Location information of pipelines is an essential part of asset management in water utilities

Enköping is a city of twenty thousand residents, located about hundred kilometres northwest from Stockholm. Enköping is surrounded by lakes and rivers, hence many of the pipelines managed by the city’s water utility are under water, which can cause challenges for maintenance. The sonar inspection by VRT offered the water utility an opportunity to update the information about the location and condition of the pipelines in one go.

VRT scanned 20 kilometres of underwater pipelines in Enköping. The small diameter of the pipelines made the project a bit challenging; the diameter was only up to 90 mm. Fortunately, a multibeam sonar scanner enables scanning of smaller objects like this, so VRT’s experienced field team had no trouble in finding the pipelines. A thorough field work and careful post processing of the data produced clear 3D visuals of the water utility’s underwater assets.

VRT’s service included an inspection report, detailed location information, and cleaned point clouds, which all were delivered via GISGRO online platform. Up-to-date location information is needed in efficient maintenance planning of the water supply network.


Multibeam sonar survey fits perfectly for inspections of wide underwater areas

VRT utilises high-end multibeam sonar scanners for underwater inspections. MBES surveys produce clear 3D models of the structures in question. The scanning is done with an agile survey vessel, which enables quick and cost-efficient inspection of long underwater pipelines. In addition to the 3D model, a MBES survey provides an exact location information of the assets. Inspections with traditional diving method take more time and are more expensive, compared to mobile surveys.

In Enköping, the pipelines to be inspected were in one water system. Hence, avoiding multiple launches of the vessel enabled quick field work for the twenty kilometres. After the field days, VRT’s office team handled the post processing and point cloud cleaning and delivered the ready-to-use 3D data to the client. With this information, it is easy to detect risky areas and to plan maintenance or possible repairs.

The underwater pipeline inspection went surprisingly smoothly. We received a detailed location information and observations of possible leakages. The next step is to check the pipelines with a pressure test. If we find leakages, it is now easy to locate the exact spot with the diver, with the help of survey data.

Sari Virkkala, VA Förvaltare, City of Enköping

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Karri Kolehmainen & Ville Mäkeläinen

Karri Koistinen

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Ville Mäkeläinen

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