Reconnaissance fieldtrips during late Autumn

After a considerable long period without fieldtrips due to the SARS-CoV-2, and just before a new wave hit us all, WoWW sought for calibration and validation data for its hydraulic numerical models. Although the likelihood of flooding decreases considerably during the cold Norwegian Autumn, Oddbjørn, Michal and Adina visited two mountainous localities, namely Oppdal in Central Norway and Stryn in West Norway.

Vekveselva river (in Oppdal) has a step-pool morphology and a steep slope, which makes it very attractive from the hydraulic and geomorphological perspectives, as this makes the river and valley susceptible to both floods and landslides. The weather was cloudy and slightly windy and snow has started to accumulate in the last few weeks (see the first gallery of photos below). These factors, together with an unstable phone/GPS signal, made the task of using an Unmanned Aerial Vehicle (aka drone) challenging. In addition, most of the selected reach had ice accumulation. In order to gain expertise and overcome the aforementioned challenges, WoWW allied with the department of Geography at the Norwegian University of Science and Technology.

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The Norwegian Meteorological Institute forecasted heavy rain for Storelva river in Utvik (in Stryn) during early November and Michal and Adina drove to the West of Norway spontaneously. Although the weather resulted drier than predicted and the river barely carried water, the snow from the mountains has not yet reached the river downstream by the fjord. The wind did not encourage to fly the drone, however, they did experiment with acoustic (i.e. ADCP) and salt dilution gauging methods (see the gallery of photos below).

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Storelva river in Utvik was flooded during summer 2017 and now flood-protection measures have been implemented. The channel has been excavated and a dyke has been built to protect the adjacent houses, formerly affected by the flash flood. The new channel shape demands for a new data set for ongoing research on flood risk in Stryn. The Norwegian winter is coming and the field work season comes to an end. Further attempts to obtain field data in Central and West Norway will be conducted during spring, once the snow has melted. A manuscript analyzing the hydrology of the 2017 flood was published in Hydrology Research this spring, and the efforts are now focused on understanding the hydrodynamics and the morphodynamics of the flood.