Abstract: A groundwater flow diversion system for reducing the rate of groundwater flow beneath a designated land area. The diversion system is comprised of one or more conduits located substantially around the circumference of a designated land area beneath the groundwater level so as to provide low resistance hydraulic connection to groundwater either continuously or at specified points of groundwater collection or discharge along the conduit structure. The diversion system reduces the groundwater potential energy differences between all points within the circumferential conduits and thereby reduces the rate of groundwater flow, essentially isolating the groundwater under the designated area from that outside of the construction.The diversion system protects property and water supplies located downstream of a contaminated area from pollution caused by contaminants carried by groundwater flow passing beneath the contaminated land.