write article on rainwater harvesting
Rainwater harvesting is the accumulation and deposition of rainwater for reuse before it reaches the aquifer. Uses include water for garden, water for livestock, water for irrigation, etc. In many places the water collected is just redirected to a deep pit with percolation. The harvested water can be used as drinking water as well as for storage and other purpose like irrigation.
AdvantagesRainwater harvesting provides an independent water supply during regional water restrictions and in developed countries is often used to supplement the main supply. It provides water when there is a drought, prevents flooding of low-lying areas, replenishes the ground water table, and enables dug wells and bore wells to yield in a sustained manner. It also helps in the availability of clean water by reducing the salinity and the presence of iron salts.
Makes use of a natural resource and reduces flooding, storm water runoff, erosion, and contamination of surface water with pesticides, sediment, metals, and fertilizers.
Excellent source of water for landscape irrigation, with no chemicals such as fluoride and chlorine, and no dissolved salts and minerals from the soil.
Home systems can be relatively simple to install and operate and it may reduce your water bill.
Promotes both water and energy conservation.
No filtration system required for landscape irrigation.
EarlierAround the third century BC, the farming communities in Baluchistan (in present-day Pakistan, Afghanistan and Iran), and Kutch (in present-day India) used rainwater harvesting for irrigation.
In ancient Tamil Nadu (India), rainwater harvesting was done by Chola kings. Rainwater from the Brihadeeswarar temple was collected in Sivaganga tank. During the later Chola period, the VÄ«rÄnam tank was built (1011 to 1037 CE) in Cuddalore district of Tamil Nadu to store water for drinking and irrigation purposes. VÄ«rÄnam is a 16-kilometre (9.9mi) long tank with a storage capacity of 1,465,000,000 cubic feet (41,500,000m3).
Rainwater harvesting was done in the Indian states of Madhya Pradesh, Maharashtra, and Chhattisgarh in the olden days. Ratanpur, in the state of Chhattisgarh, had around 150 ponds. Most of the tanks or ponds were utilised in agriculture works.
Present day- 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 to replenish ground water levels. Gansu province in China and semi-arid north east Brazil have the largest rooftop rainwater harvesting projects ongoing.
- 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 Senegal and Guinea-Bissau, the houses of the Diola-people are frequently equipped with homebrew rainwater harvesters made from local, organic materials.
- In the Irrawaddy Delta of Myanmar, the groundwater is saline and communities rely on mud-lined rainwater ponds to meet their drinking water needs throughout the dry season. Some of these ponds are centuries old and are treated with great reverence and respect.
- In the United States: until 2009 in Colorado, water rights laws almost completely restricted rainwater harvesting; a property owner who captured rainwater was deemed to be stealing it from those who have rights to take water from the watershed. Now, residential well owners that meet certain criteria may obtain a permit to install a rooftop precipitation collection system (SB 09-080). Up to 10 large scale pilot studies may also be permitted (HB 09-1129). The main factor in persuading the Colorado Legislature to change the law was a 2007 study that found that in an average year, 97% of the precipitation that fell in Douglas County, in the southern suburbs of Denver, never reached a stream—it was used by plants or evaporated on the ground. In Colorado you cannot even drill a water well unless you have at least 35 acres. In New Mexico, rainwater catchment is mandatory for new dwellings in Santa Fe. Texas offers a sales tax exemption on the purchase of rainwater harvesting equipment. Both Texas and Ohio allow the practice even for potable purposes. Oklahoma passed the Water for 2060 Act in 2012, to promote pilot projects for rainwater and graywater use among other water saving techniques.
- In Beijing, some housing societies are now adding rain water in their main water sources after proper treatment.
- In Ireland, Professor Micheal Mcginley established a project to design a rain water harvesting prototype in the Biosystems design Challenge Module at University College Dublin.
- In Australia rainwater harvesting is typically used as a supplement to the reticulated mains supply, and it is mandated in many building codes. In South East Queensland, households that harvested rainwater doubled each year from 2005 to 2008, reaching 40% penetration at that time.
- 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 revived
- Kerala: Main article: Rainwater harvesting in Kerala
- At present, in Pune (in Maharashtra), rainwater harvesting is compulsory for any new society to be registered.
- An attempt has been made at Dept. of Chemical Engineering, IISc, Bangalore to harvest rainwater using upper surface of a solar still, which was used for water distillation
- Rainwater harvesting has been a popular method of obtaining water for agriculture and for drinking purposes in rural homes.
- The legislation to promote rainwater harvesting was enacted through the Urban Development Authority (Amendment) Act, No. 36 of 2007.
- Lanka rainwater harvesting forum is leading the Sri Lanka's initiative.
In the United Kingdom, water butts are often found in domestic gardens to collect rainwater, which is then used to water the garden. However, the British government's Code For Sustainable Homes encourages fitting large underground tanks to new-build homes to collect rainwater for flushing toilets, washing clothes, watering the garden, and washing cars. This reduces by 50% the amount of mains water used by the home.
Israel- In Lod, Israel, a mixed community just south east of Tel Aviv, a rainwater harvesting school model project is under way.
- Rainwater harvesting systems are being installed in local schools for the purpose of educating schoolchildren about water conservation principles and bridging divides between people of different religious and ethnic backgrounds all while addressing the water scarcity issue that the Middle East faces