Flow measurement system design: Flumes and Flowmeters

Avizo designs the system, prepares the plans and specifications, then supports the contractor on site and verifies the measurement at commissioning.

It depends on the flow. A flume or weir suits open-channel flow, such as wastewater in an open channel. An electromagnetic or ultrasonic flowmeter suits pressurized pipes.

A Parshall flume covers a wide range of flows and handles solids well, but it needs more space and a drop downstream. A Palmer-Bowlus flume fits into an existing circular pipe, with lower head loss.

The four most common types are the Parshall flume, the Palmer-Bowlus flume, the H flume and the trapezoidal flume. Each one suits different flow conditions:

• Parshall flume: wide flow range and good tolerance of solids. It is the standard at wastewater treatment plant inlets, but it needs space and a drop downstream.
• Palmer-Bowlus flume: fits into an existing circular pipe or manhole, with low head loss. It is ideal in sewer networks.
• H flume: accurate over a very wide range, including very low flows. It is often used for runoff and small watersheds.
• Trapezoidal flume: well suited to low flows and open channels, with moderate head loss.

The right choice depends on the flow range to measure, the available head loss, the presence of solids, the space and layout of the site, and the regulatory requirements. Avizo weighs these criteria to recommend the best-suited flume. More information on our gauging and calibration of measurement equipment page.

It depends on the site: the ROMAEU (Regulation respecting municipal wastewater treatment works) for municipal facilities, ministerial authorizations and depollution attestations for industries, and municipal discharge bylaws. Avizo builds these requirements into the design from the start. More information on our gauging and calibration of measurement equipment page.

Yes. Avizo first verifies the existing system, identifies the source of the error, then recommends a correction or a new structure.

Yes. Once the system is installed, the measurement must be verified for accuracy. The check must then be repeated periodically to confirm the data remains reliable and compliant. Avizo performs these verifications on site. The applicable regulatory requirements and verification frequency are detailed on our gauging and calibration of measurement equipment page.

Yes, and it should be planned at the design stage. A flume that is hard to reach complicates every verification and raises its cost. Avizo designs access into the metering chamber: ladder rungs, an adequate opening and clearance around the flume. We also account for confined-space constraints so that verifications and calibrations can be carried out safely throughout the life of the structure.

In Quebec, Ontario, the Maritimes and the northeastern United States, for municipal, industrial and private clients.