Discharge measurements with ADCP-profiler and MF Pro-device in the River Rakkolanjoki. © Pekka Vähänäkki.
SEVIRA-project arranged a field measurement campaign with discharge measurement specialists both from the Southeast Finland ELY-centre and Finnish Environment Institute SYKE in April 14th, 2021. Discharge, water level and water temperature were measured in the River Rakkolanjoki and the River Hounijoki in Finland. The discharge i.e. the amount of the flowing water in time, is one of the key features in the hydrological monitoring linked also to the loading of water.
As in field campaign performed in autumn, Finnish discharge experts used an acoustic doppler current profiler (ADCP) device from SYKE to track the discharge and collect very accurate discharge and river channel data. The ADCP was mounted in a certain type of small boat, a catamaran, and pulled across the river channel from side to side. MF Pro electromagnetic flow meter from the Southeast Finland ELY-centre was applied at the same time in both rivers for comparison. The discharge experts can now compare the discharge data obtained with the two devices based on different measurement technique. To obtain precise river water temperature for the ADCP measurements, a conductivity, temperature and depth-profiler (CTD) device from SYKE was used in both rivers to record the water temperature accurately.
Due to the warm weather in early and mid-April, the melting period was so short that the maximum spring discharge was not measured. Nevertheless, the measurements succeeded again and good validation results for the new rating curves of the rivers as well as the comparison of measurement techniques were collected. There was also made a video in order to better illustrate the ADCP measurement and its results on the screen.