Green Cove Spring is a third-magnitude spring on the west bank of the St. Johns River. A concrete railing measuring 2 feet high with a diameter of about 15 feet encircles the main vent of the spring pool. The pool tapers downward as an irregularly shaped funnel into soft marl to a 2-foot-diameter cavern opening in its bottom, approximately 30 feet below the pool surface. The 2-foot vent then opens into a cavern 25 feet wide, trending in a northeast direction toward the St. Johns River. The roof of the cavern descends to a depth of 50 feet, and the bottom of the cavern falls to 98 feet (Rosenau et al. 1977). In August and September 2010, divers from Karst Environmental Services reported that the deepest penetrable point in the cave system was at 98 feet. The divers reported that all of the flow was coming vertically, from deeper depths.
Discharge from the spring pool is through a 4-foot-wide weir opening on its northeast side to a 50-foot by 100-foot swimming pool. The swimming pool overflows through a weir on its east end to a spring run that flows about 450 feet eastward to the St. Johns River. Some or all of the flow from the spring can be directed from a flume to bypass the swimming pool. The spring is part of a city-owned park and recreation area, with picnic tables, benches, walkways, and shade trees.