist of standardized

pre-manufactured components that can range from a simple water butt with a tap at the

base to more complicated systems that can consist of underground storage tanks, filters,

UV units, pumps and automated controls. Where the latter type of arrangement is

concerned, the use of package (proprietary) systems dominates the UK market and it is

possible to purchase a complete system from a single supplier. One supplier stated that

the overwhelming majority of their domestic sales were of the proprietary type as were

most of those for commercial, institutional and industrial applications, though bespoke

systems could be designed if required.


Konig (2001) states that in the past components such as tanks, pumps and filters

were often supplied in kit form and had to be assembled on site, necessitating the use of

skilled staff and leading to increases in both installation times and costs. Modern systems

tend to be „modularized and consist of standardized mass-produced components, usually

of high quality. Components such as tanks, pumps and filters are delivered to site as

complete units (no assembly required), are easier to install and commission than the older

types of system and offer a greater degree of design flexibility. Some suppliers sell

storage tanks with integrated filters, pump and electronic controls in what is essentially a

complete system that only requires connecting to the relevant on-site pipe work and

power points.

2.5 RAINWATER HARVESTING AROUND THE WORLD- CASE STUDIES

The increasing demand for water has accelerated and reviving the old system of

rainwater storage with the pace of technology has been adopted. The concept of rainwater

harvesting has been accepted by many cities, government agencies, societies, individuals,

etc in different countries around the world. They have the set examples of RWH systems.

There are many success stories of RWH in developing and developed countries of Asia,

Africa, Latin America, USA, Japan, Germany, Singapore and others. These case studies

can further accelerate the adoption and future strategy for rainwater harvesting to reduce

the water crisis in the world for integrated water resource management.

2.5.1 Rainwater Harvesting in Bangalore

Bangalore, a city of over 270 lakes and tanks, is now down to 80 or thereabouts.

The city is located at 920 meters above sea level. The decline in ground water levels as

well as the effects of pollution with nitrates poses threat. The Bangalore Water Supply

and Sewerage Board manages water supply to the city. Two major sources are the River

Arkavathy and the River Cauvery. The latter is now the predominant source but is located

95 kilometers away and about 500 meters below the city necessitating huge pumping

costs and energy usage. As loss of water is high, there is a large section of the population

dependent on ground water through bore wells.


Nearly 3000 million liters per day of rainwater is incident on the city of Bangalore

with area of 1279 square kilometers. This is in contrast to approximately 1500 million

liters per day which will be pumped in after the completion of two augmentation projects

under implementation. The study points out that about 20 per cent of the city’s water

requirement can be met through rainwater harvesting provided a strategy is put in place to

persuade owners to go in for rooftop rainwater harvesting and also if surface storage

structures like lakes and ponds are maintained well. Recharge structures to augment

aquifers and their utilization in a sustainable manner would benefit the city immensely.

Integrating Rainwater Harvesting Systems into Neighborhood Design:

A residential colony in Bangalore of about 4 square kilometers has managed to

put in place a decentralized water management system incorporating rainwater harvesting

more by serendipity than by design. Two small tanks, Narasipura 1 and Narasipura 2,

collect rainwater and act as percolation tanks to recharge the aquifer. About 15 bore-wells

then supply water to the colony of about 2000 houses. Sewage discharged from each

house is collected and treated both physically and biologically through an artificial

wetland system and led into Narasipura 2. The loop of water supply and sewage

treatment is completed within a small geographical area, in an ecologically and

economically appropriate manner.

Source: A conceptual Frame for RWH in Bangalore (2000): A study undertaken by

Centre for Symbiosis of Technology, Environment and Management (STEM)

commissioned by GOK.

2.5.2 Rainwater Harvesting Initiatives in Indore, Madhya Pradesh, Central India

The commercial capital of the state of Madhya Pradesh has been facing acute

shortage of drinking water. This is reflected in the wide gap in the demand and supply of

152 MLD drinking water in the city. The ever-growing water demand made the

administration think about rainwater harvesting.

Indore, one of the cities in Madhya Pradesh, is located on the basaltic lava flows

of the Deccan Trap. Weathered/vesicular/fractured and jointed basalt form aquifers in the

area. The average annual rainfall in this area is 930 mm and one-hour peak rainfall is 35


mm. Indore has got large areas of roofs and paved areas and hence a large quantum of

runoff is produced from these areas during the rainy season. This runoff goes waste as

overland flow and also creates problems of flooding in low-lying streets. In such a

scenario, rooftop water harvesting provides the desired solution. Essentially aquifer

recharging practices are being used. In order to motivate the public, Indore Municipal

Corporation (IMC) has announced a rebate of 6 per cent on property tax for those who

have implemented the rainwater harvesting work in their house/bungalow/building. To

operate these activities three committees – technical, education and execution – were

formed by the IMC in which various experts of this field were involved. The various

methods of ground water recharge used are open wells, soak pit, recharge shaft/trench

with and without injection well, lateral recharge shaft, injection wells and in big schemes

suitable combination of different methods of RWH are employed.

Techniques of water recharge used in Indore:

The technique essentially comprises diverting rainwater through trench or swale

into silt trap tank. Water from the silt trap tank is allowed to pass through a sand filter

(sand, medium and big size pebbles). A cement pipe of 300 mm diameter, fitted with wire

net (10 mm mesh) has been fitted on the wall of wells through which rainwater flows into

the well.

Figure: 2.5 Elements of the Typical Water Harvesting System

Permeable box:

Permeable boxes of 1 cubic meter, filled with big size pebbles and brick pieces

and lower portion with sand are provided at the top of the pile. Source: Proceedings of


the workshop on Rainwater Harvesting, Indore. Pile and Swales: Pile is a commonly used

technique for RWH in gardens,

playgrounds and public places. A two-

three m. deep hole is manually dug.

The bottom one-third is filled with

large (40-50 mm) pebbles, the middle

portion with medium size (20 to 30

mm) pebbles and the upper one-third

portion with sand (two-three

mm).Swales are shallow, saucer like

beds locally known as khantis. Figure: 2.6 Pile and Swales

2.5.3 Rainwater Harvesting in Aizawl (North-East India)

The water supply system in the capital of Mizoram, originally designed in 1988

for 80,000 people, is now catering to the needs of over 150,000 residents, making it

grossly inadequate. Due to inadequate and unreliable water supply people are resorting to

rooftop water harvesting, the most convenient and economical water supply system.

Mizoram receives an average rainfall

of 2,500 mm annually which is

distributed throughout the year. The

major advantage is that most of the

buildings are constructed with sloping

roofs that use Corrugated Galvanized

Iron (CGI) sheets which are conducive

to rainwater harvesting. Even today,

most buildings in Aizawl are

constructed with sloping roofs that use

Corrugated Galvanized Iron sheets. Figure: 2.7 Ferro cement and plastic tank

Rain gutters either of PVC pipes or bamboo are used to drain water into the cylindrical

storage tanks with galvanized iron semi- circular rain gutters to catch rainwater.


Gradually, reinforced cement concrete (RCC), Ferro cement and plastic tanks are being

introduced. Tanks of 10,000 liters capacity are commonly used.

At present, Aizawl has more than 10,000 rainwater harvesting tanks in individual

houses which have been constructed by the residents at their own expense or with state

government assistance. In a pollution-free state like Mizoram where major industries are

yet to come, rainwater is free from undesirable chemicals and is of potable quality.

2.5.4 Rainwater Harvesting in South East Asia, Japan

In 1994, the Tokyo International Rainwater Utilizations Conference was hosted in

Japan (Murase 1994) regarding the role, applications, and potential for rainwater

catchment system technologies worldwide. From 1994 onwards, there was a growing

recognition that rainwater collection could play a vital role in addressing many of the

water problems faced by the rapidly growing mega cities around the world, especially in

Asia. Tokyo provided an interesting case study as the city faced several water related

problems.

Existing dams supplying the city were stretched to capacity and new dam and

pipeline developments faced increasing opposition from environmentalists and

other affected groups;

Subsidence due to ground water over-exploitation had left over 2 million people

in some parts of the city living below sea level and seriously at risk from the

impacts of a tsunami;

There was also a growing concern about the possible impact of flooding within

the city and the risks associated with the worst case scenario of an earthquake

and typhoon striking simultaneously and flood waters entering the subway

system during the rush hour.

Such fears have generated considerable interest in all methods for disaster

mitigation and they are not unfounded. In 1923 the Great Kanto Earthquake killed over

120,000 people in the city and most of those who perished were victims of the firestorms

which raged through the city. In Tokyo and elsewhere in Japan there has, thus, been

much interest in the use of household water storage systems to provide water for


firefighting purposes especially following an earthquake when pipe supplies might not be

available.

Such household reservoirs could also provide emergency domestic water supplies

in the period immediately following any major seismic event. A number of interesting

demonstration projects has also been developed to illustrate this potential. At the main

sumo wrestling stadium, the Kokugikan, the rainwater runoff from the 8400 m 2 roofs is

diverted into a 1000 m3 basement tank for toilet flushing and cooling the building.

Following the example of Kokugikan, many new public facilities have started introducing

rainwater utilization systems in Tokyo.

At the community level, a simple and unique rainwater utilization facility,

“Rajison”, has been set up by local residents in the Mukojima district of Tokyo to utilize

rainwater collected from the roofs of private houses for garden watering, fire-fighting and

drinking water in emergencies. To date, about 750 private and public buildings in Tokyo

have introduced rainwater collection and utilization systems. Rainwater utilization is now

flourishing at both the public and private levels.

Figure: 2.8 ‘Rajison’ a simple and unique rainwater utilization facility at the

community level in Tokyo, Japan.


2.5.5 Rainwater Harvesting in Brazil

In Brazil, over the past decade, many NGOs and grassroots organizations have

focused their work on the supply of drinking water using rainwater harvesting, and the

irrigation of small-scale agriculture using sub-surface impoundments. In the semi-arid

tropics of the north-eastern part of Brazil, annual rainfall varies widely from 200 to 1,000

mm, with an uneven regional and seasonal rainfall pattern. People have traditionally

utilized rainwater collected in hand-dug rock catchments and river bedrock catchments.

To address the problem of unreliable rural drinking water supply in north-eastern Brazil,

a group of NGOs combined their efforts with government to initiate a project involving

the construction of one million rainwater tanks over a five year period, benefitting to 5

million people. Most of these tanks are made of pre-cast concrete plates or wire mesh

concrete.

Rainwater harvesting and utilization is now an integrated part of educational

programs for sustainable living in the semi-arid regions of Brazil. The rainwater

utilization concept is also spreading to other parts of Brazil, especially urban areas. A

further example of the growing interest in rainwater harvesting and utilization is the

establishment of the Brazilian Rainwater Catchment Systems Association, which was

founded in 1999 and held its 3rd Brazilian Rainwater Utilization Symposium in the fall of

2001.

Figure: 2.9 Tanks made of pre-cast concrete plates & wire mesh concrete


CHAPTER: 3 RAINWATER HARVESTING SYSTEMS

3.1 GENERAL

All sources of water are ultimately rain. Therefore, all water supply systems are,

in effect, rainwater-harvesting systems. A proper definition for this term to understand its

spirit would, in effect, necessarily have to take into consideration the difference in

catchments. While previously catchments were typically far off from the urban area they

served, now the city itself is seen as a catchment for its water requirement. Rooftops,

paved areas and unpaved areas and the entire city itself are, therefore, to be managed as a

water provision area. As the Centre for Science and Environment, Delhi (India) puts it

‘CATCH WATER WHERE IT FALLS’ would be a good definition of rainwater

harvesting.

The process of rainwater harvesting would encompass catching rainwater,

directing it to an appropriate location, filtering it if required and storing it for use. Storage

could be in tanks, sumps, ponds or lakes wherever appropriate and conditions permitting

recharge of ground water would also qualify as storage. Harvested water could be used

immediately as a first choice thus saving city level supplies or ground water for a future

date or a decision could be taken to store it for later use, say during water shortage days.

Domestic rainwater harvesting or rooftop rainwater harvesting is the technique through

which rainwater is captured from roof catchments and stored in tanks/reservoirs/ground

water aquifers. It also consists of conservation of roof top rainwater in urban areas and

utilizing it to augment ground water storage by artificial recharge. It requires connecting

the outlet pipe from rooftop to divert collected water to existing well/tube well/bore well

or a specially designed well. Rooftop harvested rainwater is more safe for drinking

purposes than the runoff harvested water.

Rooftop harvesting needs to have safe storage facilities to keep the water fit for

drinking. First flush of rainwater is discarded. A number of alternative technologies are

available for rooftop harvesting and storage to suit the varying situations and the budgets.


3.2 SCALE OF OPERATIONS

From a small rooftop to large areas such as that of institutions and industries,

rainwater harvesting can work well. Neighborhoods and finally the city itself should be

the ultimate scale of operation. Singapore for example plans to manage and harvest

almost all rainwater at the city-level. One primary step would be to keep the catchments

clean and this would mean managing all solid, liquid and gaseous waste streams of the

city. There are many methods for rainwater harvesting. Each method is site specific. The

flow from roofs of houses may also be collected using galvanized iron sheets, into a

channel fitted on the edge of the roof. This water can be stored adjacent to the house after

screening out the impurities.

3.3 Elements of RWH System

Figure: 3.1 Chart for elements of rain water harvesting system


Figure: 3.2 Common RWH system elements

All rainwater-harvesting systems comprise six basic elements irrespective of

the size of the system.

1. Catchment area/roof: The surface upon which the rain falls; the roof has to be

appropriately sloped preferably towards the direction of storage and recharge.

2. Gutters and downspouts: The transport channels from catchment surface to storage;

these have to be designed depending on site, rainfall characteristics and roof

characteristics.

3. Leaf screens and roof washers: The systems that remove contaminants and debris; a

first rain separator has to be put in place to divert and manage the first 2.5 mm of rain.


4. Cisterns or storage tanks: Sumps, tanks etc. where collected rain-water is safely

stored or recharging the ground water through open wells, bore wells or percolation pits

etc.

5. Conveying: The delivery system for the treated rainwater, either by gravity or pump.

6. Water treatment: Filters to remove solids and organic material and equipment, and

additives to settle, filter, and disinfect.

Figure: 3.3 Elements of typical water harvesting system

Briefly the system involves collecting water that falls on the roof of a house made

of zinc, asbestos or other material during rain storms, and conveying it by an aluminum,

PVC, wood, plastic or any other local material including bamboo drain or collector to a

nearby covered storage unit or cistern. Rainwater yield varies with the size and texture of

the catchment area. A smoother, cleaner and more impervious roofing material

contributes to better water quality and greater quantity. Each component is briefly

described below.

3.3.1 Catchment Surface

The catchment area of a water harvesting system is the surface, which receives

rainfall directly and contributes the 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.


Temporary structures like sloping sheds can also act as catchments. In Botswana, house

compounds and threshing floors are surfaced with clay cow dung plaster and used

effectively as rainwater catchments. Rainwater harvested from catchment surfaces along

the ground, because of the increased risk of contamination, should only be used for non-

potable uses such as lawn watering. For in house uses, rooftop harvested rainwater is

safer for drinking purposes than the runoff harvested water.

Catchment Area: Some Features

The nature of the catchment distinguishes rainwater collection from other kind

of harvesting.

Four types of catchment areas have been considered namely; roof, rainwater

platforms, watershed management and hill slopes.

Catchments used to collect rainwater are frequently artificial or else ground

surfaces, which have been specifically prepared and demarcated.

Rainwater may be collected from any kind of roof – tiles, metal, palm leaf, grass

thatch.

Lead flashing roof or roof painted with lead-based paint or asbestos roof is

generally regarded as unsuitable.

A well-thatched roof has been said not to be presenting much hazard to the

collected water. These have been covered with plastic sheets in some areas in

Manipur (NE India).

Catchment area consisting of rooftop area / the plot area or the complex area from

where the rainwater runoff is proposed to be collected has to be maintained so as to

ensure that the resultant rainwater runoff is not contaminated. At times paints, grease, oil

etc. are often left on the roof or in the courtyards. These can result in contamination of

the rainwater runoff. Therefore, the households have to ensure that they keep the

catchment area clean at all times especially during the rainfall season.

3.3.2 Gutters and Downspouts/Conduits

Most of the existing storm water conveyance systems are designed to drain out

the rainwater that falls in the catchment area into the nearest storm water drain or the

sewerage system.


Table: 3.1 Average rate of rainfall in mm per hour. Roof area (Sq.m.)

Sr.No.

Diameter ofpipe (mm)

Average rate of rainfall in mm/h50 75 100 125 150 200

1. 50 13.4 8.9 6.6 5.3 4.4 3.32. 65 24.1 16.0 12.0 9.6 8.0 6.03. 75 40.8 27.0 20.4 16.3 13.6 10.24. 100 85.4 57.0 42.7 34.2 28.5 21.35. 125 - - 80.5 65.3 53.5 40.06. 150 - - - - 83.6 62.7

Source: Indian National Building Code mm/h- millimeters per hour, m- meters

These connections should be redirected to the recharge location so that the

rainwater runoff can now be directed into the recharge structure. In already built up

structure it requires certain modifications to the existing drainage system but in ongoing

construction it can be easily re-designed at almost no extra cost. The choice of the

material and the design are as per the discretion of the individual owners and, like any

other drainage system, can be constructed utilizing a variety of materials.

Conduits are the pipelines or drains that carry rainwater from the catchment or

rooftop to the harvesting system. Conduits may be of any material like Poly Vinyl

Chloride (PVC), asbestos or Galvanized Iron (GI), materials that are commonly available.

The diameter of pipe required for draining out rainwater based on rainfall intensity

(average rate of rainfall in mm per hour) and roof surface area as shown in Table 3.1.

Channels have to be 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:

Locally available material such as plain galvanized iron sheet (20 to 22 gauge),

folded to the required shapes.

Semi-circular gutters of PVC material which can be readily prepared by cutting

the pipes into two equal semi-circular channels.

Bamboo or betel trunks cut vertically in half.

The size of the gutter should be according to the flow during the highest intensity

rain. It is advisable to make them 10 to 15 per cent oversize. Gutters need to be supported

so that they do not sag or fall off when loaded with water. The way in which gutters are


fixed depends on the construction of the house; it is possible to fix iron or timber brackets

into the walls, but for houses having wider eaves, some method of attachment to the

rafters is necessary.

These are the components which catch the rain from the roof catchment surface

and transport it to the cistern. Standard shapes and sizes are easily obtained and

maintained, although custom fabricated profiles are also possible to maximize the total

amount of harvested rainfall. Gutters and downspouts must be properly sized, sloped, and

installed in order to maximize the quantity of harvested rain.

3.3.3 Leaf Screens/Roof Washers

To keep leaves and other debris from entering the system, the gutters should have

a continuous leaf screen, made of 1/4-inch wire mesh in a metal frame, installed along

their entire length, and a screen or wire basket at the head of the downspout. Gutter

hangers are generally placed every 3 feet. The outside face of the gutter should be lower

than the inside face to encourage drainage away from the building wall. Where possible,

the gutters should be placed about 1/4 inch below the slope line so that debris can clear

without knocking down the gutter. To prevent leaves and debris from entering the

system, mesh filters should be provided at the mouth of the drain pipe .Further, a first

flush (foul flush) device

section should be

provided in the conduit

before it connects to the

storage container. If the

stored water is to be

used for drinking

purposes, a sand filter

should also be

provided.

Figure: 3.4 Provision of mesh filters at the mouth of the drain pipe

First Flush Device

A first flush (foul 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. Roof washing, or the collection and disposal of the first flush of water

from a roof, is of particular concern if the collected rainwater is to be used for human

consumption, since the first flush picks up most of the dirt, debris, and contaminants,

such as bird droppings that have collected on the roof and in the gutters during dry

periods. The most simple of these systems consists of a standpipe and a gutter downspout

located ahead of the downspout from the gutter to the cistern. The pipe is usually 6 or 8

inch PVC which has a valve and clean out at the bottom. Most of these types of roof

washers extend from the gutter to the ground where they are supported. The gutter

downspout and top of the pipe are fitted and sealed so water will not flow out of the top.

Once the pipe has filled, the rest of

the water flows to the downspout

connected to the cistern. These

systems should be designed so that

at least 50 liters of water are

diverted for every 1000 square feet

of collection area. Rather than

wasting the water, the first flush can

be used for non-potable uses such as

for lawn or garden irrigation. Figure: 3.5 First flush device installation

3.3.4 Storage Tanks/Cisterns

Storage tanks for collecting rainwater may be located either above or below the

ground. They may be constructed as part of the building, or may be built as a separate

unit located some distance away from the building. The design considerations vary

according to the type of tank and other factors.

Various types of rainwater storage facilities are found in practice. Storage tanks

should be constructed of inert material. Reinforced concrete, fiberglass, polyethylene, and

stainless steel are also suitable materials. Ferro-cement tanks and jars made of mortar or

earthen materials are commonly used. As an alternative, interconnected tanks made of

pottery or polyethylene are also found suitable. The polyethylene tanks are compact but


have a large storage capacity (1,000 to 2,000 liters). They are easy to clean and have

many openings which can be fitted with connecting pipes. Bamboo reinforced tanks are

less successful because the bamboo may become infested with termites, bacteria and

fungus. Precautions are required to prevent the entry of contaminants into storage tanks.

Figure: 3.6 Different types of Storage tank

Shape and Size

There are various options available for the construction of these tanks with respect

to the shape, size and the material of construction. Shapes may be cylindrical, rectangular

and square. The quantity of water stored in a water harvesting system depends on the size

of the catchment area and the size of the storage tank. The storage tank has to be designed

according to the water requirements, rainfall and catchment availability.

Suppose the system has to be designed for meeting drinking water requirement of

a 5-member family living in a building with a rooftop area of 100 sq.m. Average annual

rainfall in the region is 600 mm. Daily drinking water requirement per person (drinking

and cooking) is 10 liters.


Following details are available:

Area of the catchment (A) = 100 Sq.m.

Average annual rainfall (R) = 600 mm (0.6 m)

Runoff coefficient (C) = 0.85

Annual water harvesting potential from 100 Sq.m. Roof

= A x R x C

= 100 x 0.6 x 0.85

= 51 cu.m. (51,000 liters)

The tank capacity has to be designed for the dry period, i.e., the period between

the two consecutive rainy seasons. With the rainy season extending over four months, the

dry season is of 245 days. Particular care must be taken to ensure that potable water is not

contaminated by the collected rainwater. Drinking water requirement for the family (dry

season) = 245 x 5 x 10 = 12,250 liters.

Figure: 3.7 Daily basic need of water requirement

As a safety factor, the tank should be built 20 per cent larger than required, i.e.,

14,700 liters. This tank can meet the basic drinking water requirement of a 5-member

family for the dry period. The most commonly used material of construction is

Reinforced Cement Concrete (RCC), ferrocement, masonry, plastic (polyethylene) or

metal (galvanized iron).


3.3.5 Conveying

It should be remembered that water only flows downhill unless you pump it. The

old adage that, gravity flow works only if the tank is higher than the kitchen sink,

accurately portrays the physics at work. The water pressure for a gravity system depends

on the difference in elevation between the storage tank and the faucet. Water gains one

pound per square inch of pressure for every 2.31 feet of rise or lift. Many plumbing

fixtures and appliances require 20 psi for proper operation, while standard municipal

water supply pressures are typically in the 40-psi to 60 psi range. To achieve comparable

pressure, a cistern would have to be 92.4 feet (2.31 feet X 40 psi = 92.4 feet) above the

home’s highest plumbing fixture. That explains why pumps are frequently used, much in

the way they are used to extract well water. Pumps prefer to push water, not pull it. To

approximate the water pressure one would get from a municipal system, pressure tanks

are often installed with the pump. Pressure tanks have a pressure switch with adjustable

settings between 5 and 65 psi. For example, to keep the in house pressure at about 35 psi,

the switch should be set to turn off the pump when the pressure reaches 40 psi and turn it

on again when the pressure drops down to 30 psi.

Filters

A filter is an important part of the inflow structure of a RWH System. Once

screens and roof washers remove large debris, other filters are available which help

improve rainwater quality. Keep in mind that most filters available in the market are

designed to treat municipal water or well water. Therefore, filter selection requires

careful consideration. Screening, sedimentation, and pre-filtering occur between

catchment and storage or within the tank. A cartridge sediment filter, which traps and

removes particles of five microns or larger is the most common filter used for rainwater

harvesting. Sediment filters used in series, referred to as multi-cartridge or inline filters,

sieve the particles from increasing to decreasing size.


Types of Filtration Systems

1. Gravity Based Filter

This consists of construction of an underground / above ground filtration chamber

consisting of layers of fine sand / coarse sand and gravel. The ideal depths from below

are 60 cm thick coarse gravel layer, 40 cm coarse sand and 40 cm fine sand. Alternatively

only fine sand can also be used along with the gravel layer. Further deepening of the filter

media shall not result in an appreciable increase in the rate of recharge and the rate of

filtration is proportional to the surface area of the filter media. A unit sq.m. Surface area

of such a filter shall facilitate approx. 60 liters./hr of filtration of rainwater runoff. In

order to determine the optimum size of the surface areas just divide the total design

recharge potential with this figure. A system of coarse and fine screen is essential to be

put up before the rainwater runoff is allowed to flow into the filtration pit. A simple

charcoal 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.

Figure: 3.8 Gravity based filter

2. Sand Filters

Sand filters are commonly available, 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 of coarse sand followed by a 5-10 mm

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


are manufactured commercially on a wide scale. Most of the water purifiers available in

the market are of this type.

Figure: 3.9 Sand filters

3. Pressure Based Filter

Pressure based filters facilitate a higher rate of filtration in a pressurized system. It

requires a siltation pit of about 6-15 cu.m. in capacity so as to facilitate sedimentation

before it is pumped through the filter into the ground. Being a pressure based system it

involves a pump of capacity 0.5-1 hp. The rate of filtration is evidently high and the

quality of water is also claimed to be as per WHO guidelines. They are successful for

areas with larger rainwater runoff (>6 cu.m./hr) and limited space availability. Also these

filters can be put in combination with an existing tube well so as to recharge water into

the same bore.

3.4 Types and configurations of RWH systems

Three basic types of system for supplying non-potable water to buildings for

internal and external uses are identified by Leggett et al (2001b): directly pumped,

indirectly pumped and gravity fed. External use only systems are also available and these

are essentially direct systems that can only be used for outdoor purposes, such as garden

watering and vehicle washing. In all cases, water is collected from a catchment surface

and held in a sealed storage structure until needed. Once harvested water has been used,

for example to flush the WC, it is considered to be in the same effluent category as

potable water would be if used for the same purpose, e.g. harvested water used to flush a


WC becomes foul (black) water, the same classification that applies to potable water once

it has been used to flush a WC. The resulting effluent is treated in the same manner

regardless of the initial source.

3.4.1 Indirectly pumped systems

Rainwater is initially held in a storage tank and then pumped to a header tank

within the building, which is usually located within the roof void. Water is delivered to

appliances via gravity and the header tank should be at least one meter above the supply

points. If the storage tank runs dry, the header tank is supplied with top-up water from the

mains. If the storage tank is full, any additional incoming water will exit via an overflow

and will normally be disposed of either to a soak away infiltration device or sewer. See

figure 3.10 for a schematic of an indirectly pumped RWH system. The main advantages

of indirectly pumped systems are that if the pump fails (e.g. due to mechanical/electrical

failure or power loss) then water will still be supplied to the associated fixtures and

fittings via the mains top-up function. Low cost pumps and simple controls are possible

and systems tend to be energy efficient as the pump runs at full flow.

The main disadvantages are that they tend to deliver water at low pressures. This

can lead to slow filling of WC cisterns and the system may not provide enough pressure

to work with some appliances. Some proprietary units solve the low pressure problem by

using a hybrid system. Water for the WC is gravity fed from a header tank which also has

mains top-up whilst water for the washing machine and garden is delivered via a pump at

equivalent mains pressure. The advantage with this arrangement is that in the event of a

power failure it is still possible to flush the toilet. Indirect systems also require the use of

a header tank (Environment Agency, 2007). These can add to the overall cost of a system

(though not usually significantly) and there may not always be sufficient space in the roof

void to site the tank.


Figure: 3.10 Schematic of an indirectly pumped RWH system.

3.4.2 Directly pumped systems

In a directly pumped system (sometimes also referred to as a pressurized system)

rainwater is initially held in a storage tank and then pumped directly to the point of use

when required, e.g. to WC cisterns and washing machines. There is no header tank with a

direct system and mains top-up occurs within the storage tank. Mains top-up does not

completely fill the tank but maintains a minimum level that is able to meet short-term

demand. If the storage tank is full, any additional incoming water will exit via an

overflow and will normally be disposed of either to a soak away/infiltration device or

sewer. Figure 3.11 shows a schematic of a directly pumped RWH system. The main

advantages of directly pumped systems are that water is provided at mains pressure

which is ideal for garden hoses and washing machines, and that they do not require a

header tank (Environment Agency, 2007).


Figure: 3.11 Schematic of a directly pumped RWH system

The main disadvantages are that if the pump fails (e.g. due to

mechanical/electrical failure or power loss) then no water can be supplied. WCs would

have to be flushed manually (e.g. using a bucket of water) and washing machines would

not function. Mains top-up controls can also be more complicated than with indirect and

gravity fed systems (Environment Agency, 2007).

3.4.3 Gravity fed systems

Gravity fed systems differs from the direct and indirect variants primarily in that

the main storage tank is located within the roof void of the building. Rainwater is

collected from the roof, filtered and then piped directly to the storage (header) tank.

Water is delivered to appliances via gravity and the storage tank should be at least one

meter above the supply points. Mains top-up water is supplied directly to the tank if it

runs dry. If the tank is full, any additional incoming water will exit via an overflow and


will normally be disposed of either to a soak away/infiltration device or sewer. The main

advantages of gravity fed systems are that they do not require a pump or electrical supply

as is the case with the direct and indirect versions. Also, since there is no pump, there is

no risk of pump-associated supply failure.

Figure: 3.12 Schematic of a gravity fed RWH system

The main disadvantages are that the water pressure is likely to be less than that of

the mains supply. This can result in poor performance of some appliances, e.g. slow

filling of WC cisterns, and some appliances such as some modern washing machines may

stop working altogether. In this case a pump may be required to boost the water pressure.

There may also be issues with high structural loads, damage from leaking components

and water quality issues due to fluctuating temperatures in the stored water. It also has to

be possible to collect runoff from the roof, filter it and deliver it to the tank under the

action of gravity. In this case the relative levels of the various components (roof, filter

and tank) are critical and it may not be possible to find an arrangement that functions

hydraulically.


CHAPTER: 4 STUDY AREA PROFILE

4.1 General

The development of ground water in different areas of the country has not

been uniform. Highly intensive development of ground water in certain areas for

irrigation, drinking, domestic and industrial uses in the country has resulted in over-

exploitation leading to long term decline in ground water levels, and under certain

situations, deterioration in quality of the ground water.

For providing sustainability to ground water resources in such areas and

keeping in view the increasing thrust on development of ground water resources for

meeting the growing/increasing demands of water in various sectors, there is an

urgent need to regulate over-exploitation of ground water resources and also to

augment the depleting ground water resources.

Water requirement for industries in India is comparatively small as compared

to the quantity of water needed for agriculture. However, when industrial demand is

concentrated in specific locations, heavy withdrawals are done from available water

resources. Industries require water for processing, cooling, boiler feed and other

miscellaneous uses such as washing, maintenance of yards and domestic requirement

in townships. Mostly the industrial uses are non-consumptive, thus making reuse

through recycling and other conservation measures possible. The amount of water

consumed for any product, varies widely depending upon the processes used, plant

efficiency, technology employed, the degree to which water is re-circulated and other

factors. Industrial waste may contain different kinds of toxic pollutants, which if

untreated may result in contamination of water resources. Treatment of industrial

waste water and recycling are essential to conserve water resources.

Main source of water for Surat is the river Tapi flowing through the city.

Surface water is drawn by intake wells from perennial channel of the river throughout

the year. Water thus drawn is treated by the water treatment plants and then the same

is supplied to the citizens and industries after post‐chlorination.


4.2 CITY PROFILE

4.2.1 Locational Importance

Figure 4.1: Geographical Location for Surat City


Surat city is located in the southern part of Gujarat at 21º 12' N latitude and

72º 52' E longitude on the southern bank of river Tapi. The Arabian Sea coastline is

on its west at a distance of 14 miles by water along river Tapi and 10 miles by road

along Dumas. It is located at a height of 13 meters above mean sea level. The city

forms a major urban core in the Ahmadabad – Mumbai regional corridor, centrally

placed between both the settlements, at a distance of 260 kms. north of Bombay and

224 kms. south of Ahmadabad. The area has a gradual slope towards the western and

southern part of the city having a natural drainage system towards river Mindhola.

The river Tapi flows through the city dividing it into two parts. The pattern of the

Kakrapar canals indicates the alignments of the natural slopes from north-east to

south-west.

4.2.2 EVOLUTION OF PRESENT FORM

Surat is believed to have been established in 300 BC, by the Bhrigu kings. It

was then known as Suryapura. The present name of Surat is derived from this ancient

name. Surat was under the rule of the Chalukyas during 10th to 13th centuries, then

came under the Muslim Sultanate of Gujarat till 1573, after which the Mughals

annexed it during the reign of Akbar. The British established their first factory in

1759 and by 1800 the city was firmly under their rule. During the late 16th and 17th

centuries, Surat developed as major port and a trade centre on the western coast of

India. It continued as a trading centre till late 18th century, after which the trading

activities started shifting to Bombay. However, the social structure which developed

as a result of the trading activity continued, and there was a shift to small scale

industries and other commercial sectors.

Surat was originally established on the banks of river Tapi with a fort on the

eastern bank and a Custom House on the northern side of the fort. In the initial years,

activities were concentrated in the inner walled city. The wall was constructed in

1664 and the area within the walled city measured 440 acres. The entrances to the

walled city were through 12 gates. The outer wall was constructed in 1707 enclosing

an area of 1818 acres. In the beginning of the 20th century Surat started experiencing

the growth of sub-urban areas namely, Udhna, Athwa and Phulpada along the various

corridors opened up through the various gates. On account of such a development,

the physical expansion of the town was primarily directed towards the five main


corridors, namely, Katargam and Amroli in the north, Kamrej road in the east,

Udhana road in the south, Rander - Adajan in the west and Dumas road in south-west.

The city, as a result of such development, had a radial pattern. Today’s Surat city is

an outcome of the expansion of the city’s limits at various intervals geared to

accommodate the additional population and the increasing economic activities.

In the year 1664 the city was limited to the inner walled city covering an area

of 1.78 sq. kms. In 1707, with the construction of the outer wall, the area of the city

increased to 7.36 sq. kms. For the next almost 250 years the increase in the city area

wasn’t very significant and in 1963 the city covered an area of 8.18 sq. kms. In the

same year 13.77 sq. kms. was added to the city area, increasing its total area to 21.95

sq. kms. In the last 45 years the area of the city increased by 15 times to an area of

326.52 sq. kms. The city has a mixed land use pattern. The entire walled city has a

concentration of several small and medium scale industries. A significantly large

proportion of the total city area is vacant and agricultural land occupies 14 per cent of

the total area of the city.

4.3 DEMOGRAPHIC FEATURES

Surat is India’s twelth and Gujarat’s second most populous city. The city is

one of the 11 cities in the country which attained metropolitan status in 1991 census

by crossing the one million mark. Surat has experienced a rapid population increase

in the last two census decades (1971-’81 and 1981-’91).

Table 4.1 Area, population and growth Rate of Surat – 1951 to 2006

YearArea

(Sq. Km.)Population

Density(Persons/sq.

km.)

DecadalGrowth Rate

(%)1951 8.18 2.23 27284 -1961 8.18 2.88 35211 29.051971 33.85 4.72 13934 63.751981 55.56 7.77 13977 64.651991 111.16 14.98 13483 93.002001 112.27 24.34 21677 62.382006 326.26 28.00 8582 15.08Source: Surat City Corporate Plan (2001-2006), 2002.

At the state level Surat ranks second only to the capital Ahmedabad, which has

a population of 32.98 lakhs (Census of India, 1991). These two cities account for 34


per cent of the total urban population of the state. The city experienced an increase in

the density of population despite an increase in area between 1971 and 1981.

However, in 1991, the density declined due to a proportionally larger increase in the

area compared to the population. In 1991, the population was spread over an area of

111.16 sq. kms. resulting in a density of 13,483 persons / sq. km. In 2001, the density

increased to 21,677 persons / sq. km. but it decreased to 8,582 persons / sq. km. in

2006.

Surat city can be broadly classified into three parts; the old city covering an

area of 8.18 sq. kms.; the inner periphery and Rander zone spread over an area of

47.37 sq. kms. and the outer periphery comprising of the newly developed areas

covering 55.61 sq. kms. Although the population and density in the inner city had

increased from 1971 to 1981 a decreasing trend has been observed in these variables

in 1991. This resulted in a corresponding increase in the density in the inner

periphery. This trend points out the shift of population from the inner city due to

extreme congestion, dilapidated buildings, over-stressed civic infrastructure and an

overall deteriorating quality of life along with increasing land values.

Despite these processes the inner city still has the highest density among the

three zones with as many as 51,929 persons per sq. km. The inner periphery and the

Rander zone have emerged as the focus of population concentration during 1981-’91

with the population and density almost doubling during the same period. While the

proportion of population in case of the inner city decreased from 77 per cent in 1971

to 28 per cent in 1991, it increased in the inner periphery from 23 per cent to 43 per

cent during the same period. The outer periphery which has emerged as the current

focus of population growth accounted for 29 per cent of the total city population and

has the lowest density with 7,911 persons per sq. km.

4.4 LAND USE PATTERN

This section gives a broad assessment of existing land use distribution. The

land use details as per the Revised Development Plan (SUDA) are shown in the table

below.


Table 4.2 Land use Breakup

Sr.No.

Types of ZoneArea in

1978%

Area in1995

%Area in

2004%

1. Residential 2695.60 3.9.96 6189.00 46.77 9806.18 57.542. Commercial 141.30 2.09 256.00 1.93 415.72 2.443. Industrial 1006.40 14.92 2784.00 21.04 3023.40 17.74

4.Educational / Publicpurpose

540 8.00 735.00 5.55 579.82 3.40

5.Recreation/ garden andopen space

22.21 0.33 58.00 0.44 106.61 0.63

6.Transport andcommunication

790.92 11.72 1661.00 12.55 1661.41 9.16

7. Agriculture 1550.00 22.98 1550.00 11.71 1550.00 9.09Urbanized area 6746.43 100.00 13233.00 100.00 17143.14 100.00Non urbanized area 65453.57 - 58967.00 55056.86

Total 72200.00 72200.00 72200.00

Since 1978, the urbanized area of the city has increased almost 3 times till 2004. The

important features in the land use pattern are stated below:

Figure: 4.2 Land use Patten in SUDA (2004)


Chart: 4.1Category Wise Land use Distribution in the SMC Zones (%)


Source: Derived from actual Land use map of SUDA

The above figures show the percentage of area distribution as per land use

category. It can be noted from the above table that the highly dense central zone has

almost 40% of the land use as residential use. Commercial use is also dominant in the

central zone whereas the industrial use is dominant in the South zone of the city.

4.5 URBAN ECONOMY AND INDUSTRIAL GRWOTH

Surat is known for its textile manufacturing, trade, diamond cutting and

polishing industries, intricate zari works, chemical industries and the gas based

industries at Hazira established by leading industry houses such as ONGC, Reliance,

ESSAR, and Shell. The city economy is characterized by large number of small and

medium size unorganized industries. The industrial base is labor intensive.

4.5.1 TEXTILE INDUSTRIES

The textile industry is one of the oldest industries in the country and continues

to be a significant contributor to value of industrial production, employment

generation and to national income. An estimated 4 percent of GDP is contributed from

the sector. It adds to about 30% of country’s export earnings while adding about 7 to

8% of the gross import bill.

Surat is a dominant player in the textile sector. The traditional handloom

weaving industry has given way to power-looms, printing, and dyeing textiles. Surat

is one of the largest centers in the world for production of synthetic fabrics, mainly

nylon and polyester. The Indian Government’s policy since 1956 of providing

incentives and protection to small scale industries boosted the power-loom industry in


the city. Weavers took advantage of the incentives and converted their handlooms into

power-looms.

At present, there are about 6 lacks power-looms, 450 Process houses, 100 and

above textile markets, 50000 and more embroidery machines in the city region and

the sector provides total employment of over 12 lacks people. The total production

value of “Gray Fabrics” in Surat is about Rs. 20,000 Crore.

Table: 4.3 Estimated jobs in textile industry

Types of Textile UnitsEstimated Jobs in themetropolitan Reegion

Power looms Unit 7,50,000Processing Units 1,50,000Texturising Units 25,000Embroidery Units 25,000Cutting, Pecking, Dispatching 2,50,000Total 12,00,000Source: On basis of the estimates of the South Gujarat Art Silk Industry, Surat. (2006)

The textile processing units are the major backbone of the Surat city’s

economy. However, they depend mainly on ground water for its processing and

withdraw about 700 to 1000 cubic meter of water every day. There are about 60

thousand shops and establishments engaged in trading activity in general with textiles

as a predominant sector.

As per the latest survey conducted by Federation of Indian Art Silk Weaving

Industry, there is decrease in the migrant workers employed in the textile industry due

to the various schemes such as National Rural Employment Guarantee (NREGA) run

in states such as Bihar, Andhra Pradesh, Orissa and Uttar Pradesh.

4.5.2 DIAMOND CUTTING AND POLISHING

Gujarat accounts for almost 80 % of the diamonds processed in India. Of this,

90 % are processed by the units located in and around Surat alone. The emergence of

the industry in the region which did not have raw material, markets or worker base is

a significant feat. Even majority of the entrepreneurs are from outside. Initially the

industry began largely as an initiative of few individuals belonging to a particular

community which has now expanded to large section of the society. Under the Import

Replenishment Scheme introduced by the Government of India in 1958, diamond

traders were allowed to import rough diamonds from Diamond Trading Corporation,


London and other sources abroad and export cut and polished diamonds. Added

support came from the encouragement offered to small-scale industries during this

time. By the late 1950s, about 100 diamond cutting and polishing units had been set

up. With the setting up of the Gems and Jewellery Export Promotion Council in 1966,

diamond exports received a further impetus and consequently, the number of cutting

and polishing units also increased. Coupled with ease of establishing small-scale

industries, various governmental policies aimed at increasing the export of polished

diamonds aided the growth of such units in the city.

Like textiles, diamond cutting and polishing is also a labor intensive industry

employing about 7, 00,000 workers in about 25,000 units of all sizes operating within

the urban region. India’s first private Special Economic Zone has been functioning

near Sachin in Surat since November 2000. From household industry base, over the

years, the structure of the industry has changed to small, medium and large-scale

units. Technical advancements have also contributed to improved productivity.

Chart: 4.2 Growth of the Diamond industry in Surat, 1950-2007

The industry requires a low capital base, is non-polluting, high on employment

generation and is a leading contributor to foreign exchange reserve. Export value

increased from a mere Rs. 110 million in 1966-67 to Rs 320,000 millions in 2002-03.

However, as a result of technological advancements, during the last 10 years, though

output has increased by 5 times, there has not been any significant increase in jobs.


4.5.3 MAJOR INDUSTRIAL ESTATES

There are 605 medium and large scale industries based in Surat district. Most

of the medium and large scale industries are concentrated in Choryasi taluka (West

Surat) with 230 unit followed by Mangrol (North Surat) and Mandvi taluka (Central

Surat) with 131 and 116 units respectively.

Small Scale Industries (SSI)

There are over 41,300 small scale industries (SSI) functioning in Surat district.

Some of the main industries under SSIs in Surat are textiles, chemicals dying &

printing, diamond processing, jhari (Silver) making, and. engineering and related

activities ( manufacturing machineries & equipments)

Maximum numbers of SSI units (24,000 Units) are related to textile industry

in the district followed by repairing & service industry with more than 11,000

units.

Most of the small scale industries are located at talukas such as Choryasi

(Western).

Surat), Mangrol (Northern Surat), Olpa (Northern Surat), Mandvi (Central

Surat) and Palsana (Southern Surat).

Maximum number of SSIs, MSIs & LSI s are located in Choryasi taluka.

Table: 4.4 Industrial Estates in Surat District

Sr.No.

Industrial Estate Area in Hectares % of total area

1. Valod 1.13 0.042. Khatodara 3.07 0.113. Bardoli 4.71 0.164. Gaviyar-Meghdalla 15.34 0.545. Olpad 31.05 1.096. Hazira (GSPCL) 37.80 1.327. Katargam 38.33 1.348. Ichhapor Bhatpor (IOC) 40.00 1.409. Apparel park 54.96 1.92

10. Hazira 127.04 4.4411. Doshwada 165.14 5.7712. Pandesara 218.27 7.6313. Hazira (Reliance) 437.50 15.3014. Sachin 749.35 26.20

Source : Center for Environmental Planning and Technology


4.6 SOURCES OF WATER SUPPLY

4.6.1 Surface Water Sources

Main source of water for the city has been the river Tapi since centuries. To

cater the portable water need for the city of surat first water works was commissioned

at Varachha in the year 1898, to serve 1.08 Lacs population & 8.25 Sq.Km area with

water supply from infiltration wells. After that, tube wells were constructed at

Varachha & Sarthana to increase the capacity.

Surat city has grown at a very spur growth rate so to harness the river water

for flood control, agriculture, power generation, domestic and industrial purposes the

Kakarapar weir, the Ukai dam and Singanpore weir were constructed in the year

1954, 1972 and 1995 respectively. Wei-cum-cause way at Rander was built on PPP

model with majority of investment from Industries situated in Hazira.

The City witnessed a tremendous growth in textile, diamond and jari industries

during sixties and seventies. This was followed by a spurt in major industrial activities

in and around the city, like the development of Hazira industrial complex in nineties.

Industrial and commercial activities have given Surat a place of prominence in the

whole of India.

Chart: 4.3 Daily average water supply in SMC

After a lapse of nearly a century, second water works for the city of Surat was

commissioned at Katargam in the year 1997 at a total project cost of about Rs.25

Crores. The concept of Katargam Water Works was developed and materialized after

the construction of a weir-cumcauseway in the year 1995, across the river Tapi,

connecting Rander and Singanpore area of Surat. The biggest advantage to the


development of Katargam Water Works was the large quantity of always available

harnessed water body nearer to city as compared to other water works.

Table 4.5 Average yield and installed capacity (2009)

SourceInstalled capacity

(MLD)Average yield

(MLD)Yield / inst. Cap.

Surface source 1128 640 57%Ground source 90 60 67%

Total 1218 700 57%Source: Surat City development Plan (2008-2013)

Table 4.6 Water Supply- Quantity (2009)Purpose Quantity Supply (MLD) 2009Domestic 600Commercial 20Industrial 55Institutional 3Public stand post 5Newly merged area 17Total 700Source: Surat City development Plan (2008-2013)

Table 4.7 Water Supply- IndicatorsHead / Year 2009Total Area of Surat (sq.km.) 326.515Area covered by piped water supply (sq.km.) 125.74Total area to be covered under water supply 223.43% of area served 56Present estimated Population (lakhs) 39.00Population covered (lakhs) 31.02% of total population served 79Total water supply capacity (ground and surface) (MLD) 1218Total water supplied (ground and surface) (MLD) 700Gross daily supply (lpcd) 145Treatment capacity / Total supply 162 %Storage capacity / Total supply 85 %Supply frequency Av. 3 Hrs DailySource: Surat City development Plan (2008-2013)


4.6.2 Ground Water Sources

The general practice of using ground water in addition to the municipal supply

has lead to the existence of bore wells in almost every dwelling unit o f the city. The

total number of tube wells for water supply in the city is 34. In Chorasi taluka of

Surat district, total groundwater recharge amounts to 330 MLD, out of which the

allocation for domestic and industrial requirements is about 50 MLD. This is far

below the city’s future requirement.

It is observed that the ground water level generally rises to 2-5 meters below

ground level during the monsoon (June to October). During the rest of the year, the

ground water level drops down to below 5 meters and even up to 10 meters at some

locations. Water table in the city, which was 18 metres below ground level in 1991,

has gone down to 20 meters in 2000.

The total number of tube wells in the city is 41. At Sarthana water works,

there are 25 tube wells, out of which 5 are out of order on a permanent basis due to

intolerable sand/ gravel contents in the outflows.

The salient parameters of the tube wells around Surat city are:

Depth of water bearing strata - 30.0 m to 187.85 m

Yield - 0.59 MLD to 3.31 MLD

Hydraulic conductivity - 3.26 MLD to 52.42 MLD

Yield from Surface and Ground Sources

The installed capacity of surface water sources is fully utilized (100%) at

present. The average yield from the sources is about 70 percent of the installed

capacity. The main reason for the reduced yield of ground water appears to be the

silting of ground water sources after the construction of the Singapore weir. The yield

of french well no. 1 has substantially reduced. The yield of the tube wells at Varachha

and Sarthana Waterworks varies from 5 to 10 MLD. At present surface water sources

contribute 85 percent of the daily total water supply.


4.7 SOUTH ZONE: STUDY AREA


CHAPTER: 5 DATA COLLECTION AND ANALYSIS

5.1. General

Field study gives the real picture of the existing situation of the study area. For any

study preparation of data base is pre requisite step, it is carried out through inventory data

studies, field studies, personal interview of the industries etc...Without existing data it is

difficult to judge the present condition of the field. The next step is design after study area

imagination involves collection of data for studying the past and existing rain fall

characteristics.

5.2. Survey method

There are mainly two types of survey. The first is carried out through inventory data,

and the second is carried out through industry based interview. Inventory data helps to

develop the strategy for field survey and, it is also used to designing the questionnaires.

5.2.1. Inventory study

The inventory surveys are aimed to obtain the maximum available data from the

alternative department such as Surat municipal corporation, hydraulic department etc.

Data source for the study purpose in Surat Municipal Corporation is given below.

Detail reports of Pandesara G.I.D.C.

Map location of industry area.

Detail maps of Surat city.

Rainfall data of past 10 years.

5.2.2. Field Survey

It issued for the understanding and describes the physical condition and characteristics

of study area. Problems of area were indicated to direct observation. This survey was carried

out for industrial area by using prepared questionnaires.

The distribution of reports collected with respect to industry base interview survey at

Pandesara G.I.D.C., south zone, Surat city. In this project, study area bases on which industry

are already face problems of water in Pandesara G.I.D.C. at Surat city.


5.3. Study Parameters

In Surat city, the main water source is only river Tapi. In Pandesara G.I.D.C. the

water sources is only S.M.C. water. It is not sufficient for all industry as well as Pandesara

G.I.D.C. area.

Survey from is divided into five major heads, such as

Source of water

Bore well

Storage tank

Type of roof & roof area

Types of production

Detail of important parameters is briefly described below:

5.3.1. Source of Water

This parameter gives the idea about the present water demand of the particular

industry. Indirectly it is also a measure of cost of water affordability.

5.3.2. Bore Well

This parameter gives the idea about type of bore well, quantity of gain water for

particular industry.

5.3.3. Storage Tank

This parameter gives the idea about type of storage tank

There are mainly two type of tank

- underground storage tank

- elevated storage tank

The storage tank is made from PVC, RCC

5.3.4. Type of Roof & Roof Area

This parameter gives idea about type of roof like slope roof & RCC slab. Slope

Roofing is made from asbestos, cement, steel, PVC, etc. Total roof area is more important to

collecting rain water for storage.


5.3.5. Types of production

In our survey area Pandesara G.I.D.C. there are mainly two types of production. First

is dying & printing of grey cloth material and second is production of chemicals.

5.4. Questionnaires Design

The questionnaire is design to know the industrial satisfaction. By keeping that in

mind the components are in divided in to five major heads, such as source of water; bore

well, storage tank, roof type & roof area and types of production for the study area. The brief

overview of the major parameter is explained below.

Source of water, it contain the information regarding availability of water, quality of water,

quantity of water, in our survey area the water sources is SMC treated water, bore well,

tankers, etc. questionnaire design is attach in Annexure A.

5.4.1. Source of water

In Surat city main source of water is river Tapi. There are two types source of

water, Surat Municipal Corporation & bore well. Generally used of SMC water is high. Some

industries used bore well also. As per the below chart 97% industry are use Surat Municipal

Corporation water because they have not any alternative sources of water.

Table 5.1 Source of water

Chart 5.1 Source of Water

SOURCE OF WATERSR NO SOURCE SURVEY PRECENTAGE (%)

1 SMC 86 96.632 BORE WELL 1 1.123 BOTH 2 2.25

TOTAL 89 100.00






















TOTAL 89 100.00

97%

1%2%

SOURCE OF WATER

SMC

BORE WELL

BOTH






















TOTAL 89 100.00

SMC

BORE WELL

BOTH


5.4.2. Roof Type

In this system only rooftop is the catchment. The roofing should be of galvanised iron

sheet (G.I.), aluminium, clay tiles, asbestos or concrete. In the survey area there are mainly

two types of roof i.e. RCC slab and smooth galvanized corrugated iron sheet. According to

below analysis 44% industry having slopping roof.

Table 5.2 Type of Roof

Chart 5.2 Type of Roof

5.4.3. Present Gain Water from SMC

In our Surat city, most of industry use SMC water or tanker also. They have present

water demand is Below chart showing, the present water demands is less than 50000 liters of

water per day (37.08%). most of industry demanded on between these criteria.

Table 5.3 Present Gain Water from SMC

PRESENT GAIN WATER SMC

SR NO LITER SURVEY PERCENTAGE (%)

1 > 50000 33 37.08

2 50000 - 200000 10 11.24

3 200000 - 350000 8 8.99

4 350000 - 500000 18 20.22

5 > 500000 20 22.47

TOTAL 89 100.00

ROOF TYPE

SR NO TYPE SURVEY PERCENTAGE (%)

1 RCC 29 32.58

2 ROOF/SLOP 39 43.82

3 BOTH 21 23.60

TOTAL 89 100.00

24%


5.4.2. Roof Type














1 > 50000 33 37.08

2 50000 - 200000 10 11.24

3 200000 - 350000 8 8.99

4 350000 - 500000 18 20.22

5 > 500000 20 22.47

TOTAL 89 100.00

ROOF TYPE


1 RCC 29 32.58


3 BOTH 21 23.60

TOTAL 89 100.00

32%

44%

24%

ROOF TYPE

RCC

ROOF/SLOP

BOTH


5.4.2. Roof Type














1 > 50000 33 37.08

2 50000 - 200000 10 11.24

3 200000 - 350000 8 8.99

4 350000 - 500000 18 20.22

5 > 500000 20 22.47

TOTAL 89 100.00

ROOF TYPE


1 RCC 29 32.58


3 BOTH 21 23.60

TOTAL 89 100.00

ROOF/SLOP

BOTH


Chart 5.3 Present Water Demand

5.4.4. Storage Tank

There are mainly two types of storage tank i.e. underground or elevated. From the

below chart underground tank is most of used. In this chart 34% storage tank is underground,

and elevated tank is used only 21.35%.

Table 5.4 Type of Storage Tank

STORAGE TANKSR NO TANK SURVEY PERCENTAGE (%)

1 NONE 30 33.712 UNDERGROUND 30 33.713 ELEVATED 19 21.354 BOTH 10 11.24

TOTAL 89 100.00

Chart 5.4 Type of Storage Tank

21%11%

37.08

0.005.00

10.0015.0020.0025.0030.0035.0040.00

> 50000 50000 -200000

PRESENT WATER DEMAND



5.4.4. Storage Tank







TOTAL 89 100.00


34%

34%

11%

STORAGE TANK

NONE

UNDERGROUND

ELEVATED

BOTH

11.24 8.99

20.22 22.47

> 50000 50000 -200000

200000 -350000

350000 -500000

> 500000

PRESENT WATER DEMAND

PERCENTAGE



5.4.4. Storage Tank







TOTAL 89 100.00


UNDERGROUND

ELEVATED

PERCENTAGE


5.4.5. Present Capacity of Tank

The design of storage tank may be constructed as per water demand and according to

the type of tank and material like: reinforcement concrete, fiberglass, polyethylene, stainless

steel are also suitable material. From below chart most of industry using storage tank between

50000 to 200000 liters per day.

Table 5.5 Present Capacity of Tank

PRESENT CAPACITY OF TANK


1 > 50000 33 37.08

2 50000 - 200000 29 32.58

3 200000 - 350000 12 13.48

4 350000 - 500000 15 16.85

5 > 500000 0 0.00

TOTAL 89 100.00

Chart 5.5 Present Capacity of Tank

5.4.6. Roof Area

Rain water may be collected from any kind of roof-tiles, metal, palm leaf, grass

surfaces, which have been specifically prepared and demarcated. In survey chart approx 55 %

of area is between 1000 to 2000 m2.

37.0832.58

13.4816.85

0.000.005.00

10.0015.0020.0025.0030.0035.0040.00

> 50000 50000 -200000

200000 -350000

350000 -500000

> 500000

PRESENT CAPACITY OF TANK

PERCENTAGE


Table 5.6 Roof Area

ROOF AREASR NO AREA(Sq.m) SURVEY PERCENTAGE (%)

1 < 1000 16 17.982 1000-2000 49 55.063 2000-3000 4 4.494 3000-4000 8 8.995 4000-5000 5 5.626 > 5000 7 7.87

TOTAL 89 100.00

Chart 5.6 Roof Area

5.4.7. Future Water Demand:

In survey area they do not get sufficient required water so, they used tanker water

gives extra money. As per survey near about 39% industries are required 25000-50000 liters

additional water requirement.

Table 5.7 Future Water Demand

FUTURE WATER DEMANDSR NO LITER SURVEY PERCENTAGE (%)

1 <25000 30 33.71

2 25000-50000 36 40.45

3 50000-100000 14 15.73

4 >100000 9 10.11

TOTAL 89 100.00

0.0010.0020.0030.0040.0050.0060.00

ROOF AREA

PERCENTAGE


Chart 5.7 Future Water Demand

33.71

40.45

15.7310.11

0.005.00

10.0015.0020.0025.0030.0035.0040.0045.00

FUTURE WATER DEMAND

PERCENTAGE(%)

Planning for Rainwater Harvesting: Industrial Area 60

CHAPTER: 6 RWH SYSTEM DESIGN

6.1. General

Rainwater harvesting is not only useful for domestic purposes, but can also be

used for agricultural and Industrial/ commercial applications that have heavy water

requirements. RWH will likely see heightened importance as a water security measure

in the context of climate change, with the likelihood of changing rainfall regimes,

prolonged droughts and extreme storm events. The United Nations Commission on

Sustainable Development has called for the use of rainwater harvesting to supplement

water supplies in countries around the world.

6.2. Main RWH Component

The typical RWH system has four main parts:

6.2.1. Catchment area

Commonly a roof surface or pavement. Concrete and other impervious

pavements may be used for multiple-user community systems and can have

applications for agricultural, commercial & industrial uses with large water

requirements. Figure 6.1 shows such a catchment surface that provides water to the

industry in Pandesara GIDC.

6.2.2. Conveyance system

Network of guttering and pipes to transfer the rainwater from the catchment to

the storage tank. This consists of connections to one or more down-pipes connected to

the roof gutters. A key component of the conveyance system to improve the

cleanliness of the harvested water is a ‘first-flush device’ that diverts the dirtiest roof-

water away from the storage tank.

6.2.3. Storage device

A tank situated above, underneath or partially below the ground.


6.2.4. Distribution system

In the most basic case, this can be simply a container to extract the water from

the storage tank or a pipe functioning solely as an outlet. For a household, this will be

the piping network that supplies the building with the harvested water. For a

community RWH system, this could be a single outlet pipe or a complex network of

pipes serving multiple users. A pump may be used to transmit the water throughout

the distribution system.

6.3 The Catchment Area

For industrial water supplies, the roof of the building is generally used as the

catchment area. Some materials used to coat the roof such as bitumen, paints or

sheeting containing lead, may pose risk to human health. RWH systems are best-

suited where the roofing material is smooth and coated with chemically neutral

substances. Non-corrosive sheet metals such as galvanized sheets or aluminum are

ideally suited for use with RWH systems. They are less prone to build-up and

contamination from

dust, leaves, animal

droppings and other

debris, compared to

rougher roof surfaces

such as tile, shingles

or thatch.

Figure 6.1 Roof Catchment Areas

Follow these general guidelines when installing RWH rooftop catchment systems:

Do not use lead fittings;

Repair or replace metal roofs that are visibly corroded;

Check paints for suitability, and where possible use non-toxic acrylic-based

paints designed for exterior and roof use. Do not use paints containing lead,

chromate, tar/bitumen, fungicides or other toxins as they may pose a health

risk and/or may impart an unpleasant taste to the water;

After roof repainting, do not allow runoff water from the first rainfall to enter

the storage tank.
















contamination from


droppings and other

debris, compared to



or thatch.










the storage tank.
















contamination from


droppings and other

debris, compared to



or thatch.










the storage tank.


To calculate the volume of water that can be captured by a roof catchment.

To calculate the amount of rain that can be captured off a roof surface per

year, a procedure known as the ‘Rational Method’ can be applied. All you need to

know is the average annual rainfall for your location, the size or area of your roof and

the type of roof surface you have. The average annual rainfall should be available

from your local Meteorological Service. If you want more precise estimates you may

take into account the average, minimum and maximum rainfall on a per-month basis.

Table 6.1 Runoff Coefficients for Various Catchment Types

Type of catchment Coefficients Co efficientRoof catchmentsTilesCorrugated metal sheets

0.8 - 0.90.7 - 0.9

Ground surface coveringsConcreteBrick pavement

0.6 - 0.80.5 - 0.6

Untreated ground catchmentsSoil on slopes less than 10 percentRocky natural catchments

0.1 - 0.30.2 - 0.5

(Source: Alphonsus Daniel, pers. Comm.)

The Rational Method is given as follows:

Supply = rainfall (mm/year) x roof are (m2) x runoff coefficient

= liters per year

The runoff coefficient is the amount of water that actually drains free of the

surface relative to the amount the falls on the surface as rain. For example a runoff

coefficient of 0.8 means that of the total volume of rain that fell on the catchment

surface, 80% drained off the surface; the other 20% stayed on the surface. Smooth

metal sheet catchments with a steep gradient have higher runoff coefficients than flat

concrete catchment surfaces for moisture. Evaporation directly off the catchment

surface also affects the runoff coefficient. The roof surface area available for rainfall

harvesting depends on the width and length of the roof surface, and the angle (or

slope) of the roof.

For the amount of water you can capture in one year you will need to estimate

the area of your roof, the average annual rainfall at your location and the runoff

coefficient for the surface. The mathematical relationship is given as:

Supply (liters per year) = rainfall (mm/year) x area (m2) x runoff coefficient


The runoff coefficients for various surfaces are given in Table 6.1.The roof area is

calculated by the following relationship:

A worked example:

• Mean annual rainfall = 650 mm per year

• Roof angle = 23 degrees; sine of the angle = 0.3907

• Roof area = 60 m (length) x 20m (width) x 0.3907 = 470 m2

• Roof surface is smooth corrugated metal. This surface is assumed to have a runoff

coefficient of 0.8

Supply = 650 x 470 x 0.8 = 2, 44,400liters per year.

6.4 The Conveyance System

The conveyance system consists of the gutters, pipes and screens. The gutters

and piping collect drained runoff from the roof catchment into the storage system.

Screens prevent leaves and other organic.

6.4.1 Gutters

Polyvinyl chloride (PVC) pipes are commonly used for gutters given their low

maintenance requirements. Gutters

must slope toward the direction of the

storage tank and the gradient should

be equal to or more than 1 centimeter

per meter or 1/8 inch per foot. You

will need to regularly clean the gutters

to reduce debris collection to catch the

most rain, and ensure that leakage is

kept to a minimum. To minimize Figure 6.2 Typical PVC guttering and downpipe

the amount of leaf litter that gets on to the roof and trapped in the guttering, you

should trim away overhanging branches. However if you opt not to remove

overhanging branches, gutter screens may be used. The size (width) of the gutters

should be chosen based on the roof section area. The South Pacific Applied

Geosciences Commission (SOPAC) Handbook rainwater harvesting (2004) provides




A worked example:





coefficient of 0.8






6.4.1 Gutters



















A worked example:





coefficient of 0.8






6.4.1 Gutters

















guidance to sizing of the gutters and the downpipes appropriate to handle rainstorms

in tropical regions.

The size (width) of the gutters should be chosen based on the roof section

area. Design length of Roof is 60 meter. Select gutter size based on 1 centimeter per

meter or 1/8 inch per foot. So adopt diameter of gutter pipe is 60 centimeter.

Table 6.2 Sizing gutters and down-pipes for RWH systems

Roof area (m2) served byone gutter

Gutter width(mm)

Minimum downpipediameter (mm)

17 60 4025 70 5034 80 5046 90 6366 100 63128 125 75208 150 90

(Source: SOPAC, 2004)

6.4.2 First-flush diverterThe first rains that wash the roof surface will often contain offensive

materials, especially following a long dry spell. The material that would have

accumulated on the surface will include animal droppings, vegetable matter and dust,

all of which can degrade the quality of the stored water should this ‘first-flush’ enter

the storage tank. One option

is to use a first flush diverter

to divert this material away

before it enters the tank. A

first-flush diverter is a

simple installation that is

part of the downpipe,

configured to remove the

initial wash off the roof so it

does not enter the tank.

Figure 6.3 Simple first-flush diverter

The first flush diverter works by channeling the first flow down the downpipe

to its base where it encounters a cap with a small drain hole (the drain hole will allow

for gradually drainage else, the system will need to be drained manually). This


permits the first flow of water containing the roof debris to settle at the bottom of the

downpipe, with the cleaner

‘later’ water settling on top,

permitting relatively clean

water to enter the tank.

There are various

configurations that can be used

for first-flush diverters.

Figures are examples of the

simple first-flush diverter.

Figure 6.4 First-flush diverter

Figure 6.5 first-flush systems using float-ball mechanismThis basic design can be augmented with the use of a floating ball valve that

sits on top of the water column. The ball valve isolates the dirty first flush from thecleaner water once the water column in the downpipe floats the ball to the constrictionin the neck of the downpipe.

To calculate the volume of water you need to divert using a first flushsystem

It is generally assumed that a depth of rainfall on the roof equivalent to 0.5mm is required to wash off the accumulated contaminants. You first need todetermine the area of the roof and simply multiply by 0.5mm. Secondly, to determinethe length of first-flush down-pipe diversion requires you divide the required volumeof water to be diverted, by the cross-sectional area of the pipe, where p = 3.14 and r isthe radius or ½ the diameter of the pipe.

Volume of diverted water (liters) = Unit length (m) x Unit width (m) x 0.5(mm)

(Multiply answer by 0.22 to convert the value to imperial gallons) Pipe length (m) = Volume of diverted water (l) ÷ [3.14 x pipe radius2 (mm)

x 0.001] Pipe length (feet) = Volume of diverted water (gal) x 22.57 ÷ (3.14 x pipe

radius2 (inch)


Project DataRoof length = 60 metersRoof width = 20 metersPipe diameter = 175 mm (7 inch), therefore radius = 87.5 mm (3.5 inch)

(a) Volume of diverted water (liters) = 60 x 20x 0.5 = 600 liters (or 132 gallons)(b) Pipe length (m) =600 ÷ [3.14 x (87.5)2 x 0.001] = 25m(c) Pipe length (ft.) = 132 x 22.57 ÷ (3.14 x3.52) = 77.45 ft.

6.4.3 Screens

Screens prevent leaves, particulate matter, and other objects from entering the

storage tank. If allowed to enter, these materials decompose, providing nutrients or

‘food’ for potentially harmful microorganisms to multiply. If you can keep the storage

tank free of such materials, the less likely nutrients can accumulate; without this

nutrient supply, the bacteria eventually die-off from starvation within 2 to 20 days.

Screens are therefore among

your front-line defenses to

protect water quality. A huge

benefit derived from

installation of screens is in

the prevention of mosquito

entry and breeding.

Figure 6.6 Screens to exclude entry of insects and

other potential contaminants

A filter or screen should be durable, easy to clean and replace. filtration

screens (made of stainless steel or synthetic mesh) are the simplest, most inexpensive

and widely used. These may be mounted across the top inlet of the storage tank with

the downpipe above the screen (Figure 6.5).

Use both coarse and fine screens to improve water quality.

Coarse screens: To prevent larger size material (leaves, large insects, small

animals) from entering the tank. A 5 mm (0.2 inch mesh) installed before the

tank entry is typical.

Fine screens: To exclude mosquitoes and fine particles from entering the tank.

Insect-proof mesh or strong standard cotton/polypropylene filters installed at

the inlet and outlet of the tank is recommended.




6.4.3 Screens












entry and breeding.

















6.4.3 Screens












entry and breeding.















6.4.4 Filter

Sand filters are commonly available, easy and inexpensive to construct. These

filters can be employed for treatment of water to effectively remove turbidity

suspended be constructed domestically, the top layer comprises of coarse sand

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

Figure 6.7 Rapid Sand Filter Bed

and boulders. These filters are manufactured commercially on a wide scale. Most of

the water purifiers available in the market are of this type.

6.5 The Storage Device

The storage facility is at the core of the RWH system. In addition to having the

appropriate volume Capacity in relation to the catchment area, rainfall conditions and

needs, it must be functional, durable and cost-effective in its installation and

maintenance. An ideal or ‘universal’ storage tank design does not exist; selection of

the type of storage facility ultimately depends on purpose of use, affordability,

Availability of supplies and materials, and know-how in design and installation.

Considerations in design and operation of the storage facility:

Water-tight construction with a secure cover to keep out insects and other

vermin, dirt and sunshine (note, exposure to sunlight will cause algal growth

in stored water);

• Screened inlet to prevent particles and mosquitoes from entering the tank;

• Screened overflow pipe to prevent mosquito entry and breeding;


• In the case of cisterns, inclusion of a manhole (to permit insertion of a ladder)

to allow access for cleaning;

• An extraction system that does not contaminate the water during operation

(related to tap and pump installation);

• Soak away to prevent spilt water forming standing puddles near the tank

(minimize mosquito breeding);

• In the case of cisterns, a maximum height of 2 meters (related to water depth)

to prevent build up of high water pressure (unless additional reinforcement is

used in walls and foundations).

6.5.2 Sizing of the storage facility

The size of the storage facility depends on the rainfall regime, the roof

material and area, the expected water demand, the cost of construction/installation and

the degree of reliability the owner desires. An undersized storage system will not

satisfy demands while an oversized one might never be fully utilized. As a rule-of-

thumb, it is advised that the system be ‘over-designed’ to provide at least 20% more

than the estimated demand.

There are several methods that can be used to estimate the size of the storage tank.

(1) Dry period demand method,

(2) The graphic method,

(3) The simple method and

(4) The simple tabular method.

Adopt the simple method for storage tank.

(1) Dry period demand method

In this approach, one simply estimates the longest average time period without

any rainfall for your particular geographic area. This will typically coincide with the

dry season which in the Surat city generally runs from January to May. Your local

meteorological office can be consulted to obtain such estimates. Hence, if your

industrial daily demand in 100 liters (22 gallons) and the dry season runs on average

for 120 days, then the size of your storage should be 12,000 liters (2,640 gallons).


(2) Simple method

In this method, the average annual water consumption is estimated for the

industry, based on the consumption of water. The average duration of the longest

rainless period is also assumed in terms of number of days. This rainless duration

period is in turn expressed as a ratio (of the duration of a year) and multiplied by the

annual consumption to estimate the volume of water that will be required for this

period.

To calculate consumption by Simple Method

This is based on the consumption rates of the industry without taking the

rainfall amount or roof size into consideration. This method is applicable in cases

where sufficient rainfall and catchment area are available. It is a rough guide to

estimate your tank size. This method is used in the estimation of tank size based on

rainfall variability and demand over the course of a year. The process comprises of

four key steps.

1. Obtain monthly rainfall data for a year that was particularly dry or the rainfall

erratic. This data may be obtained from your local meteorological office.

2. Estimate the volume captured off the roof based on the area of the roof and the

runoff coefficient.

3. Estimate the monthly demand on the basis of the number of persons using the

supply, the individual daily consumption and the average number of days in a

month.

4. Use the monthly volume capture and demand estimates to calculate the

minimum storage required. This information is assembled in a tabular format

that tracks the changes in the cumulative volume captured and stored, the

cumulative demand and the total amount that is stored in any given month.The

difference between the highest volume stored and the amount left in the tank

at the end of the year represents the minimum storage volume.

6.5.2.1 Designs of tanks

In this project tank size is calculated by using tabular method. In this project

two storage tanks are design one is industrial use and other is drinking purpose.


To calculate storage tank for industrial useArea of catchment A= 1200 m3

Average annual rain fall R = 0.65 m (650 mm)Runoff co efficient C = 0.8

So, annual water harvesting = A x R x C= 1200 x 0.65 x 0.8= 624 m3

= 624000 lit.

Water required for industry in dry season = 245 x 20000= 49 x 105

Factor of safety = 10 %= 10 % of 49 x 105

= 49 x 104 lit.= 4900 m3

Industrial use tank = 50 x 33 x 3 m = 4950 m3

To calculate storage tank for drinking purposeArea of catchment A= 1200 m3



= 624000 lit.The drinking water requirement for person,

(In dry season) = 245 x 247 x 3= 181545 liter

As a safety factor = the tank should be built 20% larger than required

Total water required = 217854 liter= 217.85 m3

Size of drinking tank is = 10 x 14.5 x 1.5 m = 218 m3

6.5.1 Tank inlet and outlet configurations

The quality of water resident in the tank generally improves with time. This is

because bacteria will die-off within 2 to 20 days and suspended particles fall to the

bottom. Incoming rainwater is therefore often of lower quality than stored rainwater.

To ensure the separation of these different water qualities, the outflow of the down-

pipe should be placed at the near-bottom of the tank so that the older ‘improved’

water is forced to the top layer.


Figure 6.8 Design configurations for (a) tank inflow and (b) outflow

A low-rise pipe surrounding the down pipe called the ‘break ring’. Helps

break the force of the outflow preventing it from disturbing any sediment that may

have accumulated on the tank bottom. To extract the cleaner top layer of water, a

flexible intake hose attached to a float is recommended in figure 6.8.

6.5.3 Tank overflow configurations

An overflow is installed to reduce the possibility of system collapse during a

rainstorm when the tank may fill rapidly. Figure shows the simplest overflow

arrangement, although this means that the better quality water at the surface will be

lost to the outflow. The configurations showed in below Figures (a) & (b) are better

solutions as the good quality water within the top layer remains in the tank. The

arrangement shown in Figure allows for automatic de-sludging of the tank which is

recommended for large tanks.

Figure 6.9 Design configurations for tank overflows

The arrangement shown in Figure (d) allows for the separation of floating

material that may still enter the tank. It is recommended that the overflow should be

located close to the tank roof so as to avoid ‘dead storage’.


6.5.4 Artificial Recharge

Recharge Pits are constructed for

recharging the shallow aquifers. These are

generally on structed 1 to 2 m. wide and 2 to

3 m. deep. After excavation, the pits are

refilled with pebbles and boulders as well as

coarse sand. The excavated pit is lined with a

brick/stone wall with openings (weep-holes)

at regular intervals. The top area of the pit

can be covered with a perforated cover.

Design procedure is the same as that of a

settlement tank. The size of filter material is

generally taken as below:

Coarse sand: 1.5 - 2 mm

Gravels: 5 - 10 mm Figure 6.10 Artificial Recharge Well

Boulders: 5 - 20 mm

The filter material should be filled in graded form. Boulders at the bottom,

gravels in between and coarse sand at the top so that the silt content that will come

with runoff will be deposited on the top of the coarse sand layer and can easily be

removed. If clay layer is encountered at shallow depth, it should be punctured with

auger hole and the auger hole should be refilled with fine gravel of 3 to 6 mm size.

Recharge pits 1 to 2 m wide and 2 to 3 m deep are constructed to recharge

shallow aquifers.

After excavation, the pit is refilled with boulders and pebbles at the bottom

followed by gravel and then sand at the top.

The collected water from the rooftop is diverted to the pit through a drainpipe.

Recharge pit can be of any shape i.e. circular, square or rectangular. If the pit

is trapezoidal in shape, the side slopes should be steep enough to avoid silt

deposition.


CHAPTER: 7 CONCLUSIONS AND DESIGN SUMMERY

7.1 GENERAL

Major parts of our country have been facing continuous failure of monsoon

and consequent deficit of rainfall over the last few years. Also, due to ever increasing

population of India, the use of ground water has increased drastically leading to

constant depletion of ground water level causing the wells and tube wells to dry up.

In some places, excessive heat waves during summer create a situation similar

to drought. It is imperative to take adequate measures to meet the drinking water

needs of the people in the country besides industrial purpose. Out of 8760 hours in a

year, most of the rain in India falls in just 100 hours.

In Surat city river tapi is the main source of drinking water because

underground water level depth is so high. In particularly in industrial area water

demand is so high compare to availability of water through Surat Municipal

Corporation. According to this crisis this research is help to fulfill water demand and

to uplift underground water level. Rain water harvesting is the best solution for

underground water recharging and water is used in industrial production work.

7.2 DESIGN SUMMERY

1. The catchment area of roof

Supply (liters per year) = rainfall (mm/year) x area (m2) x runoff

coefficient




• Roof surface is smooth corrugated metal. This surface is assumed to have a

runoff

Coefficient of 0.8

Supply (liters per year) = rainfall (mm/year) x area (m2) x runoff coefficient

= 650 x 470 x 0.8

= 2, 44,400liters per year.


2. The Conveyance System

(A) Gutters

The size (width) of the gutters should be chosen based on the roof

section area. Design length of roof is 60 meter. Select gutter size based on 1

centimeter per meter or 1/8 inch per foot. So adopt diameter of gutter pipe is

60 centimeter.

(B) First-flush diverter

It is generally assumed that a depth of rainfall on the roof equivalent to

0.5 mm is required to wash off the accumulated contaminants. You first need

to determine the area of the roof and simply multiply by 0.5MM. Secondly, to

determine the length of first-flush down-pipe diversion requires you divide the

required volume of water to be diverted, by the cross-sectional area of the

pipe, where p = 3.14 and r is the radius or ½ the diameter of the pipe.

Roof length = 60 meters

Roof width = 20 meters

Pipe diameter = 175 mm (7 inch), therefore radius = 87.5 mm (3.5 inch)

Volume of diverted water (liters) = Unit length (m) x Unit width (m) x

0.5 (mm)

= 60 x 20x 0.5

= 600 liters (or 132 gallons)

Pipe length (m) = Volume of diverted water (l) ÷ [3.14 x pipe radius2

(mm) x 0.001]

= 600 ÷ [3.14 x (87.5)2 x 0.001]

= 25m

Pipe length (feet) = Volume of diverted water (gal) x 22.57 ÷ (3.14 x pipe

radius2 (inch))

= 132 x 22.57 ÷ (3.14 x3.52)

= 77.45 ft.


(C) Screens

Fine screens: To exclude mosquitoes and fine particles from

entering the tank. Insect-proof mesh or strong standard

cotton/polypropylene filters installed at the inlet and outlet of the tank

is recommended.

3. Rapid sand filter

Sand filters are commonly available, easy and inexpensive to

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

remove turbidity suspended be constructed domestically, the top layer

comprises of coarse sand followed by a 5-10 mm layer of gravel followed by

another 5-25 mm layer of gravel and boulders.

4. Size of tank

(A) Storage tank for industrial useArea of catchment A= 1200 m3



= 624000 lit.

Water required for industry in dry season = 245 x 20000= 49 x 105

Factor of safety = 10 %= 10 % of 49 x 105

= 49 x 104 lit.= 4900 m3

Industrial use tank = 50 x 33 x 3 m = 4950 m3

(B) Storage tank for drinking purposeArea of catchment A= 1200 m3

Average annual rain fall R = 0.65 m (650 mm)Runoff co efficient C = 0.8So, annual water harvesting = A x R x C

= 1200 x 0.65 x 0.8= 624 m3

= 624000 lit.


The drinking water requirement for person,(In dry season) = 245 x 247 x 3

= 181545 literAs a safety factor = the tank should be built 20% larger than required

Total water required = 217854 liter= 217.85 m3

Size of drinking tank is = 10 x 14.5 x 1.5 m = 218 m3

5. Tank inlet and outlet configurations

A low-rise pipe surrounding the down pipe called the ‘break ring’.Helps break the force of the outflow preventing it from disturbing anysediment that may have accumulated on the tank bottom. To extract thecleaner top layer of water, a flexible intake hose attached to a float.

6. Tank overflow configurationsAn overflow is installed to reduce the possibility of system collapse

during a rainstorm when the tank may fill rapidly. The separation of floating

material that may still enter the tank. It is recommended that the overflow

should be located close to the tank roof so as to avoid ‘dead storage’.

7. Artificial recharge well

Artificial Recharge well is constructed for recharging the shallow aquifers.

These are generally on structed 1 to 2 m. wide and 2 to 3 m. deep. . The size of filter

material is generally taken as Coarse sand: 1.5 - 2 mm, Gravels: 5 - 10 mm, Boulders:

5 - 20 mm.

R

REFERENCES

1. A planning guides for Tanzania, (2000) ‘Rainwater Harvesting for Natural

Resources Management’, Regional Land Management Unit, RELMA/Sida,

ICRAF House, Gigiri P. O. Box 63403, Nairobi, Kenya.

2. A Contractor’s guide,(2005) ‘Domestic Rainwater Harvesting in Queensland’,

Helping Queenslanders Build Better.

3. Adrienne LaBranche, Hans-Otto Wack,(2007) ‘Virginia Rainwater Harvesting

Manual’, the Cabell Brand Center, Salem, VA.

4. B. R. T. Vilane and E. J. Mwendera, (2011) ‘An inventory of rainwater harvesting

technologies in Swaziland’, African Journal of Agricultural Research Vol. 6(6),

pp. 1313-1321.

5. Brown, R. (2007) ‘Rainwater and Grey Water: Technical and economic

feasibility’, Draft Report. BSRIA Ltd for the Market Transformation Programme.

6. Che-Ani A.I and Shaari N, (2009) ‘Rainwater Harvesting as an Alternative Water

Supply in the Future’, European Journal of Scientific Research, ISSN 1450-216X

Vol.34 No.1 (2009), pp.132-140.

7. Christopher Kloss, (2008) ‘Rainwater Harvesting Policies’, Municipal Handbook,

Low Impact Development Center, EPA-833-F-08-010.

8. Dr. Hari J. Krishna, (2005) ‘The Texas Manual on Rainwater Harvesting’, Texas

Water Development Board, Austin

9. Dr. D. K. Chadha, (2000) ‘Rain Water Harvesting and Artificial Recharge to

Ground Water’, Central Ground Water Board Jamnagar House, Mansingh Road

New Delhi-110011.

10. Dr. L. Minaketan Singh, P.I., (2006) ‘Pilot Project on Rain Water Harvesting in

Manipur Manipur Science & Technology Council Central Jail Road, Imphal - 795

001.

11. Dr. S.C. Dhiman,(2011) ‘Rain Water and Artificial Recharge’, Central Ground

Water Board, Ministry of Water Resources, New Delhi.

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12. Environment Agency, (2008) ‘Harvesting rainwater for domestic uses: an

information guide’, Environment Agency, Rio House, Waterside Drive, Aztec

West, Almondsbury, Bristol BS32 4UD.

13. Fewkes, A. (2005) ‘The technology, design and utility of rainwater catchment

systems’, In Water Demand Management Memon, FA and Butler, D (eds). IWA

Publishing.

14. Hassell, C. (2005) ‘Rainwater harvesting in the UK – a solution to increasing

water shortages?’ Proceedings of the 9th International Conference on Rainwater

Catchment Cistern Systems. Petrolina, Brazil.

15. Janette Worm, Tim van Hattum, (2006) ‘Rainwater harvesting for domestic use’,

Agromisa Foundation and CTA, Wageningen, The Netherlands.

16. Kalyan Ray, (2005) ‘Rainwater Harvesting and Utilisation’, Settlements

Programme (UN-HABITAT) Water, Sanitation and Infrastructure Branch P.O.

Box. 30030, Nairobi, Kenya.

17. Konig, Klaus W., (2008) ‘A Low impact architecture in Germany Cooling with

Rainwater’, Architekturbüro, Jakob-Kessenring-Str. 38, 88662 Überlingen /

Germany.

18. Konig, K. W. (2001) ‘The Rainwater Technology Handbook: Rainwater

Harvesting in building’, Wilo-Brain, Dortmund.

19. Leggett, D. J., Brown, R., Brewer, D., Stanfield, G. and Holiday, E. (2001)

‘Rainwater and grey water use in buildings: Best practice guidance’, (C539).

CIRIA, London.

20. Manoj P. Samuel and A.C. Mathew, (2008) ‘Rejuvenation of Water Bodies by

Adopting Rainwater Harvesting and Groundwater Recharging Practices in

Catchment Area – A case study’, Proceedings of Taal2007: The 12th World Lake

Conference 766 776.

21. Patricia H. Waterfall, (2006) ‘Harvesting rainwater for landsace used’, Arizona

Department of Water Resources, Tucson Active Management Area, 400 W.

Congress, Suite 518, Tucson AZ 85701.

22. S. Vishvanath, (2001) ‘Rainwater Harvesting in urban area’, 2646 main 6 block,

BEL layout, Vidyaranyapura, Bangalore, 560 097.

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23. S. I. Oni, Emmanuel Ege, Charles Asenime, and S.A. Oke, (2008) ‘Rainwater

Harvesting Potential for Domestic Water Supply in Edo State’, Indus Journal of

Management & Social Sciences, Vol.2, No. 2: 87-98.

24. Surat Municipal Corporation (SMC) and Surat urban Development Authority

(SUDA), (2008-2012) ‘City Development Plan’, CEPT University Ahmadabad.

25. Sarah Ward, (2008) ‘Rainwater Harvesting in the UK – Current Practice and

Future Trends’, Centre for Water Systems, School of Engineering, Computer

Science and Mathematics University of Exeter, Exeter, EX4 4QF UK.

26. Tanuja Ariyananda, (2007) ‘Rain Water for Urban Buildings in Sri Lanka’,

Subtropical Green Building International Conference, Taipei, Taiwan 2007.

27. Websites

http://www.suratmunipalcorporation.org.in http://www.freerain.co.uk/domestic-case-study.html http://www.rainharvesting.co.uk http://www.eng.warwick.ac.uk

A

ANNEXURE A

VISIT PHOTOS

A

A

ANNEXURE B

S.T.B.S. COLLEGE OF DIPLOMA ENGINEERINGCIVIL ENGINEERING DEPARTMENT

SUB: PROJECT-2 SEM: 6TH

CLASS: 961-CIVIL BATCH: CDATE:_____________

PLANNING FOR RAIN WATER HARVESTING: INDUSTRIALAREA

CONTACT DETAILSCompany name:_________________________________________________________

Companyaddress:________________________________________________________

______________________________________________________

Telephone: ___________________ Post code:_______________________

Fax: ________________________

E-mail:_____________________________

SITE SPECIFICATION

Source of water: __________________________________________________________

Water gain from sources: SMC treated water_______________ Raw water_________

Present water demand: ___________________

Future water demand: ____________________

Bore well: Yes / No No. of bore well: _____________

Storage tank: Underground / elevated Capacity of tank: _____________

Roof type: ____________________

Roof area: ______________________

Area of structure around company:____________________________________________

Available open area of company: ___________________

Types of production:_________________________________________________

Use for garden irrigation: ___________________

Area of garden: ________________

Are you interested to install rainwater harvesting system? YES / NO

NOTE:__________________________________________________________________

_______________________________________________________________________

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ANNEXURE C

Surat City Last Five Years Rain Fall Data

A B C D E F G

Month

VolumeCaptured in

Month(liters)

CumulativeVolume

Captured

VolumeDemandin Month

CumulativeDemand

TotalAmountStored(C-E)

Deficit/surplusfor Month

(B-D)

April 0 0 1,90,625 1,90,625 –1,90,625 –1,90,625May 0 0 1,90,626 3,81,250 –3,81,250 –1,90,625June 4,18,328 4,18,328 1,90,627 5,71,875 –1,53,547 2,27,703July 1,59,5440 20,13,768 1,90,628 7,62,500 12,51,268 14,04,815

August 12,89,680 33,03,448 1,90,629 9,53,125 23,50,323 10,99,055September 9,09,216 42,12,664 1,90,630 11,43,750 30,68,914 7,18,591

October 1,53,048 43,65,712 1,90,631 13,34,375 30,31,337 –37,577November 88,951 44,54,663 1,90,632 15,25,000 29,29,663 –1,01,674December 0 44,54,663 1,90,633 17,15,625 27,39,038 –1,90,625

January 0 44,54,663 1,90,634 19,06,250 25,48,413 –1,90,625February 21,280 44,75,943 1,90,635 20,96,875 23,79,068 –1,69,345

March 0 44,75,943 1,90,636 22,87,500 21,88,443 –1,90,625

A

ANNEXURE D

Sine of the Roof angle: Multiply by Roof Dimensions

Angle(Degrees)

Sine(Angle)

Angle(Degrees)

Sine(Angle)

Angle(Degrees)

Sine(Angle)

Angle(Degrees)

Sine(Angle)

Angle(Degrees)

Sine(Angle)

1 0.0175 21 0.3584 41 0.6561 61 0.8746 81 0.9877

2 0.0349 22 0.3746 42 0.6691 62 0.8829 82 0.9903

3 0.0523 23 0.3907 43 0.6820 63 0.891 83 0.9925

4 0.0698 24 0.4067 44 0.6947 64 0.8988 84 0.9945

5 0.0872 25 0.4226 45 0.7071 65 0.9063 85 0.9962

6 0.1045 26 0.4384 46 0.7193 66 0.9135 86 0.9976

7 0.1219 27 0.4540 47 0.7314 67 0.9205 87 0.9986

8 0.1392 28 0.4695 48 0.7431 68 0.9272 88 0.9994

9 0.1564 29 0.4848 49 0.7547 69 0.9397 89 0.9998

10 0.1736 30 0.5000 50 0.7660 70 0.9455 90 1.0000

11 0.1908 31 0.5150 51 0.7771 71 0.9951

12 0.2079 32 0.5299 52 0.7880 72 0.9511

13 0.2250 33 0.5446 53 0.7986 73 0.9563

14 0.2419 34 0.5592 54 0.8090 74 0.9613

15 0.2588 35 0.5736 55 0.8192 75 0.9659

16 0.2756 36 0.5878 56 0.8290 76 0.9703

17 0.2924 37 0.6018 57 0.8387 77 0.9744

18 0.3090 38 0.61557 58 0.8780 78 0.9781

19 0.3256 39 0.6293 59 0.8572 79 0.9816

20 0.3420 40 0.6428 60 0.8660 80 0.9848

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Rainwater Harvesting