River Thames to the strong current of the river, but also other river users. Organised swimming events take place at various points generally upstream of Hampton Court, including Windsor, Marlow and Henley. In 2011 comedian David Walliams swam the from Lechlade to Westminster Bridge and raised over £1 million for charity. In non-tidal stretches swimming was, and still is, a leisure and fitness activity among experienced swimmers where safe, deeper outer channels are used in times of low stream. A Thames meander is a long-distance journey over all or part of the Thames by running, swimming or using any of the above
River Thames sediments. Other organic geochemical measurements of carbon flow such as stable carbon isotopes (δ13C) were found to be insensitive to this urban disturbance. There are several watersports prevalent on the Thames, with many clubs encouraging participation and organising racing and inter-club competitions. The Thames is the historic heartland of rowing in the United Kingdom. There are over 200 clubs on the river, and over 8,000 members of British Rowing (over 40% of its membership). Most towns and districts of any size on the river have at least one club. Internationally attended centres are Oxford, Henley-on-Thames and events and clubs on