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The key to an accurate weir installation is the correctly sizing the upstream weir pool.  You can guarantee a successful weir installation every time if you follow these nine easy steps! The approach channel should be straight and of uniform cross-section for a distance of…

With Free Flow, Inc. (formerly of Gretna, NE) closing last year, Openchannelflow would like to extend a welcome to its former customers who are in need of assistance with their flow monitoring needs. Free Flow was primarily know for three product lines: Flumes (Parshall /…

Sometimes measuring discharge from lakes and ponds can be challenging…particularly when there isn’t a convenient spot to put a discharge weir or flume. One arrangement that has been used successfully is a vertical standpipe with a weir box mounted to the top. 

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…

One problem application we see time and time again is measuring the flow out of a UV disinfection system.  UV disinfection systems usually have V-shaped overflow weirs just downstream of the lamp banks.   Parshall flumes are then placed immediately downstream to measure…

Rectangular weirs can be a good fit for Water Rights applications where the soil at the installation site is stony / has large rocks (making the installation of a flume difficult or expensive) or where a realtively large volume of water must be metered in a realtively narrow…

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. To the consulting engineer these benefits include:  installation / measurement…

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…

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.

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…

Case Study Portable stream gauging Customer Warner College of Natural Resources - Colorado State University Background Warner College of Natural Resources (WCNR) at Colorado State University (CSU) is the largest named and most comprehensive natural resources program in the United…

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.