Question: a 15 ha field near the town of oyster va...

A 15 ha field near the town of Oyster, VA received 47.8 in of precipitation over a period of one year. Estimates of evapotranspiration were about 2 mm/day. The field is almost perfectly flat and there is no appreciable surface runoff. How much groundwater runoff in m^3/s occurs from the field assuming the average volume of water stored on or below the field is constant?