The Thames Barrier was closed today due to the weather. I've never seen it closed before so I took myself down there for a look around.
I noticed that one of the gates had been opened up further into the underspill position, that allows water to flow from one side of the barrier to the other in a controlled fashion. As I was there sirens sounded and they opened up another gate into the same position. I'm not sure if they were doing that to equalise the water heights on both sides prior to opening the barrier or if they were just letting some water through because they had the capacity behind the barrier.
The difference in water heights was about 6 to 9 foot or so, quite impressive to see. They had closed off access to the riverside path itself so I'm wondering if they suspected that it would flod.
Anyway very intersting to see. I took some photos, click on the thumbnail to see a larger version.