The acronym WSA stands for a Wasserstraßen- und Schifffahrtsamt; a waterways and shipping office in Germany. WSAs are the local branches of the Wassterstraßen- und Schifffahrtsverwaltung which is responsible for Germany’s waterways, vessel traffic regulation and safety. The WSV directly reports to the Ministry of Transport. In this case study we discuss about the underwater survey projects with WSAs of Cuxhaven and Lauenburg. Cuxhaven lies on the coast of the North Sea, near to the estuary of River Elbe; Lauenburg is located in the inland in southern Schleswig-Holstein also on the Elbe.
Germany has hundreds of rivers and dozens of canals creating the largest water infrastructure networks in Europe. The cargo transported through inland waterways include for example ore, crude oil and consumer goods. In the smaller canals there’s a lot of leisure and tourist traffic. Maintaining and upgrading of the inland waterways is a federal interest; answering to the challenges set by the climate change and providing an environmentally friendly transport hence keeps also the WSAs busy.
In the territories of Cuxhaven and Lauenburg the agencies account for various water structures. Canals, waterways with embankments and locks, flood gates, quay structures up to moorings or ports; the WSAs are responsible for various federal assets. These structures are all made of different materials and must be in shape to serve the logistics industry the best possible way. With 3D underwater inspections the WSAs receive accurate information about the condition of the structures for asset management purposes in a time and cost-efficient way: Closing critical chokepoints like locks, even only partially, inevitably causes obstructions in the normal operation and traffic.
The WSAs Cuxhaven and Lauenburg chose different structures for the first surveys. VRT surveyed a flood gate in the Oste river and a measurement station for the WSA Cuxhaven; and the wooden erosion protection of the Elde canal as well as the lock structures in Geesthacht for the WSA Lauenburg. A Multibeam sonar survey offers a superb method for inspecting different water infrastructure, due to the speed and accuracy of the technology. It’s not necessary to drain the locks and flood gates to get a full view of the structures. Combined sonar and laser data can form a coherent and detailed picture of the whole structure without going through the time-consuming process of draining for each inspection.
“The Oste flood gates can’t even be fully drained, so we definitely profit from this kind of technology to see the whole picture of the structure’s condition. It is definitely a good addition to the close inspections and enables us to keep seamless track of the structure’s condition”, describes Björn Hertrampf, who is the responsible survey manager of the Oste flood gate at the WSA Cuxhaven.
The WSA Lauenburg is among other things responsible of the management of 180 kilometers long Müritz-Elde waterway. The agency wanted to see how a multibeam sonar survey directly compares to other survey methods, which have been performed previously on the canal embankments. The canal’s erosion protection is made of wooden poles and is already quite old, so damages and wearing were already known beforehand and the task was to detect them also on a larger area below water. Lauenburg was searching for a method to easily survey larger parts of the canal too, and to find and assess the condition of the erosion protection to plan maintenance and repairs efficiently.
The delivered data fulfilled the expectations of Mandy Dreier, the project manager in WSA Lauenburg, fully as it did not only show damages, scourings and accumulations but also made it possible to enter the underwater areas virtually by themselves.
The pilot surveys proved that multibeam sonar survey is an excellent method for surveying various structures. The accuracy and cost-efficiency exceed traditional surveys, and delivery of the 3D data via the online platform GISGRO enables the usage of data in many different parts of maintenance and management.