Q$.4($a$)$ Describe the incipient motion criteria with the help Shield's Diagram.

$($b$)$ For the data given below, estimate bed load in PPM using Meyer Poter and Muller's Formula.

Median particle size $(d_{si})=0\mathrm{.}25mm,$ Avg velocity of flow $=2\mathrm{.}5\frac{m}{sec},$ Slope $=0\mathrm{.}0015,$ Avg depth of channel $=3\mathrm{.}50m,$ Avg width of channel $=90m,$ Kinematics viscosity $=1{10}^{-4}\frac{m^2}{sec},$ specific gravity $=2\mathrm{.}65.$