Timescale calculation for deposition of chloride through a channel on Mars

[Deepali]

Hi All, 

I am trying to calculate the time required for a channel on Mars to deposition certain amount of chloride in an area. I know the volume (and the mass) of chloride deposit in my study area. I have calculated discharge rate of the channel using Manning's as well as Darcy Weisbach's equation. I have used CTX DEM for measurements.

Can anyone tell me how to proceed further?

Thanks 

Deepali