Portions of the following information were taken from Florida Geological Survey Bulletin 31.

A submarine spring, Tarpon Springs is at the east end of Spring Bayou near the north and west ends of Tarpon Avenue and Bath Street, respectively, in Tarpon Springs, Pinellas County. According to Wetterhall (1965, p. 10-11, 16-17), "The rim of the kidney shaped spring basin is about 130 ft long and 60 ft wide at a depth of 10 ft below sea level and is 125 ft deep at the deepest point. The north, east, and west sides slope steeply toward the spring to a depth of 60 ft, then drop vertically to about 100 ft. The south wall is vertical or over- hung from 20 ft to 125 ft. The vertical hole below 60 ft is about 40 ft long and 20 ft wide. The floor of the hole slopes quite steeply toward the 125-ft deep on the south side. The spring opening is in the south wall near the bottom."

Tarpon Springs, until May 1969, when a dam was constructed around Tarpon Sink was directly connected to Lake Tarpon by way of Tarpon Sink and an underground conduit system to Spring Bayou, in the limestone of the Tampa Formation. The situation was hydrologically somewhat similar to other Florida Gulf coast springs, and to many springs adjoining the Suwannee River in that its flow reverses owing to tidal activity or to hydraulic pressure. Examples of such springs are the springs at Spring Creek in Wakulla County, Falmouth Spring in Suwannee County, and Troy Spring in Lafayette County. Tarpon Springs was unique, however, in that its flow was sporadic and the conduit or channels connecting the spring to Lake Tarpon were deep -- in excess of 115 ft. Variations in flow were great -- on September 8, 1950, when the lake was draining, spring discharge was about 1,000 ft3/s; a reverse flow of 146 ft3/s was measured on October 10, 1946.

The dam around Tarpon Sink has stopped the natural and frequent draining and refilling of Lake Tarpon. Divers report the spring no longer flows and the vent is becoming plugged with silt. Additional information about the hydrology of Tarpon Springs and Tarpon Lake are available in reports by Heath and Smith (1954, pp, 38-42), String- field and LeGrand (1969, pp. 393-396), and Hunn (1974).