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GUJARAT TECHNOLOGICAL UNIVERSITY Chandkheda, Ahmedabad Affiliated Sardar vallabhbhai Patel institute of technology, vasad A Project Report On (RAINWATER HARVESTING) Under subject of DESIGN ENGINEERING – I B. E. II, Semester – III (Civil Branch) Submitted by: Group: Sr. Name of student Enrollment No....

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RAINWATER HARVESTING Ashish Chabhadiya

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GUJARAT TECHNOLOGICAL UNIVERSITY Chandkheda, Ahmedabad Affiliated

Sardar vallabhbhai Patel institute of technology, vasad A Project Report On

(RAINWATER HARVESTING) Under subject of

DESIGN ENGINEERING – I B. E. II, Semester – III (Civil Branch) Submitted by: Group: Sr. 1. 2. 3. 4. 5.

Name of student

Enrollment No.

Ashish j. Chabhadiya Gaurav k. Jadav Ronak Mistri Pragnesh Prajapati Vatsal d Kataria

140413106002 140413106004 140413106007 140413106010 130410206060

Prof. F.M.Patel (Faculty Guide) AAAA BBBBB CCCCC Head of the Department Academic year (2014-2015)

CERTIFICATE

This is to certify that the Project Report entitled “RAINWATER HARVESTING” submitted by Vatsal Kataria, Ashish Chabhadiya, Gaurav Jadav, Ronak Mistri, and Pragnesh Prajapati in partial fulfillment of the requirements for the award of Bachelor Of Technology Degree in Civil Engineering at Sardar valllabhbhai Patel Institute of Technology, Vasad (Gujarat technological University) is an authentic work carried out by them under our supervision and guidance.

To the best of our knowledge, the matter embodied in this Project Report has not been submitted to any other University/Institute for the award of any Degree or Diploma. DATE:-

Prof. V.R.Panchal 2|

Prof. F.M.Patel Department of civil eng., SVIT, Vasad

ACKNOWLEDGEMENTS

My heart pulsates with the thrill for tendering gratitude to those persons who helped me in completion of the project.

The most pleasant point of presenting a thesis is the opportunity to thank those who have contributed to it. Unfortunately, the list of expressions of thank no matter how extensive is always incomplete and inadequate. Indeed this page of acknowledgment shall never be able to touch the horizon of generosity of those who tendered their help to me.

We extend our deep sense of gratitude and indebtedness to our guide Prof. F.M.Patel Department Of Civil Engineering, Saradar valabhbhai patel institute of Technology, vasad for their kind attitude, invaluable guidance, keen interest, immense help, inspiration and encouragement which helped us carrying out our present work.

We are extremely grateful to Prof. V.R.Panchal, Professor and Head of the Department of Civil Engineering for providing all kind of possible help throughout the one semesters for the completion of this project work.

It is a great pleasure for us to acknowledge and express our gratitude to our classmates and friends for their understanding, unstinted support and endless encouragement during our study.

Lastly, we thank all those who are involved directly or indirectly in completion of the present project work.

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Department of civil eng., SVIT, Vasad

TABLE OF COUNT Name of topic

Page No.

Abstract…………………………………………………………………….. 6 List of figure and table…………………………………………………….. 7

No.

Topic name

Page No.

1.

Introduction

8 8 9 10

1.1. What is rainwater harvesting?? 1.2. Definition of rainwater harvesting ? 1.3. Why harvest rainwater ?

2.

How to harvest rain water?? 2.1. Surface runoff harvesting 2.2. Roof top rainwater harvesting

3.

Whether to store rainwater or use it for recharge

12

4.

Component of rainwater harvesting

13 14 14 14 14 15 16 16 16 16 17 17 18 18 19

4.1. Catchments 4.2. Coarse mesh 4.3. Gutters 4.4. Conduits 4.5. First-flushing 4.6. Filter (4.6.1) Charcoal water filter (4.6.2) Sand filters (4.6.3) Rain PC (4.6.4) Rainwater harvester (4.6.5) Filters available in the German Market (4.6.5.1) Filters developed by WISY (4.6.5.2) Filters developed by MALLBETON

4.7. Storage facility 4|

10 11 12

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4.8. Recharge structures 4.8.1. Recharging of dug wells and abandoned tube wells 4.8.2. Settlement tank 4.8.3. Recharging of service tubewells 4.8.4. Recharge pits 4.8.5. Soakaways / Percolation pit 4.8.6.Recharge trenches 4.8.7.Recharge troughs 4.8. 8. Modified injection well

5.

Benefits & Limitations

19 19 20 20 20 21 21 21 21 22 22 22 23 23 24

5.1. Main Benefits 5.1.1. Users 5.1.2. Government 5.1.3. Environment

5.2. Limitation

6.

Advantage and Disadvantage

24

7.

Quality

26

8.

Cultural acceptability

27

9.

Effectiveness of technology

28

10.

History

28 28 28 29 31 31 30

10.1. Earlier 10.2. Present day 10.2.1India 10.2.2.Iran 10.2.3. Israel 10.2.4. South Africa

11. 12. 5|

Scope of project work References

32 33 Department of civil eng., SVIT, Vasad

ABSTRACT

At the rate in which India population is increasing, it is said that India will surely replace China from its number 1 position of most densely populated country of the world after 20-30. These ill lead to high rate of o su ptio of

ost alua le atural resour e „Water‟ resulti g i

augmentation of pressures on the permitted freshwater resources. Ancient method of damming river and transporting water to urban area has its own issues of eternal troubles of social and political. In order to conserve and meet our daily demand of water requirement, we need to think for alternative cost effective and relatively easier technological methods of conserving water. Rain water harvesting is one of the best methods fulfilling those requirements. The technical aspects of this paper are rainwater harvesting collected from rooftop which is considered to be catchment areas from all hostels and Institutes departmental building at N.I.T. Rourkela Campus. First of all, required data are collected i.e. catchment areas & hydrological rainfall data. Water harvesting potential for the hostels and faculty apartments was calculated, and the tank capacity with suitable design is being considered. Volume of tank has been calculated with most appropriate method of estimation. Optimum location of tank on the basis of hydrological analysis and GIS analysis was done in the campus. Finally, Gutter design, its analysis, first flush and filtration mechanism are also dealt with in detail.

Keyword: Rainwater harvesting, first flush mechanism, Roof water system, Gutter for conveyance, Underground RCC tank, Methods of distribution of harvested rainwater. 6|

Department of civil eng., SVIT, Vasad

List of figure and Table

List of Figure

Page No.

Figure: 1. Rainwater harvesting system…………………………………………………………….8 Figure: 2. Layout Rainwater harvesting system………………………….…………………………9 Figure: 3. A Water Harvesting Manual For Urban Areas……………………………..…………..12 Figure: 4. A rainwater harvesting component……………………………………………………..13 Figure: 5.water harvesting for urban areas…………………………………...……………………14 Figure: 6. A water harvesting manual for urban areas………………………….………………….15 Figure: 7. Charcoal water filter……………………………………..….…………….…………….16 Figure: 8. Sand filter……………………………………………………..……….………………..16 Figure: 9. Rain PC…………………………………………………………..…….……………….16 Figure: 10. A filter collector diverts 90 per cent of rainwater to a storage tank through a 0.17 mm stainless steel mesh filter……………………………………………………..…………18 Figure: 11.A larger vortex fine filter can cope with run-off from roof areas of up to 500 square metre…………………………………………………………………………….…………18 Figure: 12. A floating fine suction filter for ensuring that the water pumped from the tank is extracted from the cleanest part of the tank and is free of particulates has also been developed….18 Figure: 13.storage tank made of galvanized iron sheets…………………………..……………….19 Figure: 14. A settlement chamber………………………………………………….………………20 Figure: 15 .Filter materials in a soakaway…………………………………………………………21 Figure: 16. A water harvesting manual for urban areas……………………………..……………..21 Figure: 17. Modified injection well………………………………………………………………..22 Figure: 18. Mape of iran………………………………………………………..…………………..31

Table Table: 1. Sizing of rainwater pipe for roof drainage………………………………………………………..15 Table: 2. Building with RHS……………………………………………………………………………….......30

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Department of civil eng., SVIT, Vasad

1. Introduction 1.1. What is rainwater harvesting?? Although close to three fourths of our planet is made of water, not all of it suitable for use. The water in oceans and seas cannot be used as drinking water and little of it can be utilized for other purposes. As result, there is constant storage of water that is either good for drinking or home and industrial use. Areas on the planet that have long faced water storage were able to combat this problem by harvesting what little rain water they received this slowly stared spreding to areas where there was plenty of rainfall. As result, the modern day rain water harvesting system was bought in to place.

rainwater harvesting is a technology used for collecting and storing rainwater from rooftops, the land surface or rock catchments using simple techniques such as jars and pots as well as more complex techniques such as underground check dams. The techniques usually found in Asia and Africa arise from practices employed by ancient civilizations within these regions and still serve as a major source of drinking water supply in rural areas.

Figure: 1. Rainwater harvesting system

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Department of civil eng., SVIT, Vasad

1.2. Definition of rainwater harvesting ?  

Rainwater harvesting is the accumulating and storing of rain water. http://wiki.answers.com Rainwater harvesting, in its broadest sense, is a technology used for collecting and Storing rainwater from rooftops, land surfaces and rock catchments for human use; and it utilizes simple methods such as jars and pots as well as engineered techniques for collection and storage.



UN-HABITAT Guide on Rainwater Harvesting In scientific term, Rainwater harvesting refers to collection and storage of rainwater and also other activities aimed at harvesting surface and groundwater, prevention of loses through evaporation and seepage and all other hydrological studies and engineering interventions, aimed at conservation and efficient utilization of the limited water endowment of physiographic unit as a watershed.



Agrawal and Narain, 1999 Rainwater harvesting is a technique used for collecting, storing, and using rainwater for landscape irrigation and other uses. The rainwateris collected from various hard surfaces



such as roof tops and/or other types of manmade above ground hard surfaces.



rather than allowing it to runoff.

Rainwater harvesting is the accumulation and deposition of rainwater for reuse on-site,

Rainwater harvesting is a technology used for collecting and storing rainwater for human use.

Figure: 2. Layout Rainwater harvesting system

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Department of civil eng., SVIT, Vasad

1.3. Why harvest rainwater ? ―Earth provides enough to satisfy every man's needs, but not a single man's greed.‖ -Mahatma Gandhi Water scarcity is the lack of sufficient available water resources to meet the demands of water usage within a region. According to United Nations Development Programmed, this currently affects around 2.8 billion people around the world, on all continents, at least one month out of every year and more than 1.2 billion people lack the access to clean drinking water. Over-consumption/excessive or unnecessary use of resources, Overpopulation, Slash and burn agricultural practices in developing countries, Technological and industrial development, Erosion, Habitat degradation leads to the loss of Biodiversity (i.e. species and ecosystems with its ecosystem services), Irrigation, Mining for oil and minerals, Aquifer depletion, Pollution or contamination of resources are the major factors responsible for the eminent water crisis.

This is perhaps one of the most frequently asked question, as to why one should harvest rainwater. There are many reasons but following are some of the important ones. 









To arrest ground water decline and augment ground water table To beneficiate water quality in aquifers To conserve surface water runoff during monsoon To reduce soil erosion To inculcate a culture of water conservation

2. How to harvest rain water?? Water Harvesting refers to collection and storage of rainwater and also other activity such as harvesting surface water extracting ground water , prevention of loss through evaporation and seepage. Rainwater harvesting has been practiced for more than 4,000 years, it is also a good option in areas where good quality fresh surface water or ground water is lacking. In doing so, water harvesting assures a continuous and reliable access to water. The role of rainwater harvesting systems as sources of supplementary, back-up, or emergency water supply will become more 10 |

Department of civil eng., SVIT, Vasad

important especially in view of increased climate variability and the possibility of greater frequencies of droughts and floods in many areas.

Broadly there are two ways of harvesting rainwater:

(i)

Surface runoff harvesting

(ii)

Roof top rainwater harvesting

2.1. Surface runoff harvesting:

In urban area rainwater flows away as surface runoff. This runoff could be caught and used for recharging aquifers by adopting appropriate methods. •

Rooftops

•

Paved and Unpaved Areas (Surface Runoff)

•

Water bodies

•

Storm water Drain

• 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. • Paved and Unpaved Areas (Surface runoff): 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 collecting surface is that Water can be collected from a larger area. This is particularly advantageous in areas of Low rainfall. • Water bodies: The potential of lakes, tanks and ponds to store rainwater is immense. The harvested rainwater can not only be used to meet water requirements of the city, It also recharges groundwater aquifers. • 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.

2.2. Roof top rainwater harvesting 11 |

Department of civil eng., SVIT, Vasad

It is a system of catching rainwater where it falls. In rooftop harvesting, the roof becomes the catchments, and the rainwater is collected from the roof of the house/building. It can either be stored in a tank or diverted to artificial recharge system. This method is less expensive and very effective and if implemented properly helps in augmenting the ground water level of the area.

3.Whether to store rainwater or use it for recharge The decision whether to store or recharge water depends on the rainfall pattern and the potential to do so, in a particular region. The sub-surface geology also plays an important role in making this decision. For example, Delhi, Rajasthan and Gujarat where the total annual rainfall occurs during 3 or 4 months, are examples of places where groundwater recharge is usually practiced. In places like Kerala, Mizoram, Tamil Nadu and Bangalore where rain falls throughout the year barring a few dry periods, one can depend on a small sized tank for storing rainwater, since the period between two spells of rain is short. Wherever sub-strata is impermeable recharging will not be feasible. Hence, it would be ideal to opt for storage.

Figure: 3. A Water Harvesting Manual For Urban Areas

12 |

Department of civil eng., SVIT, Vasad

In places where the groundwater is saline or not of potable standards, the alternate system could be that of storing rainwater. Beyond generalisations, it is the requirement that governs the choice of water harvesting technique. For example, in Ahemadabad, which has limited number of rainy days as that of Delhi, traditional rainwater harvesting tanks, known as tankas, are used to store rainwater even today in residential areas, temples and hotels.

4. Component of rainwater harvesting A rainwater harvesting system comprises components of various stages - transporting rainwater through pipes or drains, filtration, and storage in tanks for reuse or recharge. The common components of a rainwater harvesting system involved in these stages are illustrated here.

Figure: 4. A rainwater harvesting component

13 |

Department of civil eng., SVIT, Vasad

4.1. Catchments: The catchment of a water harvesting system is the surface which directly receives the rainfall and provides water to the system. It can be a paved area like a terrace or courtyard of a building, or an unpaved area like a lawn or open ground. A roof made of reinforced cement

Figure: 5.water harvesting for urban areas

concrete (RCC), galvanized iron or corrugated sheets can also be used for water harvesting. 4.2. Coarse mesh: at the roof to prevent the passage of debris.

4.3. Gutters: Channels all around the edge of a sloping roof to collect and transport rainwater to the storage tank. Gutters can be semi-circular or rectangular and could be made using:   

Locally available material such as plain galvanized iron sheet (20 to 22 gauge), folded to required shapes. Semi-circular gutters of PVC material can be readily prepared by cutting those 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 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. 4.4. Conduits: Conduits are pipelines or drains that carry rainwater from the catchment or rooftop

area to the harvesting system. Conduits can be of any material like polyvinyl chloride (PVC) or galvanized iron (GI), materials that are commonly available. The following table gives an idea about the diameter of pipe required for draining out rainwater based on rainfall intensity and roof area: 14 |

Department of civil eng., SVIT, Vasad

Table: 1. Sizing of rainwater pipe for roof drainage Diameter Of pipe (mm)

Average rate of rainfall in mm/h

50

75

100

125

150

200

50

13.4