Blog

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…

Fiberglass Grinder Manholes are a unique solution to the problem of mounting a open channel sewage grinder 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…

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…

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…

People make mistakes.... 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…

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

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…

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…

Flow measurement in arctic locations can be extremely difficult.  By their very nature, the locations are remote, equipment is limited, flows are highly seasonal, and frost heave is an ever-present concern.  Of these problems, frost heave can be the most difficult to…

We see Parshall flumes at wastewater treatment plants monitoring sanitary flows so often that sometimes we forget the original reason that the Parshall flume was developed – to measure irrigation flows.  With 22 sizes available, Parshall flumes are capable of measuring…

One of the primary advantaged of fiberglass flow metering manholes is the ability to accommodate flumes much larger than will fit inside the manhole. By being able to laminate the flume to the manhole barrel, flumes can readily extend upstream / downstream of the manhole barrel…