Artificial Glaciers
A great example of how decentralised approaches to water harvesting boost innovation comes from Ladakh in Jammu and Kashmir. Chewang Norphel, retired engineer of the department of rural development, has found a way to make 'artificial glaciers'. In the cold desert that is Ladakh, the only source of water is met from glaciers. But this comes in late in the summer. Norphel has developed a way to bring glaciers closer to villages, which is a bonus for farmers as water reaches their fields in spring. Norphel's innovation involves channelizing water to the shadow area of a mountain close to a village. After going through metal pipes, the water freezes, creating a glacier close to the village.
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Rajsamand ditrict in western Rajasthan has a rich legacy of rainwater harvesting structures. Nadis (ponds) once served as the principal drinking water sources in this area. They received their water supply from erratic, torrential rainfall. Since the runoff was from sandy and eroded rocky basins, large amounts of sediments were regularly deposited in them, resulting in quick siltation.

A local voluntary organisation, the Mewar Krishak Vikas Samiti (MKVS) has been working in the district for the welfare of local farmers. They have constructed 20-30 nadis with a command area in excess of 500 ha in Lambodi, Gudlia, Kharasan, Hakiawas and Bhairu Das Ka Kheda.

The organisation has added systems like spillways to the nadis, in the absence of which these structures were damaged earlier. To prevent siltation, the MKVS has promoted afforestation of the drainage basin and constructed silt traps. Since farmers construct these structure on their own fields using locally available materials, the cost of construction ranges between Rs 2,500-10,000 and is thus affordable.

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Polymer Kundis
Churu District in Rajasthan is facing acute water scarcity due to poor ground water quality and lack of water resources such as rivers and canals. To deal with this problem Bhoruka Charitable Trust (BCT) is encouraging villagers to build and renovate Kundis (tanks), Johads (ponds), Talabs(permanent ponds) and dugwells. The kundi consists of a circular catchment area sloping towards the centrally located storage structure. The quality of water from kundi is good and if maintained properly no serious water contamination occurs. Its maintenance is easy. Local materials such as clay, silt, lime,ash and gravel are traditionally used to construct the catchment area of a kundi. They do not make completely impermeable layer. As a result some part of rainwater is lost due to uncontrolled seepage.

Efforts are now being made by BCT to enhance runoff in collaboration with Hyderabad based National Geophysical Research Institute and Indian Institute of Chemical Technology. The project has identified ways to generate 60-70% runoff depending upon the intensity of rainfall, using new technique of polymer science. Water based non-toxic polymer solution that permeate the highly porous sandy soils are used to increase runoff from Kundis. These polymers act as binders and reduce permeability and infiltration rate of sandy soils. Use of water repelling chemicals, in combination to some binding agents result in better runoff.

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No water
Water war
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How to harvest
    In rural areas
 n In urban areas
Jal yodhas
Way ahead
Chauka System
The people of Laporiya of Dudu block, Jaipur, Rajasthan have dyked degraded pastures to harvest rain. In the 1970's the pastures of Laporiya were barren and degraded. In 1990, the Gram Vikas Navuyak Mandal Laporiya (GVNML), a civil society group of Laporiya mobilised the vilage community to undertake the revival of its ecology.

A gram sabha (village assembly) consisting of 11 village elders were formed. Four years later, work was initiated on 50 hectares (ha) of pastures to integrate the denuded land into a single project unit. To complete the project, the villagers contributed labour as shramdaan (voluntary labour) and the result was a system of chaukas.

Chaukas are rectangular plots in a dyked pasture and store rainwater. They are 66 metres (m) long and 132 m wide enclosures arranged in a zigzag pattern and lie along small gradient. Dykes, 1.5 m high are built along the three sides that lie towards the lower part of the land/gradient. Trees are planted on these dykes to give them additional support to withstand rain.

When it rains, water collects in the dyked lower half of the chauka. As the amount of water stored in the enclosure rises, it flows into the neighbouring chauka, and so on, gradually seeping over the entire pasture. This means that fields are never inundated with water. Grasses can grow. After reaching the last chauka, the water flows into a monsoon drain. This system not only provides adequate water for villagers, but also promotes the recharge of groundwater.

The key to the success of the project is its adaptability. The dykes have been built keeping in mind the pathways that he people use. There was no restriction on grazing in the chaukas earlier as the emphasis was on impounding water and improving the soil. Now the people of the village plan to restrict grazing to alternate chaukas.

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Jaldhar Model
To harvest rain and save paddy crops from frequent rain failures, a team of Professional Assistance For Development action (PRADAN) has found a simple solution termed Jaldhar. In this technique, a portion of the farmland is left aside for rainwater harvesting, holding back rainwater in the land itself. Depending upon the land type there are two variations of design. One design is applicable to small plots where slope is less than 2 per cent and the other design is applicable for plots where slope is between 2-8 per cent and for slopes greater than 8 per cent, the technology may need some little modification.

The five percent model: The main objective of this model is to ensure that all small land holdings should have their own water body for harvesting rain. These pits are usually 1.5 square metre in size, occupying 5 per cent area of individual fields. The plot is levelled properly and bunded to allow water to accumulate to a height of 100mm, this pit also facilitates the subsurface flow of water to downstream plots and improves the moisture regime of the area as the whole.

The jaldhar 30x40 technique: The name comes from calculations done in terms of feet. Lands having an average slope of 3-5 per cent upland areas are divided into smaller plots and the water collection pit is dug in each plot. The pit area should consist of 3-4 per cent of an individual plot with depth around 1 m and located at the lowest point of the plot.

Plots should be chosen in a staggered fashion so those pits are also staggered as far as possible to enable uniform seepage of water across the slope. Each plot size is maintained at 9m (along the slope) x10.7 (across the slope), hence area of each plot will be 111.5-130sqm. The volume of each collection pit is around 3,000 litres.

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  Tudum or monga
Tudum or monga are mechanisms used to draw water from Kohli tanks for irrigation. Different mechanisms are used depending on the size of the tank.

For a small tank or a bori, a straight tunnel across the base of the bund is constructed using stones. A log is pitched at the mouth of the tunnel and plastered with clay. It is removed when water is required.

For a medium or large tank, a straight tunnel across the base of the bund is constructed using stones over which a stair-like structure (monghad) is built, with a opening (dachcha) on each side. This is stopped with a stone slab or a wooden log carefully plastered with clay.

Sometimes, a hollow tree trunk is also placed across the base of a tank, to which another hollow tree trunk with holes at regular distances is placed vertically. These holes are plugged with cogs, which are removed to draw water. This system requires frequent repairs as tree trunks rot quickly. Besides, there are stringent forest laws, which make it difficult to obtain wooden logs.

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  Networking of Farm Ponds
The Institute for Rural Development of the Bharatiya Agro-Industries Foundation has undertaken the excavation of 330 farm ponds in Adihalli watershed, spread over an area of 700 hectares in Arasikere taluka of Hassan district in Karnataka. The approach is based on a traditional concept where structures were dug out in strategic locations, locally known as kalyani. This overcomes the shortcomings of constructing check dams, which cannot be constructed in all terrain and the benefits of which are not available to upstream communities. A series of ponds, constructed along contour lines and connected to one another, allow easy access to water and a better soil moisture regime. In the Chotanagpur plateau in Orissa, the Professional Assistance for Development Action, an NGO, has also worked on farm ponds. It has promoted the idea of leaving a small part of the farm for water harvesting.
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Horizontal Roughing Filter/ Slow sand filter

The introducton of horizontal roughing filter and slow sand filter (HRF/SSF) to treat surface water has made safe drinking water available in coastal pockets of Orissa. The major components of this filter are described below.

i) Filter channel : With an area of one square metre in cross-section and eight metre length, to be laid across the tank embankment. The filter channel consisted of three uniform compartments, the first being packed with broken bats, the second with coarse sand, followed by fine sand in the third compartment. The HRF usually consists of filter material like gravel and coarse sand that successively decreases in size from 25 mm to 4 mm. The bulk of solids in the incoming water is separated by this coarse filter media or HRF At every outlet and inlet point of the channel, fine graded mesh is implanted to prevent entry of finer materials into the sump. The length of a channel varies according to the nature of the site selected for the sump.
ii) Sump: A storage provision to collect filtered water from the tank through the filter channel for storage and collection.

While HRF acts as a physical filter and is applied to retain solid matter, SSF is primarily a biological filter, used to kill microbes in the water. Both filter types are of an equal technical level and their operation is characterised by stability. These make full use of the natural purification process of harvested surface water and donot require any chemicals.

Making Water Everybody's Business
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