A VAST and internationally important archaelogical treasure trove could be lost to future generations because of the impact of a barrage across the Severn Estuary, says a Newport-based expert.

Leading coastal scientist and oceanographer Professor Simon Haslett fears thousands of years of history could be submerged by a rising sea level, and potential future finds further obscured by layers of mud.

Professor Haslett, director of the Centre of Excellence for Learning and teaching at the University of Wales Newport, shares his fears on the BBC's Countryfile programme tomorrow. He has researched on the estuary for 20 years, being involved in a number of excavations.

"The Severn Estuary is a rich archaeological treasure trove that has artefacts spanning the Stone Age and Ice Age, through the Bronze and Iron Ages, to the Roman and Medieval periods, and one that has unearthed internationally important finds, such as preserved Stone Age footprints," he said.

"We know from models that the construction of a barrage would cause the sea level upstream to rise by three metres (10 feet), which will have the effect of submerging all the archaeological sites that occur in the low part of the tidal window.

"A barrage would also reduce the speed of tidal currents and prevent waves entering the estuary, resulting in mud and silt covering most of the foreshore, and blanketing all archaeology in a layer of mud that will make future excavations very difficult."

Five potential schemes for harnessing the tidal power of the Severn have been short-listed for consideration by the Government and for public consultation.

They include three barrage projects and two lagoon schemes.

A final decision is expected in 2010.