Laura Bagshaw THE final stage of a �4.7m flood alleviation scheme in Great Yarmouth got under way this week - and this multi-coloured monster with pointy teeth was part of it.

Laura Bagshaw

THE final stage of a �4.7m flood alleviation scheme in Great Yarmouth got under way this week - and this multi-coloured monster with pointy teeth was part of it.

The tunnelling machine similar to the gear used to bore the Channel Tunnel, was lowered four metres into the ground below Northgate Street on Monday to help finish the sewer upgrade job.

About 490m of sewer has already been installed, run-ning from a new storage tank in the car park of Northgate St Andrews First School, up Northgate Street, across Lawn Avenue and towards the existing Tar Works Road pumping station.

The 1.5m-diameter machine will tunnel 250m from the drive shaft in the grounds of Northgate Hospital, close to Beaconsfield Road, up Northgate Street to the junction with Apollo Walk.

Existing Victorian sewers will remain in use with the new sewers acting as an over-flow. The machine will take about six weeks to reach its final destination, where it will be raised out of the ground via another drive shaft.

Sam Baker, team manager at Anglian Water, said: “The

reason we are using this machinery is so we cause less disruption for traffic. Access to pedestrians and vehicles is maintained, and it is also safer.” He added that the open-and-cut method for installing sewers would cause too much disruption as it would mean the road being dug up.

The scheme was announced last August in response to the floods that happened in 2006, the worst of them in September, when a month's rain fell in just a few hours and flooded thousands of homes and businesses. Once completed, the scheme will see sewer capacity rising from 350mm to 1.5m in diameter and will include a new storage tank and pumping station.

Mr Baker said: “Most of the work will be completed by the end of March, but we will still be working behind the scenes for another couple of months on the pumping station.”

The storage tank, beneath the school car park, will be able to hold up to 850 cubic metres of water. Once this is full the water will be pumped to the Tar Works Road pump-ing station, which in heavy storms could be pumped into the river to avoid flooding.

“Normally the water is treated, but in some circum-stances it will be put into the river,” said Mr Baker. “The new system will only come into use in times of heavy rainfall so it will largely deal with surface water.”