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Turning off the pumps is one of the last things that happen when a mine is closed. Slowly many of the open spaces of the mine begin to fill up with water. Rain starts to percolate thought the roof and walls and ground water, previously held at bay by the pumps begins to seep back…

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 other meters) to…

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. From a municipal standpoint, green roofs offer a number of advantages,…

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

Weirs are best used to measure flows that contain only small amounts of suspended solids. Unfortunately in surface water applications, the amount of solids present in the flow stream cannot be controlled. Unlike flumes, which tend to be self-cleaning, weirs require regular…

The majority of errors in open channel flow measurement result from designers, installers, or operators - not from the equipment itself.  These errors result from a vareity of sources - from a lack to training to inattention to detail - and are avoidable. Avoidable flow…

In talking with customers about weirs, we run into two common misconceptions. The first misconception is that weirs can read down to zero – that there is no minimum head. The second is that weirs are more accurate at these flows than flumes. Unfortunately, both assumptions are…

A Packaged Metering Manhole (PMM) is a fiberglass manhole into which a primary device has been integrated. In addition to the above, Packaged Metering Manholes allow the integration of primary devices larger than would otherwise be able to be easily accommodated in concrete…

Portable weir plates are a good way to stretch your research dollars. Instead of the traditional approach of having a weir plate custom fabricated for each installation, Openchannelflow has simplified the process by developing a standard weir carrier with four interchangeable…

Weir boxes are frequently fabricated without the use of a baffle upstream of the point of measurement. The omission of a baffle plate (sometimes called a surge plate) saves both space and money, but at what cost? In applications where the velocity profile is normal and the…

Metering manholes are a convenient way to measure flows in a wide range of applications, including: wastewater treatment plant headworks / influent, treated effluent, in-plant flows, industrial discharge, or monitoring the flow of sewage in a collection system. Capable of…