Question 1 (50 points). An underground storage tank is leaking hydrocarbons into a sandy aquifer at a concentration of 26mg/L of water. The confined aquifer has dimensions of 210m thickness and 310m length. Hydraulic tests conducted within the aquifer yielded a transmissivity of 300m2/ day. The hydraulic head on the left boundary of the aquifer is 100m while on the right boundary it is 98m. Derive the advectiondispersion equation for hydrocarbon transport in the aquifer. Assume that the flow in the aquifer is one-dimensional and, effective porosity of 0.30 . The estimated longitudinal dispersivity is 5m and the diffusion coefficient is much smaller than dispersivity. Calculate the concentration of hydrocarbons at a monitoring water well located at 50m downstream of the tank after 2 years