MARLOW Lock is set to close temporarily later this year as part of a £2.75million repairs scheme.
The cash is being spent by The Environment Agency at 12 of its 45 locks along the River Thames to ensure they are in good condition for boaters and other river users.
A joint project for Marlow and Boulters Lock, just down river near Maidenhead, will cost about £120,000.
Both will close between November 5 and December 15 to build extensions to the escape steps.
Agency spokeswoman Michelle Southby said: "By combining the two jobs under one contract we are reducing overall costs.
"In both cases we have to install dams within the lock and drain down the water as the extension of the escape steps will go below normal water level.
"The damming and the draining down come under the heading of temporary works to allow the actual work to be completed in a safe and sound manner."
Paul Power, Environment Agency waterways engineer for the River Thames, said: "The River Thames is used by millions of people each year from boaters to anglers, and investment in the locks and associated structures is vital to providing those users with a reliable and safe service."
The biggest projects are being undertaken at Iffley, Abingdon and Old Windsor locks, where a total of £1.3 million will be spent replacing lock gates and repairing and reinforcing the lock chambers.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here