Can Doppler radar flowmeters be used on small and narrow canals? What is the minimum measurable channel width?

Yes, but narrow-canal selection starts with matching the radar beam footprint to the channel geometry. The HZ-KSLF multi-band Doppler radar flowmeter has a beam angle of about 12°, and the illuminated ellipse on the water grows with mounting height: roughly 0.1 m across at 0.5 m height, 0.4 m at 2 m. The rule of thumb is that the water surface should be at least three footprint diameters wide, so the measuring point sits in the main flow and bank reflections stay out of the signal.

From that geometry: with the mounting height kept to 0.5–1 m, the HZ-KSLF covers channels down to about 0.3 m water-surface width — tertiary canals, U-flumes and farm turnouts. Narrower reaches (0.1–0.2 m field ditches) are better served by a small contact-type ultrasonic open-channel meter or a weir/flume, which match those sites on both cost and accuracy.

Further points for narrow-canal selection:

• Minimum mounting height: 0.5 m for the HZ-KSLF; on U-flumes a compact gantry or cantilever over the crown does the job.
• Low-water measurement: tertiary canals often run under 0.1 m depth in the dry season. The HZ-KSLF's integrated level channel resolves down to about 0.05 m, and the COSP model's shallow-water correction still yields discharge.
• Power and telemetry: no mains in the fields — standard kit is solar plus Li-ion battery with 4G Cat.1 or NB-IoT (EC60 series RTU), minute-level reporting during irrigation season and automatic sleep-down off-season.
• Impact protection: add a protective cage where farm machinery works, and run cable in galvanised conduit for split sensor/RTU installs.

The typical irrigation-district configuration is one meter per canal: HZ-KSLF + EC32 RTU + solar, keeping per-point cost contained while data flows straight into the district management platform.

For more details, visit our product pages or contact our technical team.