A groundwater barrier system for preventing the generally lateral, subterranean migration of water (including both liquid and gaseous fluids) beyond an established perimeter, while providing controlled collection of same for use. The present system utilizes a barrier wall, which is formed in-ground via non-permeable membrane in sheet/roll/panel or slurry (materials can include bentonite clay). The present system will be configured to intersect the flow path of the groundwater to be routed to enhance containment or collection of the fluid. In use, the barrier of the present invention is installed by first making an excavation to accommodate the barrier system. The excavation and barrier wall is implemented to a depth so as to allow for the maximum interception with the established water table to be contained or collected, and/or processed based on benefit vs cost analysis. The barrier can also be used to prevent contaminants (including saltwater) from entering surficial freshwater aquifers.