Yorkshire Water has released more than 100 water voles at Timble Ings Woods in the Washburn Valley in the Yorkshire Dales.
Water Voles are believed to be one of the fastest declining mammals in Britain, losing 97% of their former geographical range and are identified as a key species for conservation in the Nidderdale Area of Outstanding Natural Beauty.
Preyed on by american mink, water voles have suffered a steep drop in numbers in recent years.
Timble Ings Woods is owned and managed by Yorkshire Water and is a Site of Importance for Nature Conservation.
Yorkshire Water has spent the last 18 months preparing the two hundred hectares of woodland to welcome the new inhabitant.
At the site, trees have been cleared to allow vegetation to grow alongside streams, creating just the right conditions and making it ideal for water voles.
Following the release, Yorkshire Water will continue to monitor for mink, to make sure the predator does not return, in the hope the water voles continue to thrive around the streams and riverbanks of North Yorkshire.