Water flows steadily in a rectangular open channel with a width of $10$ feet. At a certain section of the channel $($Section $1),$ the depth of flow is $4$ feet, and the flow velocity is $6$ feet per second $($fps$).$ The total discharge $($Q$)$ remains constant throughout the channel.

$$ Given:

o Channel width $($b$)=10$ feet

o Depth of flow at Section $1($y$)=4$ feet

o Velocity at Section $1($V$)=6$ fps