Dufek, Tanja

Eberle, Kristoffer

Gallbach, Ute

Prokoph, Andreas

Tietgen, Nils

Wolmeyer, Christin

English

Hydraulic Engineering Repository

Article, Published VersionDufek, Tanja; Eberle, Kristoffer; Gallbach, Ute; Prokoph, Andreas;Tietgen, Nils; Wolmeyer, ChristinInternational Hydrography Summer Camp 2010Hydrographische NachrichtenVerfügbar unter/Available at: https://hdl.handle.net/20.500.11970/108106Vorgeschlagene Zitierweise/Suggested citation:Dufek, Tanja; Eberle, Kristoffer; Gallbach, Ute; Prokoph, Andreas; Tietgen, Nils; Wolmeyer,Christin (2011): International Hydrography Summer Camp 2010. In: HydrographischeNachrichten 89. Rostock: Deutsche Hydrographische Gesellschaft e.V.. S. 16-17.https://www.dhyg.de/images/hn_ausgaben/HN089.pdf.Standardnutzungsbedingungen/Terms of Use:Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichendenNutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, dieWeiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung derNamensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigenNutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte.Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license isapplicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the materialof the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms ofthe restrictive license will be binding.16ship wrecks and a seabarrier, which was built to protect the harbour against enemies.The survey areas where chosen in cooperation with the archaeologists Dr. Nakoinz and Dr. Seg-schneider of the State Archaeological Department of Schleswig-Holstein, considering the results of the IHSC 2008, which was also held at the Schlei. In Fig. 1 an overview of the areas of investigation is shown.Besides the data acquisition different presen-tations from experts of different companies and agencies were hold to give the participants with less hydrographic background an introduction and overview of hydrography and its applications. Also an excursion to the archaeological excavation took place to get a better understanding of the ar-chaeological context.The measurements were carried out with the surveying vessel »Level-A« of the HafenCity Uni-versität Hamburg. It has a length of 8 metres, a width of 2.5 metres and a draft of 0.35 metres. For the determination of the position a Leica SR 530 GPS-receiver was used. To compensate the ship’s movements, the »Level-A« is equipped with an HN 89 — 04-2011 — BerichteThe Schlei was chosen as location for the IHSC be-cause of archeological artefacts from the Viking time in that area. One of the most important set-tlements of this period was located at the end of the fjord. The Schlei was one of the main trading routes that time, connecting the Baltic Sea via the river Treene with the North Sea. Due to the fact that the main water level changed since the Vi-king time, a lot of remains from the Vikings can be found at the bottom of the Schlei. These include International Hydrography Summer Camp 2010 In 2010 the fourth International Hydrography Summer Camp (IHSC) took place at the fjord Schlei in Schleswig-Holstein. It was organized by Prof. Böder and master students of the HafenCity Universität Hamburg. The idea behind this two week excursion was to give international students the possibility to experience the broad field of hydrograph-ic surveying and to give the master students a last chance of getting practical train-ing before their gradu-ation. Therefore nearly all measurement instru-ments of hydrographic surveying had been used like multi-beam echo-sounder, side-scan sonar, sub-bottom pro-filer, magnetometer and ADCP. An article by Tanja Dufek, Kristoffer Eberle, Ute Gallbach, Andreas Prokoph, Nils Tietgen and Christin WolmeyerSchleih | IHSC | HCU | archeology | seabarrier | multi-beam data | side-scan dataFig. 2: Multi-beam (resolution 0.1 meters) and side-scan data of the seabarrierFig. 1: Overview of the survey areas 2010Fig. 3: Difference surface of the multi-beam data of 2008 and 201017Berichte — 04-2011 — HN 89Octans III motion sensor. The single-beam system installed on the »Level-A« is a Fahrentholz Litu-Graph XL which allows simultaneously working multi-frequency surveys, ranging from 12 to 700 kHz. The installed multi-beam echo-sounder was a SeaBat 8101 with an operating frequency of 240 kHz. During the summer camp two different side-scan sonars were used. The first one was the In-nomar SES-2000 System. This sonar works with a frequency of 100 kHz and the transducer is fixed under the ship. The second side-scan system used was the C-MAX CM2 Digital Towfish ranging up to a frequency of 780 kHz. This system was modified, so that it could be installed at the side of the vessel, instead of being towed. For sub-bottom measure-ments an Innomar SES-2000 Standard parametric sediment echo-sounder was used.The datasets from the different systems were ex-amined and processed. This included the cleaning of the multi-beam data and the creation of mosa-ics from the side-scan sonar. For the cleaning of the MBES data the software QPS Qloud was used. A filter for an automatic cleaning was created to reduce the amount of work. The mosaics from C-MAX data were generated by using the Geoco-der from IVS3D. These datasets and echograms of the sub-bottom profiler were brought together in IVS3D Fledermaus to create an overview of the col-lected data in the survey area.The area of the seabarrier was of special interest. This investigated wooden structure has a length of 100 metres and a width of 12 metres. The height above the seafloor is around 30 centimetres. The seabarrier was also investigated during the IHSC 2008. It was interesting for the archeologists to check whether any changes occurred during these two years. In Fig. 2 the MBES and the side-scan data of the seabarrier is shown. The single poles are clearly visible in the side-scan data. Fig. 3 shows a difference surface from the MBES data from 2008 and 2010. Most of the surface is presented in blue, which indicates a decrease of the surface about 5 to 10 centimetres. Just a few peaks are coloured in red, which means an in-crease in height. The reason for that could be the erosion of the sediments. Another possibility could be a systematic offset between the two datasets. A further examination to determine the cause for that is required.Close to the seabarrier holes in the seafloor were visible in the MBES data. They have a diameter of 4.5 metres and a depth of 20 centimetres at most. No side-scan data was available for that part. Their origin is an anchorage stone of a buoy (Fig. 4). In the data also scratches with a length of 350 metres, a width of 1 metre and a depth of 10 cen-timetres were found (Fig. 5). It might be possible that they were caused by anchorage. Scour marks like that were found in each of the survey areas.Another object was found in the data, which could not be clearly identified (Fig. 6). It has a U-shape, a diameter of around 10 metres and a height above sea floor of 0.2 metres.All data were processed during the third master semester and the results were forwarded to the archeologist group. Further interpretation and in-vestigation from the archaeologists is essential to evaluate the importance of surveyed structures.In conclusion the combination of several instru-ments brought good results; especially the com-bination of side-scan sonar and multi-beam echo-sounder was very useful.AuthorsThe authors are Master Students of Hydrography at the HCU.Contact: firstname.lastname@ hcu-hamburg.deFig. 4: Multi-beam data of the seabarrier in the background and the holes in the foregroundFig. 5: Scour marks in the multi-beam dataFig. 6: Multi-beam and side-scan data with cross profile of unidentified structure

International Hydrography Summer Camp 2010

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International Hydrography Summer Camp 2010

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