A sedimentation basin treating $6200$ m$3$day$-1$ with a hydraulic retention time of $1$ hour was designed to remove particles with a diameter of $0\mathrm{.}02$ mm $($density$=2650$ kgm$-3)$ suspended in water $($density $=1000$ kgm$-3,$ dynamic viscosity $=1\mathrm{.}002$x$10-3$ kgm$-1$s$-1$ at $20\backslash$deg C$).$ Assume spherical particles and laminar flow.

$($a$)$ The overflow rate of the sedimentation basin is approximately $\_\_\_\_\_\_\_\_\_\_\_$ m$^3$m$^-2$day$^-1$ and it has a surface area of $\_\_\_\_\_\_\_\_\_\_\_$ m$^-2.$

$($b$)\_\_\_\_\_\_\_\_\_\_\_\_\%$ of particles with a diameter of $0\mathrm{.}01$ mm $($density $=2650$ kgm$-3)$ suspended in the water will be removed.

$($c$)$ To ensure their complete removal, the smaller particles should enter the basin at a maximum height of $\_\_\_\_\_\_\_\_\_\_$m from the bottom.