Consider saturated flow through a soil column with length $=30$ cm and diameter $=10$ cm$.$ The soil in the column is uniform. Saturated hydraulic conductivity is $10$ cm$/$day$,$ bulk density is $1\mathrm{.}35$ g$/$cm$3$ and particle density is $2\mathrm{.}7$ g$/$cm$3.$ A $2-$cm depth of water is maintained on top of the column. Water flows out freely from the bottom of the column. The water on top of the column is then changed to a $0\mathrm{.}001$ mole$/$L KCl solution. How long will it take for the outflow concentration to reach $0\mathrm{.}0005$ mol$/$L Cl$-$ concentration? Explain any necessary assumptions.