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Weir Boxes are the preferred method of monitoring seeps from concrete and earthern dams. Their ability to meaure low flows and retain sediment for future investigation make them a natural choice for the application. The small foot print and ability to have differnt inlet / outlet…

One problem application we see time and time again is measuring the flow out of a UV disinfection system. To keep the UV bulbs cooled and to increase the treatment efficiency of the disinfection system, usually the UV system provided has V-shaped overflow weirs just downstream of…

The three most common devices used to measure water rights are: Parshall flumes, V-notch weirs, and Cutthroat flumes respectively. But this doesn’t mean that other devices are used or aren’t suitable for measuring water right flows!

Fiberglass Packaged Metering Manholes are a great solution to the problem of measuring piped flows below grade and provide a unique set of benefits to consulting engineers who specify them. Accuracy, in this context means, installation accuracy by the contractor and the flow…

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…

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…

For flume and weir applications where the flow entering the device may not be as well distributed as one would like / or where the velocity profile needs adjustment, perforated baffle plates can be a good choice. Used in a series of two or more, perforated baffle plates help…

Warner College of Natural Resources - Colorado State University Warner College of Natural Resources (WCNR) at Colorado State University (CSU) is the largest named and most comprehensive natural resources program in the United States. WCNR serves as a leading institution in the…

Thin-Plate Weirs, when properly installed and maintained, are one of the most accurate means of measuring open channel flows. Under field conditions, though, without proper sizing or regular maintenance a thin-plate weir will become increasingly less accurate over time.

A problem with the application of thin-plate weirs in the field is the lack of proper conditioning of the flow before it reaches the weir crest. Baffles, placed upstream of the point of measurement, can be used to correct both poor approach velocity profiles and surface…

Freestanding staff gauges are a good solution to the need to measure level in a flume, weir, or channel. They are also useful in stream gauging or as replacements for other gauges that are damaged or no longer readable.

Reinforced Weir Boxes are a convenient way of measuring seepage flows out of a dam when the pipe is just below grade. Reinforcing the sidewalls of a weir box can allow the structure to withstand the pressures exerted by the soil in shallow burial applications.