Surface runoff

Hortonian surface runoff

Hortonian surface runoff \(q_{HOF}\) at time step \(t\) (mm \(\Delta t^{-1}\)):

\[\begin{split}q_{HOF} = \begin{cases} PREC - INT - INF & PREC - INT - INF > 0 \\ 0 & PREC - INT - INF \leq 0 \end{cases}\end{split}\]

Saturation surface runoff

Saturation surface runoff \(q_{HOF}\) at time step \(t$ (mm :math:\)Delta t^{-1}`):

\[\begin{split}q_{SOF} = \begin{cases} S_{soil} - S_{sat-soil} & S_{soil} - S_{sat-soil} > 0 \\ 0 & S_{soil} - S_{sat-soil} \leq 0 \end{cases}\end{split}\]

where \(S_{sat-soil}\) is soil water content at saturation (mm) and \(S_{soil}\) and soil water content at time step \(t\) (mm).