Buried, forgotten and rediscovered – the old Ruhlsdorf Freiarche
Until 1914, the Finowkanal was the only navigable waterway in the Eberswalde area between the Havel and Oder rivers. In order to be able to ensure the regulation of the dam and the discharge of flood water in the individual sections of the canal, there was a free ark (weir) at each lock location through which the excess water could run off.
Due to the construction of the Berlin-Stettin major shipping route, today’s Oder-Havel Canal, the damming of the waterway was redesigned, the Finowkanal was no longer needed to regulate the water level and as a result the weir in Ruhlsdorf was filled in in the 1920s. Over time, the structure fell into oblivion, the watercourses were filled in with building rubble, plenty of vegetation grew on the site and only an oxbow of the Klanfließ river hinted at the different watercourse in earlier times.
Ruhlsdorf locks around 1882 with free ark, source WSA Oder-Havel
The rediscovered defensive structure in 2022
In order to be able to continue to supply the first canal stage of the Finowkanal with water during the basic repair of the lock and to prevent it from falling dry, it was necessary to construct a water transfer during the construction period. In the course of the preparatory measures, the well-preserved remains of the old weir from 1882, which were not recorded in any plans, were discovered by chance and then partially uncovered and documented archaeologically.
In order to protect the structure from further damage and still be able to reactivate the channel for the construction work, a steel pipe was inserted into the old weir and everything was backfilled. As a result, after around 100 years of slumber, water is now once again flowing through this bypass.
During the excavation of the required trench, large quantities of brick rubble from an earlier repair of the lock, which is still in operation, were found as well as numerous granite form stones, which originally protected the corners of the lock chamber from ship impact and were replaced by concrete. It is currently being examined whether some of the recovered stones can be used for the reconstruction of the lock.
