The rivers of Manchester are really interesting, for example the Medlock which is also hidden in culverts through the city! The river Tib is culverted through its entire length as well.
Interesting that Pete, Ive never heard of that watercourse. Joining the Irwell just before the docks it obviously used to contribute to feeding the huge Aythya duck flocks that used to gather in the Quays. Also ironic that the cranes gathered around it are now of the mechanical kind, flocked across the city skyline!
Just been googling the rivers of our glorious county and came across Cornbrook which is for the most part culverted under Manchester. Apparently it runs under the university before eventually emptying into the Irwell in Salford somewhere before the docks. The derivation of the name is from Crane Brook,an area where the Cranes used to gather 100s of years ago!!!