Hambuehren: Experience hydropower and forest landscape by bike (22 km)

Cycle through beautiful forests and picturesque meadows around Hambühren. You will encounter huge sand dunes which once forced an entire village to move and at the Oldau lock you can visit the impressive hydroelectric power station which still generates electricity, today.

More than 500 years ago old farms of Hambühren, then called Abbenburen, stood close to the Aller. The forest had been cleared, the landscape barren and empty. Here the wind drove the fine, flying sand without being held up from the Aller valley into the village, so that fields, gardens and houses silted up more and more. 

 The forest had been cleared, the landscape barren and empty. Here the wind had no problem. It drove the fine, flying sand from the Aller valley into the village, so that fields, gardens and houses silted up more and more. 

So the farmers had no choice but to dismantle their farms and rebuild them further west. The old Abbenburen is still remembered today by the name "Im alten Dorf" (In the old village) on the spot where the farms used to be.

In 1906, drilling began in the Prince Adalbert potash shaft to explore the underground potash deposit. At over 1,600 m, one of these boreholes was the deepest potash borehole in Germany at the time. The bricks for the buildings of the potash works were produced in the sand-lime brickworks built in 1905. The resulting sand mining trough is now used for the Ovelgönne lido. The beach is open from mid May to the end of August when the weather is fine. The entrance is free of charge!

The potash shaft was closed again in 1925. Shortly afterwards, the demolition of the factory buildings began. Outside the factory, however, buildings such as the civil servants' residences or the directors' villa are still reminiscent of the days of potash mining. 

The Hotel zur Heideblüte, for example, was once the miners' canteen. During the Second World War the factory site was used for ammunition production. Work camps were set up for this purpose in Ovelgönne and Hambühren. Forced labourers and concentration camp inmates also had to do heavy work to prepare the planned underground production of aircraft parts, which was not carried out due to the end of the war.

The lock in Oldau was built in the course of making the Aller navigable. Potash salt and coal were transported on the river. The hydroelectric power station, which is now a listed building and still generates electricity today, is largely preserved in its original state. With a dam height of 2.80 m, a 30 m wide weir was built for this purpose in 1911.

Due to frequent changes in water levels, the hydroelectric power station was supported by a coal-fired power station on the western side of the river until 1937. 

You can find out more about the history of this technical monument in the information building, which is located between the lock and the power station (open on weekends from May to September).

A resting place and a landing stage for passenger boats make the Oldau lock a popular destination for excursions today.