I don’t know this one! I would imagine that the Nile is deeper, at least at some point, but I know that the Thames can become quite deep in parts too. The Thames does get quite shallow near to the coast though. I’m interested to see if anyone else knows 🙂
When I was in Egypt I remember being told that the deepest part in the Nile was in Aswan dam, about 180m deep…I guess the Thames will vary a bit, specially the areas heavily influenced by tides, but I would guess it would not be way over 20m deep…though tides can add quite a few meters to this! So I cannot give you a final value ;( sorry!
I know nothing about rivers – so I’m glad these guys could give a better answer than me.
All I know is that even though the River Nile is massive, it loses a lot of the water through evaporation.
Where I work in Namibia we have a river that runs right next to our tents… but it only flows at certain times of the year. It’s crazy how much the environment can change across seasons, from having a full flowing river to having nothing but sands!