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Rainfall Intensity Formula. Chow lists 24 rainfall-intensity formulas of the form: Eq. 2. I = K · Fn1 / ( t + b )n. Where: I = rainfall intensity, in/h (mm/h) K, b, n, and n1 = coefficient, factor, and exponents, respectively, depending on conditions that affect rainfall intensity, see Table 1.0.
These design equations (Steel Equation), data and calculator will determine Rainfall Intensity and Peak Storm Water Runoff Rate for proper design of drainage requirements. Using the STEEL equation ( i = a/(d + b)
Calculate rainfall intensity using the Steel Formula.
Calculations with the Rational Method equation often involve determination of the design rainfall intensity and the time of concentration of the watershed as well. This course includes discussion of the equations and the variables for these types of calculations.
The rainfall intensity is the average rainfall rate during the time of concentration. Based on this definition, it can be calculated with the equation: i=\frac {R_ {tc}} {t_ {conc}} i = tconcRtc 2:1.3.16.
Example calculations and examples using the course spreadsheet for Rational Method equation calculations and for determination of the design rainfall intensity and the time of concentration of the drainage area, are presented and discussed in this course.
Runoff Rational & Steel Formula Calculator. Units. Blocks shown as light blue are editable. duration of rain t =. hr. drainage area A =. percentage of rain as direct runoff C =. %.
