Water voles can live up to two years and can reach lengths of 20 cm
Water voles are critically endangered in many parts of the country its population has declined by up to 90% over the past 20 years.
However, surveys show that three sites in our area now have a water vole population which previously did not.
Conservation officer Karen McArthur said: "In Sunderland the decline has slowed considerably, if not halted completely in this area."
Durham Wildlife Trust is working with landowners to improve their habitat.
Water voles live by water and are well adapted to that environment, but when rivers and streams flood they have to abandon the area.
When this happens, the water vole is very vulnerable to predators when forced into the open, particularly if they are trying to move their young to a safe location.
Cover from predators
One project that has been carried out in Weardale has helped combat vulnerability, this was achieved by focussing on building fences on and around farmers' land.
Karen McArthur explained: "Fencing prevents over-grazing and poaching along the banksides of watercourses, meaning more vegetation for water voles to eat as well as providing them with cover from predators.
Often mistaken for a rat
Ratty in 'The Wind in the Willows' was actually a water vole
Life span: Up to two years
Body length: 12-20cm
Habitat: The banks of ditches, dykes, slow-moving rivers and streams, and grassland
Diet: Mainly grasses and other plant material
Behaviour: Expert swimmers, but are not particularly specialised for a life in the water
Reproduction: Up to five litters from April to September
Females give birth to an average of six young after a gestation period of 20-23 days
"There are good populations of water voles in parts of Weardale and it is hoped that this project will help protect them as well as allowing them to expand."
Durham Wildlife Trust Director, Jim Cokill, said: "Water voles are critically endangered, but thanks to work being carried out in our area, their populations are doing well.
"Our area is a real stronghold and, with the animal in such dire straits elsewhere in the country, our work gives it a chance of avoiding extinction in the UK."
Sunderland Council commissioned water vole surveys to be carried out in 2001 and 2007/8 and 2009.
The survey shows that three sites in 2001, that did not have any water voles, have now been found to have a small population.
There were only two sites to have lost their population, one of which included Rainton Meadows.
Stephen Fry and Mark Carwardine of BBC TV's series "Last Chance to See", are keen to stress the importance and have also recently backed a campaign to help save the water vole in the UK.
"We've just spent six months travelling the world in search of high profile endangered species, from kakapo to Komodo dragons," said Mr Fry.
Stephen Fry presents the popular quiz show QI on BBC One
"But it's all too easy to forget that we have endangered species in our own country that need just as much help.
"We're particularly worried about the plight of the charismatic and enchanting water vole - and strongly urge everyone to help with this vital campaign in any way you can."
You can help by adopting a water vole from the Durham Wildlife Trust by