Again, notice that as the duration increases, the intensity decreases.
Intensity and duration are inversely
proportional.
USING RAINFALL INTENSITY/DURATION CURVES
As shown in figure 1-2, page 1-4 there is a fairly consistent relationship between the average intensity of rainfall
for a period of one hour and the average rates of a comparable frequency of rainfall. Meteorologists have proven
this statistically. The relationship between intensities at one duration and intensities of other durations within the
same storm are expressed in figure 1-5. With this chart you can adjust the rainfall duration of the 60-minute
storm to a different duration. This adjustment will be needed later in the Rational Method of runoff
determination.
Figure 1-5. Standard rainfall intensity-duration curves
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