The Environment Agency is removing weed from a river to cut the risk of flooding to homes and businesses in Lincolnshire.
An excavator is being used to take the weed out of the River Ancholme, near Market Rasen.
The agency said the plants can slow the flow of water and increase the risk of flooding near Bishopbridge.
The work is expected to be finished by October.
Glyn Ellis, from the Environment Agency, said: "It is important that we keep water flowing to reduce the risk of flooding.
"During the warm summer months too many water weeds growing in our rivers and streams can create blockages.
"When we get heavy rainfall this can hamper the free flow of water and increase the risk of flooding."