Context: Accurate flow measurement is essential for fair billing and water conservation in agricultural districts.

Application: Irrigation canals often employ Parshall flumes instead of sharp-crested weirs. A weir creates a significant head loss and allows sediment to build up behind the plate, altering its calibration over time. A Parshall flume, operating on the principle of critical depth, passes sediment easily (self-cleaning) and causes much less head loss, making it ideal for the low-gradient channels typical in large irrigation networks.

Context: Measuring the flow of valuable fluids like oil requires extreme precision.

Application: Orifice meters are widely used in oil pipelines for custody transfer (where ownership of the fluid changes hands and is billed). The differential pressure across the precisely machined orifice plate is continuously monitored. Because variations in temperature and pressure affect the oil's density and viscosity, the flow calculations must dynamically correct for these properties. A slight error in the discharge coefficient can result in millions of dollars in billing discrepancies over a year.