A catchment doesn’t have geographical boundaries, instead it is an area of land that is determined by natural features such as hills or mountains. All water runs off the high ground and flows to a low point – like rain on a roof flowing to a drainpipe. Low points include any body of water such as a stream, river, lake, estuary, wetland, sea or ocean
For instance the Danube catchment runs through 10 countries but in the case of the Don Catchment (below) the water flows from the hills of the Pennines and Peak District towards the Humber Estuary. The catchment covers West and South Yorkshire, Derbyshire and a tiny part of Nottinghamshire and it’s main rivers are the Don, the Dearne and the Rother and has smaller rivers such as the Loxley, Dove, Went, Rivelin to name a few.