Water of life

The natives of Banni in Gujarat have developed a unique rainwater From highly technique from highly saline ground water

 
Last Updated: Sunday 07 June 2015 | 21:11:47 PM

Water of life

-- (Credit: Lyes Ferroukhi)IN THE depths of saline ground above a water layer that is blackish they store fresh water for their year's needs. They are the Maldharies inhabiting the vast expanse of undulating Banni porturelands located in the desert areas of the northern Kutch district of Gujarat. They are the descendents of the immigrants firom Pakistan and other parts of Gujarat during the The tough climatic conditions and scanty fixrced them to solve one problem: where to store rainwater ,md yet keep it sweet. And that is how, through centuries M10aising with nature, they learnt her different moods, irreloped the wonderful technology of virdas - a unique wer harvesting system.

The Banni grassland area is a part of the Great Kann of Kutch and together with the Little Bann of Kutch it forms The old arms" of the Arabian Sea that silted up in course of was originally the home to 40 different varieties of Today, only 7 or 8 species survive. It differs considerably the salty marshes of the Great Rann in respect of its landscape, vegetation and soil type.

Virdas are shallow wells dug in low depressions called Jheels(tanks). Here, the inhabitants collect enough rainwater To ensure the availability of fresh water throughout the year. . being practised perfectly throughout centuries, about the adaptive capacity of the Maldharis. 6wild a structure basically reaching down to into the upper layer of fresh rainwater. As fresh water is removed, the brackish water zone moves upwards, and accumulates towards the bottom of the virda.

The topography of Banni being very flat, it has only a few depressions on the ground. By studying the flow of water during monsoon rainfall, the Maldharis identified these depressions. They also found that after rainwater infiltrated the sod, it was stored at a level above the salty groundwater because of the difference in their density. To store more fresh water, they dug many virdas in the upper layers of accumulated rainwater up to about one metre above the groundwater. Between these two layers of sweet and saline waters, there exists a transition zone of brackish water.

The Maldharis, essentially nomads, gradually settled in permanent villages during the last hundred years, and dug virdas close to their villages. Thus, the unique rainwater harvesting technique survived with them, passing the knowledge to locate, build and maintain the virdas from one generation to another.

This complex rainwater harvesting technique depends on the smooth functioning of the delicate ecosystem of the area. Significant grass cover is necessary to allow free infiltration Of fresh water. Water from northwards flowing rivers during monsoon holds soil salinity by checking the ingress of the Great Rann of Kutch. Also maintenance of natural vegetation and an optimum number of animals keep the ecological balance intact. Located only 5 kin from the Great Rann of Kutch, traditionally there are five water accumulating zones in Dhordo village. Five virdas have been dug there, out of which, the one built in the northern part of the village is the main tank and attracts maximum amount of water. During normal monsoons (average rainfall is 317 nun per annum) excess water from the other four tanks flows to this fifth tank and then the water overflows towards the Great Rann of Kutch.

The main tank with its 31 virda5 is the story of the collective action taken by the community to solve their water problem. In 1961, Premji Thakkar, a politician from Bhuj district became the revenue minister of the Gujarat government. Eager to help the Maldharis, he initiated the construction of a large water storage tank in Dhordo. But the villagers chose to widen and deepen the existing tanks instead. While they deepened the big tank, they widened the other 4 small tanks.

Today, the main tank is the best and largest in the region. It collects enormous amount of water from a catchment area having a diameter of 9 Ion. Surrounded by bushes and trees, mainly Prosopis juliflora, the tank was later dug further to a depth of 4 m below the ground level. The rectangular bottom of the tank measures 46 m X 46 in, and the upper part 60 m x 60 m. Seven entrances bring rainwater runoff to the tank, although some have become gullies that bring a lot of silt too. Generally, in every two years the vifiagers clean the excess silt by shramadan (voluntary labour).

The virdas in Dhordo have an average depth of 3.3 m. The circular, bowl shaped upper half of the virda facilitates drawing of water using a rope and a bucket. Women and children can enter into the virda when the water level goes down. The bottom half is consolidated by using Ppliflora tree trunks, forming a square frame. They are horizontally put on each other with a layer of grass in between. The grass acts as a rnesh,filtering sod particles entering the virda.

This wells-in-a-tank system remains operational even in those years with inadequate rainfall. For instanc Dhordo, a normal rainy day with a rainfall oT 25 mm, is cient to make run-off water flow towards the tanks. At the of a normal monsoon, 2 m to 3 m water accumulates in main tank (about 4,000 to 6,000 cubic metres), enough for four months.

Rearing animals is the livelihood of the natives of They can graze their animals only in the particular " assigned for them. Usually two or three families together three to four virdas and connect them to a trough with add nel. They use dried sit and clay to make these troughs are held together by the branches of P juliflora. Under leadership of the elders, once or twice a week, the viul remove the silt from the bottom of the troughs and reuse repair the troughs. They also put a high fence around troughs to prevent animals entering inside at night destroying these troughs. The villagers can use the water virda from 20 days to 4 months depending on the use accumulated water in it. Afterwards the water becomes salty for use.

Virdas are inseparable parts of the social fabric Maldharis. For centuries, they have served as the con. meeting points where people come, rest under the shad the trees and relax. Today, this unique technique, a part Banni grassland's ecosystem is threatened. Proliferation wonder tree" Pjuliflora, has thwarted the growth of the and has brought up salt to the soil surface. Indigenous species of the Banni have registered an alarming decline and virdas in some areas are fast becoming saline.

The supply of the drinking water through pipeline led to the reduced dependence of the Maldharis on the water. Although its supply remains highly erratic an) quality deplorable, During summer, water which has concentration of heavy metals, rarely trickles down the pipes Even then the villagers prefer to use pipe water because of ready availability.

Shrinking grassland, the Maldharis'migration to the outside Barmi, and increasing market intervention have the fragile ecosystem of Banni at peril. As their inca from animal and forest products plunged, the Mald partly abandoned their traditional lifestyle. Spread of a cooperative societies in Gujarat have lured them to rearing as well. They have abandoned the well-adapted breed of Kankrej cows and started to raise buffaloes Buffaloes, being heavy hooved animals, have led to an inter compaction of soil. As a result, while grass cover and infiltrations have reduced, soil erosion has increase Increasing salinity due to the continuous ingress of the Rann of Kutch over the years has been another reason of declining grass growth. Major north flowing rivers area being dammed, fresh water is not readily available to )each out salts, This has led to an alarming degradable of the grassland which in turn, has reduced the available of fresh water in the virdas. If the situation goes control, the intricate rainwater harvesting system is a manifestation of the vast reservoir of t1adi knowledge of the natives of the region, may soon disappear.

---Written by Rakesh Agrawal based on An ecologically soun water harvesting system under threat, A Minor Field Study by Lyes Ferroukhi, Swedish University ofAgricultural Sciences.

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