rain water horvesting

7/28/2019 Rain Water Horvesting

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A PROJECT REPORT ON RAIN WATER HARVESTING

SynopsisWater in essential commodity but becoming scare now a day. The demand for water that too

portable water is increasing day by day to meet the water needs for even increasing population.

Surface water resource are utilized to the maximum extent and are very much depleted. Ground

water resources are also over exploited and have resulted in decline in ground water levels in the

most parts of the country. Bore wells are silting up, getting short of water or yielding polluted

water. In this content to meet the ever-increasing demand for water that too portable water, its

necessary to harvest rainwater, which falls on the terrace of the buildings. The water collected from

the terrace is of good quality and can be stored in sump tank either for direct use or can be diverted

to the existing bore well/ open well fort ground water recharge and storage. Keeping in this view, a

roof top rainwater harvesting system is designed for KSPCB Office building located at Bangalore.

For the present study of 28 years rainfall data ofBangalore town is used.

About 12 peoples work in the Karnataka state pollution control board office Bangalore.

The daily water requirement us estimated as 160lpcd. The water is mainly used for drinking and

flushing or cleaning toilets, gardening etc at present water needs are met by public water supply.

So to achieve self-dependency in water supply it is planned to harvest rainwater that falls on the

terrace of the building.

The total quantity of the rainwater that can be harvested annually from the building rooftop is

estimated and is found to be 2.07,900 liters. This quantity is enough to full fill the water designed

requirements for 145 days (nearly seven months), provided all the rainwater is harvested. But it is

not economically feasible and also not necessary taking into account various factors. Hence, a sump

is designed to store the rainwater originated from the buildings terse and its size is kept as 4m X

2.5mX 2m. it can store up to 20,000 liters of water. Since harvested rainwater is to be user mainly

for drinking purpose, a rapid sand filter is designed to improve the quality of rainwater the size of

the filter is kept as 1.25mX1.25mX1.5m. The total cost of the rainwater

DEPARTMENT OF CIVIL ENGINEERING GAPT. BANGALORE 1


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Harvesting system is estimated and is equal to Rs. 50,000.00. The cost of the sump tank works out

to be Rs. 40, 600.00 and is equal to 81.20% of the total cost of the entire the system.

The water harvested during rainy days can full fill the water needs for the entire rainy season.

Excess water (over flow water) from sump tank can be diverted to recharge the bore well. (Already

short of water) existing in the KSPCB office building premises. This water can be utilized to meet the

water needs during the other seasons of the years.



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Contents



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A PROJECT REPORT ON RAIN WATER HARVESTINGCONTENTS

CHAPTER 1 INTRODUCTION

1.1 GENERAL

1.1 RAINWATER HARVESTING TECHNIQUES1.2 ROOF TOP RAIN WATER HARVESTING1.3 NEEDS FOR RAIN WATER HARVESTING1.4 BENEFITS1.5 USES OF WATER1.6 SUITABILITY OF RAIN WATER1.7 STUDY AREACHAPTER 2 RAINWATER HARVESTING SYSTEM DISCRIPTION

3.1 ROOF TOP RAINWATER HARVESTING STRATEGY

3.2 COMPONENTS PARTS OF RRWH

3.3 TREATMENT OF STORED RAINWATER

3.4 COST

3.5 MANTENANCE TIPS FOR RRWH STRUCTURES

CHAPTER 3 DESIGN DETAILS

3.1 SIZING THE SYSTEM

3.2 SELECTION OF SYSTEM

3.3 PLACEMENT OF SYSTEM

3.4 DESIGN OF WATER CONVEYANCE SYSTEM

3.5 FILTER DESIGN

3.6 SELECTION OF SUITABLE LIFTING DEVICE

CHAPTER 4 DESIGN AND ESTIMATES

CONCLUSION

DRAWINGS



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CHAPTER 1

INTRODUCTION



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1 . INTRODUCTION

1.1GENERALThe rapid pace of the development and the increase in the population has led to the exploitation

of water resources, resulting in the over use of the surface supplies and over exploitation of ground

water.

Dependency on ground water to meet the needs of the domestic and industrial sectors resulted in

loweringof ground water levels. As a result, drying up of wells and bore well are witnessed in many

areas. There any further indiscriminate use of ground water should not take place. Also bore wells

are yielding polluted in many areas. As the ground water levels has depleted to an alarmingly

considerable levels, the problem of fluoride menace started showing its furious and venomous

effects on the health of people.

According to the UNO report, by the year 2050, the world wide availability of fresh water will

have decreased by a third as a result of global warming, population growth and west full habits. The

natural under ground aquifers will be at all time low levels. Scarcity of fresh water will become the

limiting factor for healthy livable communities using water conservation techniques like roof top

rainwater harvesting system helps reduce the negative impact on our water supply keeping our

cities and towns vibrant and healthy.

In this content it is very much essential to harvest rainwater to meet the fresh water demand of

increasing population. The rainwater collected from the roof top is of good quality and can be

stored in tank, sump either for direct use are can be diverted to the existing open well, bore well for

ground water recharge and storage.

1.2RAINWATER HARVESTING TECHNIQUESHarvesting rainwater is very simple when it rains collect this water without allowing it to go as

runoff. These are various techniques to do it

Broadly rainwater can be harvested for two purposes.

Stored for ready use in containers above or below ground level (sump). Recharge into the ground water for with drawl later

(Ground water recharge).

As indicated above rainwater falling on the terrace collected and stored in storage tank and for

direct use or diverted into a well for groundwater recharge. Rainfall over the open the spaces

around the building may also be a diverted for recharge purpose.



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1.5 BENEFITS.

Provides self sufficiency to water supply Provides high quality water, soft and low in minerals Improves the quality of groundwater through dilution when recharged to groundwater It is expensive and reduces soil erosion in urban areas Rooftop rainwater harvesting structures are easy to construct, operate and maintain. In areas with less rainfall, rainwater harvesting has been providing relief to people. Saves money. Avoid the costs associated with the purchasing water from the centralized

water system. Operating costs are lower than the cost of purchasing water from the

centralized water system.

Saves energy. By reducing water use, energy demands to pump water from the watertreatment plant to the service area are reduced.

Saves water. Reduce the demand on the scare surface and water sources. Treated water is an expensive resource and so using free rainwater instead wherever

possible makes sound ecological sense.

1.6USES OF RAINWATER

Gardening, car washing and domestic non-portable purposes like washing cloths and dishes,bathing, toilets, swabbing the flour etc.

It is ideal for washing cloths because rainwater is soft. For water intensive tasks such as dust control, cleaning processes during manufacture,washings vehicles and other specialized cleaning processes such as printed circuit board

manufacture and in agriculture and animal husbandry where farm yards and animal stalls

must be regularly hosed down.

In large offices and public buildings, rainwater can be used for flushing toilets and urinalsand for cleaning.

For all purposes including portable purpose i.e. drinking and cooking but only after filteringand boiling the water.

1.7SUTABILITY OF SYSTEM Ideally rainwater harvesting is for any person planning to build a house or who is in the

process of building a house on an independent plot.

Persons with built houses can also harvest rainwater by retrofitting such a built house forrainwater harvesting.Persons in apartment can also harvest rainwater, but a community

approach is required in such a case.

Industries and factories can also harvest rainwater since large roof areas are usuallyavailable in such constructions.



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1.8STUDY AREAAvailability of rain water from roof tops is so high in the urban areas and it properly harvested

it will help in reducing the water scarcity problem of cities and towns commonly runoff water

from roof top are led off into the drains instead the outlets can be connected to a storage tank

and let into existing open wells/ bore wells /recharge pits. This method is less expensive and

very effective and if implemented in good spirit by each house housing society will help in

augmenting the ground water availability of the area.

Keeping this in view it is planned to design and install a roof top rainwater harvesting

structure to KSPCB building located in Bangalore. At present the water needs of the KSPCB

office is met by public water supply system. But it is in sufficient and not assured. So to achieve

self-dependency on water it is planned to harvest rainwater that falls on the terrace of the

building. For the present study, about 28 years annual rain fall existing data is used and areshown is table No.1.

TABLE No.1 ANNUAL RAIN FALL DATA

SI.

No.

YEAR ANNUAL RAIN

FALL IN mm

AVERAGE RAIN

FALL

1 1975 944.30 786.90

2 1976 778.70 648.90

3 1977 562.10 468.40

4 1978 1031.6 859.7

5 1979 751.90 626.6

6 1980 748.70 623.90

7 1981 991.90 826.6

8 1982 898.2 748.5

9 1983 1144.2 953.5

10 1984 693.60 578.0

11 1985 784.20 653.5

12 1986 814.60 678.8

13 1987 1130.0 941.70

14 1988 1347.6 1102.3

15 1989 1345.8 1102.1516 1990 1324.1 110.1.34

17 1991 701.50 584.60



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18 1992 779.80 649.80

19 1993 632.20 526.80

20 1994 635.40 529.521 1995 3932.3 327.69

22 1996 751.30 626.10

23 1997 581.40 484.50

24 1998 1117.0 930.80

25 1999 925.20 771.00

26 2000 1038.6 865.70

27 2001 927.60 773.00

28 2002 738.20 615.10

Therefore,

Total amount of rainfall=32276.7mm

Total No. Of years =28 years

Therefore The average annual rainfall=834.88mm



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CHAPTER-2RAIN WATER

HARVESTING SYSTEMDISCRIPTION



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3.RAIN WATER HARVESTING SYSTEM DISCRIPTION3.1 RRWH STRATEGY

Collect water from the roof top Draw it down from pipes Filter the water and than Store in a sump or tank for later use

OR

Led the water into a well to increase ground water content

OR

Charge the ground water through a soak pit

The systems are simple to install in new buildings and need only minimum maintenance by the

user.

3.2 COMPONENT PARTS OF RRWH1. Down water pipes.

Pipes should be designed well

1. 90mm dia PVC pipes resistant to ultra violet (UV) raysappear to be the best as down waterpipes.

2. 3-4 down water pipes seems sufficient 90-110sq m (1000-1200 sq.ft approximately) roofarea.

3. A grill or mesh (Nahani trap or floor trap) has to be fixed at the entrance (inlets) of the downwater pipe in the terrace to arrest the large particles such as papers, leaves etc.

4. Sloping roof should have a gutter of PVC (half cut PVC pipes) or zinc or mild steel fitted alongthe sloping sides to collect water and channel it into the down water pipe system. Install

continuous leaf screen made of inches were mesh in a metal frame above the gutters to

prevent debris from entering the system.

5. Ground level tank occupy space and should not hinder moment or appear unsightly.6. Below the ground sump is a good option. Because they do not abstract moment less costly

to build and are hidden from you.But always provide an outlet for excess collection of water from the storage system. Once

collected filtered rainwater needs to be stored in cool and dark condition to discourage growth of

algae and bacteria.

A concrete water tank buried under ground is ideal but sump may also be considering either in

stone or brick masonry. The sides and floor of the tank are coated with waterproof material. The

size of the tank depends on the amount of water to be collected and cost resistance. But usually its

size is determined for the maximum daily rainfall of the place obtained from the rainfall records.



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3.3 TREATMENT OF STORED WATERIt is common perception that water stored for long goes bad. Water needs three conditions to go

bad thus when air, sunlight and organic matters are present within it. But excluding organic matter

through filtration and by strong rainwater in a closed container without assess to sunlight and air,water will remain for along time.

TABLE 2.0

Recommended doses of bleaching powder of disinfecting water.

Storage

Capacity of

Tank

DOSAGE OF BLEACHING POWDER IN gms

FULL TANK TANK TANK TANK

5000 50 37.50 25.00 12.50

6000 60 45 30 15

7000 70 52.5 35 17.5

8000 80 60 40 20

9000 90 67.5 45 22.5

10000 100 75 50 25

3.4 COSTSA rain water harvesting system has higher initial cost than buying water from the central water

supplier but the payback period is less than 1-2 years cost up to 50% on water bill may be saved by

re using water the largest cost of the system is the storage tank.

But it should be remembered however that currently cost of centralized water sypply is heavily

subsidized and these cost are bound to go up subtsansly alternate source will no longer remain

cheap. There fore plan for the future since the rainwater is future proofed for costs.

BASIC COST INCLUDEPipes Rs. 15/- 30/- per running feet

Bends and elbows Rs. 20/- 75/-

Filter tanks Rs. 1500/- Ls

Storage system Rs. 2/- to 4/- per liter depending upon whether the tank is made up of ferrow

cement or masonry or R.C.C.

The construction cost (Excluding costs of storage system) can range from Rs. 25,000/- to Rs. 40,000/-

or more



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3.5 MAINTANCE TIPS FOR RRWH STRUCTURES Keep the roof or terrace as clean as possible Do not store rusting iron, insecticides or detergents on the roof Remove algae from the roof tiles and asbestos sheets before the man soon Always keep surroundings of the tank clean and hygienic Provide the rain flush arrangement to drain off initial one or two rains Change the filter media or wash is every rainy season. Always provide for adequate overflow storage system for unexpectedly heavy rains. Dry the tank completely and clean from inside thoroughly before the man soon Cover all inlets and outlets pipes with closely knit nylon net or fine cloth to avoid entry of

insects, worms and mosquitoes

Leakage of cracks in the Ferro cement storage tank shall be immediately attended to bycement plastering. This will avoid major repairs due to the prorogation of cracks.

The filter material shall be washed thoroughly before replacing in the filter tank. Clean the in side of the (sump) cistern yearly. Minimize the amount of debris in the gutters

and keep leaver out of the filters. Clean gutters on a regular basis for maximum collection of

rainwater.

FILTERFilter the rainwater before storage

Filtering can be as basic as a floor trap placed before the water enters the down water pipeor pieces of sponge placed at the inlet of the down water pipe.

A PVC drum with gravel, sand and charcoal is a good filter before rain water is stored A PVC drum with sponge at the inlet and outlet is also a filter. A small filter tank can also be devised it has to be provided to filter small or minute dust

particles before diverting the rain water into the storage tank or open well or bore well a

slow sand filter(surface down flow type) can be designed for this purpose.

RAPID SAND FILTERIt consists of following three parts

1. Enclosure tank2. Base material3. Filter media of sand

ENCLOSURE TANKA water tight tank is constructed in either in stone masonry o r brick masonry. The sides and floor

are also coated with water proof material a filter tank of normal size of 2X2X26.



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BASE MATERIALThe base material used is jelly and it is placed at the bottom of the tank. It is laid in two layers.

The lower layer should be of bigger size jelly (40mm) and top most layer should be of small size jelly(20mm). The thickness of each layer is generally kept as 15 cm.

FILTER MEDIA OF SANDThe sand to be used for filter should be free from clay, vegetable matter, organic impurities etc. it

should also be uniform in nature and size. A layer of sand is placed above the jelly. The depth of

sand layer is generally kept as 15cms. The effective size of the sand varies from 0.2mm to 0.3mm.

The finer the sand is better will be the efficiency of filter regarding removal of bacteria but in that

case the outlet from filter is lowered.

The rate of filtration for a normal slow and sand filter varies from 100-200liters/hr/sqm of filter area.

The filtration process improves the biological, physical and chemical characteristic of rainwater.

Slow and filter is highly efficient in removing bacterial load from water (98-99%). It thus provides

safe drinking water at low recurrent cost. However, for complete removal of bacteria the

disinflation is essential.

It can remove the turbidity to the extent of about 50ppm.

A nylon mesh has to be provided in between the two layers (base material and filter media of

sand). The top of the filter chamber should be covered with 1M.S.cover.

The filter should be designed in such a way that there is no risk of contamination and minimum

chances of blockage.

STORAGE SYSTEMIt is ad visible to determine the storage system at the planning stage of the building itself.

A storage system may be a Roof level storage tank. (for multi storied buildings) Ground level drum or masonry tank. Under ground tank (sump) Partially bellow tank and partially above ground tank.

Proper location of storage system is very essential and is as follows:

Roof level tanks may need to be @ the rear of the house or on the sides, so that it is neitherobstructive nor visually offensive.

Ground level drums or tanks occupy space and should not hinder moment or appearunsightly.

Below the ground the sump is a good option because they do not obstruct movement, lesscostly to building to build and are hidden

But always provide an outlet for excess collection from the storage system.



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Once collected, filtered rainwater needs to be stored in cool and dark conditions to discourage

the growth of algae and bacteria. A concrete rainwater tank buried under ground is ideal. But sump

may also be constructed in stone or brick masonry. The side and floor of the tank are coated with

waterproof material. The size of the tank depends upon the amount of water to be collected and

cost restraints. But usually its size is determined for maximum daily rainfall of the place obtained

from the rainfall records.



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CHAPTER 3

Design Details



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DESIGN DETAILSDesign the roof keeping in mind the rain water harvesting requirements. That means if the roof is

flat, slope the roof in the direction of the storage system or recharge well. Sloping roofs should have

adequate gutter and down spots to handle the entire rain water incident on it.

3.1 STEP -1 SIZING OF SYSTEMThe size of rainwater collecting system depends on the size of roof. The amount of rain falls

(yearly) and the water demands for the system.

Calculate the average annual rainfall for the area using the data obtained from the rain gauge

station of the area.

Catchments area of roof = (width X length) of building

Rain water that can be harvested annually =C area of roof X

Annual rains fall.

Where c = runoff co-efficient for the roof top = 0.5.

To find how much rainwater will be collected, it is a common practice to assume a collecting

efficiency of 80% - 90%. But, a better system of calculation uses reliability of rainfall as an indicator.

3.2 STEP-2 SELECTION OF THE CLISTERN

The size of the cistern depends on the amount of rainwater to be collected and cost restraints.

Choose a cistern that fits the needs of water harvesting system. All cisterns should be of water tight,

durable and have a clean, smooth interior. The cover needs to be tight fitting to prevent

evaporation. It is best to place the cistern out of direct sun light to prevent algae and bacterial

growth, which can clog the system. Various types of cisterns can be used for storing rainwater and

are given in Table 3



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TABLE 3

CISTERN TYPE ADVANTAGES DIS-ADVANTAGES

Fiber glass type Prevents algae growth and

evaporation, rust resistant,

durable

Higher initial costs, degradable

costs, require exterior coatings.

polyethylene Various sizes, shapes alterable,

inexpensive, movable, durable

Can determine the rate of over

time if not treated foe U>R

radiation (prove to be corrosion

and dust)

Steel drums Available, durable, movable Prove to corrosion and rust

Concrete tank or Ferro cement,

stone

Durable, permanent Potential to crack difficulties to

maintain

SUMP DESIGNConstruction is a common building practice. Collecting rainwater after filtration in the sump

would be most cost effective. The size of the sump is determined for maximum daily rainfall

obtained from the rainfall records of the place.

3.3 STEP-3 PLACEMENT OF THE CISTERNPlace a cistern at a high point on the plot and elevate approximately 3 to 4 feet on s sturdy, load

bearing foundation or structure. Above ground cisterns are less expensive than a below ground

cistern and easier to maintain. Storing water below ground has aesthetic appeal while keeping the

water out of the sun.

3.4 STEP-4 DESIGN IF WATER CONVEYANCE SYSTEM

If the roof is flat, slope the roof in the direction of the sump. Pitched roofs should be provided

with adequate gutters and down spouts to handle the entire rainwater incident on it. Install

continuous leaf screens made of inch wide mesh in a metal frame, above the gutters to preventdebris from entering the system. Down water pipes should preferably be HDPE/PVC resistant to

ultra-violet rays. The national building code says that if the intensity of rain in the place is 50mm per

hour then one 75mm down pipe will serve a 40sqmtr. Roof area and one 100mm down pipe will

serve as 85sqmtr. Roof area. Usually two 100mmdia pipes are good enough for a 100 sq mtr. Roof

area.

DEPARTMET OF CIVIL ENGINEERING GAPT. BANGALORE 19


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Inter connect the rain water pipes (down water pipes) is there exists more than one. To convey

water from filter to sump provide a 110mm dia PVC pipe below ground.

3.5 STEP-5 FILTER DESIGNA rapid sand filter is to be provided to filter small and minute dust particles before diverting the

rainwater into the sump. The size of the filter tank is determined for the maximum intensity of

rainfall obtained from the rainfall records of the place. The filter media used is sand and its effective

size varies from 0.35mm to 0.6mm. The rate of normal rapid sand filter varies from 3000-6000 liters

per hour sq m of filter area.

Rain water discharge rate = intensity if rain fall X roof area

Area of filter tank required

Determine the dimensions of the filter chamber in terms of length and breadth. Provide

suitable depth taking into consideration amount of free board to be required and profile of

base material to be adopted.

3.6 STEP-6 SELECTION OF SUITABLE WATER LIFTING DEVICEProvide a proper sump to lift water from the sump and supply it to the water supply tank

or line for the distribution.

Surplus spillover water from the sump may be directed to the existing open or bore well.

In the absence of sump or open well or bore well the rainwater may be re-charged into

the ground through percolation.



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A POJECT REPORT ON RAIN WATER HARVESTING

CHAPTER 4Design and Estimates



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A PROJECT REPORT ON RAIN WATER HARVESTINGDESIGN AND ESTIMATE OF THE SYSTEM4.1 CALCULATION OF RAIN WATER QUANTITY

The total quantity of rainwater that can be harvested annually from the rooftop of the existing

building located in the KSPCB premises is estimated .to estimate the rainwater quantity, the

available 28 years rainfall data is used.

The average annual rainfall

= 32276.7/28

=834.88mm

The roof area of the building is measured and the total roof area= 327.62sq.m. The rain water

quantity is estimated for the reliable annual rain fall and its value is generally taken as 80% average

annual rain fall (AAR).

Reliable annual rain fall = 80% of AAR

= 80/100x834.88

= 667.90mm

=668mtrs. Or The total quantity of rainfall water that can be harvested annually=C x roof area

X Reliable annual rainfall

Where,

C =runoff co-efficient for roof catchments and its value is 0.95 for R.C.C. roof

The total quantity if rain water that can be harvested annually = C x roof area x reliable

annual rain fall=0.95x327.62x0.668

= 0.95 =207.90cm

=2, 07,900liters.

WATER DEMAND

For drinking purposes = 05 liters

For washing faces, hands etc = 10 liters

For cleaning and flushing toilets = 25 liters

For gardening purpose = 35 liters

For other use = 05 liters

Total = 80 liters

About 120members work in KPSCB Office Daily.

Water demand per day = 80 X 12 = 960lpd

No. of days that can be utilized = 207900/960 = 216.56

says as 215 days (7 months)

If all rain water is harvested that water can be used for 215 days but it is not economically feasible

and not practicable due to various factors. Hence sump tank is designed to accommodate for

maximum daily rainfall.



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DESIGN OF SUMP The capacity of the sump should be such that it should accommodatemaximum daily rainfall. The maximum daily rainfall is found to be 60mm/day from rainfall records.

Therefore,

Capacity of sump = maximum daily rainfall X roof area= 60/1000 X 327.62

= 19.657 cum

Say as 20 cum

Or 20,000 liters (1 cum = 1000 liters)

Therefore,

Tank capacity = 20.00 cum

Area of sump = Sump tank capacity

depth of sump tank = 20.00/2.00 = 10.00 sq.m

keep the depth of the sump tank as 2.0 m

Length of sump is kept as 4m.

Therefore, the width of the sump tank = c/s area length

Width of sump tank = 10/4

=2.5cm.

The size of the tank is 4m X 2.5m X 2m.

The details of the sump tank are shown in figure 2. The sump tank is provided with a man hole of

size 600mmX600mm with a cover for inspection and maintenance purposes. The excess water

(overflow water) from the sump tank is diverted to bore well for recharge purposes.

DESIGN OF FILTERThe size of the filter is determined bases on the maximum intensity of rainfall and infiltration rate of

sand medium used. The max intensity of rainfall from rainfall records is found to be 30mm/hour the

filter designed is rapid sand filter, the effective 6000 liters/hrs/sq.m of the filter area. The higher

value (6000 liter/hrs/sq.m) is considered for the design.

The maximum intensity of rainfall = 30mm/hr

Therefore, Max. Runoff from rooftop = Max.intensity of rain fall x roof area x 0.95

= 30/1000 x 327.62 x 0.95

= 9.34 cum/hrOr 9340 liters / hr

Area of filter tank required = Runoff/infiltration rate of sand

= 9340/6000

A = 1.56 sq.m



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ROOF TOP RAIN WATER HARVESTINGIt is the principle of collecting & storing the rainwater,the which falls on the terrace of the house or

building .the water collected from the terrace is of the good quality & can be stored in tanks or

sumps either for direct use or can be diverted to the existing borewell or open well for ground water

recharge and storage

There are five components to a rain water harvesting system.the water is collected on the rooftop

and transported by gutter and down water pipes through a filter to a sump where the water is

stored.the stored water is lifted using a proper pump and supplied to meet the various needs.it is

possible to collect 10000lit of rain water of a typical roof of 100m2,for ever 100mm rain fall.

NEED FOR ROOFTOP RAIN WATER HARVESTING

TO MEET EVER INCREASING DEMAND FOR WATER. TO DEVELOP ECOLOGICAL AND FINICIAL SENSE NOT TO WASTE TO PURE NATURAL

RESOURSES AVAILABLE IN LARGE QUANTITY IN ONES ROOF.

TO ENCOURAGE WATER CONSERVESTION AND SELF-DEPENDNESS. TO AVOID PURCHASE OF WATER FROM TANKERS WHICH IS UNRELIABLE IN QUALITY AND IS

ALSO EXPANSIVE.

TO AVOID FLOODING OF ROADS.

DEPARTMENT OF CIVIL ENGINEERING GAPT . BANGALORE 7

RAINWATER

ROOF TOPHARVESTING

DIRECTSTORAGE

SURPLUSWATER

OPEN SOACEHARVESTING

GROUNDWATER

RECHARGE


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A PROJECT REPORT ON RAINWATER HARVESTING

Therefore length and breath =1.25*1.25

Provide the depth of the filter as 1.5m

Therefore the recommened size of the filter is 1.25*1.25*1.25*1.50m

Depth of sand =20cm

Depth of 20mm jelly =20cm

Depth of 40mm jelly =25cm

Free board =80cm

The location of sump tank and the filter tank alone with pipe n/w are shown in below..

Fig 1 TABLE 1

ESTIMATION FOR SUMP TANK

SL NO PARTICULAR NO LENGTH BREATH DEPTH QUANTITY

1

2

3

4

5

6

Earthwork

excavation

Cc bed for

foundation

sump

BBM for

superstructure

a)long wall

b)short wall

plastering

for sump

tank

a)long wall

b)short wall

Rcc slab tocover sump

tant @ top

Deducation

to man hole

MS STEEL

cover plate

1

1

2

2

2

2

1

1

1

6.80

6.80

6.30

3.90

6.00

4.20

6.60

0.60

LS

5.00

5.00

0.30

0.30

_

_

4.50

0.60

_

2.15

0.15

2.00

2.00

2.00

2.00

0.10

0.10

_

73.10cum

5.10cum

7.56

4.68

12.24cum

24.00

16.80

40.80sqm

2.97

0.04

2.93cum



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TABLE 2 ESTMATION FOR PIPE LINE

SL NO PARTICULARS UNIT QUALITY RATE

RS

PS

AMOUNT

RS

PS

1

2

3

PROVINDING

AND FIXING

90mm dia PVC

PIPE

HORIZONTAL

VERTICAL

EARTHWORK

EXCAVATION

AND

REFILLING THE

TRENCH

PROVIDING

AND LAYING

110mm dia

PIPES BELOW

GL

Rm

Rm

Rm

Rm

55.622

3.4

1.2

1.2

50.92

50.92

75

95

2503

153

2656

54

114

2824

DEPARTMENT OF CIVIL ENGINEERING GAPT.BANGALORE 25


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TABLE-3 ABSTRACT ESTIMATION FOR SUMP

SL NO PARTICULARS UNIT QUALITY RATE AMOUNT

1

2

3

4

5

6

EARTHWORK

EXCAVATION

FOR SUMP

CCB FOR

FOUNDATION

BBM FOR

SUPER

STRUTURE

RCC SLAB

OVER TANK

MILD STEEL

Plastering

both side

walls

5%WORK

CHARGE

FOR

ROUNDING

Cum

Cum

Cum

Cum

LS

Sqm

73.1

5.1

12.24

2.93

40.8

45

1506.34

1550

3063.61

75.5

TOTAL

GRAND

TOTAL

3289.5

7682.334

18972

8976.377

450

3080.4

42000.61

2100.031

44100.64

0.36

44101



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TABEL-4 ABSTRACT ESTIMATION FOR FILTER

SL NO PARTICULARS UNIT QUANTITY RATE AMOUNT1

2

3

4

BED CONCRET

FOR FILTER

BBM FOR SUPER

STRUCTURE

PLASTERING

FOR WALLS

MILD STEEL

COVER

ADD 5%WORK

CHARGE

ESTABLISHMENT

FOR ROUNDING

OFF

Cum

Cum

Sqm

--

0.27

1.13

7.5

Total

Grand total

1506.34

1550

75.55

LS

406.7118

1751.5

566.625

1002824.837

141.2418

2966.079

3.92136

2970

TABLE-5 TOTAL COST OF PROJECT

SLNO ITEM OF WORK COST

1

2

3

4

SUMP TANK

FILTER

PIPELINE

CHAINAGE PUMP OF 1HP

MOTOR

40600

2750

2824

5000

TOT COST 51174

SAY 52000

TOTAL COST OF PROJECT IS FIFTY TWO THOUSAND ONLY.



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Conclusion



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CONCLUSION

To achieve self sufficient in water supply roof top rain water harvesting structure is designed for

KPSCB office building,Bangalore. The water demand is estimated as 960lpd. The amount of water

that can be harvested annually is estimated as 207900 liters. A sump capacity is estimated as

20000liters. A filter having size 1.25*1.25*1.5m proposed to improve the quality of water. The total

cost of the system is estimated as Rs 5000000.

The cost of the sump tank is works out to be Rs 4060000 and is equal to the 81.20% of total

cost of the system. The water harvesting during rainy days can fulfill the water requirements for

entire rainy seasons.

The excess water (over flow water) form sump tank can be diverted to recharge the

borewell.(already short of water ) existing in the KPSCB office building premises. This water can be

utilized to meet water needs during other seasons of the year.



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Drawings



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TECHNICAL TOUR

INTRODUCTION TO KARANJA DAM

The karanja dam is an earten dam with zonal section type. The total height of the dam is 20.6m but

water storage capacity is upto 11mtr. But the live storage of water of dam is 4m and the total

catchment area at project is about 2025.28 sq kms ie,782 sq miles.

CANALS PROVIDED TO KARANJA DAM

canal is constructed to convey water from dam either for irrigation or water supply purpose. But in a

karanja dam there are two canal are constructed one is right bank canal,both canals are of fully

cutting. The discharge capacity of left canal is 16.935cumecs,and the length of the left canal is 131

kms the ratio for side slope of canal is 1:1 for the both the canal and canal lining is done by shah bad

flooring or cc bed.

The FLOORING main purpose of canal lining is to prevent seepage and to protect the bank from

erosion.

FORE SHORE LITE TO KARANJA DAM:

From the karanja reservoir the lift irrigation can be done,the jack well be located on right bank of the

karanja river away from 7km upstream side from the dam site.

The maximum discharge available on left canal 1.98 cumces the length of intake channel is 213.35

m or 700ft max discharge required from intake channel is 3.455 cum and rising mains are 4 nos

pressure pipes of 1m dia,having length about 1370m.

And the length of lift canal is 24kms there are 5nos of 200hp pumps sets are provided

including one stand by..

DEPARTMENT OF CIVIL ENGINEERING GAPT.BANGALORE


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TECHNICAL TOUR

SAILENT FEATURES OF KARANJA DAM AND ITS APPURENANT WORK

GENERAL

A. Name of the project :: karanja irrigation project.B. Location :: karanja a tributary river manjra which joins river

GODAVARI..

2)Village :: Byalhalli.

3)Taluka :: Bhalki

4)District :: Bidar

5)Co-ordinates :: a)latitude 7753

b)longitudinal 7719

C. Hydrology

1)total catchment area at site ::2025.28 sq kms

2)weighted annual rain fall dependability ::930mm

3)75% dependable net flow at project site ::271.54mt cum

4)proposed annual utilization ::252.49mt cum

d.Dam and reservoir.

1.Gross storage capacity :: 217.65 mt cum

2.Live storage capacity :: 207.65mt cum

3.Top of dam :: Rl 590.00m

4.MWL :: Rl 587.15m

5.FTL :: Rl 584.15m

6. MWL :: 577.84M

7. Lowest river bed level :: Rl 568.45m

8. Type of dam :: earthen dam with zonal section

9. Total length of dam :: 3480m

10. Top width of dam :: 4mt

11. Height of dam above deepest bed level :: 20.60m12. free board :: 5.85m

DEPARTMENT OF CIVIL ENGINEERING GAPT.BANGALORE



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sypnois



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rain water horvesting

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