The Wekiva River is a northward flowing (exotic) river defining the Seminole/Orange/Lake county lines. The river occupies the solution valley of the St. Johns Offset (Index Map E) within the Central Lakes District (Brooks and Merrit, 1981; Merrit, 1981). Wekiva River drains the lowlands of the Offset, but is sourced by the high magnitude discharge springs located along the Apopka Upland to the south. Rock Spring, Wekiva Spring and Spring Lake source the Wekiva and Little Wekiva Rivers. The river flows through the Wekiva Swamp, incises an unnamed highland which supports a highway and the town of Wekiva and empties into the St. Johns River at the Seminole-Volusia border enhanced the broad valley through which the Wekiva, St. Johns and Oklawaha Rivers flow. The flood plain is near sea level, as well as the potentiometric surface of the Floridan aquifer. The area is characterized by numerous lakes which are at or slightly above the potentiometric surface of the Floridan aquifer. Surficial drainage is internal and water is stored in the surficial aquifer within thick sands and gravels that comprise the near surface in the area. During recharge and discharge conditions, breaches through the underlying sandy clays of the Hawthorn Group may provide a direct hydrologic connection with the Floridan aquifer.