Author(s): Katarzyna Suska; Piotr Parasiewicz
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Abstract: A few years ago a lot of work was needed to do the ortophoto of a stretch of a large river. In 2006, for example it lasted a week to take 2000 pictures. Now, only a few hours are required [1]. As a part of the Adaptive Management of Barriers on European Rivers „AMBER” project, the scientists of Stanislaw Sakowicz Inland Fisheries Institute (SSIFI), use two inexpensive lightweight drones (Phantom 3 Advanced and the Phantom 4 Professional) for mesohabitat mapping of large rivers. The second vehicle has five sensors (a pair at the front), long lasting battery and camera resolution [1], [2]. So far we used the UAVs on the two largest rivers in Poland: Vistula and Oder. In both cases it is impossible to identify hydromorphological units and its characteristics from shore or a boat. Using combination of nadir and oblique aerial pictures helps not only in identification of hydromorphologic units but also allows to reach remote areas with difficult access. This high resolution aerial photography helps to identify bottom substrate on the bottom of the river in shallow areas, submerged vegetation, branches, debris and other cover source for fish. Furthermore long distances can be covered in short time. That’s why it is effective to use UAVs despite the limitations posed by the fact that working time is restricted to specific time in a day (shadows on the river surface, reflecting the rays of the sun), or by weather conditions (fog, rain, low temperature, wind – especially blows), by water clarity and tree cover [3]. The UAV supported habitat survey consists of following steps. Collection of nadir photographs across the river channel, which are immediately stitched in Agisoft software [4] into one map. This provides the detailed map from low elevation, a permanent image which can be compared with future data collected from the same location at different flow conditions.
Year: 2018