Blog

Replacement floors (AKA “magic bottoms” or “false floors”) are a way of correcting flume hydraulics without the need for costly demolition and construction.

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…

The unique shape of the H Flume allows it to measure a wide range of flows. As a result, a common application of the flume is stream gauging - where flows can run from a trickle to a torrent.

Fiberglass Manholes are lightweight (~1/10th the weight of concrete), corrosion resistant, and watertight. Their installation is straight forward and can be accomplished with less manpower and equipment than a traditional concrete vault or manhole. Where line downtime is a…

Site selection should be viewed as only part of the requirements for a proper Parshall flume installation. While important, good site selection cannot overcome poor upstream or downstream conditions. In reading through the site selection criteria you will notice that many times…

The common method of installing a flume is to encase it in concrete or an earthen channel. Sometimes, though, flow needs to be measured where this just isn’t an option. For these installations something else is needed: a freestanding installation!

Flow from a horizontal pipe can be estimated through the use of the California Pipe Method. Developed in 1922 / 1924 by B.R. Van Leer, the Method was developed from experimental data to measure the discharge from horizontal pipes which are not flowing full.

The Cutthroat Flume is one of the more recent styles of flumes to be developed. Development of what would become the Cutthroat Flume began during the 1960’s at the Utah State Water Research Laboratory. The goal was to create a low-cost flume to monitor surface water flows…

In the right applications, galvanized steel Parshall flumes can be a good choice to measuring the flow of water. Irrigation and water rights applications (generally in the Intermountain Region of CO, UT, WY, MT, ID) were abrasive grit, stones, or debris are not present are…

In an earlier article we discussed the use of flat 45ª wing walls to transition flow into Parshall flumes. The article focused on Blaisdell’s observation that a standing wave and wave trough were generated downstream of the intersection of the inlet 45ª flat wing wall and the…

Fiberglass Grinder Manholes are a unique solution to the problem of mounting sewage grinders below grade. The all-fiberglass construction means the unit has high-strength, is watertight, and is corrosion resistant…all at about 1/10th the weight of concrete with essentially…

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…

While many flumes are grouted into place, a sizable number are also installed in earthen channels (furrows, irrigation ditches, creeks, etc.). The traditional method of excavating the area, packing the earth, installing the flume, and then backfilling with the excavation dirt…

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…

For a Parshall flume to function correctly it is important that certain guidelines be followed when selecting a site and installing the flume. In particular, the upstream conditions are of critical importance. It is tempting to say that there just isn’t room to position the…

Water storage with dams began early in human history. Dams are one of the oldest man-made constructions. Today, dams are used to store water for a variety of purposes, including: human consumption, food production, electricity production, industrial use, and flood protection.…

In applications where organic nutrients are high in the flow stream being monitored, there is always a chance of biological growth on the wetted portion of a flow meter bubbler tube. The small diameter of the opening of the tube (typically 1/8-inch [0.3175 cm] to 1/4-inch [0.635…