The very word "barrages" is evocative. In the context of tidal waters it conjures up pictures of massive structures and environmental change. Barrages represent the engineer s success where King Canute failed to stop the tide coming in. They are hardly a new concept as man has for centuries tried to harness tidal power to drive his machinery, but a new breed of barrage is emerging, aimed at regenerating depressed urban areas. One of the primary aims of such schemes has been to drown "unsightly" mud flats. If you happen to be a wading bird used to enjoying the worms that live in intertidal mud...