Organisers of the Great River Race along the Thames are taking measures to make it more environmentally friendly.
The 21.6-mile river marathon from Millwall to Ham in Richmond takes place on September 8 and involves more than 300 crews, including those from the USA, Romania and Kuwait.
On race day the organisation will provide drinking water and provide reusable mugs at the bar to stop the use of disposable plastic bottles and discourage litter dropping to stop water pollution.
Race coordinator Rose Scotland said: “We have always prided ourselves on our eco-friendly credentials, but this year have decided to go further.
“So, the GRR, Europe’s most colourful and spectacular river event, ‘Goes GRReen!’
The boat championships already use shire horses to cut the grass at the finish at Ham Riverside.
Now they will be working with projects initiated by the Port of London Authority, such as Hubbub, a social enterprise that works like a creative agency for environmental issues.
The GRR is also collaborating with Thames 21, which works with communities to improve rivers and canals for people and wildlife.
Many of the 2,500 competitors will be raising money for charity, and many are sure to add to the spectacle of the race by competing in fancy dress.
Entries include gigs, skiffs, cutters, naval whalers, Chinese dragon boats, and Hawaiian war canoes.
The race starts at 9.50am from the Millwall Slipway, opposite the Docklands Sailing Centre, Westferry Road.
The winner is due to reach Ham Riverside, below Ham House, Richmond, at about 1pm.
