Hurley Weir for canoists and also.

Hurley is arguably the UK's premier play boating venue. Its attractions include its convenient location, the power and consistency of the Hurley wave and the fact that the weir is freely available 7 days a week for up to 9 months a year. ...
There are in fact 3 weirs at Hurley, which link islands immediately north of the lock and lock cut.
The downstream weir, the 'buck gates', nearest to the lock consists of radial gates but this should not be confused with the main weir - whilst rodeo competitions have been held here, the weir is extremely dangerous. This is because the weir pool is heavily eroded, causing a retentive stopper to form between the concrete stanchions between the gates.
The next (middle) weir upstream consists of vertical sluices, which are not usually of interest.
The main attraction is the furthest, most upstream weir. This consists of 4 radial style gates, situated between concrete shelving. Flow over the northern most shelving is controlled by a row of small radials - and the gate nearest to the radials is usually left shut to protect the eddy. The southern shelving extends downstream of the gates by about 10 ft, boxing in the weir at one end. The river level drops by just under 4 ft at Hurley - one of the smallest drops of any Thames weir - however, with a shallow weir pool, the result is a shallow angled flow of water that produces a wave with a smooth green trough and white, breaking peak, about 3 ft high. The gates, with concrete stanchions in between, create a unique series of waves/ holes.

The above table of how the gates are likely to open in relation to the river flow comes from Thames Valley Freestylers.
The above illustrates how different the river can be depending on ones particular interests!
See Hurley Lock for live flow estimates - there is a problem caused by Hambleden and Temple Lock levels not being online.