Arenbergmolen (Watermill at Arenberg Castle) [S. L. Weiss - prelude & fantasia - Hopkinson Smith]

I captured the video at Arenbergmolen on 15 September, 2024. Retaining the natural sound, just making it somewhat lower, I added as the musical background Sylvius Leopold Weiss' (1687-1750) prelude in f-sharp-minor and fantasia in d minor performed by Hopkinson Smith.

The watermill at Arenberg Castle is one of the oldest mills in Flanders. The first historical mention dates from 1286. In the sixteenth century, the mill consisted of two buildings that were built on the right and left banks of the Dijle and were connected by a bridge. The mill on the right bank probably disappeared during the seventeenth century. Archive sources show that the function of the watermill changed over time. For example, the mill was used for the production of grain, buckwheat and oil or as a sawmill.

After the First World War, the Arenberg family donated the castle and the surrounding park to KU Leuven. In 1954, the mill building underwent a thorough renovation to accommodate classrooms. It is likely that the mill mechanism disappeared from the interior at that time. The wheels and the lock system – which date from the beginning of the twentieth century – were preserved but fell into disrepair, making a thorough renovation necessary. Because of its historical and industrial value, the watermill was protected as a monument from the end of the twentieth century.

Initially, the Faculty of Engineering Sciences, together with the Technical Services of KU Leuven, conceived the plan to get the watermill running at full speed again and thus generate green energy. Calculations showed that the mill wheels could produce an annual yield of no less than 216,000 kilowatt hours. "That is approximately double the current green energy yield of the university," says Joris Snaet of the Division of Monuments and Building Maintenance at KU Leuven. The yield from that energy generation would even recoup the costs of the restoration in fifteen to twenty years.

The promising plan to have this historical monument generate energy was premature. It soon became apparent that permanent operation of the mill would have disastrous ecological consequences. “The wheels do not turn on flowing water, but on the force of water pushed up,” says Joris Snaet. In order to push the water up, the bulkheads of the lock system have to be lowered. “This effectively creates two separate ecosystems in the Dijle, which is unacceptable in the context of modern nature and biodiversity management.”

With all that knowledge, the final decision was made to restore the watermill purely aesthetically. In this case, the water is no longer raised: the wheels 'freewheel' on the power of the flowing water without any energy generation. The mill is thus mainly preserved as a historical monument.

Although it was primarily an aesthetic restoration, the mill now offers new opportunities for research projects on energy generation. In collaboration with professors and even students from the university, it will be investigated whether a minimal impoundment can generate green energy without ecological consequences.

This possibility arouses curiosity and fascination among donors: 'can it work after all?' "That's how the weakness of the project turned into a strength", concludes Joris Snaet. Who knows, the watermill at Arenberg Castle might in the future evoke more than just memories.

(For the full article see: https://stories.kuleuven.be/nl/verhalen/wa...)