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The use of galvanized steel Parshall flumes is common in measuring water rights on irrigation channels.  So much so they are almost the default flume / material of construction!  In fact, some states specify the use of Parshall flumes by law for certain situations and…

There are six standard angles for V-notch weirs:  22-1/2º, 30º, 45º, 60º, 90º, and 120º, but from time to time this range of sizes is not enough. Sometimes there is a need to correct for a weir plate cut at an incorrect angle.  While other…

Of all the various sizes of Parshall Flumes that we offer, the 4-inch Parshall flume is one of the most popular. Whether in fiberglass, galvanized, or stainless steel, we get a lot of inquires for this particular size. There’s only one problem…the 4-inch Parshall…

One of the problems in applying Trapezoidal flumes has been that many of the flumes lack free-flow discharge equations in the standard (and short) format availale for other popular flumes. A solution to this problem in presented by Utah State University...

Since the Parshall flume is the most commonly applied flume in North America and fiberglass the most common material, it is not uncommon when talking with a customer for the first time to be asked:  so how much does a fiberglass Parshall flume cost anyway? Finding out this…

In the past, calculating the flow in a submerged Parshall flume has been difficult.  The solutions available were graphs (Robinson, Bureau of Reclamation), limited (size) equations (Wahl), or long, complex equations (ISO 9826:1992). A better solution was need –…

Let’s face it – we are all under pressure to save money and accomplish our jobs at a minimum of cost.  In stream gauging, it is tempting to use wood (usually plywood) to make a weir from.  Why not?  The shape of a weir is deceptively simple - just a…

Staff ("head" or "level") gauges provide a quick, visual indication of the level of water in a channel, flume, or weir. Although they should not be solely relied on when more precise level measurement devices are available, staff gauges allow operators to quickly gauge the…

Replacement floors (AKA “magic bottoms” or “false floors”) are a way of correcting flume hydraulics without the need for costly demolition and construction. These floors can be used to correct: Low floor elevations due to poor installation Submergence due…

Historically, mines were often abandoned without proper (if any) cleanup.  This lack of remediation and cleanup has meant that as water rises in the mine, pollutants, sediment, and debris can all enter what can become a flow of water out of the mine.   Flow monitoring…

Let’s not kid ourselves – landfill leachate is some nasty stuff. If it has gone into the landfill, there is the likelihood that it has concentrated in the landfill.  This environment can make it exceedingly challenging for primary devices (Flumes, Weirs, and…

Green roofs have grown in popularity in the US in the past decade.   Popularized in Germany begining in the 1960's, green roofs have shown to provide benefits to the building owners and society as a whole. WIth this popularity comes a desire to best utilize the…

In situations where flow rates are expected to vary widely, the use of a compound weir may be an appropriate solution.  The most common compound weir consists of two stages, a rectangular notch with a 90º V-notch cut into the center of the crest - but it does not have…

A great time lapse video showcasing the ability of the H Flume to handle a wide range of flow conditions.  The video covers a six day period captured in 30 minute intervals and details the dramatic increase in flows due to a significant precipitation event. From low flows…

Fiberglass Manholes are lightweight (~1/10th the weight of concrete), corrosion resistant, and watertight.  Their installation is straight forward and can be accomplished with less manpower and equipment than a traditional concrete vault or manhole.   Where line…

Site selection should be viewed as only part of the requirements for a proper Parshall flume installation. While important, good site selection cannot overcome poor upstream or downstream conditions. In selecting a site, the following should be considered: Channel location…

The common method of installing a flume is to encase it in concrete or an earthen channel.  Sometimes, though, flow needs to be measured where this just isn’t an option.  For these installations something else is needed:  a freestanding installation!…

Flow from a horizontal pipe can be estimated through the use of the California Pipe Method.   The method can be useful for measuring free-spilling discharge out of the end of horizontal pipes from 3 to 10-inches [7.62 – 25.4 cm] in diameter and flowing only partially…

The Cutthroat Flume is one of the more recent styles of flumes to be developed.  Development of what would become the Cutthroat flume began during the 1960’s at the Utah State Water Research Laboratory. The goal was to create a low cost flume to monitor surface water…

In the right applications, galvanized steel Parshall flumes can be a good choice to measuring the flow of water.  Irrigation and water rights applications (generally in the Intermountain Region of CO, UT, WY, MT, ID) were abrasive grit, stones, or debris are not present are…