Question $5.$

A brine factory has released brine solution accidentally to an underground aquifer. The chloride concentration in the brine is $1600$ mg$/$L$.$ The hydraulic gradient of the aquifer was estimated as $0\mathrm{.}00678.$ Other hydraulic properties of the aquifer are as follows:

Hydraulic conductivity$=3*10-4$ m$/$s

Effective porosity $=0\mathrm{.}3$

Longitudinal dispersivity $=4\mathrm{.}8$ m

Totuosity factor$=0\mathrm{.}99$

The diffusion coefficient of chloride in water $=2\mathrm{.}03*10-9$ m$2/$s

Using the above data,

a$.$ Calculate the hydrodynamic dispersion coefficient

b$.$ Calculate the concentration of chloride after $6$ months at a distance of $150$ m from the source.