What goes into a flume?

Flumes are among the best solutions available for flow rate measurement, but before you can find the best one for your channel conditions, you’ll need to understand how flumes work. Fortunately, the basic construction is fairly straightforward. Learn all about what goes into a flume that makes it as effective as it is.


The dimensions of a flume are essential for accurate measurements, so those dimensions need to be maintained over time. The bracing is primarily used to keep the dimensions in place with a focus on the walls and floor. Typically L- or U-shaped angles, these braces can be attached in several different ways, including welding, bolting or chemical bonding. While you can remove the bracing after installation in some cases, you may not want to since it can virtually guarantee dimensional accuracy as long as the installation went properly.

Flow Surface

A flume’s flow surface is any part of the flume that physically comes into contact with the flow. With that kind of direct exposure, you’ll want to make sure the flow surface is resilient to handle the constant contact, especially from particularly abusive flows. Additionally, this is the surface on which most of your maintenance will be focused, provided your flume material and installation are reliable. You’ll have to keep it free from any buildup of vegetative growth or scum to ensure the dimensions of the flume are maintained. That means regular cleaning, though the term “regular” can have a wide range depending on what style flume you get.


The exterior of a flume is far more lenient in terms of requirements compared to the flow surface. The flume’s exterior may be exposed to the elements, but you don’t have to worry about constant contact to flow there. Because it’s not used for measurements and flow, you don’t have to make sure it’s smooth either. Just make sure that the exterior is protected if it’s regularly exposed to direct sunlight. Fiberglass is especially vulnerable without a UV inhibited gel coat, so you’ll want to make sure that’s included in the initial construction.

Stiffening Ribs

Among the most important aspects of a flume are stiffening ribs when dealing with flat and unbroken surfaces. Attached to the outside of the flume, these add-ons provide some extra reinforcement for surfaces like the exterior side walls. The type of material you use can alter the way they’re attached. Metal flumes, for example, will typically feature stiffening ribs that are welded to the side. Fiberglass flumes, on the other hand, involve attaching some kind of form shape, like engineered foam or PVC, to the side and then laminating fiberglass over it.

Flumes From Tracom

Now that you know what goes into a flume, it’s time to get one of your own. At Tracom, our team is happy to help you find the perfect flume for your unique open channel flow conditions even if it means designing a fiberglass flume just for your application. Contact us today to get the easy process started.