The characteristic properties of an aquifer can be used to calculate groundwater velocities, v_groundwater (L/T), according to:

V_groundwater = K_H/ η (dh/dl)

where KH (L/T) is the hydraulic conductivity of the porous media in the aquifer, η is the porosity of the porous media, (dh/dl) is the hydraulic gradient. Note that the velocity of groundwater only has meaning in the direction of the hydraulic gradient which is always perpendicular to contour lines of constant head.

a. Calculate the velocity of groundwater at this site.

b. Assuming that the hydraulic gradient is constant in the region around the industrial site, use the groundwater velocity to calculate the travel time between a spill located at 75 m east and 75 m north of the southwest corner of the site and a private groundwater well located 36 m south and 4 m east of the southwest corner of the site. Note that these locations are located on a line parallel to the hydraulic gradient and perpendicular to your contour lines.