RQ-30 Non-contact discharge measurement

The RQ-30 non-contact system measures the discharge by RADAR technology. The unique feature of the RQ-30 system is the continuous capturing of flow velocity which enables an exact discharge measurement and evaluation of specific discharge situations. In case of flood the system measures the exact discharge and because of the non-contact radar technology there is no damage of the measurement system by bed loads or trees. If the floodplains get flooded the discharge is determined by combining several RQ-30 sensors to one system. The RQ-30 system measures from very low water depth up to the maximum possible discharge of a 100-year flood or even greater. To measure any discharge situation at rivers, torrents, creeks, mountain torrents or open channels the RQ-30 is a unique and reliable system.

Properties and benefits

  • Maintenance free
  • No structural construction in the water needed
  • Fully functional even in flood water situation
  • Low power consumption allows solar cell instigation
  • Detection of flow direction
  • Measurement range 0.30 to 15 m/s
  • Recognition of hysteresis effects
  • Measurement in back water situation
  • Recognition of vegetal invasion
  • Measurement in tide dependent rivers
  • Own measurement interval or externally triggerd
  • RQ-30a: analog output 4 to 20 mA

RQ-30 system - components

  • RQ-30 discharge sensor: Measures the flow velocity, integration of radar level sensor and calculation of the discharge
  • Radar level sensor
  • Protective casing for both sensors

Example of use

River "Rhine", Measurement site "Lustenau", Austria: Hydrographic discharge measurement of the hydrografic service.

Hydroelectric power plant „Kaprun“, Austria: Preservation of evidence of the discharge quantity in power plant operations.
Creek "Annabach", Graz,  Austria: Monitoring of storm-water overflow in the canal from the creek "Annabach".


Technical data

Measuring range –
rate of flow

0.3 to 15 m/s

Resolution1 mm/s
Measuring range –
water level
0 to 15 m
0 to 35 m
Resolution 1 mm
Interface – analog (RQ-30a)3 x output 4 – 20 mA for discharge, level, velocity
Interface – digital

Interface: 1x SDI-12, 1x RS485
Transfer rate: 1 ,2 to 19,2 kBd
Protocoll: various ASCII -Protocols
Output: discharge, flow velocity, level, quality parameter

Power supplySupply voltage: 6 to 30 VDC

Operating temperature

-35 to +60 °C

Storage temperature-40 to +60°C
Protection typeIP 67