Is it possible to bring a lake back to life? Here at Årslev Engsø, the answer is a resounding yes. This is a story of loss and rediscovery. It is a story about Årslev Engsø.
Årslev Engsø sits west of Brabrand Sø. This lake is more than just a scenic spot. It is a testament to nature’s resilience and human intervention.
Imagine this area long ago. Picture a 12 km long fjord called Brabrandfjorden. It stretched from Skibby to Åboulevarden. This fjord was formed 8000 years ago during the Ice Age. It was navigable until the Viking Age.
Over time the fjord slowly turned into a freshwater stream. Natural and man-made changes narrowed it. Mill constructions like Aarhus Mølle around 1289 contributed. The water gradually became less salty and finally fresh.
In the following centuries, the water level in Årslev Engsø and Brabrand Sø was higher. It was about a meter above today’s level. Both lakes powered several watermills. However in 1873 something changed. The dam at Slusebroen by Aarhus Mølle was removed. Brabrand Sø shrank and Årslev Engsø nearly vanished. The former lakebed became marsh and meadows. These areas still flooded in winter.
Constantinsborg Manor owned much of the frequently flooded land. In 1924 and 1933 the owner Alfred Pontoppidan tried to construct dikes and drain the land near Skibby and Ormslev. A pumping station was built for this purpose. It was south of Årslev Engsø. It is now the bird-watching post west of Constantinsborg.
The dikes collapsed due to the soft ground. A new attempt at drainage was made 25 years later. In 1958 Årslev-Ormslev Landvindingslag was established. The state Nature Conservation Council opposed the drainage project. After decades of drainage projects nationwide they wanted to preserve remaining lakes and streams.
The land reclamation team worked with Hedeselskabet. They secured state subsidies to cover 60 percent of the drainage costs. The landowners provided the remaining 40 percent as state loans. Drainage proceeded until 1963. The stream was moved to a canal north of the river valley. The drained areas were enclosed by dikes. Drainage canals pumped water into the new canal. Two pumps in the current bird tower north of Årslev Engsø did this job.
Although draining gave access to farming 210 hectares of land, side effects occurred. The water table lowered. Heavy farm machinery compacted the soil. The land gradually subsided approaching the damp subsoil. Only 45 percent of the land was farmed in 1996. Brabrand Sø received sand and mud that Årslev Engsø used to filter. This negatively impacted Brabrand Sø’s environment.
In the 1980s Aarhus City Council debated the area’s future. Aarhus Municipality worked with Hedeselskabet. They had helped drain Engsøen in the 1960s. In 1990 they developed a proposal to re-establish the lake. In 1997 Århus County became interested.
The lake restoration coincided with the Danish Parliament’s Water Environment Plan II. This aimed to reduce nitrogen emissions into inner Danish waters. The Water Environment Plan and approval from the Conservation Board in 2001 helped realize the nature restoration project in 2003.
Aarhus Å once again flowed freely into the river valley. On March 19 2003 a hole was dug in the dike. After about three weeks the valley filled with water. Årslev Engsø was reborn. The result was a shallow lake of 100 hectares. The deepest point is 1.25 meters. The average depth is only half a meter.
Today Årslev Engsø is part of the WaVE cultural heritage area. It is a section of the Aarhus Å from Brabrand Sø to Mindet. Around Årslev Engsø, there is an 8 km nature trail. Three bird towers offer views of the rich birdlife. Here you might spot rare birds. Examples are osprey and white-tailed eagles.
Årslev Engsø stands as a symbol. It shows what can be achieved through ecological restoration. It is a beautiful place for recreation and wildlife.