If the Quabbin Reservoir Watershed is 100 km 2 , the average precipitation in New England is 130 cm/year, and the volume of the Reservoir is 1.

If the Quabbin Reservoir Watershed is 100 km2, the average precipitation in New England is 130 cm/year, and the volume of the Reservoir is 1.5 x 1012 liters, what is the residence time of water in the Reservoir with respect to rain?    Please show your calculation and explain all your assumptions