23817508 rainwater harvesting (1)

8/14/2019 23817508 Rainwater Harvesting (1)

1/14

Rainwater

HarvestingPresentation by-

1. Swapnil Hire2. Diyvang ingle3. Nikhil Jagirdar4. Devashree Joshi

Class-F.EDiv-G Batch-G1

Roll Nos.-17,18,19,20


2/14

Introduction Rainwater harvesting is the gathering, or accumulating

and storing, of rainwater. Rainwater harvesting has beenused to provide drinking water, water for livestock,water for irrigation or to refill aquifers in a processcalled groundwater recharge. Rainwater collected fromthe roofs of houses, tents and local institutions, or fromspecially prepared areas of ground, can make animportant contribution to drinking water. In some cases,rainwater may be the only available, or economical, watersource. Rainwater systems are simple to construct frominexpensive local materials, and are potentiallysuccessful in most habitable locations. Roof rainwater isusually of good quality and does not require treatmentbefore consumption. Household rainfall catchment

systems are appropriate in areas with an average rainfallgreater than 200mm per year, and no other accessiblewater sources


3/14

Contents 1 Ground catchment systems 2 Roof catchment systems

3 Subsurface dyke 4 Groundwater recharge 5 Advantages in urban areas 6 Quality

7 System sizing 8 Around the world 9 Conclusion


4/14

Ground catchment systems Ground catchments systems channel

water from a prepared catchment area intostorage. Generally they are onlyconsidered in areas where rainwater is veryscarce and other sources of water are notavailable. They are more suited to small

communities than individual families. Ifproperly designed, ground catchments cancollect large quantities of rainwater.


5/14

Roof catchment systems Roof catchment systems

channel rainwater that fallsonto a roof into storage via asystem of gutters and pipes.The first flush of rainwater aftera dry season should be allowedto run to waste as it will becontaminated with dust, birddroppings etc. Roof guttersshould have sufficient incline toavoid standing water. Theymust be strong enough, andlarge enough to carry peakflows. Storage tanks should be

covered to prevent mosquitobreeding and to reduceevaporation losses,contamination and algalgrowth. Rainwater harvestingsystems require regularmaintenance and cleaning to

keep the system hygienic andin good working order.


6/14

Subsurface dyke A subsurface dyke is built in an aquifer to obstruct

the natural flow of groundwater, thereby raisingthe groundwater level and increasing the amountof water stored in the aquifer.

The subsurface dyke at Krishi Vigyan Kendra,Kannur under Kerela Agricultural University withthe support of ICAR, has become an effectivemethod for ground water conservation by meansof rain water harvesting technologies. The sub-surface dyke has demonstrated that it is a feasiblemethod for conserving and exploiting thegroundwater resources of the Kerala state of India.The dyke is now the largest rainwater harvestingsystem in that region.


7/14

Groundwater recharge Rainwater may also be used for

groundwater recharge, where therunoff on the ground is collectedand allowed to be absorbed,adding to the groundwater. In theUS, rooftop rainwater is collected

and stored in sump.In India thisincludes Bawdis andjohads, orponds which collect the run-offfrom small streams in wide area

In India, reservoirs called tankaswere used to store water; typically

they were shallow with mud walls.Ancient tankas still exist in someplaces.
http://en.wikipedia.org/wiki/Bawdihttp://en.wikipedia.org/wiki/Johadhttp://en.wikipedia.org/w/index.php?title=Tanka_%28reservoir&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Tanka_%28reservoir&action=edit&redlink=1http://en.wikipedia.org/wiki/Johadhttp://en.wikipedia.org/wiki/Bawdi


8/14

Advantages in urban areas Rainwater harvesting in urban areas can have manifold

reasons. Some of the reasons rainwater harvesting can beadopted in cities are to provide supplemental water for thecity's requirements, to increase soil moisture levels for urbangreenery, to increase the ground water table through artificialrecharge, to mitigate urban flooding and to improve the quality

of groundwater. In urban areas of the developed world, at ahousehold level, harvested rainwater can be used for flushingtoilets and washing laundry. Indeed in hard water areas it issuperior to mains water for this. It can also be used forshowering or bathing. It may require treatment prior to use fordrinking

In New Zealand, many houses away from the larger towns andcities routinely rely on rainwater collected from roofs as theonly source of water for all household activities. This is almostinevitably the case for many holiday homes.
http://en.wikipedia.org/wiki/Hard_waterhttp://en.wikipedia.org/wiki/New_Zealandhttp://en.wikipedia.org/wiki/Holiday_homehttp://en.wikipedia.org/wiki/Holiday_homehttp://en.wikipedia.org/wiki/New_Zealandhttp://en.wikipedia.org/wiki/Hard_water


9/14

Quality As rainwater may be contaminated, it is often not considered suitable

for drinking without treatment. However, there are many examples ofrainwater being used for all purposes including drinkingfollowing suitable treatment.

Rainwater harvested from roofs can contain animal and bird faeces,mosses and lichens, windblown dust, particulates from urban

pollution, pesticides, and inorganic ions from the sea (Ca, Mg, Na, K,Cl, SO4), and dissolved gases (CO2, NOx, SOx). High levels ofpesticide have been found in rainwater in Europe with the highestconcentrations occurring in the first rain immediately after a dry spell;the concentration of these and other contaminants are reducedsignificantly by diverting the initial flow of water to waste as describedabove. The water may need to be analysed properly, and used in a wayappropriate to its safety. In Gansu province for example, harvested

rainwater is boiled in parabolic solar cookers before being used fordrinking.In Brazil alum and chlorine is added to disinfect water beforeconsumption. So-called "appropriate technology" methods, such assolar water disinfection, provide low-cost disinfection options fortreatment of stored rainwater for drinking.


10/14

System sizing It is important that the system is sized to

meet the water demand throughout the dryseason. Generally speaking, the size of

the storage tank should be big enough tomeet the daily water requirement

throughout the dry season. In addition, the

size of the catchment area or roof shouldbe large enough to fill the tank.


11/14

Around the world Currently in China and Brazil, rooftop rainwater harvesting is

being practiced for providing drinking water, domestic water,water for livestock, water for small irrigation and a way toreplenish ground water levels. Gansu province in China andsemi-arid north east Brazil have the largest rooftop rainwater

harvesting projects ongoing. In Rajasthan, India rainwater harvesting has traditionally been

practiced by the people of the Thar Desert. In Bermuda, the law requires all new construction to include

rainwater harvesting adequate for the residents. The U.S. Virgin Islands have a similar law. In the Indus Valley Civilization, Elephanta Caves and Kanheri

Caves in Mumbai rainwater harvesting alone has been usedto supply in their water requirements
http://en.wikipedia.org/wiki/Gansuhttp://en.wikipedia.org/wiki/Northeast_Region,_Brazilhttp://en.wikipedia.org/wiki/Rajasthanhttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Thar_Deserthttp://en.wikipedia.org/wiki/Bermudahttp://en.wikipedia.org/wiki/U.S._Virgin_Islandshttp://en.wikipedia.org/wiki/Indus_Valley_Civilizationhttp://en.wikipedia.org/wiki/Mumbaihttp://en.wikipedia.org/wiki/Mumbaihttp://en.wikipedia.org/wiki/Indus_Valley_Civilizationhttp://en.wikipedia.org/wiki/U.S._Virgin_Islandshttp://en.wikipedia.org/wiki/Bermudahttp://en.wikipedia.org/wiki/Thar_Deserthttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Rajasthanhttp://en.wikipedia.org/wiki/Northeast_Region,_Brazilhttp://en.wikipedia.org/wiki/Gansu


12/14

Around the world In Senegal/Guinea-Bissau, the houses of the Diola-people are frequently

equipped with homebrew rainwater harvesters made from local, organicmaterial.

In the United Kingdom water butts are oft-found in domestic gardens tocollect rainwater which is then used to water the garden.

In the Ayerwaddy Delta of Myanmar, the groundwater is saline and

communities rely on mud lined rainwater ponds to meet their drinking waterneeds throughout the dry season. Some of these ponds are centuries oldand are treated with great reverence and respect.

Until 2009 in Colorado, water rights laws restricted rainwater harvesting; aproperty owner who captured rainwater was deemed to be stealing it fromthose who have rights to take water from the watershed. The main factor inpersuading the Colorado Legislature to change the law was a 2007 study

that found that in an average year, 97% of the precipitation that fell inDouglas County, in the southern suburbs of Denver, never reached astreamit was used by plants or evaporated on the ground. In Utah andWashington State, collecting rainwater from the roof is illegal unless the roofowner also owns water rights on the ground. In New Mexico, rainwatercatchment is mandatory for new dwellings in Santa Fe.[6]
http://en.wikipedia.org/wiki/Senegalhttp://en.wikipedia.org/wiki/Diolahttp://en.wikipedia.org/wiki/United_Kingdomhttp://en.wikipedia.org/wiki/Water_buttshttp://en.wikipedia.org/wiki/Myanmarhttp://en.wikipedia.org/wiki/Coloradohttp://en.wikipedia.org/wiki/Prior_appropriation_water_rightshttp://en.wikipedia.org/wiki/Douglas_County,_Coloradohttp://en.wikipedia.org/wiki/Denverhttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Washingtonhttp://en.wikipedia.org/wiki/Santa_Fe,_New_Mexicohttp://en.wikipedia.org/wiki/Rainwater_harvestinghttp://en.wikipedia.org/wiki/Rainwater_harvestinghttp://en.wikipedia.org/wiki/Santa_Fe,_New_Mexicohttp://en.wikipedia.org/wiki/Washingtonhttp://en.wikipedia.org/wiki/Utahhttp://en.wikipedia.org/wiki/Denverhttp://en.wikipedia.org/wiki/Douglas_County,_Coloradohttp://en.wikipedia.org/wiki/Prior_appropriation_water_rightshttp://en.wikipedia.org/wiki/Coloradohttp://en.wikipedia.org/wiki/Myanmarhttp://en.wikipedia.org/wiki/Water_buttshttp://en.wikipedia.org/wiki/United_Kingdomhttp://en.wikipedia.org/wiki/Diolahttp://en.wikipedia.org/wiki/Senegal


13/14

In Brief


14/14

Conclusion

The effectiveness of a rain waterharvesting system lies in its ability to meetthe site specific requirements and end use

preferences. Though simple, thesesystems are site specific and need to bedetailed out before implementation.With the decreasing availability of water,

rain water harvesting presents the bestoption for times to come.

23817508 rainwater harvesting (1)

Documents