The Irwell Rivers Trust works within Lancashire and Greater Manchester in the North West of England. The Trust covers the Irwell and all its tributaries and is based in the town of Bury, in the centre of the Irwell catchment.
The River Irwell rises on Deerplay Moor above Bacup and flows south to the centre of Manchester, where it joins the Manchester Ship Canal and River Mersey. It is 39 miles long with a catchment area of 715 km sq, approximately 30% of which is urbanised.
The major tributaries of the River Irwell are:
- River Roch, from the moors above Littleborough to its confluence with the Irwell at Radcliffe
- River Croal, from Bolton in the west to its confluence with the Irwell at Kearsely
- River Irk, from the moors above Oldham to its confluence with the Irwell in Manchester city centre
- River Medlock, from the moors south of Shaw to its confluence with the Irwell in Manchester city centre
Interactive Google map of the Irwell Catchment (edge highlighted green)