| Parameter | Description |
| Flow Meter Dimensions(L*W*H) | 220×120×84mm |
| Bracket Dimensions(L*W*H) | 100×100×100mm |
How Does a River Radar Flow Meter Measure Discharge?
A river radar flow meter measures water discharge without placing a sensor directly in the water. The system combines non-contact surface velocity measurement with radar water level measurement and channel cross-section data to calculate flow continuously.
For river and open-channel monitoring, discharge is not determined by surface velocity alone. The instrument first measures the surface velocity of the water and the water level. The configured channel geometry is then used to determine the corresponding wetted cross-sectional area. A velocity correction factor can be applied to convert measured surface velocity into an estimated average velocity through the cross section.
The basic relationship can be expressed as:
Discharge = Cross-Sectional Area × Average Flow Velocity
Because natural rivers, irrigation canals and drainage channels can have different velocity distributions, channel geometry and site conditions should be evaluated during commissioning. Correct site configuration is important for obtaining stable and representative discharge data.
Suitable Channel and River Conditions
The GRD-900 river radar flow meter is particularly suitable for locations where submerged sensors are difficult to install or maintain. Its non-contact measurement principle keeps the sensing system above the water surface and reduces problems caused by sediment, floating debris and direct water contact.
| Application | Why Radar Measurement Is Suitable |
|---|
| Natural Rivers | Continuous surface velocity and water level monitoring without installing a sensor in the river. |
| Irrigation Canals | Suitable for continuous water distribution and canal discharge monitoring. |
| Flood Monitoring | Non-contact installation helps reduce the risk of sensor damage during rapidly changing water levels. |
| Urban Drainage Channels | Useful where access is difficult or the channel may contain debris and sediment. |
| Reservoir or Watercourse Outlets | Provides continuous hydraulic monitoring where surface velocity measurement is practical. |
| Remote Hydrological Stations | Can provide digital measurement data for integration with external monitoring and telemetry equipment. |
How to Select a Suitable Installation Location
The measurement location has a significant influence on the quality of river discharge data. For better measurement stability, the radar flow meter should be installed where the water surface and velocity profile are as representative of the overall channel as possible.
Choose a Stable Cross Section
Select a section where the channel geometry is relatively stable. Avoid locations where the riverbed changes rapidly because of erosion, sediment accumulation or construction activities. If the cross-sectional geometry changes significantly, the configured relationship between water level and wetted area may also need to be updated.
Avoid Strong Local Turbulence
Whenever possible, do not install the sensor immediately downstream of gates, pumps, sharp bends, bridge piers, waterfalls or other structures that create strong turbulence, reverse flow or irregular surface movement.
Maintain a Clear Radar Measurement Path
The radar beam should have a clear view of the water surface. Vegetation, structural beams, bridge components and other permanent obstacles should not interfere with the measurement path.
Select a Representative Surface Velocity Zone
The fastest visible surface velocity is not always representative of the average velocity of the complete river cross section. Sensor position should therefore be selected according to the channel profile and actual flow distribution rather than installation convenience alone.
Channel Geometry and Discharge Calculation
Reliable river discharge measurement requires more than measuring velocity. The monitoring system also needs an accurate relationship between water level and channel cross-sectional area.
For engineered channels with known dimensions, channel geometry can usually be established from design drawings or field measurements. Natural rivers may require a surveyed cross section before commissioning.
Typical information required for project configuration includes:
Channel or river width
Cross-sectional profile
Maximum and minimum expected water level
Normal and maximum expected velocity
Sensor mounting height
Distance from the sensor to the water surface
Flow direction
Location of bridge piers, gates or other hydraulic structures
Providing this information before ordering allows the Gallop technical team to better evaluate whether radar surface velocity measurement is suitable for the proposed site.
River Radar Flow Meter Installation Options
Because measurement is non-contact, the radar unit can be mounted above the water surface rather than inside the flow. Depending on the project structure, typical mounting locations may include bridges, support frames, channel structures and dedicated mounting brackets.
During installation, the mounting structure should remain stable and minimize vibration or movement. The sensor orientation should also follow the specified measurement direction so that the radar beam covers the intended measurement area.
Important Installation Checks
Confirm that the expected water level remains within the instrument measurement range.
Check that no permanent obstacle blocks the radar beam.
Confirm that the selected surface area represents the main flow direction.
Record the channel cross section used for discharge calculation.
Check the installation angle and mounting stability.
Verify communication and data output before final commissioning.
Integration with Hydrological Monitoring Systems
The GRD-900 supports RS-232 and RS-485 communication as well as MODBUS-RTU, allowing measurement data to be integrated into industrial or hydrological monitoring systems.
Depending on the complete project architecture, the radar flow meter can work with an external controller, RTU, data acquisition device or remote monitoring platform. This makes it suitable not only for local flow measurement but also for distributed river, irrigation and flood-monitoring networks.
When planning system integration, buyers should confirm the required communication interface, cable distance, data collection interval, controller compatibility and remote communication architecture before ordering.
When Is a Non-Contact Radar Flow Meter a Better Choice?
A river radar flow meter is particularly useful when conventional submerged instruments would create installation or maintenance difficulties.
High sediment load: the measurement device does not need to remain submerged in sediment-bearing water.
Floating debris: non-contact sensing reduces direct impact from branches, waste and other floating material.
Rapidly changing water levels: suitable for flood monitoring and seasonal river applications.
Difficult site access: bridge or above-channel mounting can simplify routine inspection.
Long-term monitoring: there are no rotating components installed directly in the water.
When Should Another Flow Measurement Method Be Considered?
Radar surface velocity measurement is not automatically the best solution for every open-channel application. Sites with severe surface turbulence, complex reverse flow, continuously changing channel geometry or measurement locations where the surface velocity does not represent the overall flow profile may require additional site assessment.
For applications using standardized flumes or weirs, a level-based ultrasonic open channel flow meter may also be considered. The most suitable technology should be selected according to channel geometry, hydraulic conditions, installation environment and required measurement method.
Why Choose Gallop for River Flow Monitoring?
Beijing Gallop has focused on flow and level measurement instrumentation since 2005. With its own R&D capabilities, calibration and testing equipment, Gallop supports industrial users, system integrators and project contractors with instrument selection and customized measurement solutions.
Non-contact radar solutions for river and open-channel monitoring
OEM and ODM service available
ISO9001:2015 quality management system
CE-certified instrument solutions
In-house R&D and testing capabilities
Technical support for model selection and project configuration
International supply experience for industrial instrumentation projects
Information to Provide Before Requesting a Quote
For faster model selection, please provide as much of the following project information as possible:
River, canal or drainage channel type
Channel width and cross-sectional drawing
Minimum and maximum water level
Estimated minimum and maximum velocity
Expected maximum discharge
Available sensor mounting location
Required communication interface
Distance between the monitoring point and control system
Local environmental and installation conditions
River Radar Flow Meter FAQ
Can a radar flow meter measure river flow without touching the water?
Yes. The GRD-900 uses radar technology to measure surface velocity and water level from above the water surface. This non-contact arrangement is particularly useful for rivers, canals and drainage channels where submerged sensors may be difficult to maintain.
Does surface velocity equal the average river velocity?
Not necessarily. Radar measures velocity at or near the water surface. Depending on the channel and hydraulic conditions, a correction relationship may be required to estimate the representative average velocity used for discharge calculation.
Do I need to provide the river cross section?
For discharge calculation, the monitoring system needs to determine the wetted cross-sectional area at different water levels. Providing channel dimensions or a surveyed river cross section therefore helps configure the system more accurately.
Can the radar flow meter be connected to a SCADA or monitoring system?
The GRD-900 supports RS-232, RS-485 and MODBUS-RTU communication. Integration with a SCADA, RTU or remote monitoring platform depends on the architecture of the complete control system.
Is radar suitable for flood monitoring?
Radar is well suited to many flood-monitoring applications because the instrument can be installed above the water rather than submerged in the flow. Site geometry, maximum expected level, velocity and mounting position should still be evaluated before installation.
What information does Gallop need for model selection?
Channel geometry, water-level range, expected velocity, installation height, mounting conditions and communication requirements are the most useful starting points. Gallop can use this information to evaluate the proposed monitoring configuration.
Configure a Radar Flow Meter for Your Monitoring Site
River flow conditions vary significantly from one project to another. Send Gallop your channel dimensions, expected water-level and velocity range, installation photos or drawings, and communication requirements. Our team can help evaluate a suitable GRD-900 configuration for river, irrigation, drainage or flood-monitoring projects.
