Flood defences made by two beavers have "stood up well" during a wet winter, according to the man behind the scheme.
The Eurasian beavers, which were bred in captivity, were introduced at the Spains Hall Estate in Finchingfield, Essex, in March to try to reduce flooding in the nearby village.
Since then they have built about 20 dams and created an area of wetland.
Estate owner Archie Ruggles-Brise said the "natural solution... certainly seems to be working".
Finchingfield, near Braintree in north Essex, was flooded in 2014 and 2012.
Mr Ruggles-Brise had been shown research on beavers in Devon, which concluded they had reduced the risk of flash floods and so decided to introduce them himself.
It is the first time the animals have been in the wild in Essex in 400 years and, in just under a year, the animals have created a wetland area which holds the water at a higher level upstream.
They are now not building so many new dams but adding to existing ones.
Mr Ruggles-Brise said that some rain over two days just before Christmas tested both the beaver and man-made dams but "everything stood up well".
"It certainly seems to be working. You can't say for certain - there's a lot of data being collected and the experts are looking at that now - but my gut feel is yes, it probably is [working]."
The Environment Agency had described it as a "pioneering approach" to tackling local flooding.