All open channel flow measurement systems should be provided with a suitable means of correctly referencing the level measurement. It is not acceptable to rely on an empty chamber or channel floor as the base may not be level. In addition due to surface water tension the gauge zero cannot be determined with sufficient accuracy by reading the head gauge with water in the channel drawn down to the apparent crest level.
It is a requirement to ensure all open channel flow measurement system used for regulatory purposes are suitably validated and calibrated at appropriate intervals. All SIRIS open channel flow measurement systems are provided with a fixed or removable calibration plate and on commission SIRIS engineers correctly reference the “True Gauge Zero”.
Fixed or removable calibration plates can be provided.