The most severe flood crest to hit Harbin this season will torment the city for another seven days, according to flood-control officials. The crest has swollen the Songhua River to an unprecedented 120.89 metres since noon on Saturday. The only defence for the city is piles of sandbags - the river is already 80cm above the embankments. A serious breach discovered in a dyke in the city centre on Saturday was brought under control by evening, but cracks continued to appear along the 26km embankment. 'For the past five to six days, over 10 leakages have been found each day,' a Harbin flood-control official said, while stressing that 400,000 soldiers and civilians were keeping the situation under control. However, further cracks are almost inevitable as the dykes have been weakened by weeks of high water levels and more flood crests are on the way. The effects of waterlogging were demonstrated by a riverside pumping station whose foundations gave way on Saturday night. Television showed footage of a crack running down the two-storey building, part of which had sunk 30cm into the ground. Floods on the lower reaches of the Songhua River threatened a natural gas plant at Yilan that supplies Harbin, People's Daily reported. About 200 workers built a wall to protect the plant and about 47,000 people were evacuated from the town, the Guangming Daily reported. Meanwhile, tens of thousands of soldiers in Daqing finished erecting an emergency dyke after the swollen Nen River wiped out the third line of embankments protecting the country's most important oilfield. The third line was destroyed by uncontrollable torrents late on Friday, People's Daily said. The new dyke has been built 20km further back, within the limits of Daqing city. The disaster threatens to inundate 700 oil wells in addition to the 1,443 that have already succumbed to the relentless floodwaters. State television revealed that the oilfield's daily production had fallen by 11,000 tonnes a day, or about six per cent.