HYD_scs_q(): Run-off according to SCS

About:
Calculate the run-off (Q) according to Soil Conservation Soil (SCS).

\begin{equation} Q = \frac{\left( P-Ia \right)^2}{P -Ia + S} \end{equation}
 Where,
  • Q, run-off, mm
  • P, accumulated precipitation;
  • S, potential storage, mm;
  • Ia, initial abstraction.
More information about soil Conservation Service methodology please see Wikipedia.

Module: Hydrology
Function: HYD_scs_q(p,cn2,amc)
Definition of variables:
  • p, accumulated preciptation;
  • cn, curve number;
  • amc, (1, 2 or 3).
Sample code:
from Hydrology import *

p = 100 #mm
cn2 = 70

amc = 1
q = HYD_scs_q(p,cn2,amc)
print("Q (AMC I):",q,"mm")

amc = 2
q = HYD_scs_q(p,cn2,amc)
print("Q (AMC II):",q,"mm")

amc = 3
q = HYD_scs_q(p,cn2,amc)
print("Q (AMC III):",q,"mm")
Result:
Q (AMC I): 0 mm
Q (AMC II): 17.9249603472 mm
Q (AMC III): 52.7100491979 mm