Big Butts - Rochdale

Aptly named due to its wide size ‘“Big Butts” is mostly spraycrete with a dash of original brick showing through. Its a straightforward culvert with some smaller channels joining it route some of which are redundant. The outfall plonks you at the Rochdale Police station where luckily enough we didn’t have to explain our shenanigans to any curious officers. The term “when it rains no drains” coined by the Australian subterranean explorers “The Cave Clan” is a rule that proves its point in the fourth image below.

History

“Flowing beneath the town centre of Rochdale lies the river Roch, a tributary of the river Irwell. The majority of it has been culverted since the early 1900’s. The mass culverting of seven of the town's bridges resulted in the making of one of the widest bridges in the world. It now carries the river for around 450 m underground with various overflows intersecting its route. The mediaeval bridge estimated to be 14th century is the earliest and as such is an incredibly rare surviving example of mediaeval engineering. A Victorian egg shaped sewer presents itself halfway making itself known to the nose. The majority of its underground construction has been blasted with spraycrete in recent years to keep up with modern day repairs. There are currently plans in place estimated to cost 3.5 million pounds that will unearth the river once more. This "de-culverting" project aimed to reveal the historic mediaeval bridges and the river itself, bringing back some of the town's natural heritage and improving the urban environment.”

A useful bit of information detailing the medieval bridge and its layers over the years can be found walking topside along the river.

The infall to the culverted sections of the Roch.

This is an image of the same infall of the previous photo in flood almost completely submerged.

In recent years a mass amount of spraycrete has been used to ensure the culvert stays fit for purpose.

concrete and original stone walls can be seen throughout the culvert.

The water level stayed low and relatively the same throughout our visit.

Around half way through the culvert it opens to air revealing a bridge above.

On the right is an original Victorian egg shaped sewer, Through here lies a modern day Processor.

These steel reinforcements are likely for the tramline above.

More modern day reinforcements installed to accommodate modern day road infrastructure above.

To the right is a modern day 4ft RCP run off presumably to feed in rain water. To the right of that is an older Victorian sewer outfall tat is now out of use.

From here the outfall of the culvert can be seen flowing to the side of Rochdale police station.