1. (35-point) 100g of benzene were spilled into a well that penetrates an aquifer in which average ground water velocity is 10 m/yr. The aquifer is 5 m deep. Your home's well is 200 m downgradient of the well with the spill. Assume Dx=200 m-/y and Dy=D>=20 m-/y. Assume the porosity is 0.5 and no sorption between benzene and aquifer solids. (a) When will maximum benzene concentrations occur at your well? Is the tracer well- mixed before it gets to your house? (10-point) (b) What will the maximum benzene concentration be at your well? (10-point) (c) At the time that you see maximum concentrations at your house, what will the benzene concentration be at your neighbor's house located 20 meters away? (10- point) (d) Compute how chemical reaction (k=0.0005/d) will affect your answers to (a), (b), and (c). (5-point) neighbor's house groundwater flow direction 20 m benzene spill 89 your house 200 m