A key underpass beneath the A17 in Holbeach became flooded last week after a log became lodged in the drainage system there.
Coun Tracey Carter said it looked like it had been done deliberately but she hoped that wasn’t the case.
As the underpass was unusable, instead pedestrians looking to come into Holbeach from the other side of the road had to try and cross the A17.
Resident Kay Arnold said: “It is quite serious as children are trying to cross the A17.”
Due to it flooding frequently in previous years a new drainage system involving pumps had been installed.
However, when Lincolnshire County Council employees attended last week they found a stick in the mechanism which meant it was unable to work.
Coun Carter said “A lot of work was done there last year.
“Unfortunately it looks like it was deliberately tampered with and a branch was put into the mechanism.
“Hopefully no-one does that again.
“Hopefully it wasn’t deliberate and was just something that never happens again, because the impact is very serious.
“There was children crossing the main road which we never want to have.”
