By Charles Haviland BBC News, Colombo

	Five people are missing after their boat capsized during a rescue attempt

Five people are missing after their boat capsized during an attempt to rescue stranded people, while the government says the floods have also killed five others and displaced 83,000 people who are now in temporary shelters; more than 230,000 have been affected in some way.

For many people who had hardly started to settle back into their homes, the misery has begun again in large areas of eastern, central and northern Sri Lanka.

The UN’s country office for humanitarian affairs says the water is rising more quickly than it did in the January floods and that strong currents are washing away anything in their path.

It says the town of Medirigiriya and many others have been flooded; some large towns face rising waters.

Authorities have opted to open the sluice gates of the reservoirs that litter the island, fearing that otherwise they would overflow uncontrollably

Some access roads are impassable.

Much of the flooding has happened because the authorities have faced a dilemma: they have opted to open the sluice gates of the reservoirs that litter the island, fearing that otherwise they would overflow uncontrollably.

Once more, tens of thousands of people have fled their homes and are sheltering in mosques, schools and other public places.

The government has just begun a programme to provide dry food rations to every flood-affected person every six days for six months.

The Navy has deployed 20 lifeguard teams to rescue flood victims and the Air Force has sent four helicopters.

And there has been some drama. A woman gave birth to a child inside one of the rescue helicopters – and mother and child are out of danger.

There are renewed fears for the rice crop, already diminished by the earlier floods. But the UN says it is too early to assess the damage to farming.