Stargate is one of many of hundreds of opening along a 150 km fracture that starts off the north end of North Andros and continues on and off the island through South Andros and runs back into the ocean off of Crassy Cay South Andros. Flying over it, it looks like a narrow river in some areas. The openings that form along this fracture tend to be in association with paleoreef (old) development during the last sea-level highstand. Hydrologically, these system connect below the surface. The water in this system is rarely fresh except after a hurricane. Most of the time the water is brackish. These sited that are near townships tend to be polluted with human sewage and should be entered with caution.