6 SCS CN

The SCS curve number (CN) is a method developed in … ¹ CN helps with the estimation of runoff at basins where no runoff has been measured.

We have to start with some initial data.

\[ \dfrac{F}{S} = \dfrac{Q}{P-I_a} \]

\[ I_a = 0.2\cdot S \]

\[ S = \dfrac{1000}{\mathrm{CN}} \] where \(S\) is a potential maximum retention after the initial runoff.

\[ Q = \dfrac{(P-I_a)^2}{(P-I_a)+S} \]

Code

cn_table <- data.frame(
  LU_desc = c("Agricultural", "Commerical", "Forest", "Grass/Pasture", "High Density Residential"
              )
)