$\backslash$table$[[$Solids$,$Size $(mm),$Specific Gravity$],[1.$ Organic,$0\mathrm{.}30,1\mathrm{.}05],[2.$ Silt,$0\mathrm{.}02,2\mathrm{.}80],[3.$ Coarse silt,$0\mathrm{.}08,2\mathrm{.}65],[4.$ Brake dust,$0\mathrm{.}06,5\mathrm{.}40]]$The suspended solids in runoff into a detention pond after pre$-$treatment are grossly characterized by four primary particles, with characteristics given below. Determine the range of fraction of course silt retained by the pond via settling. The pond area is $0\mathrm{.}2$ ha with a depth of $4$ m $,$ and a weighted mean flow rate during operation of $4\frac{m^3}{s}.$ Use a water temperature of $20C($i$.$e$.v=1{10}^{-6}\frac{m^2}{s}).1ha=10,000$ m$^2.$