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There are times when the standard sidewall height on a flume just won’t do. Sometimes the channel is taller than the flume and there is a need or desire to match the elevations. Other times a site needs additional flow capacity but there isn’t room for a larger flume. And…

We often talk about how flumes and weirs accelerate sub-critical flow to a supercritical state and how that in turn develops the level-to-flow relationships that are used to determine the flow rate. In the past we’ve defined the various stages of critical flow by the Froude…

If circumstances allow, it is preferable to have a flow measuring device operate under free-flow conditions. The obvious advantage is that only an upstream flow depth need be measured to determine the discharge. The procedure to follow for installing Cutthroat Flumes in existing…

Beyond the normal approach and installation problems, there are a number of factors can affect the accuracy of a Palmer Bowlus flume measuring flow. These include: approach channel conditions, deposits, Froude number, longitudinal slope, and roughness.

We all know the usual points of measurement, Ha (primary point of measurement), Hb (point of measurement to determine submergence), but what about Hc? The Hc point of measurement appears in Dr. Parshall’s earliest works on what would become his namesake flume. The original…

After you’ve selected whether flume or weir for your application, you then have to think about which type of flow meter to use. Usually this comes to down to using an ultrasonic or a bubbler flow meter. Price is a strong advantage for ultrasonic meters – in many ways…

Submergence in a flume is where the downstream conditions are such that they limit or restrict flow out of the flume. It’s important to check for submergence, as limiting the discharge means that the flume will OVER INDICATE the actual flow rate. To determine if a flume is…

In his original developed of what would become the Parshall flume, Dr. Parshall arbitrarily defined the length of the converging, inlet section of his flume as: For throat widths greater than 8 feet, this relationship was found to be unsatisfactory, and the converging section…

Flow Metering Manholes can be grouped into two types: open pipe and closed pipe. Closed pipe flow metering manholes use mag meters, clamp on meters, and insertion meters. Open channel manholes incorporate flumes, weirs, or direct sensing (radar, laser, or area velocity) meters.

In an open channel, freeboard is the head measured from the maximum water level to the uppermost watertight portion of the surrounding channel. Freeboard is an important consideration when evaluating the impact of the installation of a flume or weir. Weirs in particular require…

H Flumes can be a good choice when monitoring stormwater flows, whether mounting in a channel or at the end of a discharge pipe. H Flumes provide the low flow sensitivity of a thin-plat weir with the self-cleaning features of a flume. More than any other style of flume, H Flumes…

A hot spring is a natural upwelling of geothermally head groundwater. They can vary widely in temperature from those suitable for bathing to others so hot that immersion results in death or severe injury. Hot springs may contain high level of dissolved minerals (ranging from…