Rational Equation Peak Flow Estimator


from "Oregon Hydraulics Manual (Chapter 7, Appendix F), 2014."

ODOT Table of Runoff Coefficients Tables from Oregon Hydraulics Manual

TxDOT Table for Runoff Coefficients Tables from Texas Hydraulic Design Manual

Estimates peak discharge in US customary units from

Q_p = (1.008)*C*I*A
where:
   Q_p is peak discharge in CFS
   C is the runoff coefficient (read from table)
   I is rainfall intensity in inches/hour
   A is drainage area in acres

Enter Value for Runoff Coefficient (C):

Enter Value for Area (A):

Enter Value for Average Intensity (I):