When the tunnel valley developed, meltwater flowed from north to south i.e. up hill, whereas the modern river Hellegård Å has its source near Borbjerg and flows from south to north and reaches Venø Bugt at Handbjerg. The valley generally has a quite flat, narrow floor with quite steep walls. The floor is marshy with small lakes while the steep walls are covered with scrub and coppices. More gently sloping valley walls have ben cultivated. Hellegård Å is a protected watercourse and the entire valley has a mosaic of protected types of nature: marshland, meadowland, lakes and common land (Figure 15-2).
The area around the valley has been inhabited since the Stone Age. There was easy access to the rich resources in Limfjord. There are traces of Stone Age, Bronze Age and Iron Age inhabitation on both sides of the valley. There is a particularly large concentration of prehistoric remains near Brødbæk and Store Ryde Mølle. There was probably a ford across the river here. There are several significant water mills along the river, including Borbjerg Mill that has been active for more than 600 years. The river Hellegård used to be called Oe hin Heelie which means “The Holy River”.
Much of the site has been nominated as a Natura 2000 site and contains many items of cultural historical value. The heathland plays a role in local identity, and the kettle holes at Hjelm Hede have inspired local legends and a scene in a novel by Jeppe Aakjær (1866-1930), a leading Danish author who is known for his stories about the harsh living conditions in this area.