Openchannelflow manufactures fiberglass Parshall flumes in sizes from 1 inch to 12 feet. Constructed of premium polyester resin, Openchannelflow’s Parshall flumes conform to ASTM D1941-91, ISO 9826:1992, JIS B7553, and the Bureau of Reclamation’s Water Measurement Manual.
Fiberglass construction is corrosion resistant, cost effective, lightweight, and suitable for installation in either concrete or earthen channels. Utilizing permanent fiberglass and steel molds, fiberglass Parshall flumes from Openchannelflow offer extremely tight dimensional accuracies, ensuring that they perform per specification.
Development
A short-throated flume, the Parshall is the most widely used flume in North America, with the develop of the flume stretching back to the initial investigations of Dr. Ralph Parshall, then of the U.S. Soil and Conservation Service, in 1915.
Over the years, 22 standard sizes of Parshall flumes have been developed with each flume empirically tested to determine its flow characteristics. As Parshall flumes are not scale models of each other, intermediate sizes (i.e. 30” or 42”) should not be considered to exhibit the same level of accuracy as the standard sizes and should be avoided.
Applications
As a class, Parshall flumes are used in a wide to monitor flow in a variety of applications, including:
- Water rights
- Surface water
- Edge-of-field runoff
- Industrial pre-treatment discharges
- Wastewater
- Stormwater runoff
- Mine discharge
Accuracy & Submergence
Installed accuracy is typically +/- 3-5% when used to measure properly conditioned flow streams. Typical of short-throated flumes, the submergence transition for Parshall flumes ranges from 50-80% depending upon flume size.
Configurations
Openchannelflow fiberglass Parshall flumes are available in a wide variety of configurations to help tailor the flumes to your specific site needs.
For space critical locations, Openchannelflow offers both Montana and USGS Portable modifications of the Parshall design. Montana flumes delete the throat and discharge sections and are suitable for free-spilling flows. While the USGS Portable deletes the discharge section to make the flume more, well, portable.
Should the need arise; Openchannelflow fiberglass Parshall flumes are available with shorter or taller than standard sidewalls. Shorter flumes tend to be used where upstream head needs to be limited, while taller flumes are commonly used to either gain additional flow capacity for a given footprint or to match the surrounding channel sidewalls.
Replacement floors are available to cure submergence or leveling problems, while dual range (nested) flumes are available for planned expansion or downsizing due to water conservation.
