Monitoring Sava river in Zagreb

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Geolux has installed an innovative new hydrology monitoring station at Zagreb’s iconic «Hendrix» railway bridge over river Sava. The monitoring station is part of a pilot-project intended to demonstrate the ability of contactless river discharge monitoring with precise surface flow velocity profiling across the river channel.

A combination of contactless water level meter and five surface velocity radar sensors were commissioned and installed by Geolux as part of the pilot-project. The combined sensors cover both the river bed and surrounding flooding area, helping to determine total river discharge with an unprecedented accuracy, regardless of river level. The average discharge of Sava river is 300 cubic meters per second, but during flooding season can exceed 3000 cubic meters per second.

The sensors were strategically installed below the iron railway bridge, across the river bed and flooding area. Each sensor contains an integrated accelerometer to automatically compensate for tilt angle and to detect vibrations caused by trains passing over the bridge. Vibration detection algorithm automatically discards measurements taken while the train is crossing the bridge, in order to maintain high accuracy of the system. The system is battery-powered without an external power source. The batteries were selected to provide sufficient energy for system operation during 2-year period, without any required maintenance.

Tomislav Grubeša, technical director at Geolux, says the installation was completed before the rain season and therefore required the utmost efficiency: “Geolux designed, installed and commissioned this complex system before autumn period when heavy rainfalls are expected, and before snow-melting period in late winter, when most of the flooding is expected to happen. Geolux is proud to help with providing accurate hydrological data that will be used to protect Zagreb and downstream area from possible flooding in the future.”

Additionally, Geolux implemented its HydroView software that communicates directly to the sensors via GPRS-enable datalogger. The datalogger also supports other communication technologies, such as LoRaWAN, ZigBee, WiFi and proprietary software-defined radio based protocols. HydroView cloud-based solution enables real-time monitoring of hydrological measurements, and supports data analysis, management and export. Live data from the site can be accessed by clicking on the button below.

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