This document is a project report on rainwater harvesting submitted to D. Batu University by a team of 6 students. It discusses two main methods of rainwater harvesting: surface runoff harvesting and rooftop rainwater harvesting. For rooftop rainwater harvesting, it describes the key components of catchment areas, transportation pipes, first flush devices, and filters to collect and store rainwater and remove impurities. It also summarizes several studies conducted on rainwater harvesting around the world and in India that demonstrate its benefits for groundwater recharge and agriculture.

1. 1
Rain water Harvesting
A project report submitted to D.BatuUniversity
Supervised by: Submitted by:
Prof. Amit Gawale Team:- Parth Muchandi (77)
Sami Shaikh (117)
Ayan Pathan (84)
Aseem Nalband (79)
Soham Pawar (99)
Atharva Zore (138)
Department of Basic Civil Engineering
DEPARTMENT OF COMPUTER SCIENCE & ENGG
D.BATU UNIVERSITY

2. 2
RainwaterHarvesting and its Methods
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. Commonly used systems are constructed of three principal components;
namely, the catchment area, the collection device, and the conveyance system.
There are basically two methods of Harvesting Rainwater.
1. Surface runoff harvesting
2. Rooftop rainwater harvesting
Surface runoff harvesting:-
In urban area rainwater flows away as
surface runoff. This runoff could be caught
and used forrecharging aquifers byadopting
appropriate methods.

3. 3
Rooftoprainwaterharvesting
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.
Components of the RooftopRainwaterHarvesting
The system mainly constitutes of following sub components:
 Catchments
 Transportation
 First flush
 Filter
Catchments
The surface that receives rainfall directly is the
catchment of rainwater harvesting system. It may
be terrace, courtyard, or paved or unpaved open
ground. The terrace may be flat RCC/stone roof
or sloping roof. Therefore the catchment is the
area, which actually contributes rainwater to the
harvesting system.
Transportation
Rainwater from rooftop should becarried through down take water pipes ordrains to
storage/harvesting system. Water pipes should beUV resistant (ISI HDPE/PVC pipes)
ofrequired capacity. Water from sloping roofs could be caught through gutters and
down take pipe. At terraces, mouth ofthe each drain should have wire mesh to restrict
floating material.

4. 4
First Flush
First flush is a device used to flush off the water received
in first shower. The first shower of rains needs to be
flushed-off to avoid contaminating storable/rechargeable
water by the probable contaminants of the atmosphere
and the catchment roof. It will also help in cleaning of silt
and other material deposited on roof during dry seasons
Provisions of first rain separator should be made at outlet
of each drainpipe.
Filter
Filters are used for treatment of water to effectively remove turbidity, colour and
microorganisms. After first flushing ofrainfall, water should pass through filters.
A gravel, sand and ‘netlon’ mesh filter is designed and placed on top of the
storage tank. This filter is very important in keeping the rainwater in the storage
tank clean. It removes silt, dust, leaves and other organic matter from entering the
storage tank.
The filter media should becleaned daily after every rainfall event. Clogged filters
prevent rainwater from easily entering the storage tank and the filter may
overflow. The sand or gravel media should be taken out and washed before it is
replaced in the filter.
CHARCOAL WATER FILTER:
A simple charcoal filter can be made in a drum or an earthen pot. The filter is
made of gravel, sand and charcoal, all of which are easily available.
SAND FILTERS:
Sand filters have commonly available sand as filter media. Sand filters are easy
and inexpensive to construct. Thesefilters canbe employed fortreatment of water
to effectively remove turbidity (suspended particles like silt and clay), colour and
microorganism.

5. 5
Features of rainwater harvesting:-
1. Reduces urban flooding.
2. Ease in constructing system in less time.
3. Economically cheaper in construction compared to other sources, i.e. dams,
diversion, etc.
4. Rainwater harvesting is the ideal situation for those areas where there is
inadequate groundwater supply or surface resources.
5. Helps in utilizing the primary source of water and prevent the runoff from
going into sewer or storm drains, thereby reducing the load on treatment plants.
6. Recharging water into the aquifers which help in improving the quality of
existing groundwater through dilution.
Literature
As water harvesting is a very old tradition and has been used for years, several
techniques have been developed so far. Extensive literature is available on RWH
with respectto various methods, its impacts on groundwater quantity, quality and
its modelling. Literature related to the various methods of recharge estimation,
applications of remote sensing and GIS in artificial recharge, studies on
groundwater modelling, RWH implementation and its impact studies was
collected and a critical review was carried out, as shownin the following sections.

6. 6
RAINWATER HARVESTING STUDIES ALL OVER THE WORLD
Rainwater harvesting is a very old practice that has been increasingly receiving
attention in the world, fueled by water shortages from droughts, pollution and
population growth (Nolde, 2007; Meera and Ahameed, 2006).
Runoff may be collected from roofs and ground surfaces as well as from
intermittent or ephemeral watercourses and thus water harvesting falls into two
groups. Water harvesting techniques which harvest runoff from roofs called
RWH and all systems which gathers discharges from water courses named flood
water harvesting (Critchley et al. 1991).Gitte and Pendke (2002) conducted a
study on the water conservation practices, water table fluctuations and
groundwater recharge in watershed areas. The study revealed that the water
conservation measures were found to be effective for rising of water table in
observation wells, located in the middle and lower reach of the watershed.The
overall groundwater recharge due to corresponding rainfall was to the tune of
3.76 to 8.85 cm in the influence of area of soil and water conservation structure.
Mondal and Singh (2004) conducted a study of unconfined aquifer response in
terms of rise in water level due to rainfall; a rapid and cost-effective procedure
was developed in hard rock terrain. Cross correlation of rise in water level and
precipitation was established. The entire area was divided into various zones
depending on the difference in
21 coefficient of correlation. Thus, best zone for artificial recharge was
depicted with the help of correlation coefficients.
It has been said that rainwater harvesting can promote considerable water saving
in residences in different nations. In Germany, a study done by Herrmann and
Schmida (2008) showed that the potential of potable water saving in a house
might differ from 30% to 60%, depending on the need and area of roof. In Brazil,
a study performed by Ghisi et al. (2009) revealed the potential water saving by
using water harvesting in 62 cities ranged from 34% to 92%, with an average
potential for potable saving of 69%.
Sturm et.al (2009) described Rainwater Harvesting as an alternative water
resource in rural sites in Central Northern Namibia and presented the results of
the examinations of rainwater harvesting (RWH) in central northern Namibia as
a part ofthe trans-isciplinary research project CuveWaters (Cuvelai-Etosha Basin
in central-northern Namibia). On the basis of various conditions, suitable

7. 7
solutions for RWH were developed, and evaluated. Themain aim was to analyse
their technical and economical feasibility as well as their affordability for future
users. In detail, two small-scale RWH systems were investigated i.e, roof
catchments using corrugated iron roofs as rain collection areas and ground
catchments using treated ground surfaces.
RAINWATER HARVESTING STUDIES IN INDIA
Singh and Thapaliyal (1991) assessed the effect of watershed programme on rain
fed agriculture in Jhansi district at the state of Uttar Pradesh and found that the
underground water table in the area showed a considerable increase, the average
mean increase in the water table being 3.7 meters. A change in the area from
pulses to cereals and vice versa was noted in Rabi and Kharif seasons,
respectively.
Hazra (1997) in his study of crop yield performance in Tejpura watershed
reported that, because of water and soil conservation work and water storage
structures, the wells which earlier used to get water for about 1-2 hours, got water
for more than 8-10 hours due to the increased groundwater table by 10 to 23 feet
after the construction of water storage structures.
Naik (2000) reported that the main reasons for non-adoption of water harvesting
structures in the state of Karnataka were the non-availability of credit and high
interest rates, (69% each) followed by long gestation period (68%), high hiring
charges of improved implements (65%) and small holdings (61%) etc. in the non-
watershed area.
Bisrat (2001) studied the economic analysis of watershed treatment via
groundwater recharge of Basavapura micro-watershed in Kolar district of
Karnataka and showed that the average output of bore well increased from 1150
gallons per hour (GPH) to 1426 GPH(24 per cent increase) after the construction
of water harvesting structures.
Venkatesh and Jose(2007) conducted arainfall studyonthe coastaland its nearby
areas of Karnataka. The statistical analyses conducted are cluster analysis and
analysis of variance. The study revealed that there existed three different zones
of rainfall regimes in
the study area, namely, Transition Zone,Coastal zone, and Malanad zone. It was
found that the maximum rainfall occurred on the windward side ahead of the
geographical peak. Further, the average monthly rainfall distribution over the
zones had been shown to help agricultural planning in the study area.

8. 8
Sreekanth et al. (2009) used a prediction model to forecast ground- water level at
Maheshwaram watershed, Hyderabad, India. The model’s efficiency were
calculated based on the root mean square error (RMSE) and coefficient of
determination (R2). The model gave the best fit and the predicted trend and also
the observed data closely (RMSE = 4.50 and R2 = 0.93).
Subash Chandra et al. (2011) developed lithologically Constrained Rainfall
(LCR)method for quantifying spatio-temporal recharge distribution in crystalline
rocks of Bairasagara watershed and Maheshwaram watershed of India. The LCR
method requires three input criteria i.e. vadosezonethickness, soil resistivity, and
precipitation. The average recharge at Bairasagara watershed was found varying
from 7.5% to 13.8% with a mean of 10.5% during 1990-2002. The study
concluded that the LCR was a generalized, cost method developed to quantify
natural recharge spatially and temporally
from rainfall in hard rock terrain.
Ground waterScenario in Amritsar
The climate of the district is
classified as tropical, semi arid
and hot which is mainly dry with
very hot summer and cold winter
except during south west
monsoon season. There are four
seasons in a year namely cold
season from November to March,
hot season from April to June,
south west monsoon season from
last week of June to middle
September and post monsoon
season from September to
beginning of November. During
cold season, series of western disturbances affect the climate of the district.
The normal annual rainfall of the district is 680 mm unevenly distributed over 31
rainy days. Thesouthwest monsooncontributes 75% rainfall and sets in last week
ofJune and withdraws in middle ofSeptember. Rest25% ofannual rainfall occurs
in the in non monsoon months in the wake of western disturbances and thunder
storms. The rainfall increases from southwest to northeastern part of the district.

9. 9
Methodology
1)In designing rainwater-harvesting system, capturing rainfall run off from the
roads and creating artificial connectivity to sub surface water in the hygienic
manner is the key concept.
2)The effectiveness lies in reasonable cost, coverageoflarge areas and immediate
implementation and immerse benefits in terms of additional water availability ,
improvement in water quality , increased plantation , maintaining eco-balance,
,reducing the coston maintenance and repairs of roads and many fold increase in
life of the roads.
3.Storm water harvesting along both sides of roads with the help of suitable,
simple structures, would not only control storm water hazards in cities, but will
enhance ground water availability 8 to 10 times compared to natural process of
rainfall infiltration.
4.The location and design of sustainable storm water harvesting system require
hydrogeological study of the area as well as sub surface information of most
permeable zone. Besides, average rainfall and rainfall intensity need to be
analyzed as per climatic zones.
5.Based onnormal rainfall and peak rainfall intensity, the storm water harvesting
system is designed in such a way that 70-80% runoff of roads and paved area is
sent back to ground water regime after natural filtration process based on rate of
recharge Test on existing wells/pits.
Advantages of Rainwater Harvesting
1. Easyto Maintain: Utilizing the rainwater harvesting system provides certain
advantages to the community. First of all, harvesting rainwater allows us to better
utilize an energy resource. It is important to do so since drinking water is not
easily renewable and it helps in reducing wastage. Systems for the collection of
rainwater are based on simple technology.
The overall cost of their installation and operation is much lesser than that of
water purifying orpumping systems. Maintenance requires little time and energy.
The result is the collection of water that can be used in substantial ways even
without purification.

10. 10
2. Reducing Water Bills: Water collected in the rainwater harvesting
system can be put to use for several non-drinking functions as well. For many
families and small businesses, this leads to a large reduction in their utilities bill.
On an industrial scale, harvesting rainwater can provide the needed amounts of
water for many operations to take place smoothly without having to deplete the
nearby water sources.
It also lessens the burden of soil erosion in a number of areas, allowing the land
to thrive once again. In fact, it can also be stored in cisterns for use during times
when water supplies are at an all time low.
3. Suitable for Irrigation: As such, there is little requirement for building new
infrastructure for the rainwater harvesting system. Most rooftops act as a
workable catchment area, which can be linked to the harvesting system. This also
lessens the impact on the environment by reducing use of fuel based machines.
Rainwater is free from many chemicals found in ground water, making it suitable
for irrigation and watering gardens. In fact, storing large reservoirs of harvested
water is a great idea forareas where forest fires and bushfires are commonduring
summer months.
4. Reduces Demand on Ground Water: With increase in population, the
demand for water is also continuously increasing. The end result is that many
residential colonies and industries are extracting ground water to fulfill their daily
demands. This has led to depletion of ground water which has gone to significant
low level in some areas where there is huge water scarcity.
5. Reduces FloodsandSoilErosion:During rainy season, rainwater is collected
in large storage tanks which also helps in reducing floods in somelow lying areas.
Apart from this, it also helps in reducing soilerosion and contamination ofsurface

11. 11
water with pesticides and fertilizers from rainwater run-off which results in
cleaner lakes and ponds.
6. Can be Used for Several Non-drinking Purposes: Rainwater when collected
can beused for several non-drinking functions including flushing toilets, washing
clothes, watering the garden, washing cars etc. It is unnecessary to use pure
drinking water if all we need to use it forsomeother purposerather than drinking.
Disadvantages of Rainwater Harvesting
1. Unpredictable Rainfall: Rainfall is hard to predict and sometimes little or no
rainfall can limit the supply of rainwater. It is not advisable to depend on
rainwater alone for all your water needs in areas where there is limited rainfall.
Rainwater harvesting is suitable in those areas that receive plenty of rainfall.
2. Initial High Cost: Depending on the system’s size and technology level, a
rainwater harvesting system may cost anywhere between $200 to $2000 and
benefit from it cannot be derived until it is ready for use. Like solar panels, the
cost can be recovered in 10-15 years which again depends on the amount of
rainfall and sophistication of the system.
3. Regular Maintenance: Rainwater harvesting systems require regular
maintenance as they may get prone to rodents, mosquitoes, algae growth, insects
and lizards. They can become as breeding grounds for many animals if they are
not properly maintained.
4. Certain Roof Types may Seep Chemicals or Animal Droppings: Certain
types of roofs may seep chemicals, insects, dirt or animals droppings that can
harm plants if it is used for watering the plants.

12. 12
5. Storage Limits: The collection and storage facilities may also impose some
kind of restrictions as to how much rainwater you can use. During the heavy
downpour, the collection systems may not be able to hold all rainwater which
ends in going to to drains and rivers.
Rainwater harvesting is a system that is gaining speed over time. Areas that
experience high amounts of rainfall will benefit the most from the system and
will be able to distribute water to dry lands with ease. However, the beneficial
environmental impact of the system is what drives it further as of now.
Need for rain water harvesting
Water is one of the most essential requirement for existence of living beings.
Surface water and ground water are two major sources of water. Due to over
population and higher usage levels of water in urban areas, water supply agencies
are unable to cope up demand from surface sources like dams, reservoirs, rivers
etc. This has led to digging of individual tube wells by house owners. Even water
supply agencies have resorted to ground water sources by digging tube-wells in
order to augment the water supply. Replenishment of ground water is drastically
reduced due to paving of open areas. Indiscriminate exploitation of ground water
results in lowering of water table rendering many bore-wells dry. To over come
this situation bore wells are drilled to greater depths. This further lowers the water
table and in someareas this leads to higher concentration of hazardous chemicals
such as fluorides, nitrates and arsenic. In coastal areas like Chennai, over
exploitation of ground water resulted in seawater intrusion thereby rendering
ground water bodies saline. In rural areas also, government policies on subsidized
power supply for agricultural pumps and piped water supply through bore wells
are resulting into decline in ground water table. The solution to all these problems
is to replenish ground water bodies with rain water by man made means.

13. 13
Advantages of rain waterharvesting
(a) Promotes adequacy of underground water
(b) Mitigates the effect of drought
(c) Reduces soil erosion as surface run-off is reduced
(d) Decreases load on storm water disposalsystem
(e) Reduces flood hazards
(f) Improves ground water quality / decreases salinity
(by dilution)
(g) Prevents ingress of sea water in subsurface aquifers in coastalareas.
(h) Improves ground water table, thus saving energy (to lift water)
(i) The costof recharging subsurface aquifer is lower than surface reservoirs
(j) The subsurface aquifer also serves as storage and distribution system
(k) No land is wasted for storage purposeand no population displacement is
involved
(l) Storing water underground is environment friendly
Recommendations
The following remedial measures are recommended to reduce the over
exploitation of ground water in Amritsar district and declining trend of ground
water.
1)All eight blocks in Amritsar district are over exploited; hence it is necessary
to notify all blocks for registration of ground water abstraction structures and
for regulation of ground water abstraction. After the notification permission
should be sought from Central Ground Water Authority for construction of any
tubewell.
2) Rainwater harvesting and artificial recharge to ground water should be
adopted to check further decline in ground water, since natural recharge to
aquifer system is not adequate to supportheavy withdrawal of ground water.
3) In the Holy town of Amritsar, industries are discharging toxic effluents either
on ground in the industrial premises or into city sewerage drains. Industrial

14. 14
effluents should be suitably disposed offafter tertiary treatment and solid waste
be treated using scientific techniques.
4) Farmers have adopted paddycultivation due to its profitability and incentives
from Government. Paddyrequires much more irrigation water as comparisonto
other crops. Thus a change in cropping pattern is required.
5) Paddy shown in the month of May requires more evapotranspiration than
paddyshown after 15th June. Thus a lot of water can be saved by timely
plantation of Paddy. Farmers should be made be aware of timely plantation of
paddy.
6) Canal command area in the district is very small; hence most of the irrigation
is done through tubewells. More area should be brought under canal command
area. A change in irrigation policy in the district is required.
7) Efficient irrigation practices like sprinkler irrigation should be adopted.
8) Mass awareness camps be Organized throughout the district to educate
people for ground water management and need for its efficient/economic use.
Conclusions:
Rainwater harvesting is a viable option to supplement city water for non-potable
human uses, such as irrigation. The overall efficiency of a rainwater harvesting
system to supplement city water increases as area increases. The system would
be highly effective in high commercial regions where there are warehouses and
large buildings. These areas also contain less lawn area, so that the water can be
used for uses beyond irrigation. In order to display the potential of the rainwater
harvesting project for a heavy commercial area, Ontario, CA was chosen as a
sample site. Ontario is an area with many commercial facilities, when all of the
roof area is considered with the average annual rainfall at 16 inches, a total of
2,200 acre-feet per year of water can be collected, this can meet the demands of
10,000 people. In fact, the Toyota facility located in Ontario has a roof area of
380,000 square feet. When taking into consideration the average rainfall, this
building has the ability to collect 3 million gallons of water. This single facility
can notonly meet the needs of the small patches oflawn surrounding the building,
but can supply enough water for 41 people at 200 gpcpd orthe water can be used
to recharge groundwater levels.
The simplicity of the model and the low overall costto install the system makes
rainwater harvesting easily translatable for use in developing regions. The

15. 15
rainwater harvesting projectwas specifically chosenbecauseof its potential to be
used to help those in developing regions who do not have easy access to clean
and local water sources. The water quality data shows that the water is clean for
non-consumption purposes; although, a simple filtration system may have the
ability to take the water into the potable range. The water collected from the
harvesting system is actually cleaner than many water sources found in
developing regions. In developing regions with a growing industry sector, water
sources are often contaminated by outflow of waste from the facilities as many
countries do not have stringent outflow laws. In areas with high populations,
waterways used for drinking water are overdrawn and are used for purposes such
as the cleaning of clothes and bathing. Rainwater harvesting can prevent the need
to travel far distances to obtain water and can help the overall health and growth
of communities.
Objectives:
Rainwater harvesting is the collection and storage ofprecipitation forlater human
use. This project focuses on the design, construction and analysis of a rainwater
harvesting system located at the Bourns College of Engineering at the University
of California, Riverside. The information collected from this project will be used
to build a template fordesigning a rain water harvesting systemthat can beplaced
in areas outside of the Southern California region, with a specific look at the
applicability of rain water harvesting in developing regions.
A preliminary mathematical model was created using Microsoft Excel that can
be used to determine the potential volume of rainwater captured from an inputted
rooftop area. Besides providing the volume of water that could be potentially
collected from a rain event, the Excel model outputs the estimated total cost of
installation and the amount of days harvested water can beused to irrigate a given
lawn area. The collected data from the PhaseI design will provide an opportunity
to optimize the Excel model, taking into consideration local conditions and
equipment costs.
Phase I funding was used to constructa harvesting system around one drain spout
located at the Bourns College site. To come up with a preliminary design of the
system the Excel model was used to come up with a tank size based on local
rainfall data. The system includes a catch basin connected to a roof outlet, which
flows over a weir and flow meter. An auto-sampler is also connected to thesystem
to take grab samples. The water is tested for total suspended solids and total
dissolved solids.