2012-03-18 - London's Famous Subterranean London

When we did the reccie-ride, the tide was in and the water was bubbling up in a kind of rhythmic way, we wondered whether this was anything to do with those doors opening/shutting
Would it be this?

poor quality vid here:
http://youtu.be/IdeCEZ0tMSA

What you're seeing is the secondary, unsecured flaps that link the chamber above with the Thames itself (some way behind the camera in the photo). These allow water in and out of the chamber, they tend to move a bit as the tide goes in/out but what you're probably seeing is the end result of the wake of a boat going past - if you're inside the outfall chamber then the large, cast iron flaps hitting the frame is really loud!