Over 15 miles of the River Aire will be cleared of trees next week as the Environment Agency carries out flood prevention work.
The operation will cover a stretch of the waterway in North Yorkshire from Steeton, near Keighley, to Bell Busk, north of Skipton.
The project will restore the river channels to optimum condition, maintain stability of the river banks and reduce flood risk.
Project manager Richard Anelay from contractors Turner and Townsend said:
"This is a major waterway clearance project, which will help improve flow and lessen flood risk in the area.
“A detailed ecological survey of the waterways has been carried out and the work will specifically target the removal of trees, vegetation and debris that is deemed a potential flood risk. There will also be some crown lifting and general pruning and clearance work.”
Contractors will work to clear obstructions and blockages from the river channel, improve the flow and capacity of the river, repair damage to existing flood defences from debris and manage water levels.
Waste materials and debris will be recycled for use in habitat creation, and the project has been timed to avoid bird nesting season. It will be completed by the end of March.