A practical solution to ground water recharge by rain water harvesting system
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A practical solution to ground water recharge by rain water harvesting system Document Transcript

  • 1. INTERNATIONAL JOURNAL and Technology (IJCIET), ISSN 0976 – 6308 International Journal of Civil Engineering OF CIVIL ENGINEERING AND (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME TECHNOLOGY (IJCIET)ISSN 0976 – 6308 (Print)ISSN 0976 – 6316(Online)Volume 4, Issue 2, March - April (2013), pp. 132-148 IJCIET© IAEME: www.iaeme.com/ijciet.aspJournal Impact Factor (2013): 5.3277 (Calculated by GISI) © IAEMEwww.jifactor.com A PRACTICAL SOLUTION TO GROUND WATER RECHARGE BY RAIN WATER HARVESTING SYSTEM IN PUDUKKOTTAI DIST, TAMILNADU R.Greesan Dept. of Civil Engg. Chendhuran College of Engg & Tech.,Pudukkottai,TN ABSTRACT The world was surrounded by water. Even though we are in the planet of earth which has 97% of water, we are facing our maximum of trouble regarding water. Some of the sources are saying that, Water scarcity will be the major reason to cause third world war. This case study was done in the district of Pudukkottai, which is not having any perennial resource of water and the dist was mostly depends on rain water for domestic and agri purposes. In this project we are tried to give better solution to the ground water and ground water recharge. This paper prescribed the technique of Roof Top Harvesting for storing and utilizing the rainwater and also for recharging the ground water. In the trend of urbanisation, the roof top harvesting is the effective, trouble-free system to implement with less expense. This will result in effective utilisation of water, ground water recharge, sustain our natural resources and automatically the environment will come under the greenish envelope without any doubt and drought. That’s the solution was very near to us to build a green city. WATER Water is a prime natural resource, a basic human need and a precious national asset, which is one of the most critical elements in Development Planning according to Indian National Water Policy. Planning and Development of Water Resources and their Use need to be governed by National Interest. It has been estimated that out of the Total precipitation around 4000 billion cubic metre in the country, Surface Water availability is about 1780 billion cubic metre. Out of this, only about 50% can be put to beneficial use because of topographical and other constraints. In addition, there is a Ground Water Potential of about 420 billion cubic metre. The availability of water is highly uneven in space and time. Precipitation is confined to only about 3 to 4 months with 20 – 40 significant Rainy days within a year. Hence, there is an 132
  • 2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEimperative need for effective collection of Rain Water for storing in appropriate places likeReservoir, Lakhs, Tanks, Ponds and Aquifers etc. In order to use the stored water efficientlyfor Economical and Social Purposes.Current Water Usage Usage (%) World Europe Africa India Agriculture 69 33 88 83 Industry 23 54 5 12 Domestic 8 13 7 5Future Water Usage Year Agriculture Industry Domestic Total Per Capita India Billion Lit/Day Lit/Day 2000 1658 115 93 1866 88.9 2050 1745 441 227 2413 167.0 China 2000 1024 392 105 1521 82.7 2050 1151 822 219 2192 155.4 USA 2000 542 605 166 1313 582.7 2050 315 665 187 1167 484.6 Agriculture is the dominant section in Indian Economy. Tamil Nadu has poor groundwater potential, depends mainly on the Surface Water Irrigation, as well as Ground WaterIrrigation. The Surface Water Potential largely depends on the storage of water in Reservoirs,Dams and Tanks only. The state has used the Surface and Ground Water Potentials to maximum limit andhence the future development and expansion depends only on the efficient and economicaluse of Water Potential and Resources. To achieve the Water Use Efficiency, it is necessary to improve and upgrade theexisting Conveyance and Storage System and also to introduce Modern Irrigation methods.Per Capita Water Use Continents Per Capita Water Use (m3/yr) Africa 245 Asia 519 North and C. America 1861 South America 478 Europe 1280 USSR (Former) 713 133
  • 3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEPer capita water availability in India Year Population (Million) Per capita water availability (m3/year) 1951 361 5177 1955 395 4732 1991 846 2209 2001 1027 1820 2025 1394 1341 2050 1640 1140Study AreaPudukkottai district area profilePUDUKKOTTAI Pudukkottai district is bound on the North and North West by Trichirapalli district,Sivagangai district on the West and South West, on the East and North East by Thanjavur districtand on the South East by Bay of Bengal. The district is formed in January 1974 out of certain pockets of the then Trichy andThanjavur districts, has an area of 4663 sq.km with a coastal line of 39 km.Pudukkottai district is divided into two revenue divisions with 9 taluks. There are 7 AgriculturalDivisions which is headed by the respective Assistant Director of Agriculture and 13 blocksheaded by Agricultural Development Officer. Moreover, there are two municipalities and 8 townpanchayats covering 757 revenue villages and 498 village panchayats.The average rainfall of the district is 923 mm per year. The frequency of rainfall is also uncertain.Even though the district has more number of tanks, most of the tanks are silted in nature. So thewater holding capacity of the tanks is very poor. This often leads to water scarcity for irrigationduring the critical stages of the crop, especially during maturity. The major crops of Pudukkottaidistrict are Paddy, Groundnut, Cashew, Sugarcane, Pulses, Fruits,Coconut.Geology The district is mainly covered with crystalline metamorphic rock period predominantlyoccupying the western part of the district ; the sedimentary formations comprising cretaceous,tertiary and quaternary periods occupy the eastern and south-eastern part of the district. The stageof ground water development in all the thirteen blocks is less than 65% of utilizable recharge.Genocide Pudukkottai District is a coastal covered district and lies between 9 51’ 0’’ & 10 45, 0’North latitude and 78 25’ 30’’ and 79 16’ 30’’ East longitude covering a geographical area ofabout 4661 sq.km in the South Eastern part of Tamil Nadu.Agro Ecological Region Generally Hot and dry with moderate moisture availability, but the coastal plain includingCauvery delta has moderately large moisture availability. 134
  • 4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEAgro climatic zone: Cauvery delta zone and southern zone.Physiographic and Drainage Pudukkottai district has an undulating topography with a general genital slope generaltowards Southeast. Small hillocks are seen in the Northern, Western and Southern part of thedistrict. Alluvial plains of Agniar, Ambuliar and coastal plains occupy the Aranthangi,Avudaiyarkoil and Manamelkudi blocks in the Southeastern part of the district.Rainfall DetailsClimate of Tamil Nadu Tamil Nadu is largely dependent on the monsoon rains, the failing of whichsometimes leads to droughts in the country. The climate Tamil Nadu varies from dry sub sub-humid to semi-arid. There are 3 distinct times of rainfall in Tamil Nadu, namely the South d.West monsoon from the months of June to September characterized by heavy southwestwinds; the North East monsoons from the months of October to December, characterized bynortheast winds; and the dry season from the months of January to May. The annual rainfall inds;of the state is approximately 945 mm (37.2 in), of which 32% is the South West monsoon and48% is the North East monsoon. The state can be divided into 7 agro- climatic zones: north- agrowest, north-east, southern, west, high altitude hilly, high rainfall, and Cauvery Delta. east,Rainfall Details On Pudukkottai DistClimate and Rainfall • Climate is mainly tropical in nature with a cooler period from December to February. • Maximum average temperature is 24C- 43C. emperature • Rainfall is variable both annually and seasonally. The annual rainfall ranges from 496.4mm to 1032 mm in the last 10 years period. • The season wise rainfall pattern of the district is as below: 1. Winter period 52.2 mm 2. Summer period 123.6 mm 3. South West monsoon period 350.0 mm 4. Northeast monsoon period 392.1 mm 52.2 123.6 WINTER 392.1 SUMMER 350 SW MONSOON NW MONSOON 135
  • 5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMERainwater HarvestingA Glance of RWH Figure shows the State wise Rainwater HarvestingThe principle of collecting and using precipitation from a catchments surface. An old technology is gaining popularity in a new way. Rain water harvesting isenjoying a renaissance of sorts in the world, but it traces its history to biblical times. Rainwater harvesting provides an independent water supply during regional waterrestrictions and in developed countries is often used to supplement the mains supply.Rainwater harvesting systems are appealing as they are easy to understand, install andoperate. They are effective in green droughts as water is captured from rainfall where runoffis insufficient to flow into dam storages. The quality of captured rainwater is usuallysufficient for most household needs, reducing the need for detergents because rainwater issoft. Financial benefits to the users include that rain is renewable at acceptable volumesdespite climate change forecasts, and rainwater harvesting systems generally have lowrunning costs, providing water at the point of consumption.History In ancient Tamil Nadu (India), rainwater harvesting was done by Cholakings. Rainwater from the Brihadeeswarar temple was collected in Sivaganga tank. Duringthe later Chola period, the Vīrānam tank was built (1011 to 1037 CE) in Cuddalore districtof Tamil Nadu to store water for drinking and irrigation purposes. Vīrānam is a 16-kilometre(9.9 mi) long tank with a storage capacity of 1,465,000,000 cubic feet (41,500,000 m3).At PresentIndia• In India, rain water harvesting was first introduced by Andhra Pradesh ex-Chief Minister N. Chandrababu Naidu. He made a rule that every house which is going to built in cities of that state must have a percolation pit/rainwater harvesting system. This rule increased the ground water level in good phase. 136
  • 6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME• In the state of Tamil Nadu, rainwater harvesting was made compulsory for every building to avoid ground water depletion. It proved excellent results within five years, and every other state took it as role model. Since its implementation, Chennai saw a 50 percent rise in water level in five years and the water quality significantly improved.• In Rajasthan, rainwater harvesting has traditionally been practiced by the people of the Thar Desert. There are many ancient water harvesting systems in Rajasthan, which have now been revivedNeed Of Rwh Rain water harvesting is essential because: • Surface water is inadequate to meet our demand and we have to depend on ground water • Due to rapid urbanization, infiltration of rain water into the sub-soil has decreased drastically and recharging of ground water has diminished.Rainwater Harvesting Techniques The two main techniques of rainwater harvesting are: • Storage of Rainwater on surface for future use. • Recharge of Ground water The storage of rain water on surface is a traditional techniques and structuresused were underground tanks, ponds, check dams, weirs etc.Components Of A Rainwater Harvesting System A rainwater harvesting system comprises components of various stages -transporting rainwater through pipes or drains, filtration, and storage in tanks for reuse orrecharge. The common components of a rainwater harvesting system involved in these stagesare illustrated here.1.Catchments The catchment of a water harvesting system is the surface which directly receives therainfall and provides water to the system. It can be a paved area like a terrace or courtyard ofa building, or an unpaved area like a lawn or open ground. A roof made of reinforced cementconcrete (RCC), galvanised iron or corrugated sheets can also be used for water harvesting.2.Coarse mesh at the roof to prevent the passage of debris3.Gutters Channels all around the edge of a sloping roof to collect and transport rainwater to thestorage tank. Gutters can be semi-circular or rectangular and could be made using4.Conduits Conduits are pipelines or drains that carry rainwater from the catchment or rooftop areato the harvesting system. Conduits can be of any material like polyvinyl chloride (PVC) orgalvanized iron (GI), materials that are commonly available.5.First-flushing A first flush device is a valve that ensures that runoff from the first spell of rain isflushed out and does not enter the system. This needs to be done since the first spell of raincarries a relatively larger amount of pollutants from the air and catchment surface. 137
  • 7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME6.Filter The filter is used to remove suspended pollutants from rainwater collected over roof.A filter unit is a chamber filled with filtering media such as fibre, coarse sand and gravellayers to remove debris and dirt from water before it enters the storage tank or rechargesstructure. Charcoal can be added for additional filtration. In a simple sand filter thatcan be constructed domestically, the top layer comprises coarse sand followed by a 5-10 mmlayer of gravel followed by another 5-25 cm layer of gravel and boulders.i) Charcoal water filter A simple charcoal filter can be made in a drum or an earthen pot. The filter is made ofgravel, sand and charcoal, all of which are easily available.(ii)Sand Filters Sand filters have commonly available sand as filter media. Sand filters are easy andinexpensive to construct. These filters can be employed for treatment of water to effectivelyremove turbidity (suspended particles like silt and clay), colour and microorganisms. In a simple sand filter that can be constructed domestically, the top layer comprisescoarse sand followed by a 5-10 mm layer of gravel followed by another 5-25 cm layer ofgravel and boulders. Source: A water harvesting manual for urban areasArtificial Recharge To Ground Water Artificial recharge to ground water is a process by which the ground water reservoir isaugmented at a rate exceeding that obtaining under natural conditions or replenishment. Atman-made scheme or facility that adds water to an aquifer may be considered to be anartificial recharge system. 138
  • 8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEUrbanisation Effects On Groundwater Hydrology • Increase in water demand r • More dependence on ground water use • Over exploitation of ground water • Increase in run-off, decline in well yields and fall in water levels off, • Reduction in open soil surface area • Reduction in infiltration and deterioration in water qualityMethods Of Artificial Recharge In Urban Areas • Water spreading • Recharge through pits,trenches,wells,shafts • Roof top collection of rainwater • Roadtop collection of rainwater • Induced recharge from surface water bodiesArtificial recharge methods can be classified into two broad groups tw (i) direct methods, and (ii) indirect methods.Direct Methods(a) Surface Spreading Techniques The most widely practised methods of artificial recharge of groundwater employdifferent techniques of increasing the contact area and resident time of surface-water with the watersoil so that maximum quantity of water can infiltrate and augment the groundwater storage.Areas with gently sloping land without gullies or ridges are most suited for surface-water surfacespreading techniques.Flooding The technique of flooding is very useful in selected areas where a favourable hydro que hydro-geological situation exists for recharging the unconfined aquifer by spreading the surplussurface-water from canals / streams over large area for sufficiently long period so that it waterrecharges the groundwater body. This technique can be used for gently sloping land withslope around 1 to 3 percentage points without gullies and ridges. 139
  • 9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEDitches and Furrows In areas with irregular topography, shallow, flat-bottomed and closely spaced ditchesand furrows provide maximum water contact area for recharging water from the sourcestream or canal. This technique requires less soil preparation than the recharge basintechnique and is less sensitive to silting.Recharge Basins Artificial recharge basins are either excavated or enclosed by dykes or levees. Theyare commonly built parallel to ephemeral or intermittent stream-channels. The water contactarea in this method is quite high which typically ranges from 75 to 90 percentage points ofthe total recharge area. In this method, efficient use of space is made and the shape of basinscan be adjusted to suite the terrain condition and the available space.(b) Sub-Surface Techniques When impervious layers overlie deeper aquifers, the infiltration from surface cannotrecharge the sub-surface aquifer under natural conditions. The techniques adopted to rechargethe confined aquifers directly from surface-water source are grouped under sub-surfacerecharge techniques.Injection Wells Injection wells are structures similar to a tube well but with the purpose ofaugmenting the groundwater storage of a confined aquifer by “pumping in” treated surface-water under pressure. The aquifer to be replenished is generally one that is already overexploited by tube well pumping and the declining trend of water levels in the aquifer has setin.Gravity-Head Recharge Wells In addition to specially designed injection wells, ordinary bore wells and dug wellsused for pumping may also be alternatively used as recharge wells, whenever source waterbecomes available. In certain situations, such wells may also be constructed for effectingrecharge by gravity inflow. In areas where water levels are currently declining due to over-development, using available structures for inducing recharge may be the immediatelyavailable economic option.Connector Wells Connector wells are special type of recharge wells where, due to difference inpotentiometer head in different aquifers, water can be made to flow from one aquifer to otherwithout any pumping. The aquifer horizons having higher heads start recharging aquiferhaving lower heads.Recharge pits Recharge pits are structures that overcome the difficulty of artificial recharge ofphreatic aquifer from surface-water sources. Recharge pits are excavated of variabledimensions that are sufficiently deep to penetrate less permeable strata. A canal trench is aspecial case of recharge pit dug across a canal bed. An ideal site for canal trench is influentstretch of a stream that shows up as dry patch. One variation of recharge pit is a contourtrench extending over long distances across the slope and following topographical contour.This measure is more suitable in piedmont regions and in areas with higher surface gradients.Recharge Shafts In case, poorly permeable strata overlie the water table aquifer located deep belowland surface, a shaft is used for causing artificial recharge. A recharge shaft is similar to arecharge pit but much smaller in cross-section. 140
  • 10. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEIndirect Methods(a) Induced Recharge It is an indirect method of artificial recharge involving pumping from aquiferhydraulically connected with surface water, to induce recharge to the groundwater reservoir.In hard rock areas, the abandoned channels often provide good sites for induced recharge.The greatest advantage of this method is that under favourable hydro-geological situations,the quality of surface-water generally improves due to its path through the aquifer materialsbefore it is discharged from the pumping well.Pumping Wells Induced recharge system is installed near perennial streams that are hydraulicallyconnected to an aquifer through the permeable rock material of the stream-channel. The outeredge of a bend in the stream is favourable for location of well site. The chemical quality ofsurface-water source is one of the most important considerations during induced recharge.Collector Wells For obtaining very large water supplies from river-bed, lake-bed deposits orwaterlogged areas, collector wells are constructed. The large discharges and lower lift headsmake these wells economical even if initial capital cost is higher as compared to tube well. Inareas where the phreatic aquifer adjacent to the river is of limited thickness, horizontal wellsmay be more appropriate than vertical wells. Collector well with horizontal laterals andinfiltration galleries can get more induced recharge from the stream.Infiltration Gallery Infiltration galleries are other structures used for tapping groundwater reservoir belowriver-bed strata. The gallery is a horizontal perforated or porous structure (pipe) with openjoints, surrounded by a gravel filter envelope laid in permeable saturated strata havingshallow water table and a perennial source of recharge. The galleries are usually laid atdepths between 3 to 6 metres to collect water under gravity flow. The galleries can also beconstructed across the river-bed if the river-bed is not too wide. The collector well is moresophisticated and expensive but has higher capacities than the infiltration gallery. Hence,choice should be made by the required yield followed by economic aspects.(b) Aquifer Modification These techniques modify the aquifer characteristics to increase its capacity to storeand transmit water. With such modifications, the aquifer, at least locally, becomes capable ofreceiving more natural as well as artificial recharge. Hence, in a sense these techniques areartificial yield augmentation measures rather than artificial recharge measures.(c) Groundwater Conservation Structures The water artificially recharged into an aquifer is immediately governed by naturalgroundwater flow regime. It is necessary to adopt groundwater conservation measures so thatthe recharged water remains available when needed.Groundwater Dams / Underground Barriers A groundwater dam is a sub-surface barrier across stream that retards the naturalgroundwater flow of the system and stores water below ground surface to meet the demandsduring the period of greatest need. The main purpose of groundwater dam is to arrest the flow 141
  • 11. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEof groundwater out of the sub-basin and increase the storage within the aquifer. The sub basin sub-surface barriers need not be only across the canal bed. In some micro watersheds, sub-surface subdykes can be put to conserve the groundwater flow in larger area in a valley. Sites have to be ervelocated in areas where there is a great scarcity of water during the summer months or there isa need for additional water for irrigation.Data Collection And Analysis To study about the rainwater harvesting system and ground water recharge thefollowing data’s are collected from the respective department in the district of pudukkottai.Annual Rainfall Details Month NORMAL 2005 2006 2007 2008 2009 2010 2011 2012January 3.95 1 5.3 1.25 6.2 9.9 1.4 14.36 2.01FEBRAURY 32.3 23 0 1.95 38 0 0 7.14 0WINTER 36.25 24 5.3 3.2 44.2 9.9 1.4 21.5 2.01March 24.7 6.9 42 0 185.3 3.9 0 3.66 0APRIL 29.1 76.6 39.2 19.7 19 46.6 6.6 54.05 22.12MAY 69.9 61.5 32.3 21.2 15.7 36.3 103.2 37.2 28.94SUMMER 123.7 145 113.5 40.9 220 86.8 109.8 94.91 51.06June 39.2 14.8 74.1 46.6 23.2 32 52.4 35.7 9.44JULY 46 66.6 10.5 50.6 58.2 27.1 44.9 56.5 29.51AUGUST 102.3 85.3 74.8 167.6 158.5 54.2 106.3 116.08 95.98SEPTEMBER 98.2 112.9 66 49.8 27.8 113.7 171.5 109.6 128.1S.W.MONSOON 285.7 279.6 225.4 314.6 267.7 227 375.1 317.88 263.03OCTOBER 192.3 197.2 213.4 195.3 196.5 36.9 123.2 213.2 262.2NOVEMBER 239.8 453.9 239.8 51.8 343.7 324.9 257.4 283.7 51.6DECEMBER 96.1 161.1 24.2 284.7 63.8 163.9 131.3 37.7 9.8N.E.MONSOON 528.2 812.2 477.4 531.8 604 525.7 511.9 534.6 323.6 Seasonal Rainfall 3000 Grand Total 2000 N.E.Monsoon S.W.Monsoon 1000 Summer 0 Winter 2005 2006 2007 2008 2009 2010 2011 2012 142
  • 12. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME • Annual Rainfall Details SL.NO YEAR RAINFALL IN MM 1 2005 1260.8 2 2006 821.6 3 2007 890.5 4 2008 1135.9 5 2009 849.4 6 2010 998.2 7 2011 969.1 8 2012 639.7 RAIN FALL 1400 1200 1260.8 1135.9 1000 998.2 969.1 821.6 890.5 849.4 800 600 639.7 400 200 0 2005 2006 2007 2008 2009 2010 2011 2012COMPUTATION OF GROUNDWATER RECHARGE BY ROOFTOP HARVESTINGThe computation was carried out in Individual Buildings and Multistoried Buildings asfollows: 1. Average Roof Top Area for Individual Buildings Buildings:100Sqm 2. Average Rainfall of Pudukkottai Dist: 923mm Dist 3. Effective Annual Rainfall contributing to Recharge :70% 4. Considering Losses:30% 5. Total rainfall collected in the year = 0.923 x 100 = 92.3 cum 6. Quantity available for recharge per Annum : 92.3 x 0.7 = 64.6cum/yr 7. Average family size:4Nos ly 8. Zone: Residential Zone 9. Per capita stipulated for domestic use :135lpcd 10. Per capita availability of rainwater:64.6/4 = 16.15cum/yr 143
  • 13. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME SL.NO DESCRIPTION INDIVIDUAL HOUSES MULTISTORIED BUILDINGS 01 Roof top area 100 sq.m 200 sq.m 500 Sq.m 1000Sq.m Total Quantity available for 129.2 02 64.6 cu.m 323.05 646.1 recharge per cu.m Annum Per Capita 32.30 03 Demand per 16.15 cu.m 80.76 161.525 cu.m AnnumThe computation was carried out in Multistoried Buildings as follows: 1. Average Roof Top Area for Individual Buildings:500Sqm In 2. Average Rainfall of Pudukkottai Dist: 923mm 3. Effective Annual Rainfall contributing to Recharge :70% 4. Considering Losses:30% 5. Total rainfall collected in the year = 0.923 x 500 = 461.5cum/year 6. Quantity available for recharge per Annum : 461.5 x 0.7 = 323.05cum/yr Annum 7. Average family size:4Nos 8. Zone: Residential Zone 9. Per capita stipulated for domestic use :135lpcd 10. Per capita availability of rainwater:323.05/4 = 80.76cum/yr lity 80.76 Qty of Water for Recharge 300 200 100 258.4 Qty of Water for 129.2 193.8 Recharge 64.6 0 100 200 300 400 Figure shows the Quantity of Harvested Water for Recharging Ground water d 1400 1292.2 1200 1000 969.15 800 Ground Water 646.1 Recharge Qty 600 400 Per Capita Availability 323.05 323.04 200 242.28 161.52 80.76 0 500 1000 1500 2000 144
  • 14. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEBenefits Of Artificial Recharge In Urban Areas • Improvement in infiltration and reduction in run-off. run • Improvement in groundwater levels and yields. • Reduces strain on Special Village Panchayats/ Municipal / Municipal Corporation water supply • Improvement in groundwater quality • Estimated quantity of additional recharge from 100 sq. m. and 500sq.m roof top area is64.600 and 323.050 litres. ROOF TOP AREA(Sq.m) VS ANNUAL RAINFALL(mm) Roof Top 2010 Area/ 2005 2006 2007 2008 2009 2011 2012 (998.2 Annual (1260.8) (821.6) (890.5) (8 (1135.9) (849.4) (969.02) (639.65) ) Year 50 44.13 28.76 31.17 39.76 29.73 34.94 33.92 22.39 100 88.26 57.51 62.34 79.51 59.46 69.87 67.83 44.78 150 132.38 86.27 93.50 119.27 89.19 104.81 101.75 67.16 200 176.51 115.02 124.67 159.03 118.92 139.75 135.66 89.55 250 220.64 143.78 155.84 198.78 148.65 174.69 169.58 111.94 300 264.77 172.54 187.01 238.54 178.37 209.62 203.49 134.33 350 308.90 201.29 218.17 278.30 208.10 244.56 237.41 156.71 400 353.02 230.05 249.34 318.05 237.83 279.50 271.33 179.10 450 397.15 258.80 280.51 357.81 267.56 314.43 305.24 201.49 500 441.28 287.56 311.68 397.57 297.29 349.37 339.16 223.88 1000 882.56 575.12 623.35 795.13 594.58 698.74 678.31 447.76 Roof Top Area/ Annual Year (i) 132.38 119.27 150 104.81101.75 86.27 93.5 89.19 67.16 50 100 100 50 150 0 2005 2006 2007 2008 2009 2010 2011 2012 145
  • 15. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME Roof Top Area/ Annual Year (ii) 300 150 200 250 300 100 2005 2006 2007 2008 2009 2010 2011 2012 0 Avg. Rainfall For Avg. Rainfall of 923mm 700 646.1 50 32.305 600 100 64.61 500 150 96.915 200 129.22 400 250 161.525 323.05 300 290.754 Series 1 258.44 300 193.83 226.135 200 193.83 350 161.525 226.135 129.22 400 100 96.915 258.44 64.61 1 32.305 450 290.745 0 500 50 100 150 200 250 300 350 400 450 500 1000 323.05 1000 646.1Cost Analysis Typical investment cost for rooftop harvesting systems are in range of Rs.4000/ to Rs.4000/-Rs.8000/- A completely new structure exclusively for rainwater harvesting would have a costinvolvement as follows: 146
  • 16. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME Abstract EstimateS.NO QTY DESCRI PTION OF WORK RATE UNIT AMOUNT 01 12.60 Earth work excavation for foundation 200.00 M3 2520.00 in all soils including initial lead and lift etc., and refilling the sides of foundation in the excavated earth etc., complete. 02 0.62 Filling the foundation and basement in 1000 M3 700.00 the clean river sand watering and ramming to consolidation etc., complete. 03 0.62 Cement concrete 1:5:10, using 40mm 1800 M3 1200.00 ISS HBG metal for foundation and flooring concrete etc., 04 5.78 Brick work in cement mortar 1:5, using 3700 M3 21300.00 chamber bricks size is standard etc., including materials and labour charges etc., complete. 05 23.00 Plastering in cm 1:5, 12mm thick etc., 150 M2 3450.00 including materials and labour charges etc., complete. 06 Sand layer L.S 1000.00 07 Pebbles & charcoal L.S 4000.00 08 Water supply arrangements L.S 1000.00 09 Contingencies & other unforeseen L.S 530.00 items.TOTAL 37000.00CONCLUSIONFrom the Project we can conclude that • Rainwater Harvesting plays a vital role in urbanisation to prevail over the demand of water. • Ground water recharge is the major result of Rainwater harvesting • In the Dist of Pudukkottai which was not having any perennial resource of river, the storage of rainwater is the only backbone for agriculture and production. • The sample of study shows that , For 100Sq.m we can recharge ground water with 64.6cu.m of rainfall per year • Without having any demand, up to 100days we can utilise the harvested rainwater for our own use. • The cost of instalment is also worthable to implement such valuable system. • With the rain harvesting and optimum usage of water, we can able to rebuild our environment as green city. 147
  • 17. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEMEREFERENCES1. Kawsal Kishore (2004) “ Rain Water Harvesting “. Journal of Civil Engineering & Construction Review ,may 2004,P42-P48.2. Hand book for planning water shed management works” Govt of India, Ministry of Water Resource CWC, December 2008.3. WRO _ Pudukkottai.4. Kumar, M. Dinesh. 2003. Paper: “Roof Water Harvesting for Domestic Water Security”: Who gains and who loses?5. Michael Nicklas, “Rainwater, High Performance Buildings”, Summer 2008.6. “Gawai A.A. and Aswar D.S (2006) “Towards Self Reliance for Water Needs through Rain Water Harvesting”.7. “Rain Water Harvesting Technology “ Dr.K.A.Patil & G.K.Patil National Seminar on8. Rain Water harvesting & Management 11-12, November 2006.9. IS 10500:1991 :Drinking Water Standards”10. Rain water Harvesting & Ground Water Recharge “Madharao Bhajirao Deshmukh”.11. Nadia Khelif, Imed Ben Slimène and M.Moncef Chalbaoui, “Intrinsic Vulnerability Analysis to Nitrate Contamination: Implications From Recharge in Fate and Transport in Shallow Groundwater (Case of Moulares-Redayef Mining Basin)”, International Journal of Civil Engineering & Technology (IJCIET), Volume 3, Issue 2, 2012, pp. 465 - 476, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.12. Neeraj D. Sharma and Dr. J. N. Patel, “Experimental Study of Groundwater Quality Improvement by Recharging With Rainwater”, International Journal of Civil Engineering & Technology (IJCIET), Volume 2, Issue 1, 2011, pp. 10 - 16, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. 148