Rain water harvesting
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Transcript of Rain water harvesting
RAIN WATER HARVESTING
Presentation by: Achint Jindal (IT- Branch)
Project Guide: Dr. Tanuja Nautiyal
Contents Introduction
Concept and Technology of Rainwater Harvesting
Average Rainfall of States in India
Availability of Rainwater Through Roof Top Rainwater Harvesting
Runoff Coefficients for Various Catchments Surfaces
Rainwater Harvesting System
Treatment Techniques
Rainwater Harvesting System at Siel Chemical Complex
Every year, the water level in the state PUNJAB goes down by one meter. If this continues, the state will soon turn into a desert. So it is necessary to save every drop of water.
“Every commercial building as well as big houses in the state must install Rain water harvesting system to save water”
Introduction
What is rain water harvesting ?
It is the activity of direct collection of rain water
Rain water can be stored for direct use or can be recharged into the ground water aquifer
Rain Water in IndiaTotal annual rainfall in India: 400 million hectare-
meters (area x height)India’s area: 329 million hectaresIf evenly spread, average height: 1.28mActual distribution:
Highly skewed area-wiseThe desert receives less than 200mm annually,
while Cherrapunji receives 11,400mmBut almost every part of India receives at least
100mm annuallyKey: even 100mm annual rainfall sufficient if
harvested properly and where it falls
But….Temporal distribution of rain in India also skewedRainfall in India seasonal (unlike Western countries)Most of the country receives rainfall only for about
100 hours each yearRough rule of thumb: #cm of rain = #hours rain
receivedE.g.: Jodhpur receives 40cm of rain in about 40
hoursNatural implication of such skew:
Most of the rain water lost due to runoffsUnlike the west, very little water percolates into
the groundHence, the importance of harvesting structures
for local self-sufficiency
Sl.No. State Meteorological Divisions
Average annual
rainfall (mm)
1Andaman and
Nicobar Andaman and Nicobar Islands 2,967
2Arunachal
Pradesh Arunachal Pradesh 2,782
3 Assam Assam and Meghalaya 2,818
4 Meghalaya Assam and Meghalaya 2,818
5 NagalandNagaland, Manipur, Mizoram an
Tripura 1,881
6 ManipurNagaland, Manipur, Mizoram
andTripura 1,881
7 MizoramNagaland, Manipur, Mizoram
andTripura 1,881
8 TripuraNagaland, Manipur, Mizoram
andTripura 1,881
9 West Bengal
Sub-Himalayan West Bengal and Sikkim 2,739
Gangetic West Bengal 1,439
10 SikkimSub-Himalayan West Bengal and
Sikkim 2,739
Average Rainfall of States in India
Sl. No. State Meteorological Divisions
Average annual
rainfall (mm)
11 Orissa Orissa 1,489
12 Bihar
Bihar Plateau 1,326
Bihar Plains 1,186
13 Uttar Pradesh
Uttar Pradesh 1,025
Plain of West Uttar Pradesh 896
Hills of West Uttar Pradesh 1,667
14 Haryana Haryana, Chandigarh and Delhi 617
15 Delhi Haryana, Chandigarh and Delhi 617
16 Chandigarh Haryana, Chandigarh and Delhi 617
17 Punjab Punjab 649
18Himachal Pradesh Himachal Pradesh 1,251
19Jammu and Kashmir Jammu and Kashmir 1,011
20 Rajasthan
West Rajasthan 313
East Rajasthan 675
Sl. No. State Meteorological Divisions
Average annual
rainfall (mm)
21 Madhya Pradesh
Madhya Pradesh 1,017
East Madhya Pradesh 1,338
22 Gujarat
Gujarat region 1,107
Saurashtra and Kachchh 578
23 Goa Konkan and Goa 3,005
24 Maharashtra
Konkan and Goa 3,005
Madhya Maharashtra 901
Marathwada 882
Vidarbha 1,034
25 Andhra Pradesh
Coastal Andhra Pradesh 1,094
Telengana 961
Rayalaseema 680
26 Tamil NaduTamil Nadu and Pondicherry 998
27 PondicherryTamil Nadu and Pondicherry 998
28 Karnataka
Coastal Karnataka 3,456
North Interior Karnataka 731
South Interior Karnataka 1,126
29 Kerala Kerala 3,055
30 Lakshadweep Lakshadweep 1,515
Why Rain water harvesting To conserve & augment the storage
of ground waterTo reduce water table depletionTo improve the quality of ground
water To arrest sea water intrusion in
coastal areas To avoid flood & water stagnation
in urban areas
4
Concept and Technology of Rainwater Harvesting Rainwater is a free source of nearly pure water and rainwater
harvesting refers to collection and storage of rainwater and other activities aimed at harvesting surface and ground water. It also includes prevention of losses through evaporation and seepage and all other hydrological and engineering interventions, aimed at conservation and efficient utilization of the limited water. In general, water harvestings the activity of direct collection of rainwater. The rainwater collected can be stored for direct use or can be recharged into the ground water.
There are two main techniques of rain water harvestings.
Storage of rainwater on surface for future use.
Recharge to ground water.
RAIN WATER HARVESTINGRain
Roof Top
Filtration
or
Recharge to ground water
Storage
Rooftop Water
Technology of Rainwater Harvesting
Example of Small level Rain Water harvesting in villages in India
Water available from Roof = Annual rainfall (in mm) x roof area (in sq. m) x co-efficient of run off for roof
Suppose the system has to be designed for meeting drinking water requirement of a 5-member family living in a building with a rooftop area of 100 sq.m. Average annual rainfall in the region is 600 mm. Daily drinking water requirement per person (drinking and cooking) is 10 liters.
We shall first calculate the maximum amount of rainfall that can be harvested from the rooftop .Following details are available:Area of the catchments (A) = 100 sq.m.Average annual rainfall (R) = 600 mm (0.6 m)Runoff coefficient (C) = 0.85Annual water harvesting potential from 100 sq.m. roof= A x R x C= 100 x 0.6 x 0.85= 51 cu.m. (51,000 ltr)
Availability of Rainwater Through Roof Top Rainwater Harvesting
The tank capacity has to be designed for the dry period, i.e., the period between the two consecutive rainy seasons.
With the rainy season extending over four months, the dry season is of 245 days. Particular care must be taken to ensure thatpotable water is not contaminated by the collected rainwater.
Drinking water requirement for the family(dry season) = 245 x 5 x 10
= 12,250 ltr.
As a safety factor, the tank should be built 20 per cent larger than required, i.e., 14,700 ltr. This tank can meet the basic drinking water requirement of a 5-member family for the dry period.
All rainwater-harvesting systems comprise six basic components irrespective of the size of the system.
1. Catchments area/roof: The surface upon which the rain falls; the roof has to be appropriately sloped preferably towards the direction of storage and recharge.
2. Gutters and downspouts: The transport channels from catchments surface to storage; these have to be designed depending on site, rainfall characteristics and roof characteristics.
3. Leaf screens and roof washers: The systems that remove contaminants and debris; a first rain separator has to be put in place to divert and manage the first 2.5 mm of rain.
4. Storage tanks: Sumps, tanks etc. where collected rain-water is safely stored or recharging the ground water through open wells, bore wells or percolation pits etc.
5. Conveying: The delivery system for the treated rainwater, either by gravity or pump;
6. Water treatment: Filters to remove solids and organic material and equipment, and additives to settle, filter, and disinfect.
Rain Water Distribution & Management
Screening Methods Location Results
Strainers and Leaf Screens
Gutters and Leaders
Prevent leaves and otherdebris from
Settling
Sedimentation
Within Tank Settles particulate matter
Treatment Techniques
Filtering
In-line/Multi-CartridgeActivated CarbonReverse OsmosisMixed MediaSlow Sand
After PumpAt TapAt Tap Separate Tank Separate Tank
Sieves sedimentRemoves chlorineRemoves contaminantsTraps particulate matterTraps particulate matter
Disinfecting
Boiling/DistillingChemical TreatmentsUltraviolet Light
Ozonation
Before useWithin tankAfter the activated carbon filter Before Tap
Kills microorganismsKills microorganismsKills microorganismsKills microorganisms
Rainwater Harvesting System at Siel Chemical Complex
Rainwater Harvesting System at Siel Chemical Complex SIEL Chemical Complex is a Caustic Soda production plant located at Rajpura. It has ISO 14000 certification and the organization is very much concerned to improve the Environmental standards within and outside the premises of company. To improve the Ground water level in the surrounding areas, organization is trying to implement the Rain Water Harvesting within the premises.
In SCC, we are having 02 nos units of rain water harvesting . The first unit of rain water harvesting was installed and taken in operation w.e.f. July 20,2007.
It is estimated that around 500m3 of water will be charged into the ground in a year, with an average rainfall of 82 cms .
Rainwater Harvesting System at Siel Chemical Complex
Here we are considering the only Rooftop of A & PO building, Security block building and HR and Administrative block building for rainwater harvesting.Rooftop area of A&PO building = 304 sq. m.Rooftop area of security block building = 192 sq. m.Rooftop area of HR and administrative block building = 662 sq. m.Total Rooftop Area = 1158sq.m.Average Rainfall in this region = 82.23 cm. = .82 m.Assuming that 60% of total rainfall is effectively harvested.Volume of water harvested = 1158 X .82 X .6 cu. m. = 569.736 cu. m. = 569736 ltr.So we can save 569 m3. of water annually from above said building
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