Urban Stormwater Management Manual For Malaysia - Volume 4 Design Fundamentals item 13.2.6 Polynomial Approximation of IDF Curves

Polynomial expressions in the form of equation have been fitted to the published IDF curves for the 35 main cities/towns in Malaysia
R_It= the average rainfall intensity (mm/hr) for ARI and duration t
R= average return interval (years)
t = duration (minutes)
a to d are fitting constants dependent on ARI

a= b=
c= d=
t= minutes
R_It= mm/hr