I was using CD:NGI imagery to trace the Vaal River borders and thought I would double check an inlet using Bing, was amazed to see the difference. The CD:NGI imagery is much closer to normal probably winter flow if I were to hazard a guest with the Bing imagery taken during a severe flooding event by the looks of it. Interesting.
It does raise another point though. Where is a river's boundaries? What is normal flow? Should we in an ideal world map drought, "normal/average" and flood boundaries if we had the data? I think so but it would be a massive project and accuracy would certainly need to be stepped up a bit. It also becomes a 3D problem because what would normally be an island in a river now suddenly disappears beneath the water.