Montana Flume Dimensions
The dimensions for the Montana flume are based upon those of the Parshall flume from which it's derived.
- ASTM D1941-91 (Reapproved 2013) Standard Test Method for Open Channel Flow Measurement of Water with the Parshall Flume
- ISO 9826:1992 Measurement of Liquid in Open Channels - Parshall and SANIIRI Flumes
- JIS B7553 Parshall Flume Type Flowmeters
- The Parshall Flume: Instructions for Installation and Table of Discharge, State Engineer of Colorado
The Montana flume is defined in:
- MT 9127 (AG) Montana (Short Parshall) Flume (Part 1), Montana State University
- MT 9128 (AG) Montana (Short Parshall) Flume (Part 2), Montana State University
- Water Measurement Manual, 3rd Edition, United States Department of the Interior, Bureau of Reclamation
It's critically important to note that although Montana flumes share a common layout, they are NOT scale models of each other – they are empirical devices for which investigations have been made to determine their specific flow rates.
The use of non-standard flume sizes is HIGHLY discouraged and the dimensions and flow accuracies of such devices should be considered suspect.
ASTM D1941 requires that Parshall (Montana) flumes have dimensions within +/-2% of nominal, while JIS B7553 requires tolerance of +/- 1-1.5% depending upon flume size.
Parshall (Montana) flumes with dimensions outside of these ranges should be considered to be non-conforming and should be either replaced for field rates.