Due to the (reduced) yield of ...

Due to the (reduced) yield of the wells in a well field, several wells are needed. The distance between two consecutive wells should be , in theory, two times the influence radius. As the latter can be very high and location of wells would induce significant construction and operation complications, it is necessary in most of the cases, to select a < 2xR, where a is the distance between two consecutive wells and R is the influence radius, therefore the infiltration curves can overlap, and the yield of each well decreases. For this reason, the number of wells must be increased by 20%.