Problem $13\mathrm{.}056-$ V'shaped water channel discharge rate

A cast iron V$-$shaped water channel shown in the figure has a bottom slope of $0\mathrm{.}8.$ For a flow depth of $0\mathrm{.}75m$ at the center, determine

the discharge rate in uniform flow. The Manning coefficient for an open channel of cast iron is $n=0\mathrm{.}013.$

The discharge rate in uniform flow is $6\mathrm{.}98\frac{m^3}{s}.$