Hydraulic Efficiency of Grate and Curb Inlets - Urban Drainage and ...

1
0.9
Observed
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
`
1 ft depth
0.5 ft depth
0.33 ft depth
Equal
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Predicted
R 2 Average efficiency error (%) Maximum efficiency error (%)
0.574 17.7 39.0
Figure 5-3: Predicted vs. observed efficiency for Type 16 combination inlet from UDFCD methods
For the Type R curb inlet, efficiency was determined using Equation 2-11, Equation 2-13,
and Equation 2-14 as a direct calculation. Efficiency comparison with the observed test data is
presented in Figure 5-4, where agreement is best for high flow depths. Measured top width,
velocity, and cross-sectional flow area for each inlet test were used in the calculations and are
provided in Appendix F. Accuracy of these methods for the Type 13, 16, and R inlets will be
improved in Section 5.2 when the UDFCD methods are extended to include them directly.
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