Irrigation water of 50 mm (measured with the help of Parshall flume
) was allowed to run in each plot at each irrigation.
The Parshall Flume
is the most popular for its range of flows and ability to pass flow without taking much energy from it.
Ultrasonic Modules (Isco 710) mounted over each Parshall flume
used ultrasonic reflection to measure water level.
Runoff measurements and calculations were subject to instrumental errors including head measurement by the pressure transducer and inaccuracy of the Parshall flume
head-flow rate relationship (Equation 1).
Two methods were used in order to measure stream discharge: an area-velocity method using a flow meter and a Parshall flume
. Also a topographical survey was made using a total-station theodolite.
Plant effluent flow currently is measured downstream of the secondary clarifier via a Parshall Flume
. Visual observations of the Parshall Flume
indicate that the system is intermittently operating under submerged conditions.
Measuring the flow of liquids is done in open channels and involves the use of a weir or Parshall flume
or various modifications of these devices.
Variations of the Parshall flume
as differential producers include the parabolic flume and Kennison nozzle, in that they are open channel measuring devices.