Pakistani engineers are facing a grim trade off in an attempt to drain the country’s largest freshwater lake by inundating rural villages to save larger towns. The effort to drain Lake Manchar has been under way since last week, when engineers said a protective embankment and dyke around the lake was close to being overwhelmed, amid record rainfall and melting snow in the Himalayas, which has caused severe flooding that has killed more than 1,300 people. The lake-draining exercise has led to evacuations affecting more than 100,000 people, and cut off at least two towns. The effort is already having a major impact with the town of Johi now being described as an “island,” protected by earth berms, with locals and government authorities working to strengthen flood defences. Scores of villages near Johi town in Dadu district, Sindh province, have been submerged, Pakistan’s <i>Dawn</i> newspaper reported, while the nearby town of Mehar has been cut off by rising waters. Both towns will benefit from the lake-draining exercise, which is already diverting floodwaters, officials said. “We have widened the earlier breach at [Lake] Manchar to reduce the rising water level,” Jam Khan Shoro, Sindh Irrigation Minister, told Reuters late on Monday. District official Murtaza Shah acknowledged on Tuesday that there had been enormous pressure on the dykes protecting Johi and Mehar in the period up to Monday. However, 80 per cent to 90 per cent of the residents of the two towns have already fled but those who remain are trying to strengthen the dykes using machinery provided by district officials, he said. “After the breach at Manchar, the water has started to flow; earlier it was sort of stagnant,” Akbar Lashari, a resident, said by telephone after Sunday's initial breach. The rising waters have also inundated the nearby Sehwan airport, civil aviation authorities said. The floods have come at a time of record-breaking summer temperatures, with the government and the UN blaming climate change for the extreme weather and the resulting devastation.