1. Digimap for Schools Geography Resources Examples of Change to River Channels © EDINA at University of Edinburgh 2013 This work is licensed under a Creative Commons Attribution – Non-Commercial Licence

2. Diversion The River Thames once had 21 major tributaries. Some remain above ground but are very much altered. The Serpentine was created in 1731 from the River Westbourne which was originally crossed by the “Knights’ Bridge” Regent’s Park Lake was originally fed by the River Tyburn

3. Other London Examples The Romans covered some tributaries of the Thames. River Walbrook was completely covered by the 1460s. Hampstead and Highgate Ponds were created from two streams of the River Fleet (as in Fleet Street). Those tributaries used for ornamental lakes were all eventually diverted away because they became too polluted. Peckham Rye was originally “the village by the river Peck”.

4. River Brent “disappears” under buildings River Brent flowing in a sinuous pattern

5. Straightening and Altering Both the current and historical map indicate the original course of the River Derwent (Yorkshire) Additional, straight channels were created

6. Changing Sinuosity Map of part of the Yorkshire Derwent Locations where there appears to have been change in the channel course in historic times Meander loops have become more exaggerated. This river is prone to producing cut-offs (ox- bows) as shown

7. Identifying Change (i) There are clues to change over time on the current map. The lake is called Llyn Nantlle Uchaf; “uchaf” means “upper” in Welsh. Look at the remnants of an industrial past in this area.

8. Identifying Change (ii) On the historic map, the extent of change to the Afon Drws-y-Coed and Afon Llyfni becomes apparent. The smaller lake (Isaf) was drained to protect the quarry.