(Solved): The cross section below shows a snapshot of a dissolved nitrate plume in an unconfined aquifer. Th ...

The cross section below shows a snapshot of a dissolved nitrate plume in an unconfined aquifer. The contours are based on depth-averaged concentrations in the contaminated region of the aquifer. The thickness of the plume parallel to the river is $$50\mathrm{m}$$. Assume that the aquifer has an average hydraulic conductivity of $$4\mathrm{m}/\mathrm{d}$$. Use a scale of $$1\mathrm{cm}=10\mathrm{m}$$ a) Compute the travel time required for the centre of the plume to reach the river bottom boundary. Give you answer in days. b) Estimate the daily loading ( $$J$$ - total mass flux) of nitrate into the river from the groundwater system at the time when the plume centre reaches the river bottom. Give your answer in $$\mathrm{kg}$$, $$d,m$$, system of units. Assume that the plume does not change shape. c) Make a list of the sources of error that will contribute to the uncertainty in your estimate of the loading. d) Which of these factors do you think will be the more significant in contributing uncertainty in the estimate? e) Describe how you would establish upper and lower bounds on your estimated loading.