Tracing the origin and recharge zones of Himalayan springs

 
By Salahuddin Saiphy
Published: Wednesday 31 January 2007

people from Uttaranchal's Rudraprayag district have revived 16 drying springs in their valleys with innovative research. Using the isoptope technique (see box Nature's mystery), they tracked the origin and natural recharge zones of the streams, and accordingly, built rainwater harvesting structures to augment the discharge of springs and raise the groundwater level in the arid valleys.

Located in Agastyamuni block, the valleys--Kameda, Gagotu and Nagrasu--had been experiencing an acute water crisis since the 1980s. This does not withstand the fact that as many as 16 springs flow down these valleys to feed the river Alaknanda--a major tributary of the river Ganga.
Down to Earth Eleven of them are perennial in nature, while five are seasonal. Kameda valley alone has seven springs; the other four springs flow through Gagotu and the rest through Nagrasu valley.

Crisscrossing five villages, these springs are the only source of water, for irrigation and domestic use, for the valleys' 2,500 inhabitants.

Over the last decade, water flow in these springs had drastically reduced by more than 90 per cent. The valleys faced a severe drought in 1987. They saw their last snowfall in 1994. And in 2000, water scarcity in the area resulted in disputes among the villages. "The Jal Sansthan had laid a pipeline to supply us drinking water from the nearby Dandha Khal valley. But villagers dismantled the pipelines, disagreeing to divert water from Dandha Khal, as the valley itself does not have enough water for irrigation," said Kedar Singh Rawat, a villager from Chauki.

The people in the valleys thus planned to harvest their own water. In collaboration with a local ngo, the Himalayan Environmental Studies and Research Centre (hesco), they constructed rainwater harvesting structures across the mountains. "People knew that recharge zones of the springs were somewhere in the mountains. But failing to identify the exact location, they had built rainwater harvesting structures haphazardly, which failed to yield any results," said Anil Joshi, director of hesco.
Re-directed from BARC Their effort received support from scientists from the Bhabha Atomic Research Centre (barc). Initiated on a pilot basis, the project to trace the origin of the springs using the isotope technique, began in December 2003. It received a grant of Rs 6 lakh from the prime minister's office.

The scientists conducted their study in an area spreading over 5 sq km, located along the Dehradun-Badrinath highway (towards south of the Gauchar town). They collected water samples from individual springs and the river Alaknanda. The oxygen and hydrogen isotope composition was measured using a Geo 20-20 mass spectrometer. When compared to the isotope composition of rainwater collected from the same locality, results indicated that the springs in Kameda and Gagotu valleys have a common recharge zone at 1,400 metres above mean sea level. Springs flowing in the Nagrasu valley, however, draw water from another recharge zone, further down by 200 metres.

Studies also indicate that the springs flowing in the area are not true springs but seepage waters, which drain from higher altitude to lower altitude through the topsoil. A tritium (a radioisotope of hydrogen, 3h) count of the spring water further showed that all the springs are of recent origin and indicated that the groundwater of Nagrasu valley moves slower than the other two valleys. A hydro-chemical study further hinted that while flowing down, at a later stage, the groundwater of Gagotu valley merges with that of the Nagrasu valley. Scientists also carried out geological and hydrogeological studies to confirm recharge zones of the springs.

"The study results helped the villagers build various recharging structures at the identified locations," said Joshi. Between 2003 and 2004, at least 300 recharge trenches, four check-dams, 26 check-bunds and 112 percolation ponds were built to collect, store and recharge rainwater in catchments of these valleys. Commercial trees like mulberry and Grewia optiva were planted in the vicinity to increase soil stability and help percolation. "Control of water flow in the catchment areas increases the time of water retention along the slopes and ultimately results in spring recharging. Protection of the catchment areas through vegetation is also important, as it reduces runoff water on the rocky ground and helps better percolation," said V C Goyal, director of the Department of Science and Technology (Science and Society Division), New Delhi. Goyal has worked on various watersheds in Uttaranchal.

The result is no-doubt overwhelming. A joint monitoring by barc and hesco reveals that only in Kameda valley, water flow in the springs has increased by more than 98 per cent; in Gagotu and Nagrasu, the flow has almost doubled (see graph Fountains revived). According to a previous estimation, the spring discharge used to reduce by 27 per cent every month and the springs were going dry within four-five months of the monsoon. To the residents' relief, the springs now remain full to the brim throughout the year.

"Now, there is enough water for irrigation and domestic requirement," said Sheesh Pal Singh Kohli, a farmer. Apart from traditional crops, people are growing cash crops; some of the farmers have also shifted to pisciculture, beehive and poultry farming. Unlike three years back, the yield has now doubled.

Villagers in the valley are now busy creating water hubs and planning water budgets so that spring water can be properly used for domestic and agricultural uses as well as for recharging land.



The journey ahead
Though not new to scientists, in India, the isotopic technique has been limited to the study of dynamics and water balance of Himalayan rivers like Ganga, Yamuna and Indus, and Nainital lake.

The technique's usage at Rudraprayag, to understand groundwater dynamics in the Himalayan valleys is, however, the first of its kind in the country. Experts feel the effort is an important step towards curbing water crisis in hilly areas, where springs are the only potential source of water for drinking as well as feeding the non-glacier streams.

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