What happens with no Barrier?

Increasing the height of the current sea defences would prevent inundation. However, every metre of bank has to be raised: this amounts to over 200km when tidal river banks are included! There are no additional benefits gained from doing this. The sea in front of the defences will get deeper and most of the marginal salt marsh, mudflats and sandbanks will be lost to the sea. Greater erosion of the sea defences will result, causing higher maintenance costs.

If the height of the current sea defences is not raised, then the sea will breach the defences. Initially this will be occasional, not repeated for maybe 10 years, but progressively the frequency will increase.

Any land contaminated by salt water will take three or more years and tons of chemicals to return to full productivity. Areas of fen below sea level may never be drained again. Eventually, all the fen area from Cambridge to Skegness and beyond will become tidal mudflats. Over many centuries, in areas protected from the worst tides, rushes and sphagnum moss will slowly re-establish freshwater fen, similar to that which existed before drainage.