Ed FossFor years one of the region's flagship National Trust properties has suffered damaging floods after torrential downpours - but a chance find in an archive has prompted a project which may finally solve the costly problem.Ed Foss

For years one of the region's flagship National Trust prop-erties has suffered damaging floods after torrential downpours - but a chance find in an archive has prompted a project which may finally solve the costly problem.

The floods have affected the basement and moat of Blickling Hall, near Aylsham, leading to damage to artefacts and closures to the public.

The problem has often caused scratched heads, but with heavier rain in recent years caused by changes in the climate, there have been concerted attempts to see if there is a long-term solution.

Trust surveyor Steve Cowley said a document had come to light showing a previously unknown drainage culvert running underground around the main part of the hall.

Although exact dates were not clear, he said the culvert was probably hundreds of years old - and had apparently never been cleaned out since it was hand built, so was silted up and blocked.

'As part of a survey of all of the surface-water drains around the hall, we found this culvert which we didn't know existed,' said Mr Cowley.

'It is in reasonably good order, but totally blocked - once it has been cleared out, it should help take away a lot of the water which was causing the flooding problems.'

The culvert was unknown because it had no access or inspection points and it was only when an old document was found in the Blickling archives in recent months that its existence became clear.

'It has been in the archive for donkey's years but we didn't know it was there,' said Mr Cowley. 'Finding it all these years on means we can hopefully address a problem which has been going on for all this time.'

Access points have now been added so the drains can be managed regularly, which will see them flushed twice a year.

Liquid waste and drainage specialists HFS, based near North Walsham, have been heading up the project using equipment including a remote-controlled camera and pressurised cleaning techniques.

Company spokesman Barry Munson said: 'The culvert may have been there for 300-odd years and never cleaned.

'We are using a high volume of water under low pressure to reduce the danger of damage to such an old system.'