Wahyudi Soeriaatmadja, Indonesia, Jakarta – The El Nino climate phenomenon could hit Indonesia this year, producing a dry spell that could threaten its rice fields.

The Bengawan Solo River, which meanders through Central Java and East Java, is the main source of irrigation for the island's paddies and is already fast receding, local newspapers have reported. Java's thousands of hectares of paddy fields normally produce 60per cent of the country's total rice output.

Since the beginning of this month, a main dam near the river in Central Java, called Gajah Mungkur, has lost a fifth of its water because of dry weather conditions that may be a sign of El Nino's impending return.

El Nino is a condition caused by temperature fluctuations in the oceans and atmosphere that has been blamed for floods in normally dry areas and droughts in usually wet ones, as well as other disturbances around the world.

Already in Cilacap in Central Java, 36,000 families have been struggling to get clean water from their village wells since early this month, newspapers reported last week. The water level has receded greatly in some wells. In others, water has turned yellow.

The local government is now pledging to bring in tanks of clean water to the troubled villages, as farmers have been asked to switch from planting paddy to other crops that require less water. The dry weather may continue until the end of the year, forecasters say.

Ms Ati Wasiati Hamid, a director in charge of protecting food crops at the Agriculture Ministry, told the Jakarta Globe that this may push back the rainy season – which normally starts in September – to December. This means the planting of paddy, which usually starts by early October, may also have to wait.

The declining rainfall and cold morning temperatures in some areas are signs that El Nino is coming, said Mr Winarno Tochir, head of the Indonesian Fishermen and Farmers Association. But clearer signs of its return should be evident by the middle of next month, he said.

Still, not everyone is pessimistic just yet. Even if El Nino does come, it could be moderate, as it was in 2002 and 2006, rather than severe, as in 1997, said director-general of food crops Sutarto Alimoeso, Ms Ati's boss.

The year 1997 is believed to be the worst El Nino year, with eight months of drought resulting in a huge shortfall in rice output, forcing the country to import more than five million tonnes of rice. 'We still hope it won't happen. But if it happens, we have measures we can take,' Mr Sutarto told The Straits Times. 'We will boost output from the areas where it is possible to maximise production, while areas susceptible to El Nino can switch to other crops like corn.'

El Nino occurs on average every two to five years, and typically lasts about 12months. It also causes temperatures to rise and, combined with drier conditions, increases the risk of forest fires.