Addressing Submerged Flow in Parshall Flumes

Water operators across the country know that the most versatile, accurate flow measurement tool that you could use is a Parshall flume. Ideally, your Parshall flume will operate under free flow conditions. With free flow, there is only a single point of measurement, which both eases your operations and leads to more accurate readings.

However, depending on the downstream conditions in your operation, your flume might experience submergence, which complicates measurement readings and can reduce your success. Fortunately, there are a few easy ways to combat submergence and preserve your system. Learn about fighting submerged flow in Parshall flumes and find out how you can purchase high-quality flumes from a trusted water product manufacturer.

Start Downstream

Because the largest culprit in submergence is the downstream condition, the easiest way to prevent submergence is to address these conditions. Adjusting the downstream conditions in your system is much easier than altering your flume, making this the best place to start when you’re trying to correct for submergence.

For example, it’s possible the reason you’re experiencing submergence is that the downstream flow is being blocked by sedimentation or vegetation. Have one of your operators clear any possible obstructions and see if that helps to correct the submerged flow. By keeping your downstream conditions optimal, you should be able to reduce the likelihood of submergence.

Adjust Your Flume

Depending on your water system, you may be able to adjust your Parshall flume without running the risk your flow escaping. If your application allows it, you can slightly raise your flume and prevent submergence from occurring. When you lift the flume, it reduces the submergence ratio, which makes it much harder for altered downstream conditions to result in flow submergence.

Before you alter the positioning of your flume, however, you should be sure that elevating your Parshall flume won’t alter your upstream flow. If you raise your flume too high, it can sometimes cause upstream flow to overtop your channel, which should always be avoided.

Flume Floors

If you are considering raising your flume to combat submergence but are worried about the effort and time it involves, then the perfect solution is to change the height of your flume floor instead. You can actually install a false-floor in your flume and get the exact same result that you would out of physically raising your flume.

Should you choose this approach, you should understand that raising your flume floor will reduce the flow capacity of your flume and will also increase upstream conditions. False-floors can also be installed in Cutthroat and Montana flumes.

Choose Parshall Flumes for Your System

Despite the risk of submergence, Parshall flumes are still the best flow management tool that you could use in your water management system. Parshall flumes are accurate, easy to use, and will give your operation the level of success that you’re looking for. When you want to install Parshall flumes for your operation, you want to make sure you purchase them from a trusted manufacturer like Tracom, FRP.

Tracom is the leader when it comes to fiberglass water management products, and when can help you find the flumes and other tools that you need. Contact us today for more information.