The area is situated in the Demer river valley, west and east of the town of Diest. It comprises a rich variety of former river arms, peat ponds, marshes, reedbeds, sedge-fields, humid grasslands and alluvial forests, including heathland relicts on the sandy hills bordering the valley.
A breeding and staging area for meadow birds, waders and waterfowl.
BirdLife International (2019) Important Bird Areas factsheet: Demervallei. Downloaded from http://www.birdlife.org on 06/12/2019.