Bird colonies on the Severn's Islands:

The islands of Steepholm and Flatholm have a huge population of seagulls. Walking through the colonies there provides a fascinating (and also somewhat frightening) spatial sound experience, as the birds are very defensive about their breeding grounds.

Bird migration:

Wetland wildlife is under threat. Of those species that depend on inland wetlands, 15% of birds are globally threatened with extinction. Nature researves like Slimbridge Wetland Centre are important sites to care for and study ducks, geese and swans who travel there from all over the world.

Bridge resonances:

The old Severn Bridge as well as Clifton Suspension Bridge are accessible by foot. Using contact microphones, one could record some of the interesting resonances that are caused by heavy/light traffic and in different weather conditions. In that way, one could sonify how the bridge is being 'played' by its environment.

Deep water ports:

Some ports on the Severn Estuary, such as Barry, are deep water ports. A new deep water port is also being planned for the southern side of the estuary. This allows for more large container ships to enter and leave the estuary, which benefits the UK economy, but may impact on the local environment.

Eels:

Severn eels begin their life as eel larvae. From their birthplace in the Sargasso Sea they drift for three years across the Atlantic Ocean to the Severn Estuary. Should they escape the nets of the elvermen, the young elvers continue to swim upstream and, over a period between eight and fifteen years, grow into eels. Eels feed by night and during the day bury themselves in the mud at the bottom of the river. Maturity occurs in the autumn when the eels begin their long journeys back down the river and out to breed in the Sargasso Sea, never to return.

Fish migration:

Some fish species (like the flatfish) use the tide to gradually reach their breeding grounds further upstream in the estuary: by anchoring themselves to the ground as the tide goes out, and letting themselves be carried with the tide as it comes back in.

Sediment/silt movement:

Tonnes of sands and silt are transported daily into the Severn Estuary by the rivers that end there. 30 million tonnes of fine silt is suspended in the Estuary's waters during a typical spring tide. The amount of moved material depends on the severity of the tide, contributing in this way to a constantly re-arrangement of the landmass. And like the tides that carry the silt, these 'living' geological processes are still relatively unpredictable.

Semidiurnal (twice daily) tide movements:

Using data from published tables (sun rise/set, moon rise/set and tide tables) one can sonify the movement of water in the Severn Estuary over time. This reveals the semidiurnal rhythm of the Severn, and also how the tide reaches different places at different times. The characteristic semidiurnal rhythm we find in the estuary is quite different from other large estuaries in the world, where it would be either diurnal (Mexico), or mixed (Pacific Ocean).

Severn Bore:

The Severn Bore is a famous phenomenon occurring every equinox, when we have the highest tides of the year. Like one huge wave, the tide rushes into the upper part of the Severn, getting more pronounced as the further up it travels. Surfers can ride the Severn Bore for many kilometres upstream. Because of this, the bore on the river Severn holds the world's longest surf record.

Sounds of the salt marshes:

The salt marshes near Beachley are sonically an interesting location, as the outgoing tide runs through many riverlets and rhines, creating very particular water sounds.

Underwater processes:

As recordings, these could range from very tiny sounds such as the movement of water insects or small fish, to more pronounced sounds, for example the wind and the tide washing over a situated microphone during the course of a day.

Waste management:

It is still common practice for some industries and nuclear power stations that surroundi the estuary to release some of their waste products into rivers and the estuary at low tide. This waste should then be carried by the outgoing tide into the British channel and into the sea.

Severn Phenomena
A glossary of processes that may offer themselves for further sonic work