The drain starts off in brick around 7ft tall. This then alternates between short stretches of RCP where repairs have been made, before opening up into a large egg shaped section.

Hidden on the riverbank of the Irwell the outfall looks like a portal into a time gone by.

This drain is in one of Manchester's surrounding northern towns and was a bit of a stooper, 3ft RCP being king here.

A concrete CSO overflow built into a hillside near Bolton.

This culvert is found in Radcliffe near Bury, it's about 260m long and outfalls into the Irwell.

This drain looks to have been built in the last few years. The whole system is concrete and there has been some major landscaping above ground. The dig a hole, fill it with prefab bits and scrape the earth back over method seems to have prevailed here.

I walked in from the outfall and found a large brick arch, the sides were scattered with stone debris with the river flowing sedately inbetween.