Monday, 30th October 2017

E- paper

Chemical quick-fix for dying dam

Tender floated for evaporation retardant supply to prevent Hatia reservoir level from plunging

By A.S.R.P. Mukesh
  • Published 27.10.15
TROUBLED WATERS: The level at Hatia dam has dropped to around 16ft from 37ft

Jharkhand's reservoir guardians may have found a formula to beat short-term water worries.

Concerned over the rapidly plunging level in Hatia Dam, which supplies now-rationed water to one-fifth of Ranchi's population, the state drinking water and sanitation department is mulling special chemical treatment that can minimise the rate of evaporation and, thereby, buffer any impending crisis.

As the blazing summer sun and uneven monsoon rain distribution have taken a heavy toll on the reservoir's storage capacity, department mandarins believe use of water evaporation retardants or WERs could improve conservation statistics by up to 40 per cent even though it is not a long-term solution.

K.K. Verma, executive engineer of drinking water and sanitation department's Hatia project division, said they were looking at national-level agencies for supply of the evaporation retardants. He maintained that they had floated tenders before the Durga Puja holidays and the last date for applying with quotations is November 3.

Till Monday, no party had evinced interest.

According to the Central Water Commission's definition, water evaporation retardants are chemicals developed using different fatty alcohols, which when sprayed on any solid or liquid surface forms a thin, mono-molecular film that acts as a barrier between the said surface and the atmosphere. These retardants are available in powder, solution or emulsion form.

Verma conceded that WERs had never been used in Jharkhand. "This method of controlling evaporation is widely prevalent in Hyderabad and other parts of southern India. Results have been good. The rate of evaporation is seen to drop by 20 per cent to 40 per cent," he said.

Hatia dam normally supplies 8.5 million gallons a day. The current depth of water in Hatia dam is only 16.5 feet, which is less than half of its normal level of 37 feet. To contain the crisis, water supply to 200,000 residents of Hatia, Doranda, Hinoo, Birsa Chowk and other areas has been rationed from Monday.

Instead of three-hour daily supply, consumers will get water for the same duration only thrice a week - on Wednesdays, Fridays and Sundays - till the situation normalises.

"Around this time of the year, the water level should be anywhere between 36-37 feet, but inadequate rainfall in this part of the state has caused the plunge. So, at our last departmental meeting, we decided to use evaporation retardants. Depending on the result, we will chemically treat other water bodies," Verma said, adding that the retardants had no harmful effects on human health.

Another engineer of the department pointed out why Hatia dam was under duress and needed special care.

"Construction of the outer ring road in close proximity has reduced natural flow of water. Also, at many points there are pipeline leaks. Last, but not the least, the government needs to take a call on reactivating aquifers by de-silting the dam," he said.

Do you think this unique water conservation plan will work? Tell