$2)($text $5\mathrm{.}1\mathrm{.}1)$ A $2$m wide rectangular channel with a bed slope of $0\mathrm{.}0004$ has a depth of flow of $1\mathrm{.}5$m$.$ The bottom of the channel has new smooth concrete. Determine the steady uniform discharge in the channel. What would be the percentage change in discharge if the channel is not maintained and becomes covered with dense weeds?