The inhabitants of Trondheim have on several occasions this summer observed bubbles appearing on the surface of the Nidelven river. Associated with the project Renere Havn (Cleaner Harbour), broken limestone has been laid on the seabed of the canal to cover pollution. There are theories that under this limestone layer gas pockets have occured and people are suggesting that these are the reason for the bubbles rising to the surface.
Have a look at our video from the bubble search: Embedded content: https://youtu.be/zoVhR91My4U
Together with the Norwegian newspaper Adressavisen we launched four underwater drones into the Nidelven river. Two drone pilots maneuvered the drones from land and another two from a boat while Adressa streamed video footage directly from one of our Blueye Pioneer drones.
The underwater drone, Blueye Pioneer, is equipped with powerful LED lights and a camera that provides direct video transfer in HD quality. Read more about the specifications here. With these qualities we could catch good images even in a dirty city canal and discovered bubbles that clearly was rising from the seabed. Following our inspections made in the Nidelven, the theories that the smell originates from gas pockets on the seabed are rejected and the smelly situation is yet to be uncovered.