Holckenhavn Fjord and the Ørbæk Å river valley were formed during the Ice Age when a glacial tongue filled the entire Great Belt and the land surrounding it. Meltwater rivers flowed through tunnes under the ice and were so powerful that they carved valleys in the underlying soil.
Both Vindinge Å river and Ørbæk Å river flow into Holckenhavn Fjord. With the higher water level during the Stone Age, the fjord extended all the way to Bynkel in the Ørbæk Å river valley, and as fas as Vindinge in th Vindinge Å river valley. But, following a slight land elevation and the build up of sand, silt and peat from the two rivers and wegetation along the banks of the fjord, parts of the fjord have filled up over time.
There is tremendous biodiversity in the marshes and salt meadows of Holckenhavn Fjord, and orchids can be found trowing at the outlet of Ørbæk Å river. The fjord is an excellent area for bird watching, where there is an abundance of ducks, geese, swans, coats, etc.
You may also catch a glimpse of the osprey and other birds of prey, especially during the migration season. Grey herons and the marsh barrier also breed in the area.
Holckenhavn Fjord and Ørbæk Å river valley is one of approximately 200 areas in Denmark of national geological interest.
In addition to the marked route, there are several other possible walks to the area. Starting out from Holckenhavn dam, you can for example, wald along Gl. Vindingevej to the marked path on the old railway to Vindinge Å River, and from there along the path to Vindinge. From Vindingen, walk along the public road through Rosilde to Bynkel and on back to Holckenhavn.
There are several places in the area offering wonderful views over the fjord and river valley, where you can picture the Viking ships sailing up the fjord towards Vindinge 1000 years ago.