River drainage basin boundary

Question

I'm looking for a set of outlines of the river basins in the UK - I don't need a particularly detailed or highly accurate map - just a map saying point X will drain into the Thames or point Y will just go into the sea! Just the main river names would be fine. I have the full Environment Agency rivers set and the OS DTMs if I want... but how do I convert this into a catchment boundary?

ps. Sorry about the poor tagging I can't find suitable existing and I don't have the rep to create new ones.

Thanks!

Answer 1

You could perform a watershed analysis yourself, but its a time consuming process. One good source of existing river catchment data is the HydroSHEDS project, which provides high resolution basins for much of the globe, including the UK.

Answer 2

The trick is to Google "UK river catchment map". (Other combinations that include "watershed" don't work.) You will find

• River basin management plan documents.
• River basin district maps (downloadable files).
• An interactive map.
• Maps by the UK Environment Agency.
• Scottish river basin maps and data.

A search involving "watershed" did turn up a historical (1883) map in the Rumsey Map Collection.

Answer 3

If you don't find a map, SAGA GIS has a module called watershed basins that uses a dem and the channel network (your rivers). If you use a coarse dem this goes fast. http://www.saga-gis.org/saga_modules_doc/ta_channels/index.html