Wikipedia
Rödelbach
The Rödelbachgraben, usually called the Rödelbach and also incorrectly referred to as the Rieschengraben, is a river which was altered for mining purposes. It is the oldest fully functioning part of the Lower Harz Pond and Ditch System in the Harz Mountains of Germany. The ditch was first mentioned in the records as the Oberer Rödelbachgraben in the year 1610.