Author(s) |
Shivanna, K.; Tirumalesh, K.; Noble, J.; Joseph, T. B.; Singh, G.; Joshi, A. P.; Khati, V. S.
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Environmental isotope techniques have been employed to identify the recharge areas of springs in India, in
order to construct artificial recharge structures for rainwater harvesting and groundwater augmentation
for their rejuvenation. A model project was taken up in the mountainous region of Gaucher area, Chamoli
District, Uttarakhand for this purpose. The springs in this region are seasonal and are derived from seepage
waters flowing through the shallow weathered and fractured zone. The chemistry of high-altitude springs
is similar to that of precipitation, whereas water–rock interactions contributes to increased mineralization in
low-altitude springs. The stable isotopic variation in precipitation suggests that the altitude effect for
Gaucher area is – 0.55‰ for δ18O and –3.8‰ for δ2H per 100 m rise in altitude. Based on local geology, geomorphology, hydrochemistry and isotope information, the possible recharge areas inferred for valleys 1, 2
and 3 are located at altitudes of 1250, 1330 and 1020 m amsl respectively. Water conservation and recharge
structures such as subsurface dykes, check bunds and contour trenches were constructed at the identified recharge areas in the respective valleys for controlling the subsurface flow, rainwater harvesting and groundwater augmentation respectively. As a result, during and after the following monsoon, the discharge rates of the springs not only increased
significantly, but also did not dry up even during the dry period. The study shows that the isotope techniques can be effectively used in identifying recharge areas of springs in the Himalayan region. It also demonstrates the advantage of isotope techniques over conventional methods.
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