Introduction
The Severn Estuary lies on the south-west coast of Britain at the mouth of three major rivers (the Severn, Wye and Avon) and many lesser rivers. The immense tidal range (the second highest in the world) and classic funnel shape make the Severn Estuary unique in Britain and very rare worldwide. The intertidal zone of mudflats, sandbanks, rocky platforms and saltmarsh is one of the largest and most important in Britain. The estuarine fauna includes internationally important populations of waterfowl, important invertebrate populations and large populations of migratory fish. The estuary has a diverse geological setting and a wide range of geomorphological features, especially sediment deposits. It is important for the interpretation of coastline dynamics and landforms and past changes in sea level, sediment supply, climate and river flow. The estuary's overall interest depends on its large size and on the processes and interrelationships between the intertidal and marine habitats and its fauna.
