Florida has both alluvial and nonalluvial streams. Alluvial streams carry loads of sand, silt, or clay. All streams in the panhandle are alluvial, the largest of which is the Apalachicola River. Many streams within the peninsula are nonalluvial. The St. Johns River is the largest nonalluvial river in the state. The slope of the stream bed is extremely low; therefore, the flowÊvelocity is unusually small, and a very large channel is required to transport a relatively small amount of water. For a good part of its length, the St. Johns is about 3 kilometers wide, which is much wider than the lower Mississippi River and as deep. Streams also may be permanent or intermittent. Florida's main streams are permanent.
Runoff is calculated by subtracting the amount of water that soaks into the ground, the amount retained in the soil and used by plants, and the amount that evaporates from total rainfall.
Average stream water temperature increases from cool, along the northern border, to warm, in the southeast. The variability of water temperature is greatest in the north, where air temperature varies the most.
