The Hillsborough River begins in the cypress domes and forested wetlands of the Green Swamp. Four rivers emerge from this large oasis between Tampa and Orlando. They are the Hillsborough, Withlacoochee, Ocklawaha and Peace rivers. This area has ecological and hydrologic importance because of its ability to store surface water and slow floodwaters, while sustaining flow to multiple rivers and streams. The Green Swamp also supplies water to the aquifer, which isn’t too far below the land’s surface in this area.
In addition to water supplied by the Green Swamp, the Hillsborough River also receives water from springs and tributaries.
Periodically, water from the Withlacoochee River becomes part of the Hillsborough River. How is this possible? The two rivers have an area of “shared flow” across an expanse of swamp near the Pasco/Polk County line. This area and the surrounding forested swamps are essential to the natural hydrology and wetlands of both rivers.