TIDES OF THE THAMES

Tidal peaks and troughs travel west, from the Sea (Walton) to Richmond, and never the other way
Walton: (solid light blue) Nearest to a sine shape. But the tide here drives the rest.
As you go upstream the tidal shape becomes increasingly distorted and larger and delayed
The high tides are higher and the low tides lower than at Walton.
At Richmond the high water is in line with that change, but the low is cut off by the rising bed of the river
That effect on the low tide begins to be just noticeable at Chelsea
At 1.72m ODN the Richmond movable weir operates and that is obvious in the slope on the ebb tide
At Richmond also the effect of river flow is most noticeable
The barrier is shown in red(downstream higher) or green(upstream higher) -
with a thickness proportional to the drop across it. So barrier closures will be obvious.
When the river flow is high there will be a (green) drop across the barrier despite the incoming tide