A trapezoidal canal with $B=5\mathrm{.}0m$ and side slope $1H$:$1V,$ carries a discharge of $30\mathrm{.}0\frac{m^3}{s}$ at a depth of $3\mathrm{.}0m.$ Calculate the speed and height of a positive surge $($i$)$ if the flow in the canal is suddenly stopped by the operation of a gate at a downstream section, $($ii$)$ if the discharge is suddenly increased to $45\mathrm{.}0\frac{m^3}{s}$