A �400,000 siphon linking the Wissey with the Cut-Off Channel will make it easier for eels and sea trout to travel to and from their spawning grounds.

The pipeline, near the waterworks at Stoke Ferry, also bristles with hi-tech sensors, which can tell when a tagged fish passes through it.

More than 100 eels, trout and coarse fish have been tagged with tiny transponders, as part of an Environment Agency research project. It's being carried out by Karen Twine, a fisheries scientist known in angling circles as the Barbel Lady, for her innovative research tracking tagged barbel on the Upper Ouse.

The study showed that barbel in the river were not being predated by otters, but were declining because their spawning grounds were silting up.

Now Twine, who works for the International Fisheries Institute, will be keeping an eye on both rarities and bread and butter species like roach, rudd and tench, as they travel from one part of the system to the other.

This is exciting, cutting edge research, which is going to tell us a lot about what goes on beneath the surface of our drains and rivers over the coming years, as more fish are tagged.

The Wissey siphon, the first of its kind in the country, was paid for by efficiency savings within the EA. The pipeline was designed and built in Holland, before being shipped across to Stoke Ferry in sections. It has a series of baffles and pools inside, to ensure the flow remains negotiable for all species. It also has a special eel lane, which helps anguilla ascend on its way inland, where it spends its life before returning to the sea for the long journey to its far-flung spawning grounds.

Similar schemes are planned elsewhere, as the agency steps up its work to conserve rare species and monitor the health of our rivers.

'It's an all-species, all-singing and dancing fish pass,' said Kye Jerrom, a fisheries technical specialist with the EA. 'It's a massive project. It's such a significant site it needed something like this.'

As well as the PIT (passive integrated transponder) tags, Twine intends to use radio tracking along similar lines to her work on the Upper Ouse. The siphon is also armed with infra-red cameras, which scientists can monitor remotely, for a real-time view of fish movements through the pipeline.

There are hopes that similar siphons will be installed elsewhere – another location which has been pencilled in is between the Ouse and the Relief Channel, at Denver.

The Wissey siphon will be officially opened on September 21.