A contaminant is discharged in a tidal estuary such that the concentration at the surface follows a sinusoidal pattern due to tidal action, i.e.C (0,t) = cosωt, where ω is the frequency of the...

A contaminant is discharged in a tidal estuary such that the concentration at the surface follows a sinusoidal pattern due to tidal action, i.e.C (0,t) = cosωt, where ω is the frequency of the oscillation, and the free surface is located at y=0. Consider a column of water that is in-finitely deep, and ignore the velocity of flow in the estuary. Estimate the depth at which the oscillations in the water column no longer produce significant changes in concentration