Runoff Curve Numbers with Varying Site Moisture

1 December 1978

journal article
Published by American Society of Civil Engineers (ASCE) in Journal of the Irrigation and Drainage Division

Vol. 104 (4) , 389-398
https://doi.org/10.1061/jrcea4.0001221

Abstract

Runoff curve numbers (CN) as used to estimate runoff volume (Q) from storm rainfall (P), are usually modified by handbook methods to account for the influence of watershed wetness. An alternate technique, based on the SCS rainfall-runoff formula and conservation of mass, is developed, illustrated, and discussed. The expression developed is: CN₂=1,200/(1,200/CN₁) +ET-(P-Q). The methodology requires inputs of the interim evapotranspiration and drainage (ET), but is not unreasonably sensitive to estimates of them.

Keywords

RAINFALL
EVAPOTRANSPIRATION
SCS
INPUTS
CN2
ILLUSTRATED
CURVE NUMBERS
UNREASONABLY

This publication has 0 references indexed in Scilit: