Both of the wells in your system, Well 101 & 102 are manifolded together before entering the distribution system, Knowing the following data, calculate the downstream manganese concentration when the wells are pumping simultaneously. Well 101: manganese concentration – 0.12 mg/l, average pumping rate of 675 gpm. Well 102: manganese concentration – 0.02 mg/l, average pumping rate of 1,105 gpm.