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The USGS Portable Parshall flume is a modification of the standard Parshall flume where the discharge section has been removed. The purpose of the modification is to reduce the weight of the flume and to make it easier to install.

The Stream Institute at the University of Louisville is an interdisciplinary applied research program in the Department of Civil and Environmental Engineering. The work of the Institue is primarily concerned with the mitigation of human effects on streams, wetlands, and…

Every year at Openchannelflow we talk with several hundred consultants, researchers, contractors and end-users about their flow monitoring needs. Because we work extremely hard at answering all questions "flow” on this web site – and this blog in particular - we are often…

Parshall Flume Metering Manholes are an excellent solution to the problem of how to monitor below-grade piped flows. Integrating the popular Parshall flume into a fiberglass manhole, Parshall Flume Metering Manholes are complete, factory-integrated structures capable of direct…

End Adapters are specially shaped transitions that are molded or secured to the inlet and outlet ends of Parshall flumes to connect then to inline piping so that flow can be measured. End adapters serve to transition flow from the round pipe to the rectangular cross-section of a…

Parshall Flumes – like all flumes - are obstructions placed in a flow stream that produce backwater. This backwater extends upstream of the flume and raises the water surface in the approach channel. The difference in water surface elevation with and without the flume is…

In North America, large Parshall Flumes – those with throat widths larger than 144-inches – are primarily used to measure the diversion of water from streams, lakes, and other primary sources of surface water to smaller irrigation distribution systems. Most of these…

Less well known than their more numerous Rectangular throated brethren, Trapezoidal Cutthroat flumes are a class of (3) flumes that combine the low flow sensitivity of the Trapezoidal flume with the simple, throatless design of the Cutthroat flume.

Small Parshall Flumes, those from 1-inch to 3-inches in size, are well suited to a variety of applications, from stream gauging to industrial pretreatment monitoring. The flumes posses good flow ranges, are able to measure low heads / flow rates with accuracy, and are available…

In his 1936 report, The Parshall Flume, Dr. Parshall reported the results of a limited series of tests conducted on a 2-foot Parshall flume where the approach velocity was varied. His observation was that discharge through the flume was not significantly affected when approach…

Trapezoidal flumes are popular choice when industrial users need to measure pretreatment discharges. The trapezoidal shape of the flumes provides sensitivity to the low flow rates (like during a plant shut down), while retaining the ability to handle large, peaking flows (from…

Many people confuse a flume’s resolution with its accuracy and use the terms interchangeably. The two, however, are distinct from each other. A flume may have good resolution, but poor accuracy, and vice versa. Resolution is a how much change in head is developed in the flume…