In an Olympics briefing today (10 October), Olympic Delivery Authority Chairman Jack Lemley confirmed that 'not a spoonful of dirt was turned from May to September' due to presence of the sewage line.
The problem lay in the Abbey Mills sewage works at the south of the east London site. When it rained, the works would exceed its water capacity, pumping more than 600,000m 3of raw sewage into the River Thames.
Lemley said: 'As the Thames is subject to the tides, it coursed raw sewage up through the river and on to the Olympic Park site.'
It took the workers time to figure out what the problem was and how to prevent raw sewage flooding the site when the Games were in progress.
The solution was to place a lock on Prescott's Channel - a flood relief for the River Lee. The lock was to be integrated for hauling building material to and from the site, but it also controlled the tidal flow of the River Lee, reducing the chance of sewage spilling onto the site, in the short term.
Lemley added: 'Not to have put any pounds in the ground - physically - over the summer months, was a huge problem. So it will mean a lot of dirt will have to be turned over the winter months and next year. But I'm very excited at what lies ahead.'