Custom flow design, and measurement.

The need to measure water flow has never been as great as it is today. As the world becomes smaller and more industrialized, water can no longer be taken for granted as there is no apparent vision or outlook to use another media to transport our wastes and to cool our industrial processes. Water must be preserved. It cannot be wasted or used indiscriminately, but every litre must be accounted for as though it was a commodity or a product.

MONITARIO has been dedicated to assisting industry in Environmental Stewardship for over 33 years. It is this dedication and specialization in Hydrometry which has created a calm in industry and municipalities when finding it necessary to measure flow rates exiting their facilities and entering either directly into the natural receiving body or indirectly into a municipal collection system. MONITARIO is there to give the best cost-effective solution to metering all their effluent.

Accuracy is Primary

Hundreds of installations have been completed to the satisfaction of not only the client, but also the regulatory agencies, and third parties. 


MONITARIO looks at each site specifically, weighing all conditions unique to each.

  • Channel, or sewer size, length, slope, etc.
  • Anticipated volumes, limits, variances, etc.
  • Process changes; past, present, and future long term.
  • Physical and chemical conditions of the effluent.
  • Effects caused by long term downtime.

Monitario fabricates all primary devices from 304 stainless steel.  This material has been found to stand up to corrosion, and temperature extremes.  Fasteners are all made from 316 stainless.

Flumes come in many sizes and shapes of control sections for many reasons, some of which include;

  • Low, medium, and high volume accuracy requirements.
  • Ability to transport solid material and debris.
  • Seasonal conditions, and effects on the physical condition of the flume.
  • Practical limitations dictated by the physical restraints of the site.

Accuracy in flow measurement MUST be kept as the primary objective!

Monitario retrofits your existing outfall, sewer, or ditch with a primary device conducive to the requirements of the site, keeping in mind both physical restrictions and operational ranges.  

Monitario configures a suitable secondary device flow meter/recorder to measure all flow rates through the primary device.

Monitario calibrates the installation and certify that metering site to a predetermined  and agreed state of accuracy.  Typical installations have an accuracy of better than 7% of the actual flow rate, through ranges from 10% to 100% of the stated and setup span.

All installations are calibrated to the National Institute of Standards and Technology for the secondary devices.  Primary devices and overall installations are certified by a Professional Engineer registered in the Province of Ontario.,

The installation above uses a trapezoidal flume, which is good for low, and medium flow rates, but can also accommodate high flow rates experienced less frequently.


    The trapezoidal flume is good for, self-cleaning, and passing ice floats.


    This installation also has a complete flow metering secondary device, which runs off of battery and solar. The client desired ease of operation, so this system was designed for flow rates, and total flow to be available, and on display all the time. The system was installed in 1995.


    Flumes come in many different sizes and shapes of control sections for many reasons. Some of which include:

  • Low, medium, and high-end accuracy requirements.
  • Approach conditions to the measurement point.
  • Allowable head elevation, and anticipated maximum flow rate.
  • Ability to transport solid material and debris.
  • Seasonal conditions, and effects on the physical conditions of the flume.
  • Practical limitations dictated by the physical restraints of the site.
  • Accuracy in flow measurement MUST be kept as the primary objective.

Some flumes can deliver greater accuracy, however are not suitable for all installations when retrofitting is required.  A new installation or a channel designed to measure flow rates can have such a high accurate flume built in.  These flumes are usually the Parshall design, which have been thoroughly tested and evaluated.

The critical depth flumes, or those with an elevated throat section, are typically used to retrofit a rectangular or circular sewer. 

Laminar Flow is primary.

Laminar flow is essential for proper flow measurement.  

Flumes are static in nature — having no moving parts — and develop a relationship between the water level in the flume and the flow rate by restricting the flow of water in various ways.  These relationships are repeatable and have been thoroughly tested using empirical methods.

Some secondary devices claim to be able to “filter” out the noise of turbulent flow, but this common mistake only adds more error.

  • These, custom fabricated, flow straighteners were installed, to steer the flow around a sharp corner, just before entering the primary device.  This was a necessary retrofit needed to create laminar flow.