One of the nice things about the Parshall flume is that it lends itself well to flows that shift dramatically over the life of the flume. 

In applications where water conservation has occurred and the flows that a Parshall flume was designed are no longer occurring, a smaller, nested flume can be inserted into the larger, outer Parshall flume.  Nesting can be temporary (think seasonal demand) or permanent in nature.

The flat converging floor of the Parshall means that the smaller (inner) flume can sit in:

• Just the converging section of the outer Parshall flume
• In the converging section and throat of the outer Parshall flume
• In the converging section, throat, and diverging section of the outer Parshall flume

The smaller (inner) flume is most commonly another Parshall flume, but Cutthroat, Trapezoidal, HS / H flumes, and Montana flumes can also be nested.