Drainage Design Manual, Hydrology - Flood Control District of ...

Drainage Design Manual for Maricopa County
Hydrology: Indirect Methods
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Table 8.3
FLOOD MAGNITUDE-FREQUENCY RELATIONS FOR THE SOUTHERN AZ REGION (R13)
EQUATIONS: Q, PEAK DISCHARGE, IN CUBIC FEET PER SECOND; AND AREA, DRAINAGE AREA, IN
SQUARE MILES.
Recurrence
interval,
in years
Equation
Average standard
error of model,
in percent
2 LOG 10 Q = 6.38 – 4.29 AREA -0.06 57
5 LOG 10 Q = 5.78 – 3.31 AREA -0.08 40
10 LOG 10 Q = 5.68 – 3.02 AREA -0.09 37
25 LOG 10 Q = 5.64 – 2.78 AREA -0.10 39
50 LOG 10 Q = 5.57 – 2.59 AREA -0.11 43
100 LOG 10 Q = 5.52 – 2.42 AREA -0.12 48
August 15, 2013 8-17