ADCP Discharge Measurements on the River Danube: Post-Processing and Correction of Data

Accurate measurements and analyses of river discharges are one of the key tasks of hydrology. Nowadays, the traditional methods of discharge measurements are being supplemented or even replaced by novel approaches that utilize state-of-the-art technologies. One approach, which has recently become very popular in the hydrological practice both in Slovakia and abroad, is a method utilizing the Doppler effect of sound waves. In this study, a dataset of 185 discharge measurements on the River Danube was created using a RiverRay portable Acoustic Doppler Current Profiler (ADCP). All the measurements were taken on the River Danube at four different cross-sections in Slovakia. The measurements were processed using the manufacturer’s WinRiver II software and further adjusted in Agila, which is a specialised third-party post-processing software aimed at correcting measurement errors from ADCP discharge measurements. Currently, some but not all countries lying in the Danube basin have included Agila post-processing in their methodologies. This causes problems and disputes between national water authorities when exchanging information about discharge measurements in the border regions. In order to respond to this problem, the main objective of this study was to compare the results of both original and corrected discharges, which were measured under a number of different circumstances, and to propose recommendations about the suitability of using Agila post-processing for discharge measurements of the River Danube.