Guwahati, Dec. 22: A receding Brahmaputra coupled with excessive siltation has worsened the water crisis at the Guwahati Refinery intake point near Soonsali ghat.

The refinery today said the supply of water to the residents of Noonmati, the Narengi cantonment and the army base hospital is unlikely to improve before monsoon.

"We have, since the start of the crisis in September, restricted water supply to the residents of Noonmati (community development activities) and to entities such as the Narengi cantonment and the army base hospital at Basistha (under an agreement). With the water level further receding in December, we do not see any improvement in supply before April-May," an official at the refinery's intake point told The Telegraph today.

The oldest public sector refinery in the country owned by the Indian Oil Corporation has been facing a similar crisis for the past three winters but the situation has turned precarious this year with the rains stopping towards the end of September and the river reduced to a channel crisscrossed by large sandbars.

The refinery has a floating pump house that operates throughout the day.

An over-50-year-old dredger (repaired recently and put into operation last month) owned by it and a hired dredger are currently maintaining the requisite water depth (10ft to 15ft) for the floating barge to pump water from the river.

Problems compounded in November when the refinery was unable to link the barge with the sandbar-surrounded mainstream (which has gone over a kilometre away from the pump house) in the eastern side despite the use of excavators and engagement of manpower.

"Linking the mainstream with the barge would have solved a good part of the crisis. But heavy siltation did not allow the excavators to clear areas at Soonsali ghat, Sopaidong sapori and Ramching sapori across 2km on the eastern side," he said.

Now the only "lifeline" is a narrow river channel in the western side (Kharghuli) and currently kept clear by four excavators.

"The situation has come to such a pass that we had to hire two water suction pumps last month from the Guwahati Metropolitan Development Authority to maintain flow to the pool-like enclosure linked to the barge. We have proposed to the development authority for two more pumps as a backup. Till last year, the flow of this channel from Kharghuli side was much better and we did not have to use pumps," the official said.

The refinery needs about 2,50,000 litres of water every hour for cooling purposes. Any amount of water less than this will threaten its operations and may even lead to a shutdown, sources said. The Brahmaputra, which enters the state through Arunachal Pradesh, widens into an over 10km river at Dibrugarh, about 500km upstream of Guwahati.

The breadth, however, reduces to 1.5km in Guwahati.