pumping is a kind of method for transporting water & a well is a vehicle for removing water from an aquifer ->  pumping from wells is a kind of method for removing water from aquifers  pumping from wells is a kind of method for removing water from aquifers & if too much water is removed from a location then the water may become used up ->  if too much water is pumped from a well then the water in that aquifer may become used up  if too much water is pumped from a well then the water in that aquifer may become used up & excessive means too much in quantity -> excessive pumping from wells may cause the water in that aquifer to become used up