Dehradun: A study conducted by the Uttarakhand State Council for Science and Technology (UCOST) has revealed that water near Tehri Dam and Devprayag is in the purest form. Bhagirathi River, the source stream of river Ganges, which meanders through these terrains has least polluted water in comparison to river water near Koteshwar Dam.

As per the study, presence of Hyporheic zones - also called as natural water purification zone - makes the water quality in these two regions clean and pure.

Hyporheic zone is the area under or beside the stream channel or floodplain that contributes water to the stream. The zone contains organic material, nutrients and inorganic ions which promotes survival of many useful bacteria, insect larvae and micro-organisms which help in the purification of water.

Moreover, the plants that extend their roots in this zone containing bio-geochemical ingredients get good source of nutrients. It helps them to maintain their proper life cycles.  Ultimately, it increases the purity level of the water.

In India, the study of Hyporheic zone is a new concept. To understand the functioning of Hyporheic zones in Uttarakhand, UCOST has for the first time conducted this study.

Research scientist Manisha Uniyal said, “Devprayag is the place where Alakhnanda and Bhagirathi River meet. Therefore, a large hyporheic zone exists in comparison to other regions. Also, micro-organisms which are important for water purification exist here in good numbers. Even, Zero Bridge near Tehri Dam has good quantity of such micro-organisms.”

Contrasting results were reported near Koteshwar Dam which had least hyporheic zones.

“Due to the mixing of debris released from the project site and change in river direction, hyporehic zones have completely vanished from Koteshwar dam site,” said Manisha.

The study also revealed that water near Koteshwar dam is extensively polluted in comparison to Tehri Dam. Unyal suggested that, government should frame water policies to maintain this natural water purification zone, which helps to control pollution level.

JPN/Bureau