Trapezoidal Flume Accuracy

Trapezoidal Flumes are rated as accurate to within +/2% by Humphreys and Bondurant and +/-2-5% by the U.S. Environmental Protection Agency.  These accuracies are in line with other types of flumes.

Trapezoidal Flume Flow Equations'

The free-flow discharge equations for Trapezoidal Flume have not been standardized by industry or national standards.  However, the equations for individual flumes (Q = cfs, H = feet) have been published in some academic articles and publications:

Trapezoidal Flume Size	Flow Equation (Feet / CFS)
Small 60º	Q = 1.55 Ha2.58
Large 60º	Q = 1.55 Ha2.58
Extra Large	Q = 1.55 Ha2.58
8-inch 60º	Q = 2.22 Ha1.53 + 1.467 Ha2.5
12-inch 45º SRCRC (No. 1)	Q = 0.05 + 0.63 Ha1.5 + 3.23 Ha2.5
24-inch 38º SRCRC (No. 2)	Q = 0.19 + 1.67 Ha1.5 + 4.27 Ha2.5
2-inch 45º WSC	Q = 3.32 Ha2.18

Trapezoidal Flume Flow Tables 

Free-flow discharge tables for Trapezoidal Flumes can be found in the Discharge Tables section.