How to pick the gauging section for a Doppler radar flowmeter?

The choice of gauging section determines how well an HZ-KSLF multi-band Doppler radar flowmeter performs. The rule of thumb: calm water surface, regular cross-section, single flow regime.

• Straight reach: at least 5 channel widths upstream and 3 widths downstream of the gauging point; avoid bends, gates, drops and confluences
• Section shape: prefer regular rectangular or trapezoidal sections with a stable level-area relationship; avoid sudden contractions, expansions or heavy sediment deposits
• Flow regime: avoid backwater, ponded zones and strong turbulence downstream of bridge piers, where the surface-to-mean velocity relationship is unstable
• Mounting position: install the radar above the centreline of the section, looking vertically down, tilt within 5°

Where the site cannot meet the straight-reach requirement, the COSP model's multi-point sampling plus field calibration can compensate, though accuracy will be lower than on a regular section. Before finalising the site, measure the channel width, side slope and bed slope, then set the mounting height — 2-15 m above the water surface is recommended. For more information, please visit our product pages or contact our technical team.