Flow Measuring Flumes – Fiberglass & Metal
Flumes are an accurate and effective way to measure flow rate in open channel flow applications. All flumes work by measuring how much the water rises in level before an obstruction (the flume) of known dimensions and shape. A flume is similar to a weir, but they do not create so large a change in upstream head. A flume operates in “free flow” condition, meaning that it does not completely stop the flow of water by damming the channel.
There are many different types of flumes, we recommend either the ramp flume or cutthroat flume for most irrigation flow sites, but the parshall flume is also a good choice. All of these flumes come in a wide range of sizes, and provide good accuracy. We offer other types of flumes, such as the H-flume or trapezoidal flume, these are generally used in specific applications and may be a good choice for your needs. Contact us for a no-obligation consultation.
We have relationships with companies that manufacture fiberglass and steel flumes, weirs, manholes and shelters. Contact us to receive a quote for any of these types of products.
We provide a variety of sensors, dataloggers, and data retrieval systems (including via internet) for monitoring flow rate remotely. Please call us at (435) 755-0774 to learn more, we are remote data and automation experts.
Ramp Flume
(most frequently recommended)
The ramp flume (also known as a broad-crested weir) is a very popular flume used primarily in irrigation applications. It is a flume that functions somewhat like a weir. It is often used in areas with low drop (flat ditches). We carry 4 pre-made sizes (see table), Our pre-made EZ Ramp flumes are usually less expensive than other comparable sized flumes. Also known as EZ Flow Flume or previously as a Nu-Way Flume.
The Ramp flumes ship in a compact form and can be assembled on site. Assembly requires basic tools and may take 1 to 2 hour, depending on the size. This makes our ramp flumes easier to ship and handle than most other flumes, which must be shipped pre-assembled. Stilling wells can be ordered in a variety of materials and sizes. We can provide a still well port on the side of the flume so that you may provide your own custom stilling well on-site.
We recommend ramp flumes for a number of reasons:
- Engineered for measuring flat ditches
- Wider throat widths (Pass Debry better)
- Can be designed and built to custom specifications
- Usually most affordable of the many flume types available
EZ Flow Flumes – Made in the USA
Now built by Intermountain Environmental, Inc. (IEI)
Standard Sizes: EZ Flow Ramp Flume (previously Nu-Way Flume)
| Max Flow Rate (CFS / GPM) | Throat Width (in.) | Length x Height (in.) | Shipping Weight Approx. |
|---|---|---|---|
| 3.5 / 1600 | 12-1/8 | 47-1/2 x 14-7/8 | 62 lbs |
| 7.0 / 3100 | 24-1/8 | 47-1/2 x 14-7/8 | 86 lbs |
| 10.0 / 4500 | 36-1/8 | 47-1/2 x 14-7/8 | 108 lbs |
| 20.0 / 9000 | 30-1/8 | 80 x 26 | 400 lbs |
| Custom | Varies | Varies | Varies |
Standard sizes can all ship via FedEx or UPS.
For ordering and information call (435) 755-0774 or email info@inmtn.com.
Custom Steel Ramp Flumes (Broad-crested Weir)
Let us design and build you a custom sized ramp flume(s). We consult with you or your engineering firm to design the best flume for your flow measurement needs. We also have sensors, dataloggers, and telemetry systems that can be added to a flume to record data and transmit that data to just about anywhere you desire, including a website.
We also offer systems and sensors to measure open channel flow without the use of a flume. You can click here to learn about those options.
Cutthroat Flume
The Cutthroat Flume was developed by Utah State University Water Research Lab in approx. 1967 (see report). It is sometimes called a flat-bottom flume. It is resistant to submergence, and can still be used when submerged by taking a second measurement at the effluent. We sell cutthroat flumes in steel and fiberglass, and in a variety of standardized sizes (see table).
Advantages of Cutthroat Flumes
- Can be installed low slope ditches (great for irrigation flow measurement)
- Easier to install (compared to parshall flume)
- Resistant to submergence
- Cost-effective (simple design)
Sizes
| Flume Length (in.) | Throat Width (in.) | Flume Depth (in.) | Min Flow (CFS / GPM) | Max Flow (CFS / GPM) |
|---|---|---|---|---|
| 18 | 1 | 6 | .0008 / .3536 | .1113 / 49.95 |
| 18 | 2 | 6 | .0015 / .6779 | .2134 / 95.76 |
| 18 | 4 | 6 | .014 / 6.28 | .445 / 200 |
| 18 | 8 | 6 | .029 / 12.8 | .908 / 408 |
| 36 | 2 | 12 | .003 / 1.30 | .719 / 323 |
| 36 | 4 | 12 | .021 / 9.47 | 1.46 / 655 |
| 36 | 8 | 12 | .043 / 19.3 | 2.97 / 1,333 |
| 36 | 16 | 12 | .087 / 39.2 | 6.0 / 2,711 |
| 54 | 3 | 18 | .018 / 8.21 | 1.93 / 865 |
| 54 | 6 | 18 | .037 / 16.8 | 3.94 / 1,767 |
| 54 | 12 | 18 | .076 / 34.0 | 8.0 / 3,588 |
| 54 | 24 | 18 | .153 / 68.5 | 16.1 / 7,220 |
| 108 | 12 | 36 | .096 / 43.3 | 19.4 / 8,718 |
| 108 | 24 | 36 | .196 / 87.9 | 39.5 / 17,711 |
| 108 | 48 | 36 | .399 / 179 | 80.4 / 36,094 |
| 108 | 72 | 36 | .606 / 272 | 122 / 54,801 |
For ordering and information call (435) 755-0774 or email info@inmtn.com.
Parshall Flume
The Parshall Flume has been the most widely used flume for fixed flow monitoring installations. Parshall flumes are sized by throat width, and conform to standardized dimensions published by the U.S. Department of the Interior, Bureau of Reclamation. We offer all standard sizes both in fiberglass and steel. They take 3-4 weeks on average to build. Parshall flumes are often installed incorrectly and require additional adjustments to their flow equation to be as accurate as possible. Due to this we often recommend using a different style flume in irrigation applications. We can offer consultation as to which type of flume will best fit your needs, or make recommendations on how to improve the measurement at a site that already has a Parshall installed.
Advantages of Parshall Flumes
- Very accurate in some applications
- Remain accurate under low flow conditions (wide operating range)
- Can continue to measure flow when submerged
Limitations of Parshall Flumes
- Prone to clogging in sizes below 1 ft. (when used in irrigation)
- More difficult to install in very flat ditches
- Often creates more upstream head than other flumes
Parshall Flume Sizes
| Throat Width | Min. head (ft) | Min flow (CFS / GPM) | Max. head (ft) | Max flow (CFS / GPM) |
|---|---|---|---|---|
| 1 in. | 0.10 | 0.010 / 4.28 | 0.70 | 0.194 / 87.3 |
| 2 in. | 0.10 | 0.019 / 8.55 | 0.80 | 0.478 / 215 |
| 3 in. | 0.10 | 0.028 / 12.6 | 0.80 | 1.15 / 516 |
| 6 in. | 0.10 | 0.054 / 24.3 | 1.50 | 3.91 / 1,750 |
| 9 in. | 0.10 | 0.091 / 40.7 | 2.00 | 8.87 / 3,980 |
| 1 ft. | 0.10 | 0.120 / 54 | 2.50 | 16.1 / 7,240 |
| 1.5 ft. | 0.10 | 0.174 / 78 | 2.50 | 24.6 / 11,000 |
| 2 ft. | 0.15 | 0.423 / 190 | 2.50 | 33.1 / 14,900 |
| 3 ft. | 0.15 | 0.615 / 276 | 2.50 | 50.4 / 22,600 |
| 4 ft. | 0.20 | 1.26 / 567 | 2.50 | 67.9 / 30,500 |
| 5 ft. | 0.20 | 1.56 / 698 | 2.50 | 85.6 / 38,400 |
| 6 ft. | 0.25 | 2.63 / 1180 | 2.50 | 103 / 46,400 |
| 8 ft. | 0.25 | 3.45 / 1550 | 2.50 | 140 / 62,600 |
| 10 ft. | 0.30 | 5.74 / 2570 | 2.75 | 199 / 89,200 |
| 12 ft. | 0.33 | 7.93 / 3560 | 3.50 | 347 / 156,000 |
For ordering and information call (435) 755-0774 or email info@inmtn.com
Other Flumes
These flumes are more specialized than the others listed above, but we sell and support all of them. Feel free to ask us for details.
H-Flume
Because of its V-shaped discharge, the H-Flume is accurate in both high and low flow conditions. H-flumes must be elevated above the effluent so the water can freely spill out of the flume.
Trapezoidal Flume
The Trapezoidal Flume is similar to the Cutthroat (flat-bottom) Flume, but has outward sloping walls. And like the H-flume, it is designed to be accurate in both high and low flow conditions. These are often used in irrigation or in any open channel where the flow rate may vary widely.
Palmer-Bowlus Flume
The Palmer-Bowlus Flume was designed for measuring wastewater in conduits, and they are often installed in manholes. They are very accurate, but have a smaller range of useful flow rates compared to other flumes.
Sensors & Accessories
We have a variety of sensor systems used for monitoring, logging and reporting flow rate through a flume or weir. Most of these sensors (depending on the specific model) send a signal that is recorded by a datalogger, and the data can be retrieved later in person. Or, it can be transmitted live via radio or internet, allowing you to monitor flow rates with a radio receiver, or even from a cell phone or web browser.
Water Level
Sensors and systems for measuring water depth in lakes, wells, flumes, tanks, and much more.
Open Channel Flow Monitoring Sensor
There is an alternative to installing a flume or weir into a channel. We now offer a sensor that can measure depth and velocity in your channel, partially filled pipe or culvert. This sensor is called the Bigfoot. Click on the image to your right to learn more about the Bigfoot Area Velocity Sensor.
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