Identification of hidden underwater methane hotspots with drones

Purpose and goal:

The goal of the project was to develop a method to quantify methane emissions from areas contaminated with waste material from the paper and pulp industry (fiberbanks), using drone-based measurements. During the project we were successful in developing a drone-based system and methodology to detect and quantify the methane emissions. The method was developed at several well characterised sites and then tested at two additional sites where fiberbanks were thought to exist. Uncontaminated sites were also surveyed to compare the measured methane concentrations.

Expected results and effects:

The methane concentrations measured in the air above fiberbanks are typically higher than the background concentration. However, the concentration is affected by many factors such as water depth, temperature, wind speed, waves and water current. Therefore, it is important to perform several measurements at different times to get a better estimation of the methane emissions.

During the fieldwork a small earthquake at one of the field sites led to very high methane concentrations in the air (up to 7 ppm compared to a background value of 1.98 ppm was measured 10 hours after the earthquake). Approach and implementation:

Five field trips of several days were carried out within the project. Measurements were performed at five contaminated sites and two uncontaminated sites. An engineering student did her internship within the project, wrote a report and presented the results at a conference.

Four research assistants have worked within the project. The collaboration with SGU was fruitful. Some improvements on the drone platform were done in collaboration with the company that delivered the system. The results were presented at 4 international conferences, as both posters and oral presentations.