The level of the River Stour in Sudbury has dropped by ‘five to six feet’ after a control gate was blocked further downstream.
A spokeswoman for The River Stour Trust confirmed there was a blockage at Cornard weir.
She said: “The Environment Agency was informed yesterday and they are doing what they can at the moment.
“They have been rescuing fish and have also been at Ballingdon.
“It is quite dramatic. One of the [Trust’s] volunteers said they were trying to get the blockage out.”
She added that they were not aware of any flooding upstream caused by the blockage.
Sally Freer, who lives in Cross Street, Sudbury, described the drop as incredible.
“It’s dropped by five or six feet. My neighbour noticed it yesterday but it’s dropped considerably since then overnight.
“The level is incredibly low. The old bridge spurs are exceedingly well exposed.”
The pontoon at the Boat House, Sudbury, by Ballingdon Bridge is now several meters away from where the river flows and a small boat has been left high and dry sitting on the silt.
If you spot any unusual river level changes, flooding or environmental incidents you can call the Environment Agency’s 24 hour hotline on 0800 807060.