RAINWATER HARVESTING MINIPROJECT REPORT.pdf

GOVERNMENT POLYTECHNIC COLLEGE MEENANGADI
DEPARTMENT OF CIVIL ENGINEERING, GPTC i
GOVERNMENTOF KERALA
[DEPARTMENT OF CIVIL ENGINEERING]
MINI PROJECT REPORT 2021-2022
A PROJECT ON
RAINWATER HARVESTING
PRESENTED BY
GROUP-4
DEPARTMENTOF TECHNICAL EDUCATION
GOVERNMENTPOLYTECHNIC COLLEGE
MEENANGADI--WAYANAD

DEPARTMENT OF CIVIL ENGINEERING, GPTC ii
CERTIFICATE
This is to certify that the Bonafede record of Mini Project Report titled “RAINWATER
HARVESTING” has been done by ALEENA.THOMAS-19011063, ASNA BANU T-
19011077, BASIL PS-19011082, CHITHRA C-19011086, JESLIN TJ-19011091,
MUHAMMED RAMEEZ PP-19011097, MUHAMMED YASEEN-19011099 students of
second year Civil Engineering in partial fulfillment of requirement for the award of
Diploma in Civil Engineering under the directorate of technical education govt. of Kerala,
during the academic year 2021 to 2022 under the guidance of Govt. Polytechnic College
Meenangadi.
Name of HOD Name of Guide
(---------------------) (-----------------)
Date:
Examiners:
1. Internal 2.External
GOVERNMENT POLYTECHNIC COLLEGE
MEENANGADI—WAYANAD
2021-2022

DEPARTMENT OF CIVIL ENGINEERING, GPTC iii
GROUP 4
MEMBERS
MEMBERS REGISTER NO
1) ALEENA THOMAS : 19011063
2) ASNA BANU T : 19011077
3) BASIL PS : 19011082
4) CHITHRA C : 19011086
5) JESLIN TJ : 19011091
6) MUHAMMED RAMEEZ PP : 19011097
7) MUHAMMED YASEEN : 19011099
8) SHEBA M SHAJI : 19011109
9) NAVEENA VINOD : 19012212

DEPARTMENT OF CIVIL ENGINEERING, GPTC iv
ACKNOWLEDGEMENT
In the accomplishment of mini project Successfully,many people have best owned upon
us their blessings and the heart pledged support. Our group is utilizing this time to thank
all people who have been concerned with this project. Our hearts pulsate with the thrill for
tendering gratitude to those persons who helped us in completion of the project. The most
pleasantpointof presentinga projectisthe opportunity to thank those whohave 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 us.
Primarily we would thank God for being able to complete this project with success. Our
group is grateful to thank our principal Mrs. Shobana k and Head of Department Mrs.
Aswathy k v. We are highly indebted to Mrs. Vidya k c for her guidance and constant
supervision as well as for providing necessary information regarding the project & also for
her support in completing the project. Her suggestions and her instructions have served as
the major contribution towardsthe completion of the project.
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
project.
Last but not the least we would like to thank all teaching and non-teaching staff who have
helped us a lot. Lastly, we thank all those who are involved directly or indirectly in
completion of the present project work. We would like to extend our sincere thanks to all
of them.

DEPARTMENT OF CIVIL ENGINEERING, GPTC v
ABSTRACT
At the rate in which Indian population is expanding, it is said that India will definitely
supplant China from its number 1 position of most thickly populated nation of the world
after 20-30. These will prompt high rate of utilization of most profitable regular asset;
Water's subsequent in enlargement of weights on the allowed freshwater assets. Old
technique for damming waterway and transporting water to urban zone has its own issues
of everlasting inconveniences of social and political. Keeping in mind the end goal to save
and take care of our day-by-day demand of water prerequisite, we have to think for elective
savvy and generally less demanding mechanical techniques for monitoring water.
Rainwater harvesting is a technique satisfying those necessities.
This project mainly deals with different methods of rainwater harvesting and different
components of traditional methods that were adopted by ancestors. Preventive measures,
advantages, and disadvantages of rainwater harvesting are also being included in this
project. It also comprehended how to do rainwater harvesting via solar panels? And a case
study is being included for a better understanding of rainwater harvesting.

DEPARTMENT OF CIVIL ENGINEERING, GPTC vi
TABLE OF CONTENTS
CHAPTER NAME PAGE NO.
NO.
ACKNOWLEDGEMENT………………………………….………….iii
ABSTRACT…………………………………..…..………….………...iv
LIST OF FIGURES…………………………………………..…….…viii
TABLE OF CONTENT………………...…….……………….…….vi-vii
1. INTRODUCTION……………………..……...…………………….......9
2. RAINWATER HARVESTING………………………………………..10
2.1 NEED FOR RAINWATER HARVESTING……………….…….....10-11
2.2 ADVANTAGES AND DISADVANTAGES……….....………....…11-12
2.3 APPLICATIONS……………………..……………....…………………12
2.3.1 DOMESTIC USE…………………………...….……….………….12
2.3.2 AGRICULTURE USE………....…………..……….…………..12-13
2.3.3 INDUSTRIAL USE……………...……………………...….………13
2.4 RAINWATER HARVESTING COMPONENTS………………...…….14
3. METHODS OF RAINWATER HARVESTING……...……....…..…....15
3.1 GROUND WATER HARVESTING……………………...........….…...15
3.1.1 USE OF GROUND WATER HARVESTING……………..….…..15
3.1.2 METHODS OF GROUND WATER FILLING…….……………..16
3.1.3 FACTORS AFFECTING GROUND WATER FILLING……...16-17
3.2 ROOF TOP RAINWATER HARVESTING………….…..........……....17
3.2.1 ADVANTAGES ………………….……………….....…........……18
3.2.2 DISADVANTAGES …………………………………….........…...18
3.3 SURFACE RUNOFF HARVESTING…………………...……..….…...18
3.3.1 ADAVANTAGES ………………………….……………………..18
3.3.2 DISADVATAGES ……………………………………...………...19

DEPARTMENT OF CIVIL ENGINEERING, GPTC vii
3.4 TRADITIONAL METHODS OF RAINWATER HARVESTING…...19-20
3.5 MODERN METHODS OF RAINWATER HARVESTING……..…...20-21
3.6 TYPES OF RAINWATER HARVESTING IN INDIA……………….22-23
3.7 RAINWATER HARVESTING BY FRESH WATER………...………….24
3.8 RAINWATER HARVESTING BY SOLAR POWERPANELS………....24
CASE STUDY……………………………………..………………………......25-27
CONCLUSION…………………………………………..………......……..…….28
BIBLIOGRAPHY…………………………………………………………...……29

DEPARTMENT OF CIVIL ENGINEERING, GPTC viii
LIST OF FIGURES
10
14
15
19
20
20
21
25
26
26
27
FIGURE NO. TITTLE PAGE NO.
RAINWATER HARVESTING SYSTEM
RAINWATER HARVESTING COMPONENTS
ROOFTOP RAINWATER HARVESTING
TRADITIONAL METHOD
SAZA KUVA
GROUND WATER DAM
FERROW CEMENT TANK
AREA OF TERRACE
ROOF AREA
SET UPS PROPOSED
RECHARGE PIT
2.01
2.4.1
2.1
3.4.1
3.4.2
3.4.3
3.4.4
[1]
[2]
[3]
[4]

INTRODUCTION
DEPARTMENT OF CIVIL ENGINEERING, GPTC 9
1.INTRODUCTION
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 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 forcenturies.Rainwatercan be usedfor multiple purposesrangingfrom irrigating
crops to washing, cooking and drinking.
In many areas rain water harvesting 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 rain water harvesting 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. It strives to give practical guidance for
households,CBOs, NGOs, local government staff and extension workers in designing and
applying the right systems, methods and techniques for harvesting rainwater on a small
scale (varying from 500 – 60,000 liters). It explains the principles and components of a
rooftop rainwater system for collecting and storing rainwater.
It also strives to guide the process of planning, designing and actual construction.

2.RAIN WATER HARVESTING
Rainwater harvesting, as shown in fig 2.01, is collecting the run-off from a structure or
other impervious surface in order to store it for later use. Traditionally, this involves
harvesting the rain from a roof. The rain will
collect in gutters that channel the water into
downspoutsandthen into some sortof storage
vessel.Rainwatercollection systemscan be as
simple as collecting rain in a rain barrel or as
elaborate as harvesting rainwater into large
cisterns to supply your entire household
demand. The idea of rainwater harvesting
usually conjures up images of an old farm
cistern or thoughts of developing countries.
The reality is that rainwater harvesting is
becoming a viable alternative for supplying
our householdsand businesses with water. It’s not just for the farm anymore! There are
many countries such as Germany and Australia where rainwater harvesting is a norm. Due
to the green building movement, you will be seeing rainwater harvesting systems become
more popular in America.
The collection of rainwater is known by many names throughout the world. It ranges from
rainwatercollection to rainwaterharvestingto rainwatercatchment.In addition,termssuch
as roof water collection or rooftop water collection is also used in other countries. We
believe that rainwater harvesting is a viable technology in an urban setting. All that is
necessary to take advantage of this resource is to capture the free water falling on your roof
and direct it to a rainwater storage tank. By doing this, you can take control of your water
supply and replace all or at least a substantial portion of your water needs. Rainwater
harvesting systems can be configured to supply your whole house and your landscape
needs.
2.1 NEED FOR RAIN WATER HARVESTING
The rapid rise in human population has made optimum use of fresh water imperative.
Urban watersupply systemsin particulararea undertremendouspressure to meetthe needs
of the population as well as industry and large-scale construction. The increased need for
Fig 2.01 Rain water harvesting system

waterresultsin lowergroundwater tablesand depletedreservoirs.Many piped watersupply
systems fail. Consumption of polluted water is beset with health hazards.
The use of rainwater is a useful alternative. The availability of water from sources such as
lakes, rivers and shallow groundwater can fluctuate strongly. Unchecked rainwater runoff
is causing soil erosion. Collecting and storing rainwater can provide water for domestic use
in periods of water shortage. Rainwater may also provide a solution when the water quality
is low or varies during the rainy season in rivers and other surface water resources. Using
more of rainwater helps to conserve & augment the storage of ground water. It helps to
arrest sea water intrusion in coastal areas. It helps to avoid flood & water stagnation in
urban areas Reduces water and electricity bills.
Traditional sources are located at some distance from the community. Collecting and
storing water close to households improves the accessibility and convenience of water
suppliesand hasa positive impact on health.It costs lessto collectrainwaterthan to exploit
groundwater. Only traditional knowledge, skills and materials can be used to collect the
water and no government technical assistance is required for repair and maintenance.
Collecting rainwater is the only way of recharging water sources and revitalizing dry open
wells and dry hand pumps. It can also strengthen a sense of ownership. It gives an
opportunity for communities to come together and work closer. It allows for the
decentralized control and community management of water. It will provide productive
employment to the rural poor in their own villages.
2.2. Advantages
➢ Less cost.
➢ Helps in reducing the water bill.
➢ Decreases the demand for water.
➢ Reduces the need for imported water.
➢ Promotes both water and energy conservation.
➢ Improves the quality and quantity of groundwater.
➢ Does not require a filtration system for landscape irrigation.
➢ This technology is relatively simple, easy to install and operate.
➢ It reduces soil erosion, storm water runoff, flooding, and pollution of surface water
with fertilizers, pesticides, metals and other sediments.

➢ It is an excellent source of water for landscape irrigation with no chemicals and
dissolved salts and free from all minerals.
Disadvantages
➢ Regular Maintenance is required.
➢ Requires some technical skills for installation.
➢ Limited and no rainfall can limit the supply of Rainwater.
➢ If not installed correctly, it may attract mosquitoes and other waterborne diseases.
➢ One of the significant drawbacks of the rainwater harvesting system is storage
limits.
2.3 APPLICATIONS
2.3.1 DOMESTIC USE
Rainwater harvesting is an effective and ecofriendly method of reducing water usage in
yourhome,which willlead to reduced watercharges.Switchingto an ecofriendlyrainwater
harvesting system is neither complicated or time consuming and will result in a wide range
of benefits for your home. Our rainwater harvesting systems can help home owners save
from 50% - 80% of their main water usage. As with our commercial systems, domestic
rainwater harvesting systems are available in two types of systems, direct and in-direct.
With a direct system, the harvested water is pumped directly to the appliances and with an
in-directsystem,the harvested waterispumped to a holdingtank orheadertank and gravity
feeds the appliances.
We have a wide range of tanks to suit any application. We supply both under-ground and
over-ground tanks, where they are one-piece tanks or a series of small tanks to fit into areas
with limited space. Please refer to our Brochure to learn more about our underground &
over ground range. The harvested water can be used for a number of appliances such as
toilets, washing machines, showers, sinks,baths and gardening.
2.3.2 AGRICULTURAL USE
In regards to urban agriculture, rainwater harvesting in urban areas reduces the impact of
runoff and flooding. The combination of urban ‘green’ rooftopswith rainwater catchments

has been found to reduce building temperatures by more than 1.3 degrees Celsius.
Rainwater harvesting in conjunction with urban agriculture would be a viable way to help
meet the United Nations Sustainable Development Goals for cleaner and sustainable cities,
health and wellbeing, and food and water security. The technology is available; however,
it needs to be remodeled in order to use water more efficiently, especially in an urban
setting.
Many countries, especially those with arid environments, use rainwater harvesting as a
cheap and reliable source of clean water.To enhance irrigation in arid environments,ridges
of soil are constructed to trap and prevent rainwater from running down hills and slopes.
Even in periods of low rainfall, enough water is collection for crops to grow. Water can be
collected from roofs, dams and ponds can be constructed to hold large quantities of
rainwater so that even on days when little to no rainfall occurs, enough is available to
irrigate crops.
2.3.3 INDUSTRIAL USE
The variousprocessesof a factory orindustry make a generoususe of waterresource.Some
industries like power generation, textiles and garments, beverage, etc. Make more use of
waterthan their othercounterparts.Alongwith usingwaterforproduction work,the offices
and factories also need to provide enough water for the sanitation and drinking purposes,
to their hundreds of employees. Since the main water source can provide the limited
amount, these industries and offices must rely upon the alternate source of harnessing
water, i.e., rainwater harvesting.
Industrialand otherpublic orprivate commercialbuildingsreportan excessive use ofwater.
For some businessesorindustries,waterisa majorraw material,needed forproduction and
manufacturing of finished business products. For example, car wash businesses, irrigation,
refueling areas, construction sites, etc. For fulfilling such a high demand for water, the
installation of a rainwater harvesting system is strongly advocated (and legally mandated
in some Indian states) in different typesof industrial and office buildings.
2.4 RAIN WATER HARVESTING COMPONENTS
Irrespective of the complexity, rainwater harvesting systems will have the following five
basic components as shown in figure 2.4.1.

1. Catchment: the surface from which rainwater is collected for storage.This could be
a rooftop, a paved flooring surface or a landscaped area. Catchment area is the area
of that surface, usually calculated in square meters.
2. Gutters and Down take pipes: lead the water from the catchment surface to the
storage tank
3. Filters and first flush devices: remove grit, leaves and dirt that the rainwater may
transportfrom the catchment,before the waterentersthe storage tank.When it rains
after a long gap, the rooftops are usually very dirty and the rainwater also carries
with it a lot of dissolved air pollutants. A first flush device diverts the water from
the first rain so that it does not enter the storage tank.
4. Storage tanks: These can be above the ground or below the ground.
5. Delivery systems: Piping systems that convey the stored rainwater till the point of
end-us
Fig 2.4.1 RAIN WATER HARVESTING COMPONENTS

METHODS OF RAINWATER HARVESTING
3.METHODS OF RAINWATER HARVESTING
SYSTEM
Rainwater harvesting is the collection
and storage of rainwater for reuse on-
site, rather than allowing it to run off.
These stored waters are used for various
purposes such as gardening, irrigation
etc. Various methods of rainwater
harvesting are described in this section.
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.
2 Rooftop rainwater
harvesting
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
groundwater level of the area. The roof top rain water harvesting system is shown in figure
2.1.
3.1 GROUNDWATER HARVESTING
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and
in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called
an aquifer when it can yield a usable quantity of water.The depth at which soil pore
spaces or fractures and voids in rock become completely saturated with water is called
the water table. Typically, groundwater is thought of as water flowing through shallow
aquifers, but, in the technical sense, it can also contain soil moisture, permafrost,
immobile water in very low permeability bedrock, and deep geothermal or oil
formation water. Groundwater is hypothesized to provide lubrication that can possibly
influence the movement of faults. It is likely that much of Earth's subsurface contain
some water, which may be mixed with other fluids in some instances
3.1.1 USES OF GROUNDWATER HARVESTING
Fresh groundwater was used for many important purposes, with the largest amount going
Fig2.1Rooftop rainwater harvesting

toward irrigating crops. Local city and county water departments withdraw a lot of groundwater
for public uses, such as for delivery to homes, businesses, and industries, as well as for
community uses such as firefighting, water services at public buildings, and for keeping local
residents happy by keeping community swimming pools full of
water. Industries and mining facilities also used a lot of groundwater. The majority of water used
for self-supplied domestic and livestock purposes came from groundwater sources. For the
environment groundwater plays a very important role in keeping the water level and flow into
rivers, lakes and wetlands. Specially during the drier months when there is little direct recharge
from rainfall, it provides the environmentwith groundwater flow through the bottom of these
water bodies and becomes essential for the wild life and plants living in this environment.
Groundwater also plays a very relevant role in sustain navigation through inland waters in the
drier seasons. By discharging groundwater into the rivers, it helps keeping the water levels higher.
Groundwater is found almost everywhere and its quality is usually very good. The fact that
groundwater is stored in the layers beneath the surface,and sometime at very high depths,
helps protecting it from contamination and preserve its quality. Additionally, groundwater
is a natural resource which can often be found close to the final consumers and therefore
does not require large investments in terms of infrastructure and treatment, as it often is
necessary when harvesting surface water. The most important about using groundwater is
to find the right balance between withdrawing and letting the aquifer’s level recover to
avoid overexploitation and to avoid pollution of this crucial resource.
3.1.2 METHODS OF GROUND WATER HARVESTING
I) Recharging of bore holes
II) Recharging through wells
III) Recharging through pits
IV) Recharging through trenches
V) Recharging through shafts
VI) Recharging making percolation tanks
3.1.3 FACTORS EFFECTING GROUND WATER FILLING
Climate
The future of climate change introduces the opportunity of implications regarding the
availability of groundwater recharge for future drainage basin. Groundwater recharge rates
will have the smallest impact on a climate of equal humidity and dryness. The depletion

of groundwater is evidence of the water table's response to excessive pumping. Severe
consequencesof groundwater depletion include lowering of the water table and depleting
water quality. The quantity of water in the water table can change rapidly depending on
the rate of extraction. As the level of water decreases in the aquifer, there is less available
water to be pumped. If the rate of potential groundwater recharge is less than the rate of
extraction,the watertable willbe too low foraccess. Aconsequence ofthisincludesdrilling
deeper into the water table to access more water. Drilling into the aquifer can be a costly
endeavor and it is not guaranteed that the quantity of available water will be exact to
previous yields.
Urbanization
Further implications of groundwater recharge are a consequence of urbanization. Road
networks and infrastructure within cities prevents surface water from percolating into the
soil, resulting in most surface runoff entering storm drains for local water supply. As urban
developmentcontinuesto spread acrossvariousregions,ratesof groundwaterrecharge will
increase relative to the existing rates of the previous rural region. The ecosystem will have
to adjust to the elevated groundwater surplus due to groundwater recharge rates.
Additionally, road networks are less permeable compared to soil, resulting in higher
amounts of surface runoff. Therefore, urbanization increases the rate of groundwater
recharge and reduces infiltration, resulting in flash floods as the local ecosystem
accommodates changes to the surrounding environment.
3.2 ROOF TOP RAIN WATER HARVESTING
Rooftop Rain Water Harvesting is the technique through which rain water is captured
from the roof catchments and stored in reservoirs. Harvested rain water can be stored in
sub-surface ground water reservoir by adopting artificial recharge techniques to meet the
household needs through storage in tanks. The Main Objective of rooftop rain water
harvesting is to make water available for future use. Capturing and storing rain water for
use is particularly important in dry land, hilly, urban and coastal areas. In alluvial areas
energy saving for 1m. rise in ground water level is around 0.40 kilo watt per hour.
3.2.1 ADVANTAGES OF ROOF TOP RAIN WATER
HARVESTING

1.The rain water collected on rooftops is used to improve the vegetation cover on ground.
2. With the growth of vegetation, the water seeps into the ground and replenishes the
groundwater supply.
3. There is no run off by muddy or dirty water into the drains.
3.2.2 DISADVANTAGES OF ROOF TOP RAIN WATER
HARVESTING
1. People may use the store water for washing, sanitation or for industrial purpose. It will
flow into the drains, instead of soaking into the ground and will not promote groundwater
replenishment.
2. If scientific measure is not adopted for using rainwater for drinking, it may cause harm
to the people's health than tap water.
3.3 SURFACE RUNOFF HARVESTING
Surface runoff water harvesting is the collection, accumulation, treatment or purification,
and storing of storm water for its eventual reuse. It can also include other catchment areas
from manmade surfaces, such as roads, or other urban environments such as parks, gardens
and playing fields. Surface runoff water is an excellent alternative to using mains drinking
water for many purposes. If properly designed, Surface runoff catchment systems can
collect large quantities of rainwater. The main challenge Surface runoff water harvesting
poses is the removal of pollutants in order to make this water available for reuse. Small
reservoirswith earthen bundsorembankmentsto contain runofforriverfloware builtfrom
soil excavated from within the reservoir to increase storage capacity and a spillway or weir
allows controlled overflow when storage capacity is exceeded.
3.3.1 ADVANTAGES OF SURFACE RUNOFF RAIN WATER
HARVESTING
• Easy to Maintain
• Independent Water Supply
• Reducing Water Bills
• Suitable for Irrigation
• Reduces Demand on Ground Water

• Supplemental in Drought
• Reduces Floods and Soil Erosion
• Several Non-drinking Purposes
3.3.2 DISADVANTAGES OF SURFACE RUNOFF RAIN
WATER HARVESTING
• Unpredictable Rainfall
• Initial High Cost
• Regular Maintenance
• Storage Limits
3.4 TRADITIONAL METHODS OF RAIN WATER
HARVESTING
Water has been harvested in India since antiquity, with our ancestors perfecting the art of
water management. Many water harvesting structures and water conveyance systems
specific to the eco-regions and culture has been developed. Figure 3.4.1 showsa particular
Traditional rainwater harvesting system.
• They harvested the rain drop directly.
From rooftops, they collected water and
stored it in tanks built in their courtyards.
From open community lands, they
collected the rain and stored it in artificial
wells.
• They harvested monsoon runoff by
capturing water from swollen streams
during the monsoon season and stored it
various forms of water bodies.
• They harvested water from flooded rivers.
Fig 3.4.1 Traditional rainwater
harvesting system

SAZA KUVA
An open well with multiple owners, saza kuva is
the most important source of irrigation in the
Aravallihills in Mewar, eastern Rajasthan.The soil
dug out to make the well pit is used to construct a
huge circular foundation or an elevated platform
sloping away from the well. The figure of a saza
kuva is shown in figure 3.4.2. The first is built to
accommodate the rehat, a traditional water lifting device; the sloping platform is for the
chada, in which buffaloes are used to lift water.
PAT
The diversion bunds across the stream are made by piling up stones and then lining
negotiate small nullahs that join the stream off and on,and also sheer cliffs before reaching
the fields. The villagers irrigate their fields by turns. The channel requires constant
maintenance and it is the duty of the family irrigating the fields on a particular day to take
care of the pat on that particular day. It takes about two weeks to get the pat flowing and
the winter crop is sown in early November.
3.5 MODERN METHODS OF
RAIN WATER HARVESTING
• Ground water Dams:
o The basic principle of the
groundwater dam shown in figure
3.4.3 is that instead of storing the
water in surface reservoirs,water is stored
underground.
o The main advantages of water storage in groundwater dams are that evaporation
losses are much less for water stored underground. Further, the risk of
contamination of the stored water from the surface is reduced because as parasites
Fig 3.4.2 Saza Kuva
Fig 3.4.3Ground water dam

cannot breed in underground water. The problem of submergence of land which is
normally associated with surface dams is not present with Sub-surface dams.
▪ A Sub-surface Dam: A sub-surface dam intercepts or obstructs the flow of
an aquifer and reduces the variation of the level of the groundwater table
upstream of the dam. It is built entirely under the ground
▪ Sand Storage Dam: It is constructed above ground. Sand and soil particles
transported during periods of high flow are allowed to deposit behind the
dam, and water is stored in these soil deposits. The sand storage dam is
constructed in layers to allow sand to be deposited and finer material is
washed downstream A groundwater dam can also be a combination of these
two types. When constructing a sub-surface dam in a river bed, one can
increase the storage volume by letting the wall of the Dam rise over the
surface,thuscausingadditionalaccumulationof sediments.Similarly,when
a sand-storage dam is constructed, it is necessary to excavate a trench in the
sand bed in orderto reach bedrock,which canbe used to create a sub-surface
dam too.
• Ferro cement Tanks: Ferro cement tanks are containers which are
much cheaper than masonry, RCC or plastic tanks. Tanks of 1000–2000-liter capacity can
be constructed with ease, these are easy to repair, and can be easily transported because of
their sturdy nature. Such containers have been used on a wide scale since about the past 25
years in Thailand, Malaysia and some African countries. Ferro cement containers with
capacity as much as 5000
liters have been constructed
in Thailand. The figure of a
ferro cement tank is shown in
figure 3.4.4. The process of
building a Ferro cement
container is very simple
which users can do
themselves, with some
Fig 3.4.4 Ferro cement tank

training. For a typical circular pot-shaped container, the only materials required are hessian
cloth, chaff (waste from agricultural produce), GI wire mesh, MS bars, cement and sand.
3.6 TYPES OF RAINWATER HARVESTING IN INDIA
1.Water Butt
One of the most basic types of rainwater harvesting systems; water Butt collects rainwater
in a container from natural rainfall and/or drain pipes. The collected water is used mainly
for watering the garden.
2.Direct-Pumped: Another very common and professional type of rainwater
harvesting.
• Submersible – Used particularly in domestic settings and is the easiest systems to
install. The pump is placed within the underground tank and the harvested water is
pumped directly to WCs or other appliances used daily for domestic purposes.
• Suction – In this system, the pump is located within the control unit of the house
(e.g., utility room). This unit also deals with backup from the mains water supply,
hence there is no need to direct mains water down to the underground tank.
Most rainwater harvesting systems need pumps to transfer the collected rainwater
from storage tanksto the point of use.Submersible pumps are generally more efficient
than suction pumps and do not suffer from the same limitations.
3. Indirect Pumped
This type of rainwater harvesting system doesn’t rely on gravity to supply water to the
outlets. Instead, it pumps the harvested water to a tank which can be at any level in the
building. Furthermore, a booster pump is used to provide a pressurized water supply. One

of the most significant benefits of this system is that it offers great flexibility to tailor the
booster pumps to adjust the flow and pressure requirements of a building.
4. Indirect Gravity
This system ensureswateris supplied to the outlets by gravity alone.Forthis, the harvested
water is first pumped to the header tank, i.e., high-level tank and then allowed to free-flow.
In Indirect gravity systems, the pump works only to fill the header tank.
5. Gravity Only
In few conditions, a system which functions purely through gravity may be needed.Such
systems do not demand pumps hence involve no energy use. With such an arrangement,
water can be collected only when collection tanks are located below the level of gutters,
yet higher than the outlets which it will supply. Here the only power of gravity is needed
to feed collected and harvested water to various parts of the household. Gravity only is one
of the most energy-efficient rainwater harvesting systems.
6. Retention Ponds
Retention ponds are used to collect surface runoff water and improve the quality of water
by natural processes like sedimentation, decomposition, solar disinfection, and soil
filtration. This type of pond normally has a mud bottom, but in some cases, it may be lined
with concrete. The most common use of water collected and harvested by pond harvesting
is watering livestock, however,it can also be used for groundwater recharge, irrigation or
any other purpose other than potable uses.
7. In-Ground Storage
Underground storage tanks are very popular in areas where the majority of rainfall occurs
in one single season. These underground tanks are insulated and have a very low rate of
evaporation. In addition, the water stored in these doesn’t freeze if it is buried below the
frost line, this is a huge advantage that surface storage tanks do not offer. Underground

tanks need to be connected to an electric pump to ensure supply of the stored water to the
outlets.
3.7 RAINWATER HARVESTING BY FRESHWATER
Rainwater harvesting is possible by growing freshwater-flooded forests without losing the
income from the used, submerged land. The main purpose of the rainwater harvesting is to
use the locally available rainwater to meet water requirements throughout the year without
the need of huge capital expenditure. This would facilitate the availability of
uncontaminated water for domestic, industrial, and irrigation needs.
3.8 RAIN WATER HARVESTING BY SOLAR POWER
PANALS
Good quality water resource, closer to populated areas, is becoming scarce and costly for
the consumers. In addition to solar and wind energy, rainwater is major renewable
resource of any land. The vast area is being covered by solar PV panels every year in all
partsof the world.Solar panelscan also be used forharvestingmostof the rainwaterfalling
on them and drinking quality water, free from bacteria and suspended matter can be
generated by simple filtration and disinfection processes as rainwater is very low
in salinity. Exploitation of rainwater for value-added products like bottled drinking water
makes solar PV power plants profitable even in high rainfall/ cloudy areas by the
augmented income from value-added drinking water generation.

CASE STUDY
CASE STUDY
Rainwater Harvesting (RWH) at Rizvi College of Engineering
(RCOE)PROPOSED DESIGNFOR RAIN WATER HARVESTING SYSTEM
The design of the proposed rain water harvesting system in figure [1] shows the details of
the terrace. The institute has 2 types of terraces. The first type of terrace is of 200 m2 area
and is there on 3 sides of the building. The second type which is shown in figure [2] is a
large 400 m2 area which is located at the center of the building. The figures [3] shows the
set ups proposed.Each terrace is coupled with a drain manifolds and V type parapet which
collects the water and guides it to the drains during the rains. They have proposed a U-
shaped pipingchannelwhich willguide the waterfrom the parapetto the storage tank which
will be situated at the ground floor. The U channel is indicated and shown in the figure in
blue color. Once the water is collected in the tank it can be used for various needs in the
institute. If the tank is full, they have designed a recharge ground water system which helps
to improve the ground water levels and use them later during the year.
Terraces with following area
Fig [1] Area of Terrace

CASE STUDY
Roof with following area
Fig [2] Front view of the proposed design of area
DESIGN OF RECHARGE PIT
The design of the recharge pit is as shown in the Figure [4] below. From the bottom, start
filling the pit with different materials as shown. Connect the overflow outlet of the
rainwater harvesting tank with the inlet to the recharge pit. One can also direct the slope of
the floor to allow the rain water to collect in the recharge pit.
Fig [3] Set ups proposed

CASE STUDY
FIG [4] Recharge pit design

CONCLUSION
CONCLUSION
The growing population and the rising demand for water have put a great deal of pressure
on the natural resources. Underground water is depleting at a very fast rate and soon there
will be shortage and scarcity of water all over the globe. If artificial methods are adopted
then this problem can be solved. Rainwater harvesting will not only ensure flood control
but it has other benefits like ensuring a continues supply of water, pollution control etc. As
per the discharge calculations for various intensities of floods we can conclude that
rainwater in itself is not capable of augmenting the groundwater water table. So, we need
to employ rainwaterharvestingstructures.The effectivenessofrainwaterharvestingsystem
lies in its ability to meet the site requirements and end use preferences. Though simple,
these systems are site specific and need to be detailed out before implementation. With
decrease in availability of water, rainwater harvesting presents the best option for times to
come. Recently, the interest in RWH systems as an alternative water source has increased,
due to their economic and environmental advantages. Indeed,these systems can provide a
supplementary water supply in urban areas when integrated with an existing conventional
water supply system, or the main water supply in rural areas affected by water scarcity.In
the context of climate change, the installation of RWH tanks could represent a valuable
adaptation measure against the reduction of water availability.

CONCLUSION
BIBLIOGRAPHY
[1] ANIL AGARWAL (2013): Manual on Rainwater Harvesting “Catch water Where it
Falls”
[2] KIRAN. A, NIKHIL. T, R HARISH, J KULKARNI (2012): Harvested Rainwater for
Drinking- Research paper.
[3] ARIYABANDU R. D. S (2003). Very-Low-Cost Domestic Roof Water Harvesting in
the Hu-mid Tropics: Its Role in Water Policy. Sri Lanka Domestic Roof Water Harvesting
Research pro-gramme.
[4] SIVARAMAN, K.R & THILLAIGOVINDARAJAN S. (2003), Manual on Rainwater
Harvesting. Chennai, Akash Ganga.
[5] RAINWATER HARVESTING- austinenergy.com

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