Santiago, Apr 12 (IANS): Chile unveiled guidelines to ration water in Greater Santiago, home to more than 5.6 million residents, as the record-breaking drought enters the 13th year.

"We are in an unprecedented situation in the 491-year history of Santiago, where we have to prepare for times when there is not enough water for all residents," the Governor of the Santiago Metropolitan Region Claudio Orrego said on Monday in a press conference.

"We cannot rule out rationing in the next 12 months," Orrego added.

Miguel Munoz, Regional Director of the Interior Ministry's National Emergency Office, said the guidelines include four alert stages depending on the flow levels of the Maipo and Mapocho rivers, the main water tributaries irrigating the metropolitan area.

"For the most critical red alert, programmed rotating cuts (lasting a maximum of 24 hours) and emergency resource allocations will go into effect," Munoz added.

According to the authority, the guidelines will apply to all the municipalities of the Santiago province, plus Puente Alto and San Bernardo, the most populated territories adjacent to the capital, Xinhua news agency reported.

The government estimates that Chile's water availability has dropped 10-37 per cent over the past 30 years and expects another 50-per cent drop in northern and central Chile by 2060.