As an Engineer interested in both the potential of barrage/lagoon
energy production and sediment extraction in the Severn Estuary, could
anyone point me to any published research on the potential effects of
a barrage on sediment movement?

The current extraction of sand off the Gower coast is a sensitive one,
yet no-one appears to have questioned how a Severn Barrage will affect
this. It is recognised that sediment in the estruary moves tidally in
an anti-clockwise pattern up the English coast and down the Welsh
coast. I realise that my description is a little simplistic as it
takes no account of the huge sediment movements resulting from storm
surges, but it would appear to me that a huge tidal wall could at the
very least disrupt sediment movement.

Any help on this would be gratefully accepted.