Renovation of the B242 starts: diversions and construction work in the Harz!

Renovation of the B242 starts: diversions and construction work in the Harz!

The construction site is booming in Clausthal-Zellerfeld: On August 13, 2025, the second phase of the road renovation work on Harzhochstrasse (Bundesstrasse 242) will begin. This measure extends between Sonnenberg and the junction with federal highway 4 and is being carried out in cooperation with Harzwasserwerke GmbH. After the successful completion of the first section to the Oderteich car park, which was completed in just five weeks, we can now look forward to the upcoming work with good cheer.

Completion is scheduled for the end of September 2025. But as is so often the case in construction, weather conditions or monument protection requirements, especially when working on the artfully designed ditches of the Upper Harz Water Shelf, can disrupt the schedule. In order to direct traffic during this time, appropriate diversions have been set up, which will take drivers via Altenau and Torfhaus to the B4.

Renovation with an eye on history

Harzwasserwerke GmbH not only takes care of the roads, but also has extensive renovation work on the roadside support structures and the Oderteich dam structure on its agenda. The Oderteich itself - an impressive structure - was built between 1715 and 1722 and was the largest dam in Germany for over 175 years. With a storage volume of around 1.7 million cubic meters and an impressive height of 21 meters, the Oderteich plays an important role in the Upper Harz water shelf, which has been a UNESCO World Heritage Site since 2010.

The variety of historical water supply systems, consisting of ponds and ditches, not only provide important water for the region's mines, but also attract numerous interested parties and hikers. The extensive pond cascade near Clausthal-Zellerfeld is a paradise for nature lovers and visitors interested in history. Particularly noteworthy here are the peacock ponds, all of which were built by 1579, and the traditional Hirschler pond from 1660.

Logistical challenges and accompanying archaeological research

In addition to the roadway renewal, three bridge structures will also be renovated and modern vehicle restraint systems will be installed. In order to ensure the smooth implementation of the construction work, the Lower Saxony State Office for Monument Preservation will carry out archaeological documentation during construction. This is particularly important because the region is rich in history and many of the hydraulic engineering facilities that were built here date from past centuries and are of enormous importance for the history of the Upper Harz water management.

While traffic coming from Clausthal is routed to Altenau via federal highway 498, the parking lot at the Oderteich remains accessible from the direction of Sonnenberg. Traffic lines of this type ensure that, despite the extensive construction work, accessibility to the region is not lost and that the stories of the historic water shelf remain alive.

Anyone who wants to experience the unique beauty of the region should not miss this BAU phase - because history is not only preserved here, but also rewritten. Please continue to find out about the progress of the construction work on the website Regional Today, Yumpu and Weser courier.