3 Factors to Consider Before Installing a Thin-Plate Weir

Every flow device has its own distinct pros and cons, including thin-plate weirs. In a vacuum, a thin-plate weir is one of the most accurate flow devices you could ask for, but in a real-world setting, there are several factors that can impact the accuracy of your device.

Before purchasing your weir, it’s a good idea to learn more about this flow device and the different issues that can impact its operation. Learn about several factors that you should consider before installing a thin-plate weir for your flow measurement needs. 

Size of the Weir Pool

A weir pool is a body of water that must be formed upstream of the weir for the device to function correctly. The purpose of the weir pool is to condition the flow so that it has the correct characteristics before entering the weir, and the pool must be the right size to function correctly.

When installing a weir, it’s common to be surprised at how large the pool actually needs to be. If the pool is undersized, accurate readings will be nearly impossible. Before installing a thin-plate weir, you need to carefully examine the installation site to make sure there is adequate space for your weir pool. 


Another factor to consider before you install your weir is if your operators will be able to keep up with the device’s ongoing maintenance needs. Both the weir itself and the weir pool require regular maintenance, which can be time-consuming, depending on where the device is installed.

For instance, if your weir is installed outdoors, you must keep the weir pool free from sediment and other forms of debris, and you also need to make sure that the crest of the weir is clear to promote free spillage. If your weir pool and your weir are surrounded by plant life, maintenance will be a lot more time-consuming than in other settings. 

Preventing Submergence

Unlike flumes, weirs are not designed to function when submergence is present. This means that you must be very careful when installing your weir so that submerged conditions are not possible.

For instance, the crest of the weir must be at least 2 inches above the maximum flow level in the downstream channel. You may need to install the crest even higher depending on the downstream flow level, as flow levels that are too high can prevent the nappe from aerating properly. 

Purchase Your Flow Device

As you can now see, there are a number of factors that can impact whether installing a thin-plate weir is the right choice for your operations. After you’ve carefully weighed these issues and determined what type of flow device matches your needs, you can make your purchase with Tracom, FRP.

We are a leader in the open channel flow management industry, and we produce a wide range of products that we know you’ll appreciate, from fiberglass flumes in several styles to weir boxes that make flow management easy. You can contact us today with your questions about our products, or request a quote so that you can purchase the tool that you need.