Can a Doppler radar flowmeter measure flow when rivers freeze over?

The instrument itself is no problem in winter, but ice-cover data needs special handling. The HZ-KSLF multi-band Doppler radar flowmeter operates from -40°C to +70°C with IP68 protection; the antenna radome and electronics run reliably in severe northern cold, and snow or low temperature alone does not cause failures.

The point to understand: radar waves cannot penetrate ice. Once a river freezes, the reflecting surface changes from water to ice, and the measured surface velocity no longer represents the flow beneath the ice. Fed directly into the flow calculation it produces bias. Conditions are worst during early-winter drifting ice and spring break-up, when the reflecting surface is unstable.

Three common engineering practices:

• Tag ice-period flow data and switch to the stage-discharge (Q-H) rating curve for estimation
• Apply an ice-period correction factor, then re-calibrate after break-up to resume automatic gauging
• Irrigation channels drained for the winter are unaffected and can remain in continuous monitoring

Do one manual comparison before and after the ice season and store the correction parameters in the EC60 series RTU configuration. For more information, please visit our product pages or contact our technical team.