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The 4-inch Palmer Bowlus Flume is the smallest of the Palmer Bowlus family of flumes. The flume can pass sanitary solids without clogging. Palmer Bowlus Flumes are not usually used to measure surface waters.

The domed top style is the most popular style of top for fiberglass metering manholes - outselling both H-20 traffic reducer and aluminum top styles 2:1. The dome top is specifically formed to provide rigidity and strength while still being light enough for operators to open. A…

The 18-inch Parshall Flume is mainstay at wastewater treatment plants. It can also be found out in the field helping to measure water rights. Openchannelflow's 18-inch Parshall Flume is available in several configurations:

The 6-inch Parshall Flume is one of the sizes developed by Dr. Parshall during his initial studies. The flume works well in measuring water rights and can be found as smaller wastewater treatment plants. The 6-inch Parshall Flume has been successfully used to measure flow in a…

For a flume to operate properly the flow entering it must be: In below grade applications, one device can help a user do all three: The Energy Absorbing Manhole.

For a weir box to provide accurate flow measurement, the flow approaching the weir needs to be well distributed as it enters the weir pool. Unfortunately, weir boxes are usually used to measure flows in gravity pipe systems. The answer is upstream baffles. Properly configured,…

A defining characteristic of a weir is its need for the approaching flow to be sub-critical (Fr 1) by means of the weir notch and spilling discharge. The acceleration of flow from the sub-critical to the super-critical allows for the establishment of the level-to-flow…

One of the things to look at when selecting a material for your Parshall flume is how long the flume will actually last. A flume's lifespan can be as important as it's cost if a poor material selection results in a short useful life.

End-of-pipe applications always present a problem when it comes to measuring the flow. One good idea that we’ve run across is using a precast trough with a weir plate. The trough is butted up against the end of the pipe to direct all the flow through the weir.

There are times when the standard sidewall height on a flume just won’t do. Sometimes the channel is taller than the flume and there is a need or desire to match the elevations. Other times a site needs additional flow capacity but there isn’t room for a larger flume. And…

A key parameter in measuring water quality is Dissolved Oxygen (DO). DO is often used as a quality of water indicator for water used by people or which serves as a habitat for aquatic flora and fauna. While it has been known that weirs can affect DO levels, a systematic…

One way of calculating open channel flow in pipes and channels without using a flume or weir is the Manning Formula. Although not as accurate as a hydraulic structure, the formula can provide a sufficient level of accuracy in some applications. The Manning formula uses water…

We often talk about how flumes and weirs accelerate sub-critical flow to a supercritical state and how that in turn develops the level-to-flow relationships that are used to determine the flow rate. In the past we’ve defined the various stages of critical flow by the Froude…

If circumstances allow, it is preferable to have a flow measuring device operate under free-flow conditions. The obvious advantage is that only an upstream flow depth need be measured to determine the discharge. The procedure to follow for installing Cutthroat Flumes in existing…

Beyond the normal approach and installation problems, there are a number of factors can affect the accuracy of a Palmer Bowlus flume measuring flow. These include: approach channel conditions, deposits, Froude number, longitudinal slope, and roughness.

We all know the usual points of measurement, Ha (primary point of measurement), Hb (point of measurement to determine submergence), but what about Hc? The Hc point of measurement appears in Dr. Parshall’s earliest works on what would become his namesake flume. The original…

After you’ve selected whether flume or weir for your application, you then have to think about which type of flow meter to use. Usually this comes to down to using an ultrasonic or a bubbler flow meter. Price is a strong advantage for ultrasonic meters – in many ways…

Submergence in a flume is where the downstream conditions are such that they limit or restrict flow out of the flume. It’s important to check for submergence, as limiting the discharge means that the flume will OVER INDICATE the actual flow rate. To determine if a flume is…

In his original developed of what would become the Parshall flume, Dr. Parshall arbitrarily defined the length of the converging, inlet section of his flume as: For throat widths greater than 8 feet, this relationship was found to be unsatisfactory, and the converging section…

Openchannelflow is pleased to announce that ProViro Instrumentation has partnered with Openchannelflow to distrbute products for the country of Canada.