Calculate the discharge in a gutter section. Given a design water spread of $3$m$,$ a cross slope of $1\mathrm{.}5\%,$ a longitudinal bottom slope of $0\mathrm{.}025,$ a gutter depression $\text{'}$a$\text{'}$ of $0\mathrm{.}015$m$,$ a depressed section width of $0\mathrm{.}60$m$,$ calculate discharge in a gutter section using Manning's roughness coefficient $($n$)$ of $0\mathrm{.}015$ and kn of $1\mathrm{.}2$m$3/$s