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

Observed
1
0.9
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
Figure 5-9: Predicted vs. observed efficiency for Type 16 combination-inlet from empirical equation
Observed
1
0.9
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
Figure 5-10: Predicted vs. observed efficiency for Type R curb inlet from empirical equation
By developing new equations to predict efficiency, it was possible to further improve
predictions for inlet efficiency over previous sections. With new equations presented here, the
average error in predicted efficiency was reduced to about 5% for all inlets with R 2 values
between 0.84 and 0.90. Overall agreement between observed and predicted efficiency is
improved over previous methods for all test depths. A comparison is shown in Figure 5-11
through Figure 5-13 between the empirical equations and the improved UDFCD methods.
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